1 <!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook V3.1//EN" [
2 <!entity % dummy "IGNORE">
3 <!entity supported SYSTEM "supported.sgml">
4 <!entity newfeatures SYSTEM "newfeatures.sgml">
5 <!entity p-intro SYSTEM "privoxy.sgml">
6 <!entity seealso SYSTEM "seealso.sgml">
7 <!entity buildsource SYSTEM "buildsource.sgml">
8 <!entity contacting SYSTEM "contacting.sgml">
9 <!entity history SYSTEM "history.sgml">
10 <!entity copyright SYSTEM "copyright.sgml">
11 <!entity license SYSTEM "license.sgml">
12 <!entity p-authors SYSTEM "p-authors.sgml">
13 <!entity config SYSTEM "p-config.sgml">
14 <!entity p-version "3.0.20">
15 <!entity p-status "beta">
16 <!entity % p-authors-formal "INCLUDE"> <!-- include additional text, etc -->
17 <!entity % p-not-stable "INCLUDE">
18 <!entity % p-stable "IGNORE">
19 <!entity % p-text "IGNORE"> <!-- define we are not a text only doc -->
20 <!entity % p-doc "INCLUDE"> <!-- and we are a formal doc -->
21 <!entity % p-readme "IGNORE">
22 <!entity % user-man "IGNORE">
23 <!entity % config-file "IGNORE">
24 <!entity % p-supp-userman "IGNORE"> <!-- Omit some from supported.sgml -->
25 <!entity my-copy "©"> <!-- kludge for docbook2man -->
26 <!entity % draft "IGNORE"> <!-- WIP stuff -->
27 <!entity % seealso-extra "INCLUDE"> <!-- extra stuff from seealso.sgml -->
28 <!entity my-app "<application>Privoxy</application>">
31 File : $Source: /cvsroot/ijbswa/current/doc/source/user-manual.sgml,v $
34 This file belongs into
35 ijbswa.sourceforge.net:/home/groups/i/ij/ijbswa/htdocs/
37 $Id: user-manual.sgml,v 2.160 2013/01/12 12:20:29 fabiankeil Exp $
39 Copyright (C) 2001-2013 Privoxy Developers http://www.privoxy.org/
42 ========================================================================
43 NOTE: Please read developer-manual/documentation.html before touching
44 anything in this, or other Privoxy documentation.
45 ========================================================================
52 <title>Privoxy &p-version; User Manual</title>
56 <!-- Completely the wrong markup, but very little is allowed -->
57 <!-- in this part of an article. FIXME -->
58 <link linkend="copyright">Copyright</link> &my-copy; 2001-2013 by
59 <ulink url="http://www.privoxy.org/">Privoxy Developers</ulink>
63 <pubdate>$Id: user-manual.sgml,v 2.160 2013/01/12 12:20:29 fabiankeil Exp $</pubdate>
67 Note: the following should generate a separate page, and a live link to it,
68 all nicely done. But it doesn't for some mysterious reason. Please leave
69 commented unless it can be fixed proper. For the time being, the
70 copyright/license declarations will be in their own sgml.
83 This is here to keep vim syntax file from breaking :/
84 If I knew enough to fix it, I would.
85 PLEASE DO NOT REMOVE! HB: hal@foobox.net
91 The <citetitle>Privoxy User Manual</citetitle> gives users information on how to
92 install, configure and use <ulink
93 url="http://www.privoxy.org/">Privoxy</ulink>.
96 <!-- Include privoxy.sgml boilerplate: -->
98 <!-- end privoxy.sgml -->
101 You can find the latest version of the <citetitle>Privoxy User Manual</citetitle> at <ulink
102 url="http://www.privoxy.org/user-manual/">http://www.privoxy.org/user-manual/</ulink>.
103 Please see the <link linkend="contact">Contact section</link> on how to
104 contact the developers.
108 <!-- Feel free to send a note to the developers at <email>ijbswa-developers@lists.sourceforge.net</email>. -->
114 <!-- ~~~~~ New section ~~~~~ -->
115 <sect1 label="1" id="introduction"><title>Introduction</title>
117 This documentation is included with the current &p-status; version of
118 <application>Privoxy</application>, v.&p-version;<![%p-not-stable;[,
119 and is mostly complete at this point. The most up to date reference for the
120 time being is still the comments in the source files and in the individual
121 configuration files. Development of a new version is currently nearing
122 completion, and includes significant changes and enhancements over
126 <!-- include only in non-stable versions -->
129 Since this is a &p-status; version, not all new features are well tested. This
130 documentation may be slightly out of sync as a result (especially with
131 CVS sources). And there <emphasis>may be</emphasis> bugs, though hopefully
136 <!-- ~~~~~ New section ~~~~~ -->
137 <sect2 id="features"><title>Features</title>
139 In addition to the core
140 features of ad blocking and
141 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookie</ulink> management,
142 <application>Privoxy</application> provides many supplemental
143 features<![%p-not-stable;[, some of them currently under development]]>,
144 that give the end-user more control, more privacy and more freedom:
146 <!-- Include newfeatures.sgml boilerplate here: -->
148 <!-- end boilerplate -->
153 <!-- ~ End section ~ -->
156 <!-- ~~~~~ New section ~~~~~ -->
157 <sect1 id="installation"><title>Installation</title>
160 <application>Privoxy</application> is available both in convenient pre-compiled
161 packages for a wide range of operating systems, and as raw source code.
162 For most users, we recommend using the packages, which can be downloaded from our
163 <ulink url="http://sourceforge.net/projects/ijbswa/">Privoxy Project
169 On some platforms, the installer may remove previously installed versions, if
170 found. (See below for your platform). In any case <emphasis>be sure to backup
171 your old configuration if it is valuable to you.</emphasis> See the <link
172 linkend="upgradersnote">note to upgraders</link> section below.
175 <!-- ~~~~~ New section ~~~~~ -->
176 <sect2 id="installation-packages"><title>Binary Packages</title>
178 How to install the binary packages depends on your operating system:
181 <!-- XXX: The installation sections should be sorted -->
183 <!-- ~~~~~ New section ~~~~~ -->
184 <sect3 id="installation-deb"><title>Debian and Ubuntu</title>
186 DEBs can be installed with <literal>apt-get install privoxy</literal>,
187 and will use <filename>/etc/privoxy</filename> for the location of
192 <!-- ~~~~~ New section ~~~~~ -->
193 <sect3 id="installation-pack-win"><title>Windows</title>
196 Just double-click the installer, which will guide you through
197 the installation process. You will find the configuration files
198 in the same directory as you installed <application>Privoxy</application> in.
201 Version 3.0.5 beta introduced full <application>Windows</application> service
202 functionality. On Windows only, the <application>Privoxy</application>
203 program has two new command line arguments to install and uninstall
204 <application>Privoxy</application> as a <emphasis>service</emphasis>.
208 <term>Arguments:</term>
211 <replaceable class="parameter">--install</replaceable>[:<replaceable class="parameter">service_name</replaceable>]
214 <replaceable class="parameter">--uninstall</replaceable>[:<replaceable class="parameter">service_name</replaceable>]
220 After invoking <application>Privoxy</application> with
221 <command>--install</command>, you will need to bring up the
222 <application>Windows</application> service console to assign the user you
223 want <application>Privoxy</application> to run under, and whether or not you
224 want it to run whenever the system starts. You can start the
225 <application>Windows</application> services console with the following
226 command: <command>services.msc</command>. If you do not take the manual step
227 of modifying <application>Privoxy's</application> service settings, it will
228 not start. Note too that you will need to give Privoxy a user account that
229 actually exists, or it will not be permitted to
230 write to its log and configuration files.
235 <!-- ~~~~~ New section ~~~~~ -->
236 <sect3 id="installation-os2"><title>OS/2</title>
239 First, make sure that no previous installations of
240 <application>Junkbuster</application> and / or
241 <application>Privoxy</application> are left on your
242 system. Check that no <application>Junkbuster</application>
243 or <application>Privoxy</application> objects are in
249 Then, just double-click the WarpIN self-installing archive, which will
250 guide you through the installation process. A shadow of the
251 <application>Privoxy</application> executable will be placed in your
252 startup folder so it will start automatically whenever OS/2 starts.
256 The directory you choose to install <application>Privoxy</application>
257 into will contain all of the configuration files.
261 <!-- ~~~~~ New section ~~~~~ -->
262 <sect3 id="installation-mac"><title>Mac OS X</title>
264 Installation instructions for the OS X platform depend upon whether
265 you downloaded a ready-built installation package (.pkg or .mpkg) or have
266 downloaded the source code.
269 <sect3 renderas="sect4" id="OS-X-install-from-package">
270 <title>Installation from ready-built package</title>
272 The downloaded file will either be a .pkg (for OS X 10.5 upwards) or a bzipped
273 .mpkg file (for OS X 10.4). The former can be double-clicked as is and the
274 installation will start; double-clicking the latter will unzip the .mpkg file
275 which can then be double-clicked to commence the installation.
278 The privoxy service will automatically start after a successful installation
279 (and thereafter every time your computer starts up) however you will need to
280 configure your web browser(s) to use it. To do so, configure them to use a
281 proxy for HTTP and HTTPS at the address 127.0.0.1:8118.
284 To prevent the privoxy service from automatically starting when your computer
285 starts up, remove or rename the file <literal>/Library/LaunchDaemons/org.ijbswa.privoxy.plist</literal>
286 (on OS X 10.5 and higher) or the folder named
287 <literal>/Library/StartupItems/Privoxy</literal> (on OS X 10.4 'Tiger').
290 To manually start or stop the privoxy service, use the scripts startPrivoxy.sh
291 and stopPrivoxy.sh supplied in /Applications/Privoxy. They must be run from an
292 administrator account, using sudo.
295 To uninstall, run /Applications/Privoxy/uninstall.command as sudo from an
296 administrator account.
299 <sect3 renderas="sect4" id="OS-X-install-from-source">
300 <title>Installation from source</title>
302 To build and install the Privoxy source code on OS X you will need to obtain
303 the macsetup module from the Privoxy Sourceforge CVS repository (refer to
304 Sourceforge help for details of how to set up a CVS client to have read-only
305 access to the repository). This module contains scripts that leverage the usual
306 open-source tools (available as part of Apple's free of charge Xcode
307 distribution or via the usual open-source software package managers for OS X
308 (MacPorts, Homebrew, Fink etc.) to build and then install the privoxy binary
309 and associated files. The macsetup module's README file contains complete
310 instructions for its use.
313 The privoxy service will automatically start after a successful installation
314 (and thereafter every time your computer starts up) however you will need to
315 configure your web browser(s) to use it. To do so, configure them to use a
316 proxy for HTTP and HTTPS at the address 127.0.0.1:8118.
319 To prevent the privoxy service from automatically starting when your computer
320 starts up, remove or rename the file <literal>/Library/LaunchDaemons/org.ijbswa.privoxy.plist</literal>
321 (on OS X 10.5 and higher) or the folder named
322 <literal>/Library/StartupItems/Privoxy</literal> (on OS X 10.4 'Tiger').
325 To manually start or stop the privoxy service, use the Privoxy Utility
326 for Mac OS X (also part of the macsetup module). This application can start
327 and stop the privoxy service and display its log and configuration files.
330 To uninstall, run the macsetup module's uninstall.sh as sudo from an
331 administrator account.
335 <!-- ~~~~~ New section ~~~~~ -->
336 <sect3 id="installation-tbz"><title>FreeBSD</title>
339 Privoxy is part of FreeBSD's Ports Collection, you can build and install
340 it with <literal>cd /usr/ports/www/privoxy; make install clean</literal>.
343 If you don't use the ports, you can fetch and install
344 the package with <literal>pkg_add -r privoxy</literal>.
347 The port skeleton and the package can also be downloaded from the
348 <ulink url="https://sourceforge.net/project/showfiles.php?group_id=11118">File Release
349 Page</ulink>, but there's no reason to use them unless you're interested in the
350 beta releases which are only available there.
356 <!-- ~~~~~ New section ~~~~~ -->
357 <sect2 id="installation-source"><title>Building from Source</title>
360 The most convenient way to obtain the <application>Privoxy</application> sources
361 is to download the source tarball from our
362 <ulink url="http://sourceforge.net/project/showfiles.php?group_id=11118&package_id=10571">project download
367 If you like to live on the bleeding edge and are not afraid of using
368 possibly unstable development versions, you can check out the up-to-the-minute
369 version directly from <ulink url="http://sourceforge.net/cvs/?group_id=11118">the
370 CVS repository</ulink>.
372 deprecated...out of business.
373 or simply download <ulink
374 url="http://cvs.sourceforge.net/cvstarballs/ijbswa-cvsroot.tar.bz2">the nightly CVS
379 <!-- include buildsource.sgml boilerplate: -->
381 <!-- end boilerplate -->
384 <!-- ~~~~~ New section ~~~~~ -->
385 <sect2 id="installation-keepupdated"><title>Keeping your Installation Up-to-Date</title>
388 If you wish to receive an email notification whenever we release updates of
389 <application>Privoxy</application> or the actions file, <ulink
390 url="http://lists.sourceforge.net/lists/listinfo/ijbswa-announce/">subscribe
391 to our announce mailing list</ulink>, ijbswa-announce@lists.sourceforge.net.
395 In order not to lose your personal changes and adjustments when updating
396 to the latest <literal>default.action</literal> file we <emphasis>strongly
397 recommend</emphasis> that you use <literal>user.action</literal> and
398 <literal>user.filter</literal> for your local
399 customizations of <application>Privoxy</application>. See the <link
400 linkend="actions-file">Chapter on actions files</link> for details.
408 <!-- ~ End section ~ -->
410 <!-- ~~~~~ New section ~~~~~ -->
411 <sect1 id="whatsnew">
412 <title>What's New in this Release</title>
414 <application>Privoxy 3.0.19</application> is a stable release.
415 The changes since 3.0.18 stable are:
426 Prevent a segmentation fault when de-chunking buffered content.
427 It could be triggered by malicious web servers if Privoxy was
428 configured to filter the content and running on a platform
429 where SIZE_T_MAX isn't larger than UINT_MAX, which probably
430 includes most 32-bit systems. On those platforms, all Privoxy
431 versions before 3.0.19 appear to be affected.
432 To be on the safe side, this bug should be presumed to allow
433 code execution as proving that it doesn't seems unrealistic.
438 Do not expect a response from the SOCKS4/4A server until it
439 got something to respond to. This regression was introduced
440 in 3.0.18 and prevented the SOCKS4/4A negotiation from working.
441 Reported by qqqqqw in #3459781.
449 General improvements:
453 Fix an off-by-one in an error message about connect failures.
458 Use a GNUMakefile variable for the webserver root directory and
459 update the path. Sourceforge changed it which broke various
465 Update the CODE_STATUS description.
475 The following changes were made between 3.0.17 and 3.0.18:
486 If a generated redirect URL contains characters RFC 3986 doesn't
487 permit, they are (re)encoded. Not doing this makes Privoxy versions
488 from 3.0.5 to 3.0.17 susceptible to HTTP response splitting (CWE-113)
489 attacks if the +fast-redirects{check-decoded-url} action is used.
494 Fix a logic bug that could cause Privoxy to reuse a server
495 socket after it got tainted by a server-header-tagger-induced
496 block that was triggered before the whole server response had
497 been read. If keep-alive was enabled and the request following
498 the blocked one was to the same host and using the same forwarding
499 settings, Privoxy would send it on the tainted server socket.
500 While the server would simply treat it as a pipelined request,
501 Privoxy would later on fail to properly parse the server's
502 response as it would try to parse the unread data from the
503 first response as server headers for the second one.
504 Regression introduced in 3.0.17.
509 When implying keep-alive in client_connection(), remember that
510 the client didn't. Fixes a regression introduced in 3.0.13 that
511 would cause Privoxy to wait for additional client requests after
512 receiving a HTTP/1.1 request with "Connection: close" set
513 and connection sharing enabled.
514 With clients which terminates the client connection after detecting
515 that the whole body has been received it doesn't really matter,
516 but with clients that don't the connection would be kept open until
522 Fix a subtle race condition between prepare_csp_for_next_request()
523 and sweep(). A thread preparing itself for the next client request
524 could briefly appear to be inactive.
525 If all other threads were already using more recent files,
526 the thread could get its files swept away under its feet.
527 So far this has only been reproduced while stress testing in
528 valgrind while touching action files in a loop. It's unlikely
529 to have caused any actual problems in the real world.
534 Disable filters if SDCH compression is used unless filtering is forced.
535 If SDCH was combined with a supported compression algorithm, Privoxy
536 previously could try to decompress it and ditch the Content-Encoding
537 header even though the SDCH compression wasn't dealt with.
538 Reported by zebul666 in #3225863.
543 Make a copy of the --user value and only mess with that when splitting
544 user and group. On some operating systems modifying the value directly
545 is reflected in the output of ps and friends and can be misleading.
546 Reported by zepard in #3292710.
551 If forwarded-connect-retries is set, only retry if Privoxy is actually
552 forwarding the request. Previously direct connections would be retried
558 Fixed a small memory leak when retrying connections with IPv6
564 Remove an incorrect assertion in compile_dynamic_pcrs_job_list()
565 It could be triggered by a pcrs job with an invalid pcre
566 pattern (for example one that contains a lone quantifier).
571 If the --user argument user[.group] contains a dot, always bail out
572 if no group has been specified. Previously the intended, but undocumented
573 (and apparently untested), behaviour was to try interpreting the whole
574 argument as user name, but the detection was flawed and checked for '0'
575 instead of '\0', thus merely preventing group names beginning with a zero.
580 In html_code_map[], use a numeric character reference instead of '
581 which wasn't standardized before XHTML 1.0.
586 Fix an invalid free when compiled with FEATURE_GRACEFUL_TERMINATION
587 and shut down through http://config.privoxy.org/die
592 In get_actions(), fix the "temporary" backwards compatibility hack
593 to accept block actions without reason.
594 It also covered other actions that should be rejected as invalid.
595 Reported by Billy Crook.
603 General improvements:
607 Privoxy can (re)compress buffered content before delivering
608 it to the client. Disabled by default as most users wouldn't
614 The +fast-redirects{check-decoded-url} action checks URL
615 segments separately. If there are other parameters behind
616 the redirect URL, this makes it unnecessary to cut them off
617 by additionally using a +redirect{} pcrs command.
618 Initial patch submitted by Jamie Zawinski in #3429848.
623 When loading action sections, verify that the referenced filters
624 exist. Currently missing filters only result in an error message,
625 but eventually the severity will be upgraded to fatal.
630 Allow to bind to multiple separate addresses.
631 Patch set submitted by Petr Pisar in #3354485.
636 Set socket_error to errno if connecting fails in rfc2553_connect_to().
637 Previously rejected direct connections could be incorrectly reported
638 as DNS issues if Privoxy was compiled with IPv6 support.
643 Adjust url_code_map[] so spaces are replaced with %20 instead of '+'
644 While '+' can be used by client's submitting form data, this is not
645 actually what Privoxy is using the lookups for. This is more of a
646 cosmetic issue and doesn't fix any known problems.
651 When compiled without FEATURE_FAST_REDIRECTS, do not silently
652 ignore +fast-redirect{} directives
657 Added a workaround for GNU libc's strptime() reporting negative
658 year values when the parsed year is only specified with two digits.
659 On affected systems cookies with such a date would not be turned
660 into session cookies by the +session-cookies-only action.
661 Reported by Vaeinoe in #3403560
666 Fixed bind failures with certain GNU libc versions if no non-loopback
667 IP address has been configured on the system. This is mainly an issue
668 if the system is using DHCP and Privoxy is started before the network
669 is completely configured.
670 Reported by Raphael Marichez in #3349356.
671 Additional insight from Petr Pisar.
676 Privoxy log messages now use the ISO 8601 date format %Y-%m-%d.
677 It's only slightly longer than the old format, but contains
678 the full date including the year and allows sorting by date
679 (when grepping in multiple log files) without hassle.
684 In get_last_url(), do not bother trying to decode URLs that do
685 not contain at least one '%' sign. It reduces the log noise and
686 a number of unnecessary memory allocations.
691 In case of SOCKS5 failures, dump the socks response in the log message.
696 Simplify the signal setup in main().
701 Streamline socks5_connect() slightly.
706 In socks5_connect(), require a complete socks response from the server.
707 Previously Privoxy didn't care how much data the server response
708 contained as long as the first two bytes contained the expected
709 values. While at it, shrink the buffer size so Privoxy can't read
710 more than a whole socks response.
715 In chat(), do not bother to generate a client request in case of
716 direct CONNECT requests. It will not be used anyway.
721 Reduce server_last_modified()'s stack size.
726 Shorten get_http_time() by using strftime().
731 Constify the known_http_methods pointers in unknown_method().
736 Constify the time_formats pointers in parse_header_time().
741 Constify the formerly_valid_actions pointers in action_used_to_be_valid().
746 Introduce a GNUMakefile MAN_PAGE variable that defaults to privoxy.1.
747 The Debian package uses section 8 for the man page and this
748 should simplify the patch.
753 Deduplicate the INADDR_NONE definition for Solaris by moving it to jbsockets.h
758 In block_url(), ditch the obsolete workaround for ancient Netscape versions
759 that supposedly couldn't properly deal with status code 403.
764 Remove a useless NULL pointer check in load_trustfile().
769 Remove two useless NULL pointer checks in load_one_re_filterfile().
774 Change url_code_map[] from an array of pointers to an array of arrays
775 It removes an unnecessary layer of indirection and on 64bit system reduces
776 the size of the binary a bit.
781 Fix various typos. Fixes taken from Debian's 29_typos.dpatch by Roland Rosenfeld.
786 Add a dok-tidy GNUMakefile target to clean up the messy HTML
787 generated by the other dok targets.
792 GNUisms in the GNUMakefile have been removed.
797 Change the HTTP version in static responses to 1.1
802 Synced config.sub and config.guess with upstream
803 2011-11-11/386c7218162c145f5f9e1ff7f558a3fbb66c37c5.
808 Add a dedicated function to parse the values of toggles. Reduces duplicated
809 code in load_config() and provides better error handling. Invalid or missing
810 toggle values are now a fatal error instead of being silently ignored.
815 Terminate HTML lines in static error messages with \n instead of \r\n.
820 Simplify cgi_error_unknown() a bit.
825 In LogPutString(), don't bother looking at pszText when not
826 actually logging anything.
831 Change ssplit()'s fourth parameter from int to size_t.
832 Fixes a clang complaint.
837 Add a warning that the statistics currently can't be trusted.
838 Mention Privoxy-Log-Parser's --statistics option as
839 an alternative for the time being.
844 In rfc2553_connect_to(), start setting cgi->error_message on error.
849 Change the expected status code returned for http://p.p/die depending
850 on whether or not FEATURE_GRACEFUL_TERMINATION is available.
855 In cgi_die(), mark the client connection for closing.
856 If the client will fetch the style sheet through another connection
857 it gets the main thread out of the accept() state and should thus
858 trigger the actual shutdown.
863 Add a proper CGI message for cgi_die().
868 Don't enforce a logical line length limit in read_config_line().
873 Slightly refactor server_last_modified() to remove useless gmtime*() calls.
878 In get_content_type(), also recognize '.jpeg' as JPEG extension.
883 Add '.png' to the list of recognized file extensions in get_content_type().
888 In block_url(), consistently use the block reason "Request blocked by Privoxy"
889 In two places the reason was "Request for blocked URL" which hides the
890 fact that the request got blocked by Privoxy and isn't necessarily
891 correct as the block may be due to tags.
896 In listen_loop(), reload the configuration files after accepting
897 a new connection instead of before.
898 Previously the first connection that arrived after a configuration
899 change would still be handled with the old configuration.
904 In chat()'s receive-data loop, skip a client socket check if
905 the socket will be written to right away anyway. This can
906 increase the transfer speed for unfiltered content on fast
912 The socket timeout is used for SOCKS negotiations as well which
913 previously couldn't timeout.
918 Don't keep the client connection alive if any configuration file
919 changed since the time the connection came in. This is closer to
920 Privoxy's behaviour before keep-alive support for client connection
921 has been added and also less confusing in general.
926 Treat all Content-Type header values containing the pattern
927 'script' as a sign of text. Reported by pribog in #3134970.
935 Action file improvements:
939 Moved the site-specific block pattern section below the one for the
940 generic patterns so for requests that are matched in both, the block
941 reason for the domain is shown which is usually more useful than showing
942 the one for the generic pattern.
947 Remove -prevent-compression from the fragile alias. It's no longer
948 used anywhere by default and isn't known to break stuff anyway.
953 Add a (disabled) section to block various Facebook tracking URLs.
954 Reported by Dan Stahlke in #3421764.
959 Add a (disabled) section to rewrite and redirect click-tracking
960 URLs used on news.google.com.
961 Reported by Dan Stahlke in #3421755.
966 Unblock linuxcounter.net/.
967 Reported by Dan Stahlke in #3422612.
972 Block 'www91.intel.com/' which is used by Omniture.
973 Reported by Adam Piggott in #3167370.
978 Disable the handle-as-empty-doc-returns-ok option and mark it as deprecated.
979 Reminded by tceverling in #2790091.
984 Add ".ivwbox.de/" to the "Cross-site user tracking" section.
985 Reported by Nettozahler in #3172525.
990 Unblock and fast-redirect ".awin1.com/.*=http://".
991 Reported by Adam Piggott in #3170921.
996 Block "b.collective-media.net/".
1001 Widen the Debian popcon exception to "qa.debian.org/popcon".
1002 Seen in Debian's 05_default_action.dpatch by Roland Rosenfeld.
1007 Block ".gemius.pl/" which only seems to be used for user tracking.
1008 Reported by johnd16 in #3002731. Additional input from Lee and movax.
1013 Disable banners-by-size filters for '.thinkgeek.com/'.
1014 The filter only seems to catch pictures of the inventory.
1019 Block requests for 'go.idmnet.bbelements.com/please/showit/'.
1020 Reported by kacperdominik in #3372959.
1025 Unblock adainitiative.org/.
1030 Add a fast-redirects exception for '.googleusercontent.com/.*=cache'.
1035 Add a fast-redirects exception for webcache.googleusercontent.com/.
1040 Unblock http://adassier.wordpress.com/ and http://adassier.files.wordpress.com/.
1048 Filter file improvements:
1052 Let the yahoo filter hide '.ads'.
1057 Let the msn filter hide overlay ads for Facebook 'likes' in search
1058 results and elements with the id 's_notf_div'. They only seem to be
1059 used to advertise site 'enhancements'.
1064 Let the js-events filter additionally disarm setInterval().
1065 Suggested by dg1727 in #3423775.
1073 Documentation improvements:
1077 Clarify the effect of compiling Privoxy with zlib support.
1078 Suggested by dg1727 in #3423782.
1083 Point out that the SourceForge messaging system works like a black
1084 hole and should thus not be used to contact individual developers.
1089 Mention some of the problems one can experience when not explicitly
1090 configuring an IP addresses as listen address.
1095 Explicitly mention that hostnames can be used instead of IP addresses
1096 for the listen-address, that only the first address returned will be
1097 used and what happens if the address is invalid.
1098 Requested by Calestyo in #3302213.
1106 Log message improvements:
1110 If only the server connection is kept alive, do not pretend to
1111 wait for a new client request.
1116 Remove a superfluous log message in forget_connection().
1121 In chat(), properly report missing server responses as such
1122 instead of calling them empty.
1127 In forwarded_connect(), fix a log message nobody should ever see.
1132 Fix a log message in socks5_connect(), a failed write operation
1133 was logged as failed read operation.
1138 Let load_one_actions_file() properly complain about a missing
1139 '{' at the beginning of the file.
1140 Simply stating that a line is invalid isn't particularly helpful.
1145 Do not claim to listen on a socket until Privoxy actually does.
1146 Patch submitted by Petr Pisar #3354485
1151 Prevent a duplicated LOG_LEVEL_CLF message when sending out
1152 the "no-server-data" response.
1157 Also log the client socket when dropping a connection.
1162 Include the destination host in the 'Request ... marked for
1163 blocking. limit-connect{...} doesn't allow CONNECT ...' message
1164 Patch submitted by Saperski in #3296250.
1169 Prevent a duplicated log message if none of the resolved IP
1170 addresses were reachable.
1175 In connect_to(), do not pretend to retry if forwarded-connect-retries
1181 When a specified user or group can't be found, put the name in
1182 single-quotes when logging it.
1187 In rfc2553_connect_to(), explain getnameinfo() errors better.
1192 Remove a useless log message in chat().
1197 When retrying to connect, also log the maximum number of connection
1203 Rephrase a log message in compile_dynamic_pcrs_job_list().
1204 Divide the error code and its meaning with a colon. Call the pcrs
1205 job dynamic and not the filter. Filters may contain dynamic and
1206 non-dynamic pcrs jobs at the same time. Only mention the name of
1207 the filter or tagger, but don't claim it's a filter when it could
1213 In a fatal error message in load_one_actions_file(), cover both
1214 URL and TAG patterns.
1219 In pcrs_strerror(), properly report unknown positive error code
1220 values as such. Previously they were handled like 0 (no error).
1225 In compile_dynamic_pcrs_job_list(), also log the actual error code as
1226 pcrs_strerror() doesn't handle all errors reported by pcre.
1231 Don't bother trying to continue chatting if the client didn't ask for it.
1232 Reduces log noise a bit.
1237 Make two fatal error message in load_one_actions_file() more descriptive.
1242 In cgi_send_user_manual(), log when rejecting a file name due to '/' or '..'.
1247 In load_file(), log a message if opening a file failed.
1248 The CGI error message alone isn't too helpful.
1253 In connection_destination_matches(), improve two log messages
1254 to help understand why the destinations don't match.
1259 Rephrase a log message in serve(). Client request arrival
1260 should be differentiated from closed client connections now.
1265 In serve(), log if a client connection isn't reused due to a
1266 configuration file change.
1271 Let mark_server_socket_tainted() always mark the server socket tainted,
1272 just don't talk about it in cases where it has no effect. It doesn't change
1273 Privoxy's behaviour, but makes understanding the log file easier.
1285 Added a --disable-ipv6-support switch for platforms where support
1286 is detected but doesn't actually work.
1291 Do not check for the existence of strerror() and memmove() twice
1296 Remove a useless test for setpgrp(2). Privoxy doesn't need it and
1297 it can cause problems when cross-compiling.
1302 Rename the --disable-acl-files switch to --disable-acl-support.
1303 Since about 2001, ACL directives are specified in the standard
1309 Update the URL of the 'Removing outdated PCRE version after the
1310 next stable release' posting. The old URL stopped working after
1311 one of SF's recent site "optimizations". Reported by Han Liu.
1319 Privoxy-Regression-Test:
1323 Added --shuffle-tests option to increase the chances of detection race conditions.
1328 Added a --local-test-file option that allows to use Privoxy-Regression-Test without Privoxy.
1333 Added tests for missing socks4 and socks4a forwarders.
1338 The --privoxy-address option now works with IPv6 addresses containing brackets, too.
1343 Perform limited sanity checks for parameters that are supposed to have numerical values.
1348 Added a --sleep-time option to specify a number of seconds to
1349 sleep between tests, defaults to 0.
1354 Disable the range-requests tagger for tests that break if it's enabled.
1359 Log messages use the ISO 8601 date format %Y-%m-%d.
1364 Fix spelling in two error messages.
1369 In the --help output, include a list of supported tests and their default levels.
1374 Adjust the tests to properly deal with FEATURE_TOGGLE being disabled.
1386 Perform limited sanity checks for command line parameters that
1387 are supposed to have numerical values.
1392 Implement a --unbreak-lines-only option to try to revert MUA breakage.
1397 Accept and highlight: Added header: Content-Encoding: deflate
1402 Accept and highlight: Compressed content from 29258 to 8630 bytes.
1407 Accept and highlight: Client request arrived in time on socket 21.
1412 Highlight: Didn't receive data in time: a.fsdn.com:443
1417 Accept log messages with ISO 8601 time stamps, too.
1429 Bump generated Firefox version to 8.0.
1434 Only randomize the release date if the new --randomize-release-date
1435 option is enabled. Firefox versions after 4 use a fixed date string
1446 <!-- ~~~~~ New section ~~~~~ -->
1448 <sect2 id="upgradersnote">
1449 <title>Note to Upgraders</title>
1452 A quick list of things to be aware of before upgrading from earlier
1453 versions of <application>Privoxy</application>:
1461 The recommended way to upgrade &my-app; is to backup your old
1462 configuration files, install the new ones, verify that &my-app;
1463 is working correctly and finally merge back your changes using
1464 <application>diff</application> and maybe <application>patch</application>.
1467 There are a number of new features in each &my-app; release and
1468 most of them have to be explicitly enabled in the configuration
1469 files. Old configuration files obviously don't do that and due
1470 to syntax changes using old configuration files with a new
1471 &my-app; isn't always possible anyway.
1476 Note that some installers remove earlier versions completely,
1477 including configuration files, therefore you should really save
1478 any important configuration files!
1483 On the other hand, other installers don't overwrite existing configuration
1484 files, thinking you will want to do that yourself.
1489 <filename>standard.action</filename> has been merged into
1490 the <filename>default.action</filename> file.
1495 In the default configuration only fatal errors are logged now.
1496 You can change that in the <link linkend="DEBUG">debug section</link>
1497 of the configuration file. You may also want to enable more verbose
1498 logging until you verified that the new &my-app; version is working
1505 Three other config file settings are now off by default:
1506 <link linkend="enable-remote-toggle">enable-remote-toggle</link>,
1507 <link linkend="enable-remote-http-toggle">enable-remote-http-toggle</link>,
1508 and <link linkend="enable-edit-actions">enable-edit-actions</link>.
1509 If you use or want these, you will need to explicitly enable them, and
1510 be aware of the security issues involved.
1517 What constitutes a <quote>default</quote> configuration has changed,
1518 and you may want to review which actions are <quote>on</quote> by
1519 default. This is primarily a matter of emphasis, but some features
1520 you may have been used to, may now be <quote>off</quote> by default.
1521 There are also a number of new actions and filters you may want to
1522 consider, most of which are not fully incorporated into the default
1523 settings as yet (see above).
1530 The default actions setting is now <literal>Cautious</literal>. Previous
1531 releases had a default setting of <literal>Medium</literal>. Experienced
1532 users may want to adjust this, as it is fairly conservative by &my-app;
1533 standards and past practices. See <ulink
1534 url="http://config.privoxy.org/edit-actions-list?f=default">
1535 http://config.privoxy.org/edit-actions-list?f=default</ulink>. New users
1536 should try the default settings for a while before turning up the volume.
1542 The default setting has filtering turned <emphasis>off</emphasis>, which
1543 subsequently means that compression is <emphasis>on</emphasis>. Remember
1544 that filtering does not work on compressed pages, so if you use, or want to
1545 use, filtering, you will need to force compression off. Example:
1549 { +<link linkend="filter">filter</link>{google} +<link linkend="prevent-compression">prevent-compression</link> }
1553 Or if you use a number of filters, or filter many sites, you may just want
1554 to turn off compression for all sites in
1555 <filename>default.action</filename> (or
1556 <filename>user.action</filename>).
1563 Also, <link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> is
1564 off by default now. If you've liked this feature in the past, you may want
1565 to turn it back on in <filename>user.action</filename> now.
1572 Some installers may not automatically start
1573 <application>Privoxy</application> after installation.
1584 <!-- ~~~~~ New section ~~~~~ -->
1585 <sect1 id="quickstart"><title>Quickstart to Using Privoxy</title>
1591 Install <application>Privoxy</application>. See the <link
1592 linkend="installation">Installation Section</link> below for platform specific
1599 Advanced users and those who want to offer <application>Privoxy</application>
1600 service to more than just their local machine should check the <link
1601 linkend="config">main config file</link>, especially the <link
1602 linkend="access-control">security-relevant</link> options. These are
1609 Start <application>Privoxy</application>, if the installation program has
1610 not done this already (may vary according to platform). See the section
1611 <link linkend="startup">Starting <application>Privoxy</application></link>.
1617 Set your browser to use <application>Privoxy</application> as HTTP and
1618 HTTPS (SSL) <ulink url="http://en.wikipedia.org/wiki/Proxy_server">proxy</ulink>
1619 by setting the proxy configuration for address of
1620 <literal>127.0.0.1</literal> and port <literal>8118</literal>.
1621 <emphasis>DO NOT</emphasis> activate proxying for <literal>FTP</literal> or
1622 any protocols besides HTTP and HTTPS (SSL) unless you intend to prevent your
1623 browser from using these protocols.
1629 Flush your browser's disk and memory caches, to remove any cached ad images.
1630 If using <application>Privoxy</application> to manage
1631 <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>,
1632 you should remove any currently stored cookies too.
1638 A default installation should provide a reasonable starting point for
1639 most. There will undoubtedly be occasions where you will want to adjust the
1640 configuration, but that can be dealt with as the need arises. Little
1641 to no initial configuration is required in most cases, you may want
1643 <ulink url="config.html#ENABLE-EDIT-ACTIONS">web-based action editor</ulink> though.
1644 Be sure to read the warnings first.
1647 See the <link linkend="configuration">Configuration section</link> for more
1648 configuration options, and how to customize your installation.
1649 You might also want to look at the <link
1650 linkend="quickstart-ad-blocking">next section</link> for a quick
1651 introduction to how <application>Privoxy</application> blocks ads and
1658 If you experience ads that slip through, innocent images that are
1659 blocked, or otherwise feel the need to fine-tune
1660 <application>Privoxy's</application> behavior, take a look at the <link
1661 linkend="actions-file">actions files</link>. As a quick start, you might
1662 find the <link linkend="act-examples">richly commented examples</link>
1663 helpful. You can also view and edit the actions files through the <ulink
1664 url="http://config.privoxy.org">web-based user interface</ulink>. The
1665 Appendix <quote><link linkend="actionsanat">Troubleshooting: Anatomy of an
1666 Action</link></quote> has hints on how to understand and debug actions that
1667 <quote>misbehave</quote>.
1672 Did anyone test these lately?
1676 For easy access to &my-app;'s most important controls, drag the provided
1677 <link linkend="bookmarklets">Bookmarklets</link> into your browser's
1685 Please see the section <link linkend="contact">Contacting the
1686 Developers</link> on how to report bugs, problems with websites or to get
1693 Now enjoy surfing with enhanced control, comfort and privacy!
1701 <!-- ~~~~~ New section ~~~~~ -->
1703 <sect2 id="quickstart-ad-blocking">
1704 <title>Quickstart to Ad Blocking</title>
1706 NOTE: This section is deliberately redundant for those that don't
1707 want to read the whole thing (which is getting lengthy).
1710 Ad blocking is but one of <application>Privoxy's</application>
1711 array of features. Many of these features are for the technically minded advanced
1712 user. But, ad and banner blocking is surely common ground for everybody.
1715 This section will provide a quick summary of ad blocking so
1716 you can get up to speed quickly without having to read the more extensive
1717 information provided below, though this is highly recommended.
1720 First a bit of a warning ... blocking ads is much like blocking SPAM: the
1721 more aggressive you are about it, the more likely you are to block
1722 things that were not intended. And the more likely that some things
1723 may not work as intended. So there is a trade off here. If you want
1724 extreme ad free browsing, be prepared to deal with more
1725 <quote>problem</quote> sites, and to spend more time adjusting the
1726 configuration to solve these unintended consequences. In short, there is
1727 not an easy way to eliminate <emphasis>all</emphasis> ads. Either take
1728 the easy way and settle for <emphasis>most</emphasis> ads blocked with the
1729 default configuration, or jump in and tweak it for your personal surfing
1730 habits and preferences.
1733 Secondly, a brief explanation of <application>Privoxy's </application>
1734 <quote>actions</quote>. <quote>Actions</quote> in this context, are
1735 the directives we use to tell <application>Privoxy</application> to perform
1736 some task relating to HTTP transactions (i.e. web browsing). We tell
1737 <application>Privoxy</application> to take some <quote>action</quote>. Each
1738 action has a unique name and function. While there are many potential
1739 <application>actions</application> in <application>Privoxy's</application>
1740 arsenal, only a few are used for ad blocking. <link
1741 linkend="actions">Actions</link>, and <link linkend="actions-file">action
1742 configuration files</link>, are explained in depth below.
1745 Actions are specified in <application>Privoxy's</application> configuration,
1746 followed by one or more URLs to which the action should apply. URLs
1747 can actually be URL type <link linkend="af-patterns">patterns</link> that use
1748 wildcards so they can apply potentially to a range of similar URLs. The
1749 actions, together with the URL patterns are called a section.
1752 When you connect to a website, the full URL will either match one or more
1753 of the sections as defined in <application>Privoxy's</application> configuration,
1754 or not. If so, then <application>Privoxy</application> will perform the
1755 respective actions. If not, then nothing special happens. Furthermore, web
1756 pages may contain embedded, secondary URLs that your web browser will
1757 use to load additional components of the page, as it parses the
1758 original page's HTML content. An ad image for instance, is just an URL
1759 embedded in the page somewhere. The image itself may be on the same server,
1760 or a server somewhere else on the Internet. Complex web pages will have many
1761 such embedded URLs. &my-app; can deal with each URL individually, so, for
1762 instance, the main page text is not touched, but images from such-and-such
1767 The most important actions for basic ad blocking are: <literal><link
1768 linkend="block">block</link></literal>, <literal><link
1769 linkend="handle-as-image">handle-as-image</link></literal>,
1771 linkend="handle-as-empty-document">handle-as-empty-document</link></literal>,and
1772 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>:
1780 <literal><link linkend="block">block</link></literal> - this is perhaps
1781 the single most used action, and is particularly important for ad blocking.
1782 This action stops any contact between your browser and any URL patterns
1783 that match this action's configuration. It can be used for blocking ads,
1784 but also anything that is determined to be unwanted. By itself, it simply
1785 stops any communication with the remote server and sends
1786 <application>Privoxy</application>'s own built-in BLOCKED page instead to
1787 let you now what has happened (with some exceptions, see below).
1793 <literal><link linkend="handle-as-image">handle-as-image</link></literal> -
1794 tells <application>Privoxy</application> to treat this URL as an image.
1795 <application>Privoxy</application>'s default configuration already does this
1796 for all common image types (e.g. GIF), but there are many situations where this
1797 is not so easy to determine. So we'll force it in these cases. This is particularly
1798 important for ad blocking, since only if we know that it's an image of
1799 some kind, can we replace it with an image of our choosing, instead of the
1800 <application>Privoxy</application> BLOCKED page (which would only result in
1801 a <quote>broken image</quote> icon). There are some limitations to this
1802 though. For instance, you can't just brute-force an image substitution for
1803 an entire HTML page in most situations.
1809 <literal><link linkend="handle-as-empty-document">handle-as-empty-document</link></literal> -
1810 sends an empty document instead of <application>Privoxy's</application>
1811 normal BLOCKED HTML page. This is useful for file types that are neither
1812 HTML nor images, such as blocking JavaScript files.
1819 linkend="set-image-blocker">set-image-blocker</link></literal> - tells
1820 <application>Privoxy</application> what to display in place of an ad image that
1821 has hit a block rule. For this to come into play, the URL must match a
1822 <literal><link linkend="block">block</link></literal> action somewhere in the
1823 configuration, <emphasis>and</emphasis>, it must also match an
1824 <literal><link linkend="handle-as-image">handle-as-image</link></literal> action.
1827 The configuration options on what to display instead of the ad are:
1831 <emphasis>pattern</emphasis> - a checkerboard pattern, so that an ad
1832 replacement is obvious. This is the default.
1837 <emphasis>blank</emphasis> - A very small empty GIF image is displayed.
1838 This is the so-called <quote>invisible</quote> configuration option.
1843 <emphasis>http://<URL></emphasis> - A redirect to any image anywhere
1844 of the user's choosing (advanced usage).
1853 Advanced users will eventually want to explore &my-app;
1854 <literal><link linkend="filter">filters</link></literal> as well. Filters
1855 are very different from <literal><link
1856 linkend="block">blocks</link></literal>.
1857 A <quote>block</quote> blocks a site, page, or unwanted contented. Filters
1858 are a way of filtering or modifying what is actually on the page. An example
1859 filter usage: a text replacement of <quote>no-no</quote> for
1860 <quote>nasty-word</quote>. That is a very simple example. This process can be
1861 used for ad blocking, but it is more in the realm of advanced usage and has
1862 some pitfalls to be wary off.
1866 The quickest way to adjust any of these settings is with your browser through
1867 the special <application>Privoxy</application> editor at <ulink
1868 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1869 (shortcut: <ulink url="http://p.p/">http://p.p/show-status</ulink>). This
1870 is an internal page, and does not require Internet access.
1874 Note that as of <application>Privoxy</application> 3.0.7 beta the
1875 action editor is disabled by default. Check the
1876 <ulink url="config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions
1877 section in the configuration file</ulink> to learn why and in which
1878 cases it's safe to enable again.
1882 If you decided to enable the action editor, select the appropriate
1883 <quote>actions</quote> file, and click
1884 <quote><guibutton>Edit</guibutton></quote>. It is best to put personal or
1885 local preferences in <filename>user.action</filename> since this is not
1886 meant to be overwritten during upgrades, and will over-ride the settings in
1887 other files. Here you can insert new <quote>actions</quote>, and URLs for ad
1888 blocking or other purposes, and make other adjustments to the configuration.
1889 <application>Privoxy</application> will detect these changes automatically.
1893 A quick and simple step by step example:
1901 Right click on the ad image to be blocked, then select
1902 <quote><guimenuitem>Copy Link Location</guimenuitem></quote> from the
1910 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1915 Find <filename>user.action</filename> in the top section, and click
1916 on <quote><guibutton>Edit</guibutton></quote>:
1919 <!-- image of editor and actions files selections -->
1921 <figure pgwide="0" float="0"><title>Actions Files in Use</title>
1924 <imagedata fileref="files-in-use.jpg" format="jpg">
1927 <phrase>[ Screenshot of Actions Files in Use ]</phrase>
1936 You should have a section with only
1937 <literal><link linkend="block">block</link></literal> listed under
1938 <quote>Actions:</quote>.
1939 If not, click a <quote><guibutton>Insert new section below</guibutton></quote>
1940 button, and in the new section that just appeared, click the
1941 <guibutton>Edit</guibutton> button right under the word <quote>Actions:</quote>.
1942 This will bring up a list of all actions. Find
1943 <literal><link linkend="block">block</link></literal> near the top, and click
1944 in the <quote>Enabled</quote> column, then <quote><guibutton>Submit</guibutton></quote>
1945 just below the list.
1950 Now, in the <literal><link linkend="block">block</link></literal> actions section,
1951 click the <quote><guibutton>Add</guibutton></quote> button, and paste the URL the
1952 browser got from <quote><guimenuitem>Copy Link Location</guimenuitem></quote>.
1953 Remove the <literal>http://</literal> at the beginning of the URL. Then, click
1954 <quote><guibutton>Submit</guibutton></quote> (or
1955 <quote><guibutton>OK</guibutton></quote> if in a pop-up window).
1960 Now go back to the original page, and press <keycap>SHIFT-Reload</keycap>
1961 (or flush all browser caches). The image should be gone now.
1969 This is a very crude and simple example. There might be good reasons to use a
1970 wildcard pattern match to include potentially similar images from the same
1971 site. For a more extensive explanation of <quote>patterns</quote>, and
1972 the entire actions concept, see <link linkend="actions-file">the Actions
1977 For advanced users who want to hand edit their config files, you might want
1978 to now go to the <link linkend="act-examples">Actions Files Tutorial</link>.
1979 The ideas explained therein also apply to the web-based editor.
1982 There are also various
1983 <link linkend="filter">filters</link> that can be used for ad blocking
1984 (filters are a special subset of actions). These
1985 fall into the <quote>advanced</quote> usage category, and are explained in
1986 depth in later sections.
1993 <!-- ~ End section ~ -->
1996 <!-- ~~~~~ New section ~~~~~ -->
1997 <sect1 id="startup">
1998 <title>Starting Privoxy</title>
2000 Before launching <application>Privoxy</application> for the first time, you
2001 will want to configure your browser(s) to use
2002 <application>Privoxy</application> as a HTTP and HTTPS (SSL)
2003 <ulink url="http://en.wikipedia.org/wiki/Proxy_server">proxy</ulink>. The default is
2004 127.0.0.1 (or localhost) for the proxy address, and port 8118 (earlier versions
2005 used port 8000). This is the one configuration step <emphasis>that must be done
2009 Please note that <application>Privoxy</application> can only proxy HTTP and
2010 HTTPS traffic. It will not work with FTP or other protocols.
2013 <!-- image of Mozilla Proxy configuration -->
2015 <figure pgwide="0" float="0"><title>Proxy Configuration Showing
2016 Mozilla/Netscape HTTP and HTTPS (SSL) Settings</title>
2019 <imagedata fileref="proxy_setup.jpg" format="jpg">
2022 <phrase>[ Screenshot of Mozilla Proxy Configuration ]</phrase>
2030 With <application>Firefox</application>, this is typically set under:
2034 <guibutton>Tools</guibutton> -> <guibutton>Options</guibutton> -> <guibutton>Advanced</guibutton> -> <guibutton>Network</guibutton> -><guibutton>Connection</guibutton> -> <guibutton>Settings</guibutton>
2039 Or optionally on some platforms:
2043 <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>General</guibutton> -> <guibutton>Connection Settings</guibutton> -> <guibutton>Manual Proxy Configuration</guibutton>
2049 With <application>Netscape</application> (and
2050 <application>Mozilla</application>), this can be set under:
2055 <!-- Mix ascii and gui art, something for everybody -->
2056 <!-- spacing on this is tricky -->
2057 <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>Advanced</guibutton> -> <guibutton>Proxies</guibutton> -> <guibutton>HTTP Proxy</guibutton>
2062 For <application>Internet Explorer v.5-7</application>:
2066 <guibutton>Tools</guibutton> -> <guibutton>Internet Options</guibutton> -> <guibutton>Connections</guibutton> -> <guibutton>LAN Settings</guibutton>
2070 Then, check <quote>Use Proxy</quote> and fill in the appropriate info
2071 (Address: 127.0.0.1, Port: 8118). Include HTTPS (SSL), if you want HTTPS
2072 proxy support too (sometimes labeled <quote>Secure</quote>). Make sure any
2073 checkboxes like <quote>Use the same proxy server for all protocols</quote> is
2074 <emphasis>UNCHECKED</emphasis>. You want only HTTP and HTTPS (SSL)!
2077 <!-- image of IE Proxy configuration -->
2079 <figure pgwide="0" float="0"><title>Proxy Configuration Showing
2080 Internet Explorer HTTP and HTTPS (Secure) Settings</title>
2083 <imagedata fileref="proxy2.jpg" format="jpg">
2086 <phrase>[ Screenshot of IE Proxy Configuration ]</phrase>
2094 After doing this, flush your browser's disk and memory caches to force a
2095 re-reading of all pages and to get rid of any ads that may be cached. Remove
2096 any <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>,
2097 if you want <application>Privoxy</application> to manage that. You are now
2098 ready to start enjoying the benefits of using
2099 <application>Privoxy</application>!
2103 <application>Privoxy</application> itself is typically started by specifying the
2104 main configuration file to be used on the command line. If no configuration
2105 file is specified on the command line, <application>Privoxy</application>
2106 will look for a file named <filename>config</filename> in the current
2107 directory. Except on Win32 where it will try <filename>config.txt</filename>.
2110 <sect2 id="start-redhat">
2111 <title>Red Hat and Fedora</title>
2113 A default Red Hat installation may not start &my-app; upon boot. It will use
2114 the file <filename>/etc/privoxy/config</filename> as its main configuration
2119 # /etc/rc.d/init.d/privoxy start
2127 # service privoxy start
2132 <sect2 id="start-debian">
2133 <title>Debian</title>
2135 We use a script. Note that Debian typically starts &my-app; upon booting per
2136 default. It will use the file
2137 <filename>/etc/privoxy/config</filename> as its main configuration
2142 # /etc/init.d/privoxy start
2147 <sect2 id="start-windows">
2148 <title>Windows</title>
2150 Click on the &my-app; Icon to start <application>Privoxy</application>. If no configuration file is
2151 specified on the command line, <application>Privoxy</application> will look
2152 for a file named <filename>config.txt</filename>. Note that Windows will
2153 automatically start &my-app; when the system starts if you chose that option
2157 <application>Privoxy</application> can run with full Windows service functionality.
2158 On Windows only, the &my-app; program has two new command line arguments
2159 to install and uninstall &my-app; as a service. See the
2160 <link linkend="installation-pack-win">Windows Installation
2161 instructions</link> for details.
2165 <sect2 id="start-unices">
2166 <title>Solaris, NetBSD, FreeBSD, HP-UX and others</title>
2168 Example Unix startup command:
2172 # /usr/sbin/privoxy /etc/privoxy/config
2177 <sect2 id="start-os2">
2180 During installation, <application>Privoxy</application> is configured to
2181 start automatically when the system restarts. You can start it manually by
2182 double-clicking on the <application>Privoxy</application> icon in the
2183 <application>Privoxy</application> folder.
2187 <sect2 id="start-macosx">
2188 <title>Mac OS X</title>
2190 After downloading the privoxy software, unzip the downloaded file by
2191 double-clicking on the zip file icon. Then, double-click on the
2192 installer package icon and follow the installation process.
2195 The privoxy service will automatically start after a successful
2196 installation. In addition, the privoxy service will automatically
2197 start every time your computer starts up.
2200 To prevent the privoxy service from automatically starting when your
2201 computer starts up, remove or rename the folder named
2202 /Library/StartupItems/Privoxy.
2205 A simple application named Privoxy Utility has been created which
2206 enables administrators to easily start and stop the privoxy service.
2209 In addition, the Privoxy Utility presents a simple way for
2210 administrators to edit the various privoxy config files. A method
2211 to uninstall the software is also available.
2214 An administrator username and password must be supplied in order for
2215 the Privoxy Utility to perform any of the tasks.
2220 <sect2 id="start-amigaos">
2221 <title>AmigaOS</title>
2223 Start <application>Privoxy</application> (with RUN <>NIL:) in your
2224 <filename>startnet</filename> script (AmiTCP), in
2225 <filename>s:user-startup</filename> (RoadShow), as startup program in your
2226 startup script (Genesis), or as startup action (Miami and MiamiDx).
2227 <application>Privoxy</application> will automatically quit when you quit your
2228 TCP/IP stack (just ignore the harmless warning your TCP/IP stack may display that
2229 <application>Privoxy</application> is still running).
2233 <sect2 id="start-gentoo">
2234 <title>Gentoo</title>
2236 A script is again used. It will use the file <filename>/etc/privoxy/config
2237 </filename> as its main configuration file.
2241 /etc/init.d/privoxy start
2245 Note that <application>Privoxy</application> is not automatically started at
2246 boot time by default. You can change this with the <literal>rc-update</literal>
2251 rc-update add privoxy default
2259 See the section <link linkend="cmdoptions">Command line options</link> for
2263 must find a better place for this paragraph
2266 The included default configuration files should give a reasonable starting
2267 point. Most of the per site configuration is done in the
2268 <ulink url="actions-file.html"><quote>actions</quote></ulink> files. These are
2269 where various cookie actions are defined, ad and banner blocking, and other
2270 aspects of <application>Privoxy</application> configuration. There are several
2271 such files included, with varying levels of aggressiveness.
2275 You will probably want to keep an eye out for sites for which you may prefer
2276 persistent cookies, and add these to your actions configuration as needed. By
2277 default, most of these will be accepted only during the current browser
2278 session (aka <quote>session cookies</quote>), unless you add them to the
2279 configuration. If you want the browser to handle this instead, you will need
2280 to edit <filename>user.action</filename> (or through the web based interface)
2281 and disable this feature. If you use more than one browser, it would make
2282 more sense to let <application>Privoxy</application> handle this. In which
2283 case, the browser(s) should be set to accept all cookies.
2287 Another feature where you will probably want to define exceptions for trusted
2288 sites is the popup-killing (through <ulink
2289 url="actions-file.html#FILTER-POPUPS"><quote>+filter{popups}</quote></ulink>),
2290 because your favorite shopping, banking, or leisure site may need
2291 popups (explained below).
2295 <application>Privoxy</application> does not support all of the optional HTTP/1.1
2296 features yet. In the unlikely event that you experience inexplicable problems
2297 with browsers that use HTTP/1.1 per default
2298 (like <application>Mozilla</application> or recent versions of I.E.), you might
2299 try to force HTTP/1.0 compatibility. For Mozilla, look under <literal>Edit ->
2300 Preferences -> Debug -> Networking</literal>.
2301 Alternatively, set the <quote>+downgrade-http-version</quote> config option in
2302 <filename>default.action</filename> which will downgrade your browser's HTTP
2303 requests from HTTP/1.1 to HTTP/1.0 before processing them.
2307 After running <application>Privoxy</application> for a while, you can
2308 start to fine tune the configuration to suit your personal, or site,
2309 preferences and requirements. There are many, many aspects that can
2310 be customized. <quote>Actions</quote>
2311 can be adjusted by pointing your browser to
2312 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
2313 (shortcut: <ulink url="http://p.p/">http://p.p/</ulink>),
2314 and then follow the link to <quote>View & Change the Current Configuration</quote>.
2315 (This is an internal page and does not require Internet access.)
2319 In fact, various aspects of <application>Privoxy</application>
2320 configuration can be viewed from this page, including
2321 current configuration parameters, source code version numbers,
2322 the browser's request headers, and <quote>actions</quote> that apply
2323 to a given URL. In addition to the actions file
2324 editor mentioned above, <application>Privoxy</application> can also
2325 be turned <quote>on</quote> and <quote>off</quote> (toggled) from this page.
2329 If you encounter problems, try loading the page without
2330 <application>Privoxy</application>. If that helps, enter the URL where
2331 you have the problems into <ulink url="http://p.p/show-url-info">the browser
2332 based rule tracing utility</ulink>. See which rules apply and why, and
2333 then try turning them off for that site one after the other, until the problem
2334 is gone. When you have found the culprit, you might want to turn the rest on
2339 If the above paragraph sounds gibberish to you, you might want to <link
2340 linkend="actions-file">read more about the actions concept</link>
2341 or even dive deep into the <link linkend="actionsanat">Appendix
2346 If you can't get rid of the problem at all, think you've found a bug in
2347 Privoxy, want to propose a new feature or smarter rules, please see the
2348 section <link linkend="contact"><quote>Contacting the
2349 Developers</quote></link> below.
2354 <!-- ~~~~~ New section ~~~~~ -->
2355 <sect2 id="cmdoptions">
2356 <title>Command Line Options</title>
2358 <application>Privoxy</application> may be invoked with the following
2359 command-line options:
2367 <emphasis>--config-test</emphasis>
2370 Exit after loading the configuration files before binding to
2371 the listen address. The exit code signals whether or not the
2372 configuration files have been successfully loaded.
2375 If the exit code is 1, at least one of the configuration files
2376 is invalid, if it is 0, all the configuration files have been
2377 successfully loaded (but may still contain errors that can
2378 currently only be detected at run time).
2381 This option doesn't affect the log setting, combination with
2382 <emphasis>--no-daemon</emphasis> is recommended if a configured
2383 log file shouldn't be used.
2388 <emphasis>--version</emphasis>
2391 Print version info and exit. Unix only.
2396 <emphasis>--help</emphasis>
2399 Print short usage info and exit. Unix only.
2404 <emphasis>--no-daemon</emphasis>
2407 Don't become a daemon, i.e. don't fork and become process group
2408 leader, and don't detach from controlling tty. Unix only.
2413 <emphasis>--pidfile FILE</emphasis>
2416 On startup, write the process ID to <emphasis>FILE</emphasis>. Delete the
2417 <emphasis>FILE</emphasis> on exit. Failure to create or delete the
2418 <emphasis>FILE</emphasis> is non-fatal. If no <emphasis>FILE</emphasis>
2419 option is given, no PID file will be used. Unix only.
2424 <emphasis>--user USER[.GROUP]</emphasis>
2427 After (optionally) writing the PID file, assume the user ID of
2428 <emphasis>USER</emphasis>, and if included the GID of GROUP. Exit if the
2429 privileges are not sufficient to do so. Unix only.
2434 <emphasis>--chroot</emphasis>
2437 Before changing to the user ID given in the <emphasis>--user</emphasis> option,
2438 chroot to that user's home directory, i.e. make the kernel pretend to the &my-app;
2439 process that the directory tree starts there. If set up carefully, this can limit
2440 the impact of possible vulnerabilities in &my-app; to the files contained in that hierarchy.
2446 <emphasis>--pre-chroot-nslookup hostname</emphasis>
2449 Specifies a hostname to look up before doing a chroot. On some systems, initializing the
2450 resolver library involves reading config files from /etc and/or loading additional shared
2451 libraries from /lib. On these systems, doing a hostname lookup before the chroot reduces
2452 the number of files that must be copied into the chroot tree.
2455 For fastest startup speed, a good value is a hostname that is not in /etc/hosts but that
2456 your local name server (listed in /etc/resolv.conf) can resolve without recursion
2457 (that is, without having to ask any other name servers). The hostname need not exist,
2458 but if it doesn't, an error message (which can be ignored) will be output.
2464 <emphasis>configfile</emphasis>
2467 If no <emphasis>configfile</emphasis> is included on the command line,
2468 <application>Privoxy</application> will look for a file named
2469 <quote>config</quote> in the current directory (except on Win32
2470 where it will look for <quote>config.txt</quote> instead). Specify
2471 full path to avoid confusion. If no config file is found,
2472 <application>Privoxy</application> will fail to start.
2480 On <application>MS Windows</application> only there are two additional
2481 command-line options to allow <application>Privoxy</application> to install and
2482 run as a <emphasis>service</emphasis>. See the
2483 <link linkend="installation-pack-win">Window Installation section</link>
2491 <!-- ~ End section ~ -->
2494 <!-- ~~~~~ New section ~~~~~ -->
2495 <sect1 id="configuration"><title>Privoxy Configuration</title>
2497 All <application>Privoxy</application> configuration is stored
2498 in text files. These files can be edited with a text editor.
2499 Many important aspects of <application>Privoxy</application> can
2500 also be controlled easily with a web browser.
2504 <!-- ~~~~~ New section ~~~~~ -->
2507 <title>Controlling Privoxy with Your Web Browser</title>
2509 <application>Privoxy</application>'s user interface can be reached through the special
2510 URL <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
2511 (shortcut: <ulink url="http://p.p/">http://p.p/</ulink>),
2512 which is a built-in page and works without Internet access.
2513 You will see the following section:
2517 <!-- Needs to be put in a table and colorized -->
2520 <bridgehead renderas="sect2"> Privoxy Menu</bridgehead>
2524 ▪ <ulink url="http://config.privoxy.org/show-status">View & change the current configuration</ulink>
2527 ▪ <ulink url="http://config.privoxy.org/show-version">View the source code version numbers</ulink>
2530 ▪ <ulink url="http://config.privoxy.org/show-request">View the request headers.</ulink>
2533 ▪ <ulink url="http://config.privoxy.org/show-url-info">Look up which actions apply to a URL and why</ulink>
2536 ▪ <ulink url="http://config.privoxy.org/toggle">Toggle Privoxy on or off</ulink>
2539 ▪ <ulink
2540 url="http://www.privoxy.org/&p-version;/user-manual/">Documentation</ulink>
2548 This should be self-explanatory. Note the first item leads to an editor for the
2549 <link linkend="actions-file">actions files</link>, which is where the ad, banner,
2550 cookie, and URL blocking magic is configured as well as other advanced features of
2551 <application>Privoxy</application>. This is an easy way to adjust various
2552 aspects of <application>Privoxy</application> configuration. The actions
2553 file, and other configuration files, are explained in detail below.
2557 <quote>Toggle Privoxy On or Off</quote> is handy for sites that might
2558 have problems with your current actions and filters. You can in fact use
2559 it as a test to see whether it is <application>Privoxy</application>
2560 causing the problem or not. <application>Privoxy</application> continues
2561 to run as a proxy in this case, but all manipulation is disabled, i.e.
2562 <application>Privoxy</application> acts like a normal forwarding proxy. There
2563 is even a toggle <link linkend="bookmarklets">Bookmarklet</link> offered, so
2564 that you can toggle <application>Privoxy</application> with one click from
2569 Note that several of the features described above are disabled by default
2570 in <application>Privoxy</application> 3.0.7 beta and later.
2572 <ulink url="config.html">configuration file</ulink> to learn why
2573 and in which cases it's safe to enable them again.
2578 <!-- ~ End section ~ -->
2583 <!-- ~~~~~ New section ~~~~~ -->
2585 <sect2 id="confoverview">
2586 <title>Configuration Files Overview</title>
2588 For Unix, *BSD and Linux, all configuration files are located in
2589 <filename>/etc/privoxy/</filename> by default. For MS Windows, OS/2, and
2590 AmigaOS these are all in the same directory as the
2591 <application>Privoxy</application> executable. <![%p-not-stable;[ The name
2592 and number of configuration files has changed from previous versions, and is
2593 subject to change as development progresses.]]>
2597 The installed defaults provide a reasonable starting point, though
2598 some settings may be aggressive by some standards. For the time being, the
2599 principle configuration files are:
2607 The <link linkend="config">main configuration file</link> is named <filename>config</filename>
2608 on Linux, Unix, BSD, OS/2, and AmigaOS and <filename>config.txt</filename>
2609 on Windows. This is a required file.
2615 <filename>match-all.action</filename> is used to define which <quote>actions</quote>
2616 relating to banner-blocking, images, pop-ups, content modification, cookie handling
2617 etc should be applied by default. It should be the first actions file loaded.
2620 <filename>default.action</filename> defines many exceptions (both positive and negative)
2621 from the default set of actions that's configured in <filename>match-all.action</filename>.
2622 It should be the second actions file loaded and shouldn't be edited by the user.
2625 Multiple actions files may be defined in <filename>config</filename>. These
2626 are processed in the order they are defined. Local customizations and locally
2627 preferred exceptions to the default policies as defined in
2628 <filename>match-all.action</filename> (which you will most probably want
2629 to define sooner or later) are best applied in <filename>user.action</filename>,
2630 where you can preserve them across upgrades. The file isn't installed by all
2631 installers, but you can easily create it yourself with a text editor.
2634 There is also a web based editor that can be accessed from
2636 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
2638 url="http://p.p/show-status">http://p.p/show-status</ulink>) for the
2639 various actions files.
2645 <quote>Filter files</quote> (the <link linkend="filter-file">filter
2646 file</link>) can be used to re-write the raw page content, including
2647 viewable text as well as embedded HTML and JavaScript, and whatever else
2648 lurks on any given web page. The filtering jobs are only pre-defined here;
2649 whether to apply them or not is up to the actions files.
2650 <filename>default.filter</filename> includes various filters made
2651 available for use by the developers. Some are much more intrusive than
2652 others, and all should be used with caution. You may define additional
2653 filter files in <filename>config</filename> as you can with
2654 actions files. We suggest <filename>user.filter</filename> for any
2655 locally defined filters or customizations.
2663 The syntax of the configuration and filter files may change between different
2664 Privoxy versions, unfortunately some enhancements cost backwards compatibility.
2665 <!-- Add link to documentation-->
2669 All files use the <quote><literal>#</literal></quote> character to denote a
2670 comment (the rest of the line will be ignored) and understand line continuation
2671 through placing a backslash ("<literal>\</literal>") as the very last character
2672 in a line. If the <literal>#</literal> is preceded by a backslash, it looses
2673 its special function. Placing a <literal>#</literal> in front of an otherwise
2674 valid configuration line to prevent it from being interpreted is called "commenting
2675 out" that line. Blank lines are ignored.
2679 The actions files and filter files
2680 can use Perl style <link linkend="regex">regular expressions</link> for
2681 maximum flexibility.
2685 After making any changes, there is no need to restart
2686 <application>Privoxy</application> in order for the changes to take
2687 effect. <application>Privoxy</application> detects such changes
2688 automatically. Note, however, that it may take one or two additional
2689 requests for the change to take effect. When changing the listening address
2690 of <application>Privoxy</application>, these <quote>wake up</quote> requests
2691 must obviously be sent to the <emphasis>old</emphasis> listening address.
2696 While under development, the configuration content is subject to change.
2697 The below documentation may not be accurate by the time you read this.
2698 Also, what constitutes a <quote>default</quote> setting, may change, so
2699 please check all your configuration files on important issues.
2705 <!-- ~ End section ~ -->
2708 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
2710 <!-- **************************************************** -->
2711 <!-- Include config.sgml here -->
2712 <!-- This is where the entire config file is detailed. -->
2714 <!-- end include -->
2717 <!-- ~ End section ~ -->
2721 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
2723 <sect1 id="actions-file"><title>Actions Files</title>
2727 XXX: similar descriptions are in the Configuration Files sections.
2728 We should only describe them at one place.
2731 The actions files are used to define what <emphasis>actions</emphasis>
2732 <application>Privoxy</application> takes for which URLs, and thus determines
2733 how ad images, cookies and various other aspects of HTTP content and
2734 transactions are handled, and on which sites (or even parts thereof).
2735 There are a number of such actions, with a wide range of functionality.
2736 Each action does something a little different.
2737 These actions give us a veritable arsenal of tools with which to exert
2738 our control, preferences and independence. Actions can be combined so that
2739 their effects are aggregated when applied against a given set of URLs.
2743 are three action files included with <application>Privoxy</application> with
2750 <filename>match-all.action</filename> - is used to define which
2751 <quote>actions</quote> relating to banner-blocking, images, pop-ups,
2752 content modification, cookie handling etc should be applied by default.
2753 It should be the first actions file loaded
2758 <filename>default.action</filename> - defines many exceptions (both
2759 positive and negative) from the default set of actions that's configured
2760 in <filename>match-all.action</filename>. It is a set of rules that should
2761 work reasonably well as-is for most users. This file is only supposed to
2762 be edited by the developers. It should be the second actions file loaded.
2767 <filename>user.action</filename> - is intended to be for local site
2768 preferences and exceptions. As an example, if your ISP or your bank
2769 has specific requirements, and need special handling, this kind of
2770 thing should go here. This file will not be upgraded.
2775 <guibutton>Edit</guibutton> <guibutton>Set to Cautious</guibutton> <guibutton>Set to Medium</guibutton> <guibutton>Set to Advanced</guibutton>
2778 These have increasing levels of aggressiveness <emphasis>and have no
2779 influence on your browsing unless you select them explicitly in the
2780 editor</emphasis>. A default installation should be pre-set to
2781 <literal>Cautious</literal>. New users should try this for a while before
2782 adjusting the settings to more aggressive levels. The more aggressive
2783 the settings, then the more likelihood there is of problems such as sites
2784 not working as they should.
2787 The <guibutton>Edit</guibutton> button allows you to turn each
2788 action on/off individually for fine-tuning. The <guibutton>Cautious</guibutton>
2789 button changes the actions list to low/safe settings which will activate
2790 ad blocking and a minimal set of &my-app;'s features, and subsequently
2791 there will be less of a chance for accidental problems. The
2792 <guibutton>Medium</guibutton> button sets the list to a medium level of
2793 other features and a low level set of privacy features. The
2794 <guibutton>Advanced</guibutton> button sets the list to a high level of
2795 ad blocking and medium level of privacy. See the chart below. The latter
2796 three buttons over-ride any changes via with the
2797 <guibutton>Edit</guibutton> button. More fine-tuning can be done in the
2798 lower sections of this internal page.
2801 While the actions file editor allows to enable these settings in all
2802 actions files, they are only supposed to be enabled in the first one
2803 to make sure you don't unintentionally overrule earlier rules.
2806 The default profiles, and their associated actions, as pre-defined in
2807 <filename>default.action</filename> are:
2810 <table frame=all><title>Default Configurations</title>
2811 <tgroup cols=4 align=left colsep=1 rowsep=1>
2812 <colspec colname=c1>
2813 <colspec colname=c2>
2814 <colspec colname=c3>
2815 <colspec colname=c4>
2818 <entry>Feature</entry>
2819 <entry>Cautious</entry>
2820 <entry>Medium</entry>
2821 <entry>Advanced</entry>
2826 <!-- <entry>f1</entry> -->
2827 <!-- <entry>f2</entry> -->
2828 <!-- <entry>f3</entry> -->
2829 <!-- <entry>f4</entry> -->
2835 <entry>Ad-blocking Aggressiveness</entry>
2836 <entry>medium</entry>
2842 <entry>Ad-filtering by size</entry>
2849 <entry>Ad-filtering by link</entry>
2855 <entry>Pop-up killing</entry>
2856 <entry>blocks only</entry>
2857 <entry>blocks only</entry>
2858 <entry>blocks only</entry>
2862 <entry>Privacy Features</entry>
2864 <entry>medium</entry>
2865 <entry>medium/high</entry>
2869 <entry>Cookie handling</entry>
2871 <entry>session-only</entry>
2876 <entry>Referer forging</entry>
2883 <entry>GIF de-animation</entry>
2890 <entry>Fast redirects</entry>
2897 <entry>HTML taming</entry>
2904 <entry>JavaScript taming</entry>
2911 <entry>Web-bug killing</entry>
2918 <entry>Image tag reordering</entry>
2934 The list of actions files to be used are defined in the main configuration
2935 file, and are processed in the order they are defined (e.g.
2936 <filename>default.action</filename> is typically processed before
2937 <filename>user.action</filename>). The content of these can all be viewed and
2939 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
2940 The over-riding principle when applying actions, is that the last action that
2941 matches a given URL wins. The broadest, most general rules go first
2942 (defined in <filename>default.action</filename>),
2943 followed by any exceptions (typically also in
2944 <filename>default.action</filename>), which are then followed lastly by any
2945 local preferences (typically in <emphasis>user</emphasis><filename>.action</filename>).
2946 Generally, <filename>user.action</filename> has the last word.
2950 An actions file typically has multiple sections. If you want to use
2951 <quote>aliases</quote> in an actions file, you have to place the (optional)
2952 <link linkend="aliases">alias section</link> at the top of that file.
2953 Then comes the default set of rules which will apply universally to all
2954 sites and pages (be <emphasis>very careful</emphasis> with using such a
2955 universal set in <filename>user.action</filename> or any other actions file after
2956 <filename>default.action</filename>, because it will override the result
2957 from consulting any previous file). And then below that,
2958 exceptions to the defined universal policies. You can regard
2959 <filename>user.action</filename> as an appendix to <filename>default.action</filename>,
2960 with the advantage that it is a separate file, which makes preserving your
2961 personal settings across <application>Privoxy</application> upgrades easier.
2965 Actions can be used to block anything you want, including ads, banners, or
2966 just some obnoxious URL whose content you would rather not see. Cookies can be accepted
2967 or rejected, or accepted only during the current browser session (i.e. not
2968 written to disk), content can be modified, some JavaScripts tamed, user-tracking
2969 fooled, and much more. See below for a <link linkend="actions">complete list
2973 <!-- ~~~~~ New section ~~~~~ -->
2975 <title>Finding the Right Mix</title>
2977 Note that some <link linkend="actions">actions</link>, like cookie suppression
2978 or script disabling, may render some sites unusable that rely on these
2979 techniques to work properly. Finding the right mix of actions is not always easy and
2980 certainly a matter of personal taste. And, things can always change, requiring
2981 refinements in the configuration. In general, it can be said that the more
2982 <quote>aggressive</quote> your default settings (in the top section of the
2983 actions file) are, the more exceptions for <quote>trusted</quote> sites you
2984 will have to make later. If, for example, you want to crunch all cookies per
2985 default, you'll have to make exceptions from that rule for sites that you
2986 regularly use and that require cookies for actually useful purposes, like maybe
2987 your bank, favorite shop, or newspaper.
2991 We have tried to provide you with reasonable rules to start from in the
2992 distribution actions files. But there is no general rule of thumb on these
2993 things. There just are too many variables, and sites are constantly changing.
2994 Sooner or later you will want to change the rules (and read this chapter again :).
2998 <!-- ~~~~~ New section ~~~~~ -->
3000 <title>How to Edit</title>
3002 The easiest way to edit the actions files is with a browser by
3003 using our browser-based editor, which can be reached from <ulink
3004 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
3005 Note: the config file option <link
3006 linkend="enable-edit-actions">enable-edit-actions</link> must be enabled for
3007 this to work. The editor allows both fine-grained control over every single
3008 feature on a per-URL basis, and easy choosing from wholesale sets of defaults
3009 like <quote>Cautious</quote>, <quote>Medium</quote> or
3010 <quote>Advanced</quote>. Warning: the <quote>Advanced</quote> setting is more
3011 aggressive, and will be more likely to cause problems for some sites.
3012 Experienced users only!
3016 If you prefer plain text editing to GUIs, you can of course also directly edit the
3017 the actions files with your favorite text editor. Look at
3018 <filename>default.action</filename> which is richly commented with many
3024 <sect2 id="actions-apply">
3025 <title>How Actions are Applied to Requests</title>
3027 Actions files are divided into sections. There are special sections,
3028 like the <quote><link linkend="aliases">alias</link></quote> sections which will
3029 be discussed later. For now let's concentrate on regular sections: They have a
3030 heading line (often split up to multiple lines for readability) which consist
3031 of a list of actions, separated by whitespace and enclosed in curly braces.
3032 Below that, there is a list of URL and tag patterns, each on a separate line.
3036 To determine which actions apply to a request, the URL of the request is
3037 compared to all URL patterns in each <quote>action file</quote>.
3038 Every time it matches, the list of applicable actions for the request is
3039 incrementally updated, using the heading of the section in which the
3040 pattern is located. The same is done again for tags and tag patterns later on.
3044 If multiple applying sections set the same action differently,
3045 the last match wins. If not, the effects are aggregated.
3046 E.g. a URL might match a regular section with a heading line of <literal>{
3047 +<link linkend="handle-as-image">handle-as-image</link> }</literal>,
3048 then later another one with just <literal>{
3049 +<link linkend="block">block</link> }</literal>, resulting
3050 in <emphasis>both</emphasis> actions to apply. And there may well be
3051 cases where you will want to combine actions together. Such a section then
3057 { +<literal>handle-as-image</literal> +<literal>block{Banner ads.}</literal> }
3058 # Block these as if they were images. Send no block page.
3060 media.example.com/.*banners
3061 .example.com/images/ads/</screen>
3065 You can trace this process for URL patterns and any given URL by visiting <ulink
3066 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>.
3070 Examples and more detail on this is provided in the Appendix, <link linkend="ACTIONSANAT">
3071 Troubleshooting: Anatomy of an Action</link> section.
3075 <!-- ~~~~~ New section ~~~~~ -->
3076 <sect2 id="af-patterns">
3077 <title>Patterns</title>
3079 As mentioned, <application>Privoxy</application> uses <quote>patterns</quote>
3080 to determine what <emphasis>actions</emphasis> might apply to which sites and
3081 pages your browser attempts to access. These <quote>patterns</quote> use wild
3082 card type <emphasis>pattern</emphasis> matching to achieve a high degree of
3083 flexibility. This allows one expression to be expanded and potentially match
3084 against many similar patterns.
3088 Generally, an URL pattern has the form
3089 <literal><domain><port>/<path></literal>, where the
3090 <literal><domain></literal>, the <literal><port></literal>
3091 and the <literal><path></literal> are optional. (This is why the special
3092 <literal>/</literal> pattern matches all URLs). Note that the protocol
3093 portion of the URL pattern (e.g. <literal>http://</literal>) should
3094 <emphasis>not</emphasis> be included in the pattern. This is assumed already!
3097 The pattern matching syntax is different for the domain and path parts of
3098 the URL. The domain part uses a simple globbing type matching technique,
3099 while the path part uses more flexible
3100 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
3101 Expressions</quote></ulink> (POSIX 1003.2).
3104 The port part of a pattern is a decimal port number preceded by a colon
3105 (<literal>:</literal>). If the domain part contains a numerical IPv6 address,
3106 it has to be put into angle brackets
3107 (<literal><</literal>, <literal>></literal>).
3112 <term><literal>www.example.com/</literal></term>
3115 is a domain-only pattern and will match any request to <literal>www.example.com</literal>,
3116 regardless of which document on that server is requested. So ALL pages in
3117 this domain would be covered by the scope of this action. Note that a
3118 simple <literal>example.com</literal> is different and would NOT match.
3123 <term><literal>www.example.com</literal></term>
3126 means exactly the same. For domain-only patterns, the trailing <literal>/</literal> may
3132 <term><literal>www.example.com/index.html</literal></term>
3135 matches all the documents on <literal>www.example.com</literal>
3136 whose name starts with <literal>/index.html</literal>.
3141 <term><literal>www.example.com/index.html$</literal></term>
3144 matches only the single document <literal>/index.html</literal>
3145 on <literal>www.example.com</literal>.
3150 <term><literal>/index.html$</literal></term>
3153 matches the document <literal>/index.html</literal>, regardless of the domain,
3154 i.e. on <emphasis>any</emphasis> web server anywhere.
3159 <term><literal>/</literal></term>
3162 Matches any URL because there's no requirement for either the
3163 domain or the path to match anything.
3168 <term><literal>:8000/</literal></term>
3171 Matches any URL pointing to TCP port 8000.
3176 <term><literal><2001:db8::1>/</literal></term>
3179 Matches any URL with the host address <literal>2001:db8::1</literal>.
3180 (Note that the real URL uses plain brackets, not angle brackets.)
3185 <term><literal>index.html</literal></term>
3188 matches nothing, since it would be interpreted as a domain name and
3189 there is no top-level domain called <literal>.html</literal>. So its
3197 <!-- ~~~~~ New section ~~~~~ -->
3198 <sect3><title>The Domain Pattern</title>
3201 The matching of the domain part offers some flexible options: if the
3202 domain starts or ends with a dot, it becomes unanchored at that end.
3208 <term><literal>.example.com</literal></term>
3211 matches any domain with first-level domain <literal>com</literal>
3212 and second-level domain <literal>example</literal>.
3213 For example <literal>www.example.com</literal>,
3214 <literal>example.com</literal> and <literal>foo.bar.baz.example.com</literal>.
3215 Note that it wouldn't match if the second-level domain was <literal>another-example</literal>.
3220 <term><literal>www.</literal></term>
3223 matches any domain that <emphasis>STARTS</emphasis> with
3224 <literal>www.</literal> (It also matches the domain
3225 <literal>www</literal> but most of the time that doesn't matter.)
3230 <term><literal>.example.</literal></term>
3233 matches any domain that <emphasis>CONTAINS</emphasis> <literal>.example.</literal>.
3234 And, by the way, also included would be any files or documents that exist
3235 within that domain since no path limitations are specified. (Correctly
3236 speaking: It matches any FQDN that contains <literal>example</literal> as
3237 a domain.) This might be <literal>www.example.com</literal>,
3238 <literal>news.example.de</literal>, or
3239 <literal>www.example.net/cgi/testing.pl</literal> for instance. All these
3247 Additionally, there are wild-cards that you can use in the domain names
3248 themselves. These work similarly to shell globbing type wild-cards:
3249 <quote>*</quote> represents zero or more arbitrary characters (this is
3251 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
3252 Expression</quote></ulink> based syntax of <quote>.*</quote>),
3253 <quote>?</quote> represents any single character (this is equivalent to the
3254 regular expression syntax of a simple <quote>.</quote>), and you can define
3255 <quote>character classes</quote> in square brackets which is similar to
3256 the same regular expression technique. All of this can be freely mixed:
3261 <term><literal>ad*.example.com</literal></term>
3264 matches <quote>adserver.example.com</quote>,
3265 <quote>ads.example.com</quote>, etc but not <quote>sfads.example.com</quote>
3270 <term><literal>*ad*.example.com</literal></term>
3273 matches all of the above, and then some.
3278 <term><literal>.?pix.com</literal></term>
3281 matches <literal>www.ipix.com</literal>,
3282 <literal>pictures.epix.com</literal>, <literal>a.b.c.d.e.upix.com</literal> etc.
3287 <term><literal>www[1-9a-ez].example.c*</literal></term>
3290 matches <literal>www1.example.com</literal>,
3291 <literal>www4.example.cc</literal>, <literal>wwwd.example.cy</literal>,
3292 <literal>wwwz.example.com</literal> etc., but <emphasis>not</emphasis>
3293 <literal>wwww.example.com</literal>.
3300 While flexible, this is not the sophistication of full regular expression based syntax.
3305 <!-- ~ End section ~ -->
3308 <!-- ~~~~~ New section ~~~~~ -->
3309 <sect3><title>The Path Pattern</title>
3312 <application>Privoxy</application> uses <quote>modern</quote> POSIX 1003.2
3313 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
3314 Expressions</quote></ulink> for matching the path portion (after the slash),
3315 and is thus more flexible.
3319 There is an <link linkend="regex">Appendix</link> with a brief quick-start into regular
3320 expressions, you also might want to have a look at your operating system's documentation
3321 on regular expressions (try <literal>man re_format</literal>).
3325 Note that the path pattern is automatically left-anchored at the <quote>/</quote>,
3326 i.e. it matches as if it would start with a <quote>^</quote> (regular expression speak
3327 for the beginning of a line).
3331 Please also note that matching in the path is <emphasis>CASE INSENSITIVE</emphasis>
3332 by default, but you can switch to case sensitive at any point in the pattern by using the
3333 <quote>(?-i)</quote> switch: <literal>www.example.com/(?-i)PaTtErN.*</literal> will match
3334 only documents whose path starts with <literal>PaTtErN</literal> in
3335 <emphasis>exactly</emphasis> this capitalization.
3340 <term><literal>.example.com/.*</literal></term>
3343 Is equivalent to just <quote>.example.com</quote>, since any documents
3344 within that domain are matched with or without the <quote>.*</quote>
3345 regular expression. This is redundant
3350 <term><literal>.example.com/.*/index.html$</literal></term>
3353 Will match any page in the domain of <quote>example.com</quote> that is
3354 named <quote>index.html</quote>, and that is part of some path. For
3355 example, it matches <quote>www.example.com/testing/index.html</quote> but
3356 NOT <quote>www.example.com/index.html</quote> because the regular
3357 expression called for at least two <quote>/'s</quote>, thus the path
3358 requirement. It also would match
3359 <quote>www.example.com/testing/index_html</quote>, because of the
3360 special meta-character <quote>.</quote>.
3365 <term><literal>.example.com/(.*/)?index\.html$</literal></term>
3368 This regular expression is conditional so it will match any page
3369 named <quote>index.html</quote> regardless of path which in this case can
3370 have one or more <quote>/'s</quote>. And this one must contain exactly
3371 <quote>.html</quote> (but does not have to end with that!).
3376 <term><literal>.example.com/(.*/)(ads|banners?|junk)</literal></term>
3379 This regular expression will match any path of <quote>example.com</quote>
3380 that contains any of the words <quote>ads</quote>, <quote>banner</quote>,
3381 <quote>banners</quote> (because of the <quote>?</quote>) or <quote>junk</quote>.
3382 The path does not have to end in these words, just contain them.
3387 <term><literal>.example.com/(.*/)(ads|banners?|junk)/.*\.(jpe?g|gif|png)$</literal></term>
3390 This is very much the same as above, except now it must end in either
3391 <quote>.jpg</quote>, <quote>.jpeg</quote>, <quote>.gif</quote> or <quote>.png</quote>. So this
3392 one is limited to common image formats.
3399 There are many, many good examples to be found in <filename>default.action</filename>,
3400 and more tutorials below in <link linkend="regex">Appendix on regular expressions</link>.
3405 <!-- ~ End section ~ -->
3408 <!-- ~~~~~ New section ~~~~~ -->
3409 <sect3 id="tag-pattern"><title>The Tag Pattern</title>
3412 Tag patterns are used to change the applying actions based on the
3413 request's tags. Tags can be created with either the
3414 <link linkend="CLIENT-HEADER-TAGGER">client-header-tagger</link>
3415 or the <link linkend="SERVER-HEADER-TAGGER">server-header-tagger</link> action.
3419 Tag patterns have to start with <quote>TAG:</quote>, so &my-app;
3420 can tell them apart from URL patterns. Everything after the colon
3421 including white space, is interpreted as a regular expression with
3422 path pattern syntax, except that tag patterns aren't left-anchored
3423 automatically (&my-app; doesn't silently add a <quote>^</quote>,
3424 you have to do it yourself if you need it).
3428 To match all requests that are tagged with <quote>foo</quote>
3429 your pattern line should be <quote>TAG:^foo$</quote>,
3430 <quote>TAG:foo</quote> would work as well, but it would also
3431 match requests whose tags contain <quote>foo</quote> somewhere.
3432 <quote>TAG: foo</quote> wouldn't work as it requires white space.
3436 Sections can contain URL and tag patterns at the same time,
3437 but tag patterns are checked after the URL patterns and thus
3438 always overrule them, even if they are located before the URL patterns.
3442 Once a new tag is added, Privoxy checks right away if it's matched by one
3443 of the tag patterns and updates the action settings accordingly. As a result
3444 tags can be used to activate other tagger actions, as long as these other
3445 taggers look for headers that haven't already be parsed.
3449 For example you could tag client requests which use the
3450 <literal>POST</literal> method,
3451 then use this tag to activate another tagger that adds a tag if cookies
3452 are sent, and then use a block action based on the cookie tag. This allows
3453 the outcome of one action, to be input into a subsequent action. However if
3454 you'd reverse the position of the described taggers, and activated the
3455 method tagger based on the cookie tagger, no method tags would be created.
3456 The method tagger would look for the request line, but at the time
3457 the cookie tag is created, the request line has already been parsed.
3461 While this is a limitation you should be aware of, this kind of
3462 indirection is seldom needed anyway and even the example doesn't
3463 make too much sense.
3470 <!-- ~ End section ~ -->
3473 <!-- ~~~~~ New section ~~~~~ -->
3475 <sect2 id="actions">
3476 <title>Actions</title>
3478 All actions are disabled by default, until they are explicitly enabled
3479 somewhere in an actions file. Actions are turned on if preceded with a
3480 <quote>+</quote>, and turned off if preceded with a <quote>-</quote>. So a
3481 <literal>+action</literal> means <quote>do that action</quote>, e.g.
3482 <literal>+block</literal> means <quote>please block URLs that match the
3483 following patterns</quote>, and <literal>-block</literal> means <quote>don't
3484 block URLs that match the following patterns, even if <literal>+block</literal>
3485 previously applied.</quote>
3490 Again, actions are invoked by placing them on a line, enclosed in curly braces and
3491 separated by whitespace, like in
3492 <literal>{+some-action -some-other-action{some-parameter}}</literal>,
3493 followed by a list of URL patterns, one per line, to which they apply.
3494 Together, the actions line and the following pattern lines make up a section
3495 of the actions file.
3499 Actions fall into three categories:
3506 Boolean, i.e the action can only be <quote>enabled</quote> or
3507 <quote>disabled</quote>. Syntax:
3511 +<replaceable class="function">name</replaceable> # enable action <replaceable class="parameter">name</replaceable>
3512 -<replaceable class="function">name</replaceable> # disable action <replaceable class="parameter">name</replaceable></screen>
3515 Example: <literal>+handle-as-image</literal>
3522 Parameterized, where some value is required in order to enable this type of action.
3527 +<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # enable action and set parameter to <replaceable class="parameter">param</replaceable>,
3528 # overwriting parameter from previous match if necessary
3529 -<replaceable class="function">name</replaceable> # disable action. The parameter can be omitted</screen>
3532 Note that if the URL matches multiple positive forms of a parameterized action,
3533 the last match wins, i.e. the params from earlier matches are simply ignored.
3536 Example: <literal>+hide-user-agent{Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.8.1.4) Gecko/20070602 Firefox/2.0.0.4}</literal>
3542 Multi-value. These look exactly like parameterized actions,
3543 but they behave differently: If the action applies multiple times to the
3544 same URL, but with different parameters, <emphasis>all</emphasis> the parameters
3545 from <emphasis>all</emphasis> matches are remembered. This is used for actions
3546 that can be executed for the same request repeatedly, like adding multiple
3547 headers, or filtering through multiple filters. Syntax:
3551 +<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # enable action and add <replaceable class="parameter">param</replaceable> to the list of parameters
3552 -<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # remove the parameter <replaceable class="parameter">param</replaceable> from the list of parameters
3553 # If it was the last one left, disable the action.
3554 <replaceable class="parameter">-name</replaceable> # disable this action completely and remove all parameters from the list</screen>
3557 Examples: <literal>+add-header{X-Fun-Header: Some text}</literal> and
3558 <literal>+filter{html-annoyances}</literal>
3566 If nothing is specified in any actions file, no <quote>actions</quote> are
3567 taken. So in this case <application>Privoxy</application> would just be a
3568 normal, non-blocking, non-filtering proxy. You must specifically enable the
3569 privacy and blocking features you need (although the provided default actions
3570 files will give a good starting point).
3574 Later defined action sections always over-ride earlier ones of the same type.
3575 So exceptions to any rules you make, should come in the latter part of the file (or
3576 in a file that is processed later when using multiple actions files such
3577 as <filename>user.action</filename>). For multi-valued actions, the actions
3578 are applied in the order they are specified. Actions files are processed in
3579 the order they are defined in <filename>config</filename> (the default
3580 installation has three actions files). It also quite possible for any given
3581 URL to match more than one <quote>pattern</quote> (because of wildcards and
3582 regular expressions), and thus to trigger more than one set of actions! Last
3586 <!-- start actions listing -->
3588 The list of valid <application>Privoxy</application> actions are:
3592 <!-- ********************************************************** -->
3593 <!-- Please note the below defined actions use id's that are -->
3594 <!-- probably linked from other places, so please don't change. -->
3596 <!-- ********************************************************** -->
3599 <!-- ~~~~~ New section ~~~~~ -->
3601 <sect3 renderas="sect4" id="add-header">
3602 <title>add-header</title>
3606 <term>Typical use:</term>
3608 <para>Confuse log analysis, custom applications</para>
3613 <term>Effect:</term>
3616 Sends a user defined HTTP header to the web server.
3623 <!-- boolean, parameterized, Multi-value -->
3625 <para>Multi-value.</para>
3630 <term>Parameter:</term>
3633 Any string value is possible. Validity of the defined HTTP headers is not checked.
3634 It is recommended that you use the <quote><literal>X-</literal></quote> prefix
3644 This action may be specified multiple times, in order to define multiple
3645 headers. This is rarely needed for the typical user. If you don't know what
3646 <quote>HTTP headers</quote> are, you definitely don't need to worry about this
3650 Headers added by this action are not modified by other actions.
3656 <term>Example usage:</term>
3659 <screen>+add-header{X-User-Tracking: sucks}</screen>
3667 <!-- ~~~~~ New section ~~~~~ -->
3668 <sect3 renderas="sect4" id="block">
3669 <title>block</title>
3673 <term>Typical use:</term>
3675 <para>Block ads or other unwanted content</para>
3680 <term>Effect:</term>
3683 Requests for URLs to which this action applies are blocked, i.e. the
3684 requests are trapped by &my-app; and the requested URL is never retrieved,
3685 but is answered locally with a substitute page or image, as determined by
3687 linkend="handle-as-image">handle-as-image</link></literal>,
3689 linkend="set-image-blocker">set-image-blocker</link></literal>, and
3691 linkend="handle-as-empty-document">handle-as-empty-document</link></literal> actions.
3699 <!-- boolean, parameterized, Multi-value -->
3701 <para>Parameterized.</para>
3706 <term>Parameter:</term>
3708 <para>A block reason that should be given to the user.</para>
3716 <application>Privoxy</application> sends a special <quote>BLOCKED</quote> page
3717 for requests to blocked pages. This page contains the block reason given as
3718 parameter, a link to find out why the block action applies, and a click-through
3719 to the blocked content (the latter only if the force feature is available and
3723 A very important exception occurs if <emphasis>both</emphasis>
3724 <literal>block</literal> and <literal><link linkend="handle-as-image">handle-as-image</link></literal>,
3725 apply to the same request: it will then be replaced by an image. If
3726 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>
3727 (see below) also applies, the type of image will be determined by its parameter,
3728 if not, the standard checkerboard pattern is sent.
3731 It is important to understand this process, in order
3732 to understand how <application>Privoxy</application> deals with
3733 ads and other unwanted content. Blocking is a core feature, and one
3734 upon which various other features depend.
3737 The <literal><link linkend="filter">filter</link></literal>
3738 action can perform a very similar task, by <quote>blocking</quote>
3739 banner images and other content through rewriting the relevant URLs in the
3740 document's HTML source, so they don't get requested in the first place.
3741 Note that this is a totally different technique, and it's easy to confuse the two.
3747 <term>Example usage (section):</term>
3750 <screen>{+block{No nasty stuff for you.}}
3751 # Block and replace with "blocked" page
3752 .nasty-stuff.example.com
3754 {+block{Doubleclick banners.} +handle-as-image}
3755 # Block and replace with image
3759 {+block{Layered ads.} +handle-as-empty-document}
3760 # Block and then ignore
3761 adserver.example.net/.*\.js$</screen>
3771 <!-- ~~~~~ New section ~~~~~ -->
3772 <sect3 renderas="sect4" id="change-x-forwarded-for">
3773 <title>change-x-forwarded-for</title>
3777 <term>Typical use:</term>
3779 <para>Improve privacy by not forwarding the source of the request in the HTTP headers.</para>
3784 <term>Effect:</term>
3787 Deletes the <quote>X-Forwarded-For:</quote> HTTP header from the client request,
3795 <!-- Boolean, Parameterized, Multi-value -->
3797 <para>Parameterized.</para>
3802 <term>Parameter:</term>
3806 <para><quote>block</quote> to delete the header.</para>
3810 <quote>add</quote> to create the header (or append
3811 the client's IP address to an already existing one).
3822 It is safe and recommended to use <literal>block</literal>.
3825 Forwarding the source address of the request may make
3826 sense in some multi-user setups but is also a privacy risk.
3831 <term>Example usage:</term>
3834 <screen>+change-x-forwarded-for{block}</screen>
3841 <!-- ~~~~~ New section ~~~~~ -->
3842 <sect3 renderas="sect4" id="client-header-filter">
3843 <title>client-header-filter</title>
3847 <term>Typical use:</term>
3850 Rewrite or remove single client headers.
3856 <term>Effect:</term>
3859 All client headers to which this action applies are filtered on-the-fly through
3860 the specified regular expression based substitutions.
3867 <!-- boolean, parameterized, Multi-value -->
3869 <para>Parameterized.</para>
3874 <term>Parameter:</term>
3877 The name of a client-header filter, as defined in one of the
3878 <link linkend="filter-file">filter files</link>.
3887 Client-header filters are applied to each header on its own, not to
3888 all at once. This makes it easier to diagnose problems, but on the downside
3889 you can't write filters that only change header x if header y's value is z.
3890 You can do that by using tags though.
3893 Client-header filters are executed after the other header actions have finished
3894 and use their output as input.
3897 If the request URI gets changed, &my-app; will detect that and use the new
3898 one. This can be used to rewrite the request destination behind the client's
3899 back, for example to specify a Tor exit relay for certain requests.
3902 Please refer to the <link linkend="filter-file">filter file chapter</link>
3903 to learn which client-header filters are available by default, and how to
3911 <term>Example usage (section):</term>
3915 # Hide Tor exit notation in Host and Referer Headers
3916 {+client-header-filter{hide-tor-exit-notation}}
3927 <!-- ~~~~~ New section ~~~~~ -->
3928 <sect3 renderas="sect4" id="client-header-tagger">
3929 <title>client-header-tagger</title>
3933 <term>Typical use:</term>
3936 Block requests based on their headers.
3942 <term>Effect:</term>
3945 Client headers to which this action applies are filtered on-the-fly through
3946 the specified regular expression based substitutions, the result is used as
3954 <!-- boolean, parameterized, Multi-value -->
3956 <para>Parameterized.</para>
3961 <term>Parameter:</term>
3964 The name of a client-header tagger, as defined in one of the
3965 <link linkend="filter-file">filter files</link>.
3974 Client-header taggers are applied to each header on its own,
3975 and as the header isn't modified, each tagger <quote>sees</quote>
3979 Client-header taggers are the first actions that are executed
3980 and their tags can be used to control every other action.
3986 <term>Example usage (section):</term>
3990 # Tag every request with the User-Agent header
3991 {+client-header-tagger{user-agent}}
3994 # Tagging itself doesn't change the action
3995 # settings, sections with TAG patterns do:
3997 # If it's a download agent, use a different forwarding proxy,
3998 # show the real User-Agent and make sure resume works.
3999 {+forward-override{forward-socks5 10.0.0.2:2222 .} \
4000 -hide-if-modified-since \
4001 -overwrite-last-modified \
4006 TAG:^User-Agent: NetBSD-ftp/
4007 TAG:^User-Agent: Novell ZYPP Installer
4008 TAG:^User-Agent: RPM APT-HTTP/
4009 TAG:^User-Agent: fetch libfetch/
4010 TAG:^User-Agent: Ubuntu APT-HTTP/
4011 TAG:^User-Agent: MPlayer/
4016 # Tag all requests with the Range header set
4017 {+client-header-tagger{range-requests}}
4020 # Disable filtering for the tagged requests.
4022 # With filtering enabled Privoxy would remove the Range headers
4023 # to be able to filter the whole response. The downside is that
4024 # it prevents clients from resuming downloads or skipping over
4025 # parts of multimedia files.
4026 {-filter -deanimate-gifs}
4037 <!-- ~~~~~ New section ~~~~~ -->
4038 <sect3 renderas="sect4" id="content-type-overwrite">
4039 <title>content-type-overwrite</title>
4043 <term>Typical use:</term>
4045 <para>Stop useless download menus from popping up, or change the browser's rendering mode</para>
4050 <term>Effect:</term>
4053 Replaces the <quote>Content-Type:</quote> HTTP server header.
4060 <!-- Boolean, Parameterized, Multi-value -->
4062 <para>Parameterized.</para>
4067 <term>Parameter:</term>
4079 The <quote>Content-Type:</quote> HTTP server header is used by the
4080 browser to decide what to do with the document. The value of this
4081 header can cause the browser to open a download menu instead of
4082 displaying the document by itself, even if the document's format is
4083 supported by the browser.
4086 The declared content type can also affect which rendering mode
4087 the browser chooses. If XHTML is delivered as <quote>text/html</quote>,
4088 many browsers treat it as yet another broken HTML document.
4089 If it is send as <quote>application/xml</quote>, browsers with
4090 XHTML support will only display it, if the syntax is correct.
4093 If you see a web site that proudly uses XHTML buttons, but sets
4094 <quote>Content-Type: text/html</quote>, you can use &my-app;
4095 to overwrite it with <quote>application/xml</quote> and validate
4096 the web master's claim inside your XHTML-supporting browser.
4097 If the syntax is incorrect, the browser will complain loudly.
4100 You can also go the opposite direction: if your browser prints
4101 error messages instead of rendering a document falsely declared
4102 as XHTML, you can overwrite the content type with
4103 <quote>text/html</quote> and have it rendered as broken HTML document.
4106 By default <literal>content-type-overwrite</literal> only replaces
4107 <quote>Content-Type:</quote> headers that look like some kind of text.
4108 If you want to overwrite it unconditionally, you have to combine it with
4109 <literal><link linkend="force-text-mode">force-text-mode</link></literal>.
4110 This limitation exists for a reason, think twice before circumventing it.
4113 Most of the time it's easier to replace this action with a custom
4114 <literal><link linkend="server-header-filter">server-header filter</link></literal>.
4115 It allows you to activate it for every document of a certain site and it will still
4116 only replace the content types you aimed at.
4119 Of course you can apply <literal>content-type-overwrite</literal>
4120 to a whole site and then make URL based exceptions, but it's a lot
4121 more work to get the same precision.
4127 <term>Example usage (sections):</term>
4130 <screen># Check if www.example.net/ really uses valid XHTML
4131 { +content-type-overwrite{application/xml} }
4134 # but leave the content type unmodified if the URL looks like a style sheet
4135 {-content-type-overwrite}
4136 www.example.net/.*\.css$
4137 www.example.net/.*style
4146 <!-- ~~~~~ New section ~~~~~ -->
4147 <sect3 renderas="sect4" id="crunch-client-header">
4151 <title>crunch-client-header</title>
4155 <term>Typical use:</term>
4157 <para>Remove a client header <application>Privoxy</application> has no dedicated action for.</para>
4162 <term>Effect:</term>
4165 Deletes every header sent by the client that contains the string the user supplied as parameter.
4172 <!-- Boolean, Parameterized, Multi-value -->
4174 <para>Parameterized.</para>
4179 <term>Parameter:</term>
4191 This action allows you to block client headers for which no dedicated
4192 <application>Privoxy</application> action exists.
4193 <application>Privoxy</application> will remove every client header that
4194 contains the string you supplied as parameter.
4197 Regular expressions are <emphasis>not supported</emphasis> and you can't
4198 use this action to block different headers in the same request, unless
4199 they contain the same string.
4202 <literal>crunch-client-header</literal> is only meant for quick tests.
4203 If you have to block several different headers, or only want to modify
4204 parts of them, you should use a
4205 <literal><link linkend="client-header-filter">client-header filter</link></literal>.
4209 Don't block any header without understanding the consequences.
4216 <term>Example usage (section):</term>
4219 <screen># Block the non-existent "Privacy-Violation:" client header
4220 { +crunch-client-header{Privacy-Violation:} }
4230 <!-- ~~~~~ New section ~~~~~ -->
4231 <sect3 renderas="sect4" id="crunch-if-none-match">
4232 <title>crunch-if-none-match</title>
4238 <term>Typical use:</term>
4240 <para>Prevent yet another way to track the user's steps between sessions.</para>
4245 <term>Effect:</term>
4248 Deletes the <quote>If-None-Match:</quote> HTTP client header.
4255 <!-- Boolean, Parameterized, Multi-value -->
4257 <para>Boolean.</para>
4262 <term>Parameter:</term>
4274 Removing the <quote>If-None-Match:</quote> HTTP client header
4275 is useful for filter testing, where you want to force a real
4276 reload instead of getting status code <quote>304</quote> which
4277 would cause the browser to use a cached copy of the page.
4280 It is also useful to make sure the header isn't used as a cookie
4281 replacement (unlikely but possible).
4284 Blocking the <quote>If-None-Match:</quote> header shouldn't cause any
4285 caching problems, as long as the <quote>If-Modified-Since:</quote> header
4286 isn't blocked or missing as well.
4289 It is recommended to use this action together with
4290 <literal><link linkend="hide-if-modified-since">hide-if-modified-since</link></literal>
4292 <literal><link linkend="overwrite-last-modified">overwrite-last-modified</link></literal>.
4298 <term>Example usage (section):</term>
4301 <screen># Let the browser revalidate cached documents but don't
4302 # allow the server to use the revalidation headers for user tracking.
4303 {+hide-if-modified-since{-60} \
4304 +overwrite-last-modified{randomize} \
4305 +crunch-if-none-match}
4314 <!-- ~~~~~ New section ~~~~~ -->
4315 <sect3 renderas="sect4" id="crunch-incoming-cookies">
4316 <title>crunch-incoming-cookies</title>
4320 <term>Typical use:</term>
4323 Prevent the web server from setting HTTP cookies on your system
4329 <term>Effect:</term>
4332 Deletes any <quote>Set-Cookie:</quote> HTTP headers from server replies.
4339 <!-- Boolean, Parameterized, Multi-value -->
4341 <para>Boolean.</para>
4346 <term>Parameter:</term>
4358 This action is only concerned with <emphasis>incoming</emphasis> HTTP cookies. For
4359 <emphasis>outgoing</emphasis> HTTP cookies, use
4360 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>.
4361 Use <emphasis>both</emphasis> to disable HTTP cookies completely.
4364 It makes <emphasis>no sense at all</emphasis> to use this action in conjunction
4365 with the <literal><link linkend="session-cookies-only">session-cookies-only</link></literal> action,
4366 since it would prevent the session cookies from being set. See also
4367 <literal><link linkend="filter-content-cookies">filter-content-cookies</link></literal>.
4373 <term>Example usage:</term>
4376 <screen>+crunch-incoming-cookies</screen>
4384 <!-- ~~~~~ New section ~~~~~ -->
4385 <sect3 renderas="sect4" id="crunch-server-header">
4386 <title>crunch-server-header</title>
4392 <term>Typical use:</term>
4394 <para>Remove a server header <application>Privoxy</application> has no dedicated action for.</para>
4399 <term>Effect:</term>
4402 Deletes every header sent by the server that contains the string the user supplied as parameter.
4409 <!-- Boolean, Parameterized, Multi-value -->
4411 <para>Parameterized.</para>
4416 <term>Parameter:</term>
4428 This action allows you to block server headers for which no dedicated
4429 <application>Privoxy</application> action exists. <application>Privoxy</application>
4430 will remove every server header that contains the string you supplied as parameter.
4433 Regular expressions are <emphasis>not supported</emphasis> and you can't
4434 use this action to block different headers in the same request, unless
4435 they contain the same string.
4438 <literal>crunch-server-header</literal> is only meant for quick tests.
4439 If you have to block several different headers, or only want to modify
4440 parts of them, you should use a custom
4441 <literal><link linkend="server-header-filter">server-header filter</link></literal>.
4445 Don't block any header without understanding the consequences.
4452 <term>Example usage (section):</term>
4455 <screen># Crunch server headers that try to prevent caching
4456 { +crunch-server-header{no-cache} }
4465 <!-- ~~~~~ New section ~~~~~ -->
4466 <sect3 renderas="sect4" id="crunch-outgoing-cookies">
4467 <title>crunch-outgoing-cookies</title>
4471 <term>Typical use:</term>
4474 Prevent the web server from reading any HTTP cookies from your system
4480 <term>Effect:</term>
4483 Deletes any <quote>Cookie:</quote> HTTP headers from client requests.
4490 <!-- Boolean, Parameterized, Multi-value -->
4492 <para>Boolean.</para>
4497 <term>Parameter:</term>
4509 This action is only concerned with <emphasis>outgoing</emphasis> HTTP cookies. For
4510 <emphasis>incoming</emphasis> HTTP cookies, use
4511 <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal>.
4512 Use <emphasis>both</emphasis> to disable HTTP cookies completely.
4515 It makes <emphasis>no sense at all</emphasis> to use this action in conjunction
4516 with the <literal><link linkend="session-cookies-only">session-cookies-only</link></literal> action,
4517 since it would prevent the session cookies from being read.
4523 <term>Example usage:</term>
4526 <screen>+crunch-outgoing-cookies</screen>
4535 <!-- ~~~~~ New section ~~~~~ -->
4536 <sect3 renderas="sect4" id="deanimate-gifs">
4537 <title>deanimate-gifs</title>
4541 <term>Typical use:</term>
4543 <para>Stop those annoying, distracting animated GIF images.</para>
4548 <term>Effect:</term>
4551 De-animate GIF animations, i.e. reduce them to their first or last image.
4558 <!-- boolean, parameterized, Multi-value -->
4560 <para>Parameterized.</para>
4565 <term>Parameter:</term>
4568 <quote>last</quote> or <quote>first</quote>
4577 This will also shrink the images considerably (in bytes, not pixels!). If
4578 the option <quote>first</quote> is given, the first frame of the animation
4579 is used as the replacement. If <quote>last</quote> is given, the last
4580 frame of the animation is used instead, which probably makes more sense for
4581 most banner animations, but also has the risk of not showing the entire
4582 last frame (if it is only a delta to an earlier frame).
4585 You can safely use this action with patterns that will also match non-GIF
4586 objects, because no attempt will be made at anything that doesn't look like
4593 <term>Example usage:</term>
4596 <screen>+deanimate-gifs{last}</screen>
4603 <!-- ~~~~~ New section ~~~~~ -->
4604 <sect3 renderas="sect4" id="downgrade-http-version">
4605 <title>downgrade-http-version</title>
4609 <term>Typical use:</term>
4611 <para>Work around (very rare) problems with HTTP/1.1</para>
4616 <term>Effect:</term>
4619 Downgrades HTTP/1.1 client requests and server replies to HTTP/1.0.
4626 <!-- boolean, parameterized, Multi-value -->
4628 <para>Boolean.</para>
4633 <term>Parameter:</term>
4645 This is a left-over from the time when <application>Privoxy</application>
4646 didn't support important HTTP/1.1 features well. It is left here for the
4647 unlikely case that you experience HTTP/1.1-related problems with some server
4651 Note that enabling this action is only a workaround. It should not
4652 be enabled for sites that work without it. While it shouldn't break
4653 any pages, it has an (usually negative) performance impact.
4656 If you come across a site where enabling this action helps, please report it,
4657 so the cause of the problem can be analyzed. If the problem turns out to be
4658 caused by a bug in <application>Privoxy</application> it should be
4659 fixed so the following release works without the work around.
4665 <term>Example usage (section):</term>
4668 <screen>{+downgrade-http-version}
4669 problem-host.example.com</screen>
4677 <!-- ~~~~~ New section ~~~~~ -->
4678 <sect3 renderas="sect4" id="fast-redirects">
4679 <title>fast-redirects</title>
4683 <term>Typical use:</term>
4685 <para>Fool some click-tracking scripts and speed up indirect links.</para>
4690 <term>Effect:</term>
4693 Detects redirection URLs and redirects the browser without contacting
4694 the redirection server first.
4701 <!-- boolean, parameterized, Multi-value -->
4703 <para>Parameterized.</para>
4708 <term>Parameter:</term>
4713 <quote>simple-check</quote> to just search for the string <quote>http://</quote>
4714 to detect redirection URLs.
4719 <quote>check-decoded-url</quote> to decode URLs (if necessary) before searching
4720 for redirection URLs.
4731 Many sites, like yahoo.com, don't just link to other sites. Instead, they
4732 will link to some script on their own servers, giving the destination as a
4733 parameter, which will then redirect you to the final target. URLs
4734 resulting from this scheme typically look like:
4735 <quote>http://www.example.org/click-tracker.cgi?target=http%3a//www.example.net/</quote>.
4738 Sometimes, there are even multiple consecutive redirects encoded in the
4739 URL. These redirections via scripts make your web browsing more traceable,
4740 since the server from which you follow such a link can see where you go
4741 to. Apart from that, valuable bandwidth and time is wasted, while your
4742 browser asks the server for one redirect after the other. Plus, it feeds
4746 This feature is currently not very smart and is scheduled for improvement.
4747 If it is enabled by default, you will have to create some exceptions to
4748 this action. It can lead to failures in several ways:
4751 Not every URLs with other URLs as parameters is evil.
4752 Some sites offer a real service that requires this information to work.
4753 For example a validation service needs to know, which document to validate.
4754 <literal>fast-redirects</literal> assumes that every URL parameter that
4755 looks like another URL is a redirection target, and will always redirect to
4756 the last one. Most of the time the assumption is correct, but if it isn't,
4757 the user gets redirected anyway.
4760 Another failure occurs if the URL contains other parameters after the URL parameter.
4762 <quote>http://www.example.org/?redirect=http%3a//www.example.net/&foo=bar</quote>.
4763 contains the redirection URL <quote>http://www.example.net/</quote>,
4764 followed by another parameter. <literal>fast-redirects</literal> doesn't know that
4765 and will cause a redirect to <quote>http://www.example.net/&foo=bar</quote>.
4766 Depending on the target server configuration, the parameter will be silently ignored
4767 or lead to a <quote>page not found</quote> error. You can prevent this problem by
4768 first using the <literal><link linkend="redirect">redirect</link></literal> action
4769 to remove the last part of the URL, but it requires a little effort.
4772 To detect a redirection URL, <literal>fast-redirects</literal> only
4773 looks for the string <quote>http://</quote>, either in plain text
4774 (invalid but often used) or encoded as <quote>http%3a//</quote>.
4775 Some sites use their own URL encoding scheme, encrypt the address
4776 of the target server or replace it with a database id. In theses cases
4777 <literal>fast-redirects</literal> is fooled and the request reaches the
4778 redirection server where it probably gets logged.
4784 <term>Example usage:</term>
4788 { +fast-redirects{simple-check} }
4791 { +fast-redirects{check-decoded-url} }
4792 another.example.com/testing</screen>
4801 <!-- ~~~~~ New section ~~~~~ -->
4802 <sect3 renderas="sect4" id="filter">
4803 <title>filter</title>
4807 <term>Typical use:</term>
4809 <para>Get rid of HTML and JavaScript annoyances, banner advertisements (by size),
4810 do fun text replacements, add personalized effects, etc.</para>
4815 <term>Effect:</term>
4818 All instances of text-based type, most notably HTML and JavaScript, to which
4819 this action applies, can be filtered on-the-fly through the specified regular
4820 expression based substitutions. (Note: as of version 3.0.3 plain text documents
4821 are exempted from filtering, because web servers often use the
4822 <literal>text/plain</literal> MIME type for all files whose type they don't know.)
4829 <!-- boolean, parameterized, Multi-value -->
4831 <para>Parameterized.</para>
4836 <term>Parameter:</term>
4839 The name of a content filter, as defined in the <link linkend="filter-file">filter file</link>.
4840 Filters can be defined in one or more files as defined by the
4841 <literal><link linkend="filterfile">filterfile</link></literal>
4842 option in the <link linkend="config">config file</link>.
4843 <filename>default.filter</filename> is the collection of filters
4844 supplied by the developers. Locally defined filters should go
4845 in their own file, such as <filename>user.filter</filename>.
4848 When used in its negative form,
4849 and without parameters, <emphasis>all</emphasis> filtering is completely disabled.
4858 For your convenience, there are a number of pre-defined filters available
4859 in the distribution filter file that you can use. See the examples below for
4863 Filtering requires buffering the page content, which may appear to
4864 slow down page rendering since nothing is displayed until all content has
4865 passed the filters. (The total time until the page is completely rendered
4866 doesn't change much, but it may be perceived as slower since the page is
4867 not incrementally displayed.)
4868 This effect will be more noticeable on slower connections.
4871 <quote>Rolling your own</quote>
4872 filters requires a knowledge of
4873 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
4874 Expressions</quote></ulink> and
4875 <ulink url="http://en.wikipedia.org/wiki/Html"><quote>HTML</quote></ulink>.
4876 This is very powerful feature, and potentially very intrusive.
4877 Filters should be used with caution, and where an equivalent
4878 <quote>action</quote> is not available.
4881 The amount of data that can be filtered is limited to the
4882 <literal><link linkend="buffer-limit">buffer-limit</link></literal>
4883 option in the main <link linkend="config">config file</link>. The
4884 default is 4096 KB (4 Megs). Once this limit is exceeded, the buffered
4885 data, and all pending data, is passed through unfiltered.
4888 Inappropriate MIME types, such as zipped files, are not filtered at all.
4889 (Again, only text-based types except plain text). Encrypted SSL data
4890 (from HTTPS servers) cannot be filtered either, since this would violate
4891 the integrity of the secure transaction. In some situations it might
4892 be necessary to protect certain text, like source code, from filtering
4893 by defining appropriate <literal>-filter</literal> exceptions.
4896 Compressed content can't be filtered either, but if &my-app;
4897 is compiled with zlib support and a supported compression algorithm
4898 is used (gzip or deflate), &my-app; can first decompress the content
4902 If you use a &my-app; version without zlib support, but want filtering to work on
4903 as much documents as possible, even those that would normally be sent compressed,
4904 you must use the <literal><link linkend="prevent-compression">prevent-compression</link></literal>
4905 action in conjunction with <literal>filter</literal>.
4908 Content filtering can achieve some of the same effects as the
4909 <literal><link linkend="block">block</link></literal>
4910 action, i.e. it can be used to block ads and banners. But the mechanism
4911 works quite differently. One effective use, is to block ad banners
4912 based on their size (see below), since many of these seem to be somewhat
4916 <link linkend="contact">Feedback</link> with suggestions for new or
4917 improved filters is particularly welcome!
4920 The below list has only the names and a one-line description of each
4921 predefined filter. There are <link linkend="predefined-filters">more
4922 verbose explanations</link> of what these filters do in the <link
4923 linkend="filter-file">filter file chapter</link>.
4929 <term>Example usage (with filters from the distribution <filename>default.filter</filename> file).
4930 See <link linkend="PREDEFINED-FILTERS">the Predefined Filters section</link> for
4931 more explanation on each:</term>
4934 <anchor id="filter-js-annoyances">
4935 <screen>+filter{js-annoyances} # Get rid of particularly annoying JavaScript abuse.</screen>
4938 <anchor id="filter-js-events">
4939 <screen>+filter{js-events} # Kill all JS event bindings and timers (Radically destructive! Only for extra nasty sites).</screen>
4942 <anchor id="filter-html-annoyances">
4943 <screen>+filter{html-annoyances} # Get rid of particularly annoying HTML abuse.</screen>
4946 <anchor id="filter-content-cookies">
4947 <screen>+filter{content-cookies} # Kill cookies that come in the HTML or JS content.</screen>
4950 <anchor id="filter-refresh-tags">
4951 <screen>+filter{refresh-tags} # Kill automatic refresh tags (for dial-on-demand setups).</screen>
4954 <anchor id="filter-unsolicited-popups">
4955 <screen>+filter{unsolicited-popups} # Disable only unsolicited pop-up windows. Useful if your browser lacks this ability.</screen>
4958 <anchor id="filter-all-popups">
4959 <screen>+filter{all-popups} # Kill all popups in JavaScript and HTML. Useful if your browser lacks this ability.</screen>
4962 <anchor id="filter-img-reorder">
4963 <screen>+filter{img-reorder} # Reorder attributes in <img> tags to make the banners-by-* filters more effective.</screen>
4966 <anchor id="filter-banners-by-size">
4967 <screen>+filter{banners-by-size} # Kill banners by size.</screen>
4970 <anchor id="filter-banners-by-link">
4971 <screen>+filter{banners-by-link} # Kill banners by their links to known clicktrackers.</screen>
4974 <anchor id="filter-webbugs">
4975 <screen>+filter{webbugs} # Squish WebBugs (1x1 invisible GIFs used for user tracking).</screen>
4978 <anchor id="filter-tiny-textforms">
4979 <screen>+filter{tiny-textforms} # Extend those tiny textareas up to 40x80 and kill the hard wrap.</screen>
4982 <anchor id="filter-jumping-windows">
4983 <screen>+filter{jumping-windows} # Prevent windows from resizing and moving themselves.</screen>
4986 <anchor id="filter-frameset-borders">
4987 <screen>+filter{frameset-borders} # Give frames a border and make them resizable.</screen>
4990 <anchor id="filter-demoronizer">
4991 <screen>+filter{demoronizer} # Fix MS's non-standard use of standard charsets.</screen>
4994 <anchor id="filter-shockwave-flash">
4995 <screen>+filter{shockwave-flash} # Kill embedded Shockwave Flash objects.</screen>
4998 <anchor id="filter-quicktime-kioskmode">
4999 <screen>+filter{quicktime-kioskmode} # Make Quicktime movies saveable.</screen>
5002 <anchor id="filter-fun">
5003 <screen>+filter{fun} # Text replacements for subversive browsing fun!</screen>
5006 <anchor id="filter-crude-parental">
5007 <screen>+filter{crude-parental} # Crude parental filtering. Note that this filter doesn't work reliably.</screen>
5010 <anchor id="filter-ie-exploits">
5011 <screen>+filter{ie-exploits} # Disable some known Internet Explorer bug exploits.</screen>
5014 <anchor id="filter-site-specifics">
5015 <screen>+filter{site-specifics} # Cure for site-specific problems. Don't apply generally!</screen>
5018 <anchor id="filter-no-ping">
5019 <screen>+filter{no-ping} # Removes non-standard ping attributes in <a> and <area> tags.</screen>
5022 <anchor id="filter-google">
5023 <screen>+filter{google} # CSS-based block for Google text ads. Also removes a width limitation and the toolbar advertisement.</screen>
5026 <anchor id="filter-yahoo">
5027 <screen>+filter{yahoo} # CSS-based block for Yahoo text ads. Also removes a width limitation.</screen>
5030 <anchor id="filter-msn">
5031 <screen>+filter{msn} # CSS-based block for MSN text ads. Also removes tracking URLs and a width limitation.</screen>
5034 <anchor id="filter-blogspot">
5035 <screen>+filter{blogspot} # Cleans up some Blogspot blogs. Read the fine print before using this.</screen>
5043 <!-- ~~~~~ New section ~~~~~ -->
5044 <sect3 renderas="sect4" id="force-text-mode">
5045 <title>force-text-mode</title>
5051 <term>Typical use:</term>
5053 <para>Force <application>Privoxy</application> to treat a document as if it was in some kind of <emphasis>text</emphasis> format. </para>
5058 <term>Effect:</term>
5061 Declares a document as text, even if the <quote>Content-Type:</quote> isn't detected as such.
5068 <!-- Boolean, Parameterized, Multi-value -->
5070 <para>Boolean.</para>
5075 <term>Parameter:</term>
5087 As explained <literal><link linkend="filter">above</link></literal>,
5088 <application>Privoxy</application> tries to only filter files that are
5089 in some kind of text format. The same restrictions apply to
5090 <literal><link linkend="content-type-overwrite">content-type-overwrite</link></literal>.
5091 <literal>force-text-mode</literal> declares a document as text,
5092 without looking at the <quote>Content-Type:</quote> first.
5096 Think twice before activating this action. Filtering binary data
5097 with regular expressions can cause file damage.
5104 <term>Example usage:</term>
5117 <!-- ~~~~~ New section ~~~~~ -->
5118 <sect3 renderas="sect4" id="forward-override">
5119 <title>forward-override</title>
5125 <term>Typical use:</term>
5127 <para>Change the forwarding settings based on User-Agent or request origin</para>
5132 <term>Effect:</term>
5135 Overrules the forward directives in the configuration file.
5142 <!-- Boolean, Parameterized, Multi-value -->
5144 <para>Multi-value.</para>
5149 <term>Parameter:</term>
5153 <para><quote>forward .</quote> to use a direct connection without any additional proxies.</para>
5157 <quote>forward 127.0.0.1:8123</quote> to use the HTTP proxy listening at 127.0.0.1 port 8123.
5162 <quote>forward-socks4a 127.0.0.1:9050 .</quote> to use the socks4a proxy listening at
5163 127.0.0.1 port 9050. Replace <quote>forward-socks4a</quote> with <quote>forward-socks4</quote>
5164 to use a socks4 connection (with local DNS resolution) instead, use <quote>forward-socks5</quote>
5165 for socks5 connections (with remote DNS resolution).
5170 <quote>forward-socks4a 127.0.0.1:9050 proxy.example.org:8000</quote> to use the socks4a proxy
5171 listening at 127.0.0.1 port 9050 to reach the HTTP proxy listening at proxy.example.org port 8000.
5172 Replace <quote>forward-socks4a</quote> with <quote>forward-socks4</quote> to use a socks4 connection
5173 (with local DNS resolution) instead, use <quote>forward-socks5</quote>
5174 for socks5 connections (with remote DNS resolution).
5185 This action takes parameters similar to the
5186 <link linkend="forwarding">forward</link> directives in the configuration
5187 file, but without the URL pattern. It can be used as replacement, but normally it's only
5188 used in cases where matching based on the request URL isn't sufficient.
5192 Please read the description for the <link linkend="forwarding">forward</link> directives before
5193 using this action. Forwarding to the wrong people will reduce your privacy and increase the
5194 chances of man-in-the-middle attacks.
5197 If the ports are missing or invalid, default values will be used. This might change
5198 in the future and you shouldn't rely on it. Otherwise incorrect syntax causes Privoxy
5202 Use the <ulink url="http://config.privoxy.org/show-url-info">show-url-info CGI page</ulink>
5203 to verify that your forward settings do what you thought the do.
5210 <term>Example usage:</term>
5214 # Always use direct connections for requests previously tagged as
5215 # <quote>User-Agent: fetch libfetch/2.0</quote> and make sure
5216 # resuming downloads continues to work.
5217 # This way you can continue to use Tor for your normal browsing,
5218 # without overloading the Tor network with your FreeBSD ports updates
5219 # or downloads of bigger files like ISOs.
5220 # Note that HTTP headers are easy to fake and therefore their
5221 # values are as (un)trustworthy as your clients and users.
5222 {+forward-override{forward .} \
5223 -hide-if-modified-since \
5224 -overwrite-last-modified \
5226 TAG:^User-Agent: fetch libfetch/2\.0$
5235 <!-- ~~~~~ New section ~~~~~ -->
5236 <sect3 renderas="sect4" id="handle-as-empty-document">
5237 <title>handle-as-empty-document</title>
5243 <term>Typical use:</term>
5245 <para>Mark URLs that should be replaced by empty documents <emphasis>if they get blocked</emphasis></para>
5250 <term>Effect:</term>
5253 This action alone doesn't do anything noticeable. It just marks URLs.
5254 If the <literal><link linkend="block">block</link></literal> action <emphasis>also applies</emphasis>,
5255 the presence or absence of this mark decides whether an HTML <quote>BLOCKED</quote>
5256 page, or an empty document will be sent to the client as a substitute for the blocked content.
5257 The <emphasis>empty</emphasis> document isn't literally empty, but actually contains a single space.
5264 <!-- Boolean, Parameterized, Multi-value -->
5266 <para>Boolean.</para>
5271 <term>Parameter:</term>
5283 Some browsers complain about syntax errors if JavaScript documents
5284 are blocked with <application>Privoxy's</application>
5285 default HTML page; this option can be used to silence them.
5286 And of course this action can also be used to eliminate the &my-app;
5287 BLOCKED message in frames.
5290 The content type for the empty document can be specified with
5291 <literal><link linkend="content-type-overwrite">content-type-overwrite{}</link></literal>,
5292 but usually this isn't necessary.
5298 <term>Example usage:</term>
5301 <screen># Block all documents on example.org that end with ".js",
5302 # but send an empty document instead of the usual HTML message.
5303 {+block{Blocked JavaScript} +handle-as-empty-document}
5313 <!-- ~~~~~ New section ~~~~~ -->
5314 <sect3 renderas="sect4" id="handle-as-image">
5315 <title>handle-as-image</title>
5319 <term>Typical use:</term>
5321 <para>Mark URLs as belonging to images (so they'll be replaced by images <emphasis>if they do get blocked</emphasis>, rather than HTML pages)</para>
5326 <term>Effect:</term>
5329 This action alone doesn't do anything noticeable. It just marks URLs as images.
5330 If the <literal><link linkend="block">block</link></literal> action <emphasis>also applies</emphasis>,
5331 the presence or absence of this mark decides whether an HTML <quote>blocked</quote>
5332 page, or a replacement image (as determined by the <literal><link
5333 linkend="set-image-blocker">set-image-blocker</link></literal> action) will be sent to the
5334 client as a substitute for the blocked content.
5341 <!-- Boolean, Parameterized, Multi-value -->
5343 <para>Boolean.</para>
5348 <term>Parameter:</term>
5360 The below generic example section is actually part of <filename>default.action</filename>.
5361 It marks all URLs with well-known image file name extensions as images and should
5365 Users will probably only want to use the handle-as-image action in conjunction with
5366 <literal><link linkend="block">block</link></literal>, to block sources of banners, whose URLs don't
5367 reflect the file type, like in the second example section.
5370 Note that you cannot treat HTML pages as images in most cases. For instance, (in-line) ad
5371 frames require an HTML page to be sent, or they won't display properly.
5372 Forcing <literal>handle-as-image</literal> in this situation will not replace the
5373 ad frame with an image, but lead to error messages.
5379 <term>Example usage (sections):</term>
5382 <screen># Generic image extensions:
5385 /.*\.(gif|jpg|jpeg|png|bmp|ico)$
5387 # These don't look like images, but they're banners and should be
5388 # blocked as images:
5390 {+block{Nasty banners.} +handle-as-image}
5391 nasty-banner-server.example.com/junk.cgi\?output=trash
5400 <!-- ~~~~~ New section ~~~~~ -->
5401 <sect3 renderas="sect4" id="hide-accept-language">
5402 <title>hide-accept-language</title>
5408 <term>Typical use:</term>
5410 <para>Pretend to use different language settings.</para>
5415 <term>Effect:</term>
5418 Deletes or replaces the <quote>Accept-Language:</quote> HTTP header in client requests.
5425 <!-- Boolean, Parameterized, Multi-value -->
5427 <para>Parameterized.</para>
5432 <term>Parameter:</term>
5435 Keyword: <quote>block</quote>, or any user defined value.
5444 Faking the browser's language settings can be useful to make a
5445 foreign User-Agent set with
5446 <literal><link linkend="hide-user-agent">hide-user-agent</link></literal>
5450 However some sites with content in different languages check the
5451 <quote>Accept-Language:</quote> to decide which one to take by default.
5452 Sometimes it isn't possible to later switch to another language without
5453 changing the <quote>Accept-Language:</quote> header first.
5456 Therefore it's a good idea to either only change the
5457 <quote>Accept-Language:</quote> header to languages you understand,
5458 or to languages that aren't wide spread.
5461 Before setting the <quote>Accept-Language:</quote> header
5462 to a rare language, you should consider that it helps to
5463 make your requests unique and thus easier to trace.
5464 If you don't plan to change this header frequently,
5465 you should stick to a common language.
5471 <term>Example usage (section):</term>
5474 <screen># Pretend to use Canadian language settings.
5475 {+hide-accept-language{en-ca} \
5476 +hide-user-agent{Mozilla/5.0 (X11; U; OpenBSD i386; en-CA; rv:1.8.0.4) Gecko/20060628 Firefox/1.5.0.4} \
5486 <!-- ~~~~~ New section ~~~~~ -->
5487 <sect3 renderas="sect4" id="hide-content-disposition">
5488 <title>hide-content-disposition</title>
5494 <term>Typical use:</term>
5496 <para>Prevent download menus for content you prefer to view inside the browser.</para>
5501 <term>Effect:</term>
5504 Deletes or replaces the <quote>Content-Disposition:</quote> HTTP header set by some servers.
5511 <!-- Boolean, Parameterized, Multi-value -->
5513 <para>Parameterized.</para>
5518 <term>Parameter:</term>
5521 Keyword: <quote>block</quote>, or any user defined value.
5530 Some servers set the <quote>Content-Disposition:</quote> HTTP header for
5531 documents they assume you want to save locally before viewing them.
5532 The <quote>Content-Disposition:</quote> header contains the file name
5533 the browser is supposed to use by default.
5536 In most browsers that understand this header, it makes it impossible to
5537 <emphasis>just view</emphasis> the document, without downloading it first,
5538 even if it's just a simple text file or an image.
5541 Removing the <quote>Content-Disposition:</quote> header helps
5542 to prevent this annoyance, but some browsers additionally check the
5543 <quote>Content-Type:</quote> header, before they decide if they can
5544 display a document without saving it first. In these cases, you have
5545 to change this header as well, before the browser stops displaying
5549 It is also possible to change the server's file name suggestion
5550 to another one, but in most cases it isn't worth the time to set
5554 This action will probably be removed in the future,
5555 use server-header filters instead.
5561 <term>Example usage:</term>
5564 <screen># Disarm the download link in Sourceforge's patch tracker
5566 +content-type-overwrite{text/plain}\
5567 +hide-content-disposition{block} }
5568 .sourceforge.net/tracker/download\.php</screen>
5576 <!-- ~~~~~ New section ~~~~~ -->
5577 <sect3 renderas="sect4" id="hide-if-modified-since">
5578 <title>hide-if-modified-since</title>
5584 <term>Typical use:</term>
5586 <para>Prevent yet another way to track the user's steps between sessions.</para>
5591 <term>Effect:</term>
5594 Deletes the <quote>If-Modified-Since:</quote> HTTP client header or modifies its value.
5601 <!-- Boolean, Parameterized, Multi-value -->
5603 <para>Parameterized.</para>
5608 <term>Parameter:</term>
5611 Keyword: <quote>block</quote>, or a user defined value that specifies a range of hours.
5620 Removing this header is useful for filter testing, where you want to force a real
5621 reload instead of getting status code <quote>304</quote>, which would cause the
5622 browser to use a cached copy of the page.
5625 Instead of removing the header, <literal>hide-if-modified-since</literal> can
5626 also add or subtract a random amount of time to/from the header's value.
5627 You specify a range of minutes where the random factor should be chosen from and
5628 <application>Privoxy</application> does the rest. A negative value means
5629 subtracting, a positive value adding.
5632 Randomizing the value of the <quote>If-Modified-Since:</quote> makes
5633 it less likely that the server can use the time as a cookie replacement,
5634 but you will run into caching problems if the random range is too high.
5637 It is a good idea to only use a small negative value and let
5638 <literal><link linkend="overwrite-last-modified">overwrite-last-modified</link></literal>
5639 handle the greater changes.
5642 It is also recommended to use this action together with
5643 <literal><link linkend="crunch-if-none-match">crunch-if-none-match</link></literal>,
5644 otherwise it's more or less pointless.
5650 <term>Example usage (section):</term>
5653 <screen># Let the browser revalidate but make tracking based on the time less likely.
5654 {+hide-if-modified-since{-60} \
5655 +overwrite-last-modified{randomize} \
5656 +crunch-if-none-match}
5665 <!-- ~~~~~ New section ~~~~~ -->
5666 <sect3 renderas="sect4" id="hide-from-header">
5667 <title>hide-from-header</title>
5671 <term>Typical use:</term>
5673 <para>Keep your (old and ill) browser from telling web servers your email address</para>
5678 <term>Effect:</term>
5681 Deletes any existing <quote>From:</quote> HTTP header, or replaces it with the
5689 <!-- Boolean, Parameterized, Multi-value -->
5691 <para>Parameterized.</para>
5696 <term>Parameter:</term>
5699 Keyword: <quote>block</quote>, or any user defined value.
5708 The keyword <quote>block</quote> will completely remove the header
5709 (not to be confused with the <literal><link linkend="block">block</link></literal>
5713 Alternately, you can specify any value you prefer to be sent to the web
5714 server. If you do, it is a matter of fairness not to use any address that
5715 is actually used by a real person.
5718 This action is rarely needed, as modern web browsers don't send
5719 <quote>From:</quote> headers anymore.
5725 <term>Example usage:</term>
5728 <screen>+hide-from-header{block}</screen> or
5729 <screen>+hide-from-header{spam-me-senseless@sittingduck.example.com}</screen>
5737 <!-- ~~~~~ New section ~~~~~ -->
5738 <sect3 renderas="sect4" id="hide-referrer">
5739 <title>hide-referrer</title>
5740 <anchor id="hide-referer">
5743 <term>Typical use:</term>
5745 <para>Conceal which link you followed to get to a particular site</para>
5750 <term>Effect:</term>
5753 Deletes the <quote>Referer:</quote> (sic) HTTP header from the client request,
5754 or replaces it with a forged one.
5761 <!-- Boolean, Parameterized, Multi-value -->
5763 <para>Parameterized.</para>
5768 <term>Parameter:</term>
5772 <para><quote>conditional-block</quote> to delete the header completely if the host has changed.</para>
5775 <para><quote>conditional-forge</quote> to forge the header if the host has changed.</para>
5778 <para><quote>block</quote> to delete the header unconditionally.</para>
5781 <para><quote>forge</quote> to pretend to be coming from the homepage of the server we are talking to.</para>
5784 <para>Any other string to set a user defined referrer.</para>
5794 <literal>conditional-block</literal> is the only parameter,
5795 that isn't easily detected in the server's log file. If it blocks the
5796 referrer, the request will look like the visitor used a bookmark or
5797 typed in the address directly.
5800 Leaving the referrer unmodified for requests on the same host
5801 allows the server owner to see the visitor's <quote>click path</quote>,
5802 but in most cases she could also get that information by comparing
5803 other parts of the log file: for example the User-Agent if it isn't
5804 a very common one, or the user's IP address if it doesn't change between
5808 Always blocking the referrer, or using a custom one, can lead to
5809 failures on servers that check the referrer before they answer any
5810 requests, in an attempt to prevent their content from being
5811 embedded or linked to elsewhere.
5814 Both <literal>conditional-block</literal> and <literal>forge</literal>
5815 will work with referrer checks, as long as content and valid referring page
5816 are on the same host. Most of the time that's the case.
5819 <literal>hide-referer</literal> is an alternate spelling of
5820 <literal>hide-referrer</literal> and the two can be can be freely
5821 substituted with each other. (<quote>referrer</quote> is the
5822 correct English spelling, however the HTTP specification has a bug - it
5823 requires it to be spelled as <quote>referer</quote>.)
5829 <term>Example usage:</term>
5832 <screen>+hide-referrer{forge}</screen> or
5833 <screen>+hide-referrer{http://www.yahoo.com/}</screen>
5841 <!-- ~~~~~ New section ~~~~~ -->
5842 <sect3 renderas="sect4" id="hide-user-agent">
5843 <title>hide-user-agent</title>
5847 <term>Typical use:</term>
5849 <para>Try to conceal your type of browser and client operating system</para>
5854 <term>Effect:</term>
5857 Replaces the value of the <quote>User-Agent:</quote> HTTP header
5858 in client requests with the specified value.
5865 <!-- Boolean, Parameterized, Multi-value -->
5867 <para>Parameterized.</para>
5872 <term>Parameter:</term>
5875 Any user-defined string.
5885 This can lead to problems on web sites that depend on looking at this header in
5886 order to customize their content for different browsers (which, by the
5887 way, is <emphasis>NOT</emphasis> the right thing to do: good web sites
5888 work browser-independently).
5892 Using this action in multi-user setups or wherever different types of
5893 browsers will access the same <application>Privoxy</application> is
5894 <emphasis>not recommended</emphasis>. In single-user, single-browser
5895 setups, you might use it to delete your OS version information from
5896 the headers, because it is an invitation to exploit known bugs for your
5897 OS. It is also occasionally useful to forge this in order to access
5898 sites that won't let you in otherwise (though there may be a good
5899 reason in some cases).
5902 More information on known user-agent strings can be found at
5903 <ulink url="http://www.user-agents.org/">http://www.user-agents.org/</ulink>
5905 <ulink url="http://en.wikipedia.org/wiki/User_agent">http://en.wikipedia.org/wiki/User_agent</ulink>.
5911 <term>Example usage:</term>
5914 <screen>+hide-user-agent{Netscape 6.1 (X11; I; Linux 2.4.18 i686)}</screen>
5922 <!-- ~~~~~ New section ~~~~~ -->
5923 <sect3 renderas="sect4" id="limit-connect">
5924 <title>limit-connect</title>
5928 <term>Typical use:</term>
5930 <para>Prevent abuse of <application>Privoxy</application> as a TCP proxy relay or disable SSL for untrusted sites</para>
5935 <term>Effect:</term>
5938 Specifies to which ports HTTP CONNECT requests are allowable.
5945 <!-- Boolean, Parameterized, Multi-value -->
5947 <para>Parameterized.</para>
5952 <term>Parameter:</term>
5955 A comma-separated list of ports or port ranges (the latter using dashes, with the minimum
5956 defaulting to 0 and the maximum to 65K).
5965 By default, i.e. if no <literal>limit-connect</literal> action applies,
5966 <application>Privoxy</application> allows HTTP CONNECT requests to all
5967 ports. Use <literal>limit-connect</literal> if fine-grained control
5968 is desired for some or all destinations.
5971 The CONNECT methods exists in HTTP to allow access to secure websites
5972 (<quote>https://</quote> URLs) through proxies. It works very simply:
5973 the proxy connects to the server on the specified port, and then
5974 short-circuits its connections to the client and to the remote server.
5975 This means CONNECT-enabled proxies can be used as TCP relays very easily.
5978 <application>Privoxy</application> relays HTTPS traffic without seeing
5979 the decoded content. Websites can leverage this limitation to circumvent &my-app;'s
5980 filters. By specifying an invalid port range you can disable HTTPS entirely.
5986 <term>Example usages:</term>
5988 <!-- I had trouble getting the spacing to look right in my browser -->
5989 <!-- I probably have the wrong font setup, bollocks. -->
5990 <!-- Apparently the emphasis tag uses a proportional font no matter what -->
5992 <screen>+limit-connect{443} # Port 443 is OK.
5993 +limit-connect{80,443} # Ports 80 and 443 are OK.
5994 +limit-connect{-3, 7, 20-100, 500-} # Ports less than 3, 7, 20 to 100 and above 500 are OK.
5995 +limit-connect{-} # All ports are OK
5996 +limit-connect{,} # No HTTPS/SSL traffic is allowed</screen>
6004 <!-- ~~~~~ New section ~~~~~ -->
6005 <sect3 renderas="sect4" id="limit-cookie-lifetime">
6006 <title>limit-cookie-lifetime</title>
6010 <term>Typical use:</term>
6012 <para>Limit the lifetime of HTTP cookies to a couple of minutes or hours.</para>
6017 <term>Effect:</term>
6020 Overwrites the expires field in Set-Cookie server headers if it's above the specified limit.
6027 <!-- Boolean, Parameterized, Multi-value -->
6029 <para>Parameterized.</para>
6034 <term>Parameter:</term>
6037 The lifetime limit in minutes, or 0.
6046 This action reduces the lifetime of HTTP cookies coming from the
6047 server to the specified number of minutes, starting from the time
6048 the cookie passes Privoxy.
6051 Cookies with a lifetime below the limit are not modified.
6052 The lifetime of session cookies is set to the specified limit.
6055 The effect of this action depends on the server.
6058 In case of servers which refresh their cookies with each response
6059 (or at least frequently), the lifetime limit set by this action
6061 Thus, a session associated with the cookie continues to work with
6062 this action enabled, as long as a new request is made before the
6063 last limit set is reached.
6066 However, some servers send their cookies once, with a lifetime of several
6067 years (the year 2037 is a popular choice), and do not refresh them
6068 until a certain event in the future, for example the user logging out.
6069 In this case this action may limit the absolute lifetime of the session,
6070 even if requests are made frequently.
6073 If the parameter is <quote>0</quote>, this action behaves like
6074 <literal><link linkend="session-cookies-only">session-cookies-only</link></literal>.
6080 <term>Example usages:</term>
6083 <screen>+limit-cookie-lifetime{60}
6091 <!-- ~~~~~ New section ~~~~~ -->
6092 <sect3 renderas="sect4" id="prevent-compression">
6093 <title>prevent-compression</title>
6097 <term>Typical use:</term>
6100 Ensure that servers send the content uncompressed, so it can be
6101 passed through <literal><link linkend="filter">filter</link></literal>s.
6107 <term>Effect:</term>
6110 Removes the Accept-Encoding header which can be used to ask for compressed transfer.
6117 <!-- Boolean, Parameterized, Multi-value -->
6119 <para>Boolean.</para>
6124 <term>Parameter:</term>
6136 More and more websites send their content compressed by default, which
6137 is generally a good idea and saves bandwidth. But the <literal><link
6138 linkend="filter">filter</link></literal> and
6139 <literal><link linkend="deanimate-gifs">deanimate-gifs</link></literal>
6140 actions need access to the uncompressed data.
6143 When compiled with zlib support (available since &my-app; 3.0.7), content that should be
6144 filtered is decompressed on-the-fly and you don't have to worry about this action.
6145 If you are using an older &my-app; version, or one that hasn't been compiled with zlib
6146 support, this action can be used to convince the server to send the content uncompressed.
6149 Most text-based instances compress very well, the size is seldom decreased by less than 50%,
6150 for markup-heavy instances like news feeds saving more than 90% of the original size isn't
6154 Not using compression will therefore slow down the transfer, and you should only
6155 enable this action if you really need it. As of &my-app; 3.0.7 it's disabled in all
6156 predefined action settings.
6159 Note that some (rare) ill-configured sites don't handle requests for uncompressed
6160 documents correctly. Broken PHP applications tend to send an empty document body,
6161 some IIS versions only send the beginning of the content. If you enable
6162 <literal>prevent-compression</literal> per default, you might want to add
6163 exceptions for those sites. See the example for how to do that.
6169 <term>Example usage (sections):</term>
6173 # Selectively turn off compression, and enable a filter
6175 { +filter{tiny-textforms} +prevent-compression }
6176 # Match only these sites
6181 # Or instead, we could set a universal default:
6183 { +prevent-compression }
6186 # Then maybe make exceptions for broken sites:
6188 { -prevent-compression }
6189 .compusa.com/</screen>
6198 <!-- ~~~~~ New section ~~~~~ -->
6199 <sect3 renderas="sect4" id="overwrite-last-modified">
6200 <title>overwrite-last-modified</title>
6206 <term>Typical use:</term>
6208 <para>Prevent yet another way to track the user's steps between sessions.</para>
6213 <term>Effect:</term>
6216 Deletes the <quote>Last-Modified:</quote> HTTP server header or modifies its value.
6223 <!-- Boolean, Parameterized, Multi-value -->
6225 <para>Parameterized.</para>
6230 <term>Parameter:</term>
6233 One of the keywords: <quote>block</quote>, <quote>reset-to-request-time</quote>
6234 and <quote>randomize</quote>
6243 Removing the <quote>Last-Modified:</quote> header is useful for filter
6244 testing, where you want to force a real reload instead of getting status
6245 code <quote>304</quote>, which would cause the browser to reuse the old
6246 version of the page.
6249 The <quote>randomize</quote> option overwrites the value of the
6250 <quote>Last-Modified:</quote> header with a randomly chosen time
6251 between the original value and the current time. In theory the server
6252 could send each document with a different <quote>Last-Modified:</quote>
6253 header to track visits without using cookies. <quote>Randomize</quote>
6254 makes it impossible and the browser can still revalidate cached documents.
6257 <quote>reset-to-request-time</quote> overwrites the value of the
6258 <quote>Last-Modified:</quote> header with the current time. You could use
6259 this option together with
6260 <literal><link linkend="hide-if-modified-since">hide-if-modified-since</link></literal>
6261 to further customize your random range.
6264 The preferred parameter here is <quote>randomize</quote>. It is safe
6265 to use, as long as the time settings are more or less correct.
6266 If the server sets the <quote>Last-Modified:</quote> header to the time
6267 of the request, the random range becomes zero and the value stays the same.
6268 Therefore you should later randomize it a second time with
6269 <literal><link linkend="hide-if-modified-since">hided-if-modified-since</link></literal>,
6273 It is also recommended to use this action together with
6274 <literal><link linkend="crunch-if-none-match">crunch-if-none-match</link></literal>.
6280 <term>Example usage:</term>
6283 <screen># Let the browser revalidate without being tracked across sessions
6284 { +hide-if-modified-since{-60} \
6285 +overwrite-last-modified{randomize} \
6286 +crunch-if-none-match}
6295 <!-- ~~~~~ New section ~~~~~ -->
6296 <sect3 renderas="sect4" id="redirect">
6297 <title>redirect</title>
6303 <term>Typical use:</term>
6306 Redirect requests to other sites.
6312 <term>Effect:</term>
6315 Convinces the browser that the requested document has been moved
6316 to another location and the browser should get it from there.
6323 <!-- Boolean, Parameterized, Multi-value -->
6325 <para>Parameterized</para>
6330 <term>Parameter:</term>
6333 An absolute URL or a single pcrs command.
6342 Requests to which this action applies are answered with a
6343 HTTP redirect to URLs of your choosing. The new URL is
6344 either provided as parameter, or derived by applying a
6345 single pcrs command to the original URL.
6348 The syntax for pcrs commands is documented in the
6349 <link linkend="filter-file">filter file</link> section.
6352 This action will be ignored if you use it together with
6353 <literal><link linkend="block">block</link></literal>.
6354 It can be combined with
6355 <literal><link linkend="fast-redirects">fast-redirects{check-decoded-url}</link></literal>
6356 to redirect to a decoded version of a rewritten URL.
6359 Use this action carefully, make sure not to create redirection loops
6360 and be aware that using your own redirects might make it
6361 possible to fingerprint your requests.
6364 In case of problems with your redirects, or simply to watch
6365 them working, enable <link linkend="DEBUG">debug 128</link>.
6371 <term>Example usages:</term>
6374 <screen># Replace example.com's style sheet with another one
6375 { +redirect{http://localhost/css-replacements/example.com.css} }
6376 example.com/stylesheet\.css
6378 # Create a short, easy to remember nickname for a favorite site
6379 # (relies on the browser accept and forward invalid URLs to &my-app;)
6380 { +redirect{http://www.privoxy.org/user-manual/actions-file.html} }
6383 # Always use the expanded view for Undeadly.org articles
6384 # (Note the $ at the end of the URL pattern to make sure
6385 # the request for the rewritten URL isn't redirected as well)
6386 {+redirect{s@$@&mode=expanded@}}
6387 undeadly.org/cgi\?action=article&sid=\d*$
6389 # Redirect Google search requests to MSN
6390 {+redirect{s@^http://[^/]*/search\?q=([^&]*).*@http://search.msn.com/results.aspx?q=$1@}}
6393 # Redirect MSN search requests to Yahoo
6394 {+redirect{s@^http://[^/]*/results\.aspx\?q=([^&]*).*@http://search.yahoo.com/search?p=$1@}}
6395 search.msn.com//results\.aspx\?q=
6397 # Redirect remote requests for this manual
6398 # to the local version delivered by Privoxy
6399 {+redirect{s@^http://www@http://config@}}
6400 www.privoxy.org/user-manual/</screen>
6409 <!-- ~~~~~ New section ~~~~~ -->
6410 <sect3 renderas="sect4" id="server-header-filter">
6411 <title>server-header-filter</title>
6415 <term>Typical use:</term>
6418 Rewrite or remove single server headers.
6424 <term>Effect:</term>
6427 All server headers to which this action applies are filtered on-the-fly
6428 through the specified regular expression based substitutions.
6435 <!-- boolean, parameterized, Multi-value -->
6437 <para>Parameterized.</para>
6442 <term>Parameter:</term>
6445 The name of a server-header filter, as defined in one of the
6446 <link linkend="filter-file">filter files</link>.
6455 Server-header filters are applied to each header on its own, not to
6456 all at once. This makes it easier to diagnose problems, but on the downside
6457 you can't write filters that only change header x if header y's value is z.
6458 You can do that by using tags though.
6461 Server-header filters are executed after the other header actions have finished
6462 and use their output as input.
6465 Please refer to the <link linkend="filter-file">filter file chapter</link>
6466 to learn which server-header filters are available by default, and how to
6473 <term>Example usage (section):</term>
6477 {+server-header-filter{html-to-xml}}
6478 example.org/xml-instance-that-is-delivered-as-html
6480 {+server-header-filter{xml-to-html}}
6481 example.org/instance-that-is-delivered-as-xml-but-is-not
6491 <!-- ~~~~~ New section ~~~~~ -->
6492 <sect3 renderas="sect4" id="server-header-tagger">
6493 <title>server-header-tagger</title>
6497 <term>Typical use:</term>
6500 Enable or disable filters based on the Content-Type header.
6506 <term>Effect:</term>
6509 Server headers to which this action applies are filtered on-the-fly through
6510 the specified regular expression based substitutions, the result is used as
6518 <!-- boolean, parameterized, Multi-value -->
6520 <para>Parameterized.</para>
6525 <term>Parameter:</term>
6528 The name of a server-header tagger, as defined in one of the
6529 <link linkend="filter-file">filter files</link>.
6538 Server-header taggers are applied to each header on its own,
6539 and as the header isn't modified, each tagger <quote>sees</quote>
6543 Server-header taggers are executed before all other header actions
6544 that modify server headers. Their tags can be used to control
6545 all of the other server-header actions, the content filters
6546 and the crunch actions (<link linkend="redirect">redirect</link>
6547 and <link linkend="block">block</link>).
6550 Obviously crunching based on tags created by server-header taggers
6551 doesn't prevent the request from showing up in the server's log file.
6558 <term>Example usage (section):</term>
6562 # Tag every request with the content type declared by the server
6563 {+server-header-tagger{content-type}}
6574 <!-- ~~~~~ New section ~~~~~ -->
6575 <sect3 renderas="sect4" id="session-cookies-only">
6576 <title>session-cookies-only</title>
6580 <term>Typical use:</term>
6583 Allow only temporary <quote>session</quote> cookies (for the current
6584 browser session <emphasis>only</emphasis>).
6590 <term>Effect:</term>
6593 Deletes the <quote>expires</quote> field from <quote>Set-Cookie:</quote>
6594 server headers. Most browsers will not store such cookies permanently and
6595 forget them in between sessions.
6602 <!-- Boolean, Parameterized, Multi-value -->
6604 <para>Boolean.</para>
6609 <term>Parameter:</term>
6621 This is less strict than <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal> /
6622 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal> and allows you to browse
6623 websites that insist or rely on setting cookies, without compromising your privacy too badly.
6626 Most browsers will not permanently store cookies that have been processed by
6627 <literal>session-cookies-only</literal> and will forget about them between sessions.
6628 This makes profiling cookies useless, but won't break sites which require cookies so
6629 that you can log in for transactions. This is generally turned on for all
6630 sites, and is the recommended setting.
6633 It makes <emphasis>no sense at all</emphasis> to use <literal>session-cookies-only</literal>
6634 together with <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal> or
6635 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>. If you do, cookies
6636 will be plainly killed.
6639 Note that it is up to the browser how it handles such cookies without an <quote>expires</quote>
6640 field. If you use an exotic browser, you might want to try it out to be sure.
6643 This setting also has no effect on cookies that may have been stored
6644 previously by the browser before starting <application>Privoxy</application>.
6645 These would have to be removed manually.
6648 <application>Privoxy</application> also uses
6649 the <link linkend="filter-content-cookies">content-cookies filter</link>
6650 to block some types of cookies. Content cookies are not effected by
6651 <literal>session-cookies-only</literal>.
6657 <term>Example usage:</term>
6660 <screen>+session-cookies-only</screen>
6668 <!-- ~~~~~ New section ~~~~~ -->
6669 <sect3 renderas="sect4" id="set-image-blocker">
6670 <title>set-image-blocker</title>
6674 <term>Typical use:</term>
6676 <para>Choose the replacement for blocked images</para>
6681 <term>Effect:</term>
6684 This action alone doesn't do anything noticeable. If <emphasis>both</emphasis>
6685 <literal><link linkend="block">block</link></literal> <emphasis>and</emphasis> <literal><link
6686 linkend="handle-as-image">handle-as-image</link></literal> <emphasis>also</emphasis>
6687 apply, i.e. if the request is to be blocked as an image,
6688 <emphasis>then</emphasis> the parameter of this action decides what will be
6689 sent as a replacement.
6696 <!-- Boolean, Parameterized, Multi-value -->
6698 <para>Parameterized.</para>
6703 <term>Parameter:</term>
6708 <quote>pattern</quote> to send a built-in checkerboard pattern image. The image is visually
6709 decent, scales very well, and makes it obvious where banners were busted.
6714 <quote>blank</quote> to send a built-in transparent image. This makes banners disappear
6715 completely, but makes it hard to detect where <application>Privoxy</application> has blocked
6716 images on a given page and complicates troubleshooting if <application>Privoxy</application>
6717 has blocked innocent images, like navigation icons.
6722 <quote><replaceable class="parameter">target-url</replaceable></quote> to
6723 send a redirect to <replaceable class="parameter">target-url</replaceable>. You can redirect
6724 to any image anywhere, even in your local filesystem via <quote>file:///</quote> URL.
6725 (But note that not all browsers support redirecting to a local file system).
6728 A good application of redirects is to use special <application>Privoxy</application>-built-in
6729 URLs, which send the built-in images, as <replaceable class="parameter">target-url</replaceable>.
6730 This has the same visual effect as specifying <quote>blank</quote> or <quote>pattern</quote> in
6731 the first place, but enables your browser to cache the replacement image, instead of requesting
6732 it over and over again.
6743 The URLs for the built-in images are <quote>http://config.privoxy.org/send-banner?type=<replaceable
6744 class="parameter">type</replaceable></quote>, where <replaceable class="parameter">type</replaceable> is
6745 either <quote>blank</quote> or <quote>pattern</quote>.
6748 There is a third (advanced) type, called <quote>auto</quote>. It is <emphasis>NOT</emphasis> to be
6749 used in <literal>set-image-blocker</literal>, but meant for use from <link linkend="filter-file">filters</link>.
6750 Auto will select the type of image that would have applied to the referring page, had it been an image.
6756 <term>Example usage:</term>
6762 <screen>+set-image-blocker{pattern}</screen>
6765 Redirect to the BSD daemon:
6768 <screen>+set-image-blocker{http://www.freebsd.org/gifs/dae_up3.gif}</screen>
6771 Redirect to the built-in pattern for better caching:
6774 <screen>+set-image-blocker{http://config.privoxy.org/send-banner?type=pattern}</screen>
6782 <!-- ~~~~~ New section ~~~~~ -->
6784 <title>Summary</title>
6786 Note that many of these actions have the potential to cause a page to
6787 misbehave, possibly even not to display at all. There are many ways
6788 a site designer may choose to design his site, and what HTTP header
6789 content, and other criteria, he may depend on. There is no way to have hard
6790 and fast rules for all sites. See the <link
6791 linkend="ACTIONSANAT">Appendix</link> for a brief example on troubleshooting
6797 <!-- ~~~~~ New section ~~~~~ -->
6798 <sect2 id="aliases">
6799 <title>Aliases</title>
6801 Custom <quote>actions</quote>, known to <application>Privoxy</application>
6802 as <quote>aliases</quote>, can be defined by combining other actions.
6803 These can in turn be invoked just like the built-in actions.
6804 Currently, an alias name can contain any character except space, tab,
6806 <quote>{</quote> and <quote>}</quote>, but we <emphasis>strongly
6807 recommend</emphasis> that you only use <quote>a</quote> to <quote>z</quote>,
6808 <quote>0</quote> to <quote>9</quote>, <quote>+</quote>, and <quote>-</quote>.
6809 Alias names are not case sensitive, and are not required to start with a
6810 <quote>+</quote> or <quote>-</quote> sign, since they are merely textually
6814 Aliases can be used throughout the actions file, but they <emphasis>must be
6815 defined in a special section at the top of the file!</emphasis>
6816 And there can only be one such section per actions file. Each actions file may
6817 have its own alias section, and the aliases defined in it are only visible
6821 There are two main reasons to use aliases: One is to save typing for frequently
6822 used combinations of actions, the other one is a gain in flexibility: If you
6823 decide once how you want to handle shops by defining an alias called
6824 <quote>shop</quote>, you can later change your policy on shops in
6825 <emphasis>one</emphasis> place, and your changes will take effect everywhere
6826 in the actions file where the <quote>shop</quote> alias is used. Calling aliases
6827 by their purpose also makes your actions files more readable.
6830 Currently, there is one big drawback to using aliases, though:
6831 <application>Privoxy</application>'s built-in web-based action file
6832 editor honors aliases when reading the actions files, but it expands
6833 them before writing. So the effects of your aliases are of course preserved,
6834 but the aliases themselves are lost when you edit sections that use aliases
6839 Now let's define some aliases...
6844 # Useful custom aliases we can use later.
6846 # Note the (required!) section header line and that this section
6847 # must be at the top of the actions file!
6851 # These aliases just save typing later:
6852 # (Note that some already use other aliases!)
6854 +crunch-all-cookies = +<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> +<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
6855 -crunch-all-cookies = -<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> -<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
6856 +block-as-image = +block{Blocked image.} +handle-as-image
6857 allow-all-cookies = -crunch-all-cookies -<link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> -<link linkend="FILTER-CONTENT-COOKIES">filter{content-cookies}</link>
6859 # These aliases define combinations of actions
6860 # that are useful for certain types of sites:
6862 fragile = -<link linkend="BLOCK">block</link> -<link linkend="FILTER">filter</link> -crunch-all-cookies -<link linkend="FAST-REDIRECTS">fast-redirects</link> -<link linkend="HIDE-REFERER">hide-referrer</link> -<link linkend="PREVENT-COMPRESSION">prevent-compression</link>
6864 shop = -crunch-all-cookies -<link linkend="FILTER-ALL-POPUPS">filter{all-popups}</link>
6866 # Short names for other aliases, for really lazy people ;-)
6868 c0 = +crunch-all-cookies
6869 c1 = -crunch-all-cookies</screen>
6873 ...and put them to use. These sections would appear in the lower part of an
6874 actions file and define exceptions to the default actions (as specified further
6875 up for the <quote>/</quote> pattern):
6880 # These sites are either very complex or very keen on
6881 # user data and require minimal interference to work:
6884 .office.microsoft.com
6885 .windowsupdate.microsoft.com
6886 # Gmail is really mail.google.com, not gmail.com
6890 # Allow cookies (for setting and retrieving your customer data)
6894 .worldpay.com # for quietpc.com
6897 # These shops require pop-ups:
6899 {-filter{all-popups} -filter{unsolicited-popups}}
6901 .overclockers.co.uk</screen>
6905 Aliases like <quote>shop</quote> and <quote>fragile</quote> are typically used for
6906 <quote>problem</quote> sites that require more than one action to be disabled
6907 in order to function properly.
6913 <!-- ~~~~~ New section ~~~~~ -->
6914 <sect2 id="act-examples">
6915 <title>Actions Files Tutorial</title>
6917 The above chapters have shown <link linkend="actions-file">which actions files
6918 there are and how they are organized</link>, how actions are <link
6919 linkend="actions">specified</link> and <link linkend="actions-apply">applied
6920 to URLs</link>, how <link linkend="af-patterns">patterns</link> work, and how to
6921 define and use <link linkend="aliases">aliases</link>. Now, let's look at an
6922 example <filename>match-all.action</filename>, <filename>default.action</filename>
6923 and <filename>user.action</filename> file and see how all these pieces come together:
6927 <title>match-all.action</title>
6929 Remember <emphasis>all actions are disabled when matching starts</emphasis>,
6930 so we have to explicitly enable the ones we want.
6934 While the <filename>match-all.action</filename> file only contains a
6935 single section, it is probably the most important one. It has only one
6936 pattern, <quote><literal>/</literal></quote>, but this pattern
6937 <link linkend="af-patterns">matches all URLs</link>. Therefore, the set of
6938 actions used in this <quote>default</quote> section <emphasis>will
6939 be applied to all requests as a start</emphasis>. It can be partly or
6940 wholly overridden by other actions files like <filename>default.action</filename>
6941 and <filename>user.action</filename>, but it will still be largely responsible
6942 for your overall browsing experience.
6946 Again, at the start of matching, all actions are disabled, so there is
6947 no need to disable any actions here. (Remember: a <quote>+</quote>
6948 preceding the action name enables the action, a <quote>-</quote> disables!).
6949 Also note how this long line has been made more readable by splitting it into
6950 multiple lines with line continuation.
6956 +<link linkend="CHANGE-X-FORWARDED-FOR">change-x-forwarded-for{block}</link> \
6957 +<link linkend="HIDE-FROM-HEADER">hide-from-header{block}</link> \
6958 +<link linkend="SET-IMAGE-BLOCKER">set-image-blocker{pattern}</link> \
6965 The default behavior is now set.
6970 <title>default.action</title>
6973 If you aren't a developer, there's no need for you to edit the
6974 <filename>default.action</filename> file. It is maintained by
6975 the &my-app; developers and if you disagree with some of the
6976 sections, you should overrule them in your <filename>user.action</filename>.
6980 Understanding the <filename>default.action</filename> file can
6981 help you with your <filename>user.action</filename>, though.
6985 The first section in this file is a special section for internal use
6986 that prevents older &my-app; versions from reading the file:
6991 ##########################################################################
6992 # Settings -- Don't change! For internal Privoxy use ONLY.
6993 ##########################################################################
6995 for-privoxy-version=3.0.11</screen>
6999 After that comes the (optional) alias section. We'll use the example
7000 section from the above <link linkend="aliases">chapter on aliases</link>,
7001 that also explains why and how aliases are used:
7006 ##########################################################################
7008 ##########################################################################
7011 # These aliases just save typing later:
7012 # (Note that some already use other aliases!)
7014 +crunch-all-cookies = +<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> +<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
7015 -crunch-all-cookies = -<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> -<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
7016 +block-as-image = +block{Blocked image.} +handle-as-image
7017 mercy-for-cookies = -crunch-all-cookies -<link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> -<link linkend="FILTER-CONTENT-COOKIES">filter{content-cookies}</link>
7019 # These aliases define combinations of actions
7020 # that are useful for certain types of sites:
7022 fragile = -<link linkend="BLOCK">block</link> -<link linkend="FILTER">filter</link> -crunch-all-cookies -<link linkend="FAST-REDIRECTS">fast-redirects</link> -<link linkend="HIDE-REFERER">hide-referrer</link>
7023 shop = -crunch-all-cookies -<link linkend="FILTER-ALL-POPUPS">filter{all-popups}</link></screen>
7027 The first of our specialized sections is concerned with <quote>fragile</quote>
7028 sites, i.e. sites that require minimum interference, because they are either
7029 very complex or very keen on tracking you (and have mechanisms in place that
7030 make them unusable for people who avoid being tracked). We will simply use
7031 our pre-defined <literal>fragile</literal> alias instead of stating the list
7032 of actions explicitly:
7037 ##########################################################################
7038 # Exceptions for sites that'll break under the default action set:
7039 ##########################################################################
7041 # "Fragile" Use a minimum set of actions for these sites (see alias above):
7044 .office.microsoft.com # surprise, surprise!
7045 .windowsupdate.microsoft.com
7046 mail.google.com</screen>
7050 Shopping sites are not as fragile, but they typically
7051 require cookies to log in, and pop-up windows for shopping
7052 carts or item details. Again, we'll use a pre-defined alias:
7061 .worldpay.com # for quietpc.com
7063 .scan.co.uk</screen>
7067 The <literal><link linkend="FAST-REDIRECTS">fast-redirects</link></literal>
7068 action, which may have been enabled in <filename>match-all.action</filename>,
7069 breaks some sites. So disable it for popular sites where we know it misbehaves:
7074 { -<link linkend="FAST-REDIRECTS">fast-redirects</link> }
7078 .altavista.com/.*(like|url|link):http
7079 .altavista.com/trans.*urltext=http
7080 .nytimes.com</screen>
7084 It is important that <application>Privoxy</application> knows which
7085 URLs belong to images, so that <emphasis>if</emphasis> they are to
7086 be blocked, a substitute image can be sent, rather than an HTML page.
7087 Contacting the remote site to find out is not an option, since it
7088 would destroy the loading time advantage of banner blocking, and it
7089 would feed the advertisers information about you. We can mark any
7090 URL as an image with the <literal><link
7091 linkend="handle-as-image">handle-as-image</link></literal> action,
7092 and marking all URLs that end in a known image file extension is a
7098 ##########################################################################
7100 ##########################################################################
7102 # Define which file types will be treated as images, in case they get
7103 # blocked further down this file:
7105 { +<link linkend="HANDLE-AS-IMAGE">handle-as-image</link> }
7106 /.*\.(gif|jpe?g|png|bmp|ico)$</screen>
7110 And then there are known banner sources. They often use scripts to
7111 generate the banners, so it won't be visible from the URL that the
7112 request is for an image. Hence we block them <emphasis>and</emphasis>
7113 mark them as images in one go, with the help of our
7114 <literal>+block-as-image</literal> alias defined above. (We could of
7115 course just as well use <literal>+<link linkend="block">block</link>
7116 +<link linkend="handle-as-image">handle-as-image</link></literal> here.)
7117 Remember that the type of the replacement image is chosen by the
7118 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>
7119 action. Since all URLs have matched the default section with its
7120 <literal>+<link linkend="set-image-blocker">set-image-blocker</link>{pattern}</literal>
7121 action before, it still applies and needn't be repeated:
7126 # Known ad generators:
7131 .ad.*.doubleclick.net
7132 .a.yimg.com/(?:(?!/i/).)*$
7133 .a[0-9].yimg.com/(?:(?!/i/).)*$
7139 One of the most important jobs of <application>Privoxy</application>
7140 is to block banners. Many of these can be <quote>blocked</quote>
7141 by the <literal><link linkend="filter">filter</link>{banners-by-size}</literal>
7142 action, which we enabled above, and which deletes the references to banner
7143 images from the pages while they are loaded, so the browser doesn't request
7144 them anymore, and hence they don't need to be blocked here. But this naturally
7145 doesn't catch all banners, and some people choose not to use filters, so we
7146 need a comprehensive list of patterns for banner URLs here, and apply the
7147 <literal><link linkend="block">block</link></literal> action to them.
7150 First comes many generic patterns, which do most of the work, by
7151 matching typical domain and path name components of banners. Then comes
7152 a list of individual patterns for specific sites, which is omitted here
7153 to keep the example short:
7158 ##########################################################################
7159 # Block these fine banners:
7160 ##########################################################################
7161 { <link linkend="BLOCK">+block{Banner ads.}</link> }
7169 /.*count(er)?\.(pl|cgi|exe|dll|asp|php[34]?)
7170 /(?:.*/)?(publicite|werbung|rekla(ma|me|am)|annonse|maino(kset|nta|s)?)/
7172 # Site-specific patterns (abbreviated):
7174 .hitbox.com</screen>
7178 It's quite remarkable how many advertisers actually call their banner
7179 servers ads.<replaceable>company</replaceable>.com, or call the directory
7180 in which the banners are stored simply <quote>banners</quote>. So the above
7181 generic patterns are surprisingly effective.
7184 But being very generic, they necessarily also catch URLs that we don't want
7185 to block. The pattern <literal>.*ads.</literal> e.g. catches
7186 <quote>nasty-<emphasis>ads</emphasis>.nasty-corp.com</quote> as intended,
7187 but also <quote>downlo<emphasis>ads</emphasis>.sourcefroge.net</quote> or
7188 <quote><emphasis>ads</emphasis>l.some-provider.net.</quote> So here come some
7189 well-known exceptions to the <literal>+<link linkend="BLOCK">block</link></literal>
7193 Note that these are exceptions to exceptions from the default! Consider the URL
7194 <quote>downloads.sourcefroge.net</quote>: Initially, all actions are deactivated,
7195 so it wouldn't get blocked. Then comes the defaults section, which matches the
7196 URL, but just deactivates the <literal><link linkend="BLOCK">block</link></literal>
7197 action once again. Then it matches <literal>.*ads.</literal>, an exception to the
7198 general non-blocking policy, and suddenly
7199 <literal><link linkend="BLOCK">+block</link></literal> applies. And now, it'll match
7200 <literal>.*loads.</literal>, where <literal><link linkend="BLOCK">-block</link></literal>
7201 applies, so (unless it matches <emphasis>again</emphasis> further down) it ends up
7202 with no <literal><link linkend="BLOCK">block</link></literal> action applying.
7207 ##########################################################################
7208 # Save some innocent victims of the above generic block patterns:
7209 ##########################################################################
7213 { -<link linkend="BLOCK">block</link> }
7214 adv[io]*. # (for advogato.org and advice.*)
7215 adsl. # (has nothing to do with ads)
7216 adobe. # (has nothing to do with ads either)
7217 ad[ud]*. # (adult.* and add.*)
7218 .edu # (universities don't host banners (yet!))
7219 .*loads. # (downloads, uploads etc)
7227 www.globalintersec.com/adv # (adv = advanced)
7228 www.ugu.com/sui/ugu/adv</screen>
7232 Filtering source code can have nasty side effects,
7233 so make an exception for our friends at sourceforge.net,
7234 and all paths with <quote>cvs</quote> in them. Note that
7235 <literal>-<link linkend="FILTER">filter</link></literal>
7236 disables <emphasis>all</emphasis> filters in one fell swoop!
7241 # Don't filter code!
7243 { -<link linkend="FILTER">filter</link> }
7248 .sourceforge.net</screen>
7252 The actual <filename>default.action</filename> is of course much more
7253 comprehensive, but we hope this example made clear how it works.
7258 <sect3><title>user.action</title>
7261 So far we are painting with a broad brush by setting general policies,
7262 which would be a reasonable starting point for many people. Now,
7263 you might want to be more specific and have customized rules that
7264 are more suitable to your personal habits and preferences. These would
7265 be for narrowly defined situations like your ISP or your bank, and should
7266 be placed in <filename>user.action</filename>, which is parsed after all other
7267 actions files and hence has the last word, over-riding any previously
7268 defined actions. <filename>user.action</filename> is also a
7269 <emphasis>safe</emphasis> place for your personal settings, since
7270 <filename>default.action</filename> is actively maintained by the
7271 <application>Privoxy</application> developers and you'll probably want
7272 to install updated versions from time to time.
7276 So let's look at a few examples of things that one might typically do in
7277 <filename>user.action</filename>:
7281 <!-- brief sample user.action here -->
7285 # My user.action file. <fred@example.com></screen>
7289 As <link linkend="aliases">aliases</link> are local to the actions
7290 file that they are defined in, you can't use the ones from
7291 <filename>default.action</filename>, unless you repeat them here:
7296 # Aliases are local to the file they are defined in.
7297 # (Re-)define aliases for this file:
7301 # These aliases just save typing later, and the alias names should
7302 # be self explanatory.
7304 +crunch-all-cookies = +crunch-incoming-cookies +crunch-outgoing-cookies
7305 -crunch-all-cookies = -crunch-incoming-cookies -crunch-outgoing-cookies
7306 allow-all-cookies = -crunch-all-cookies -session-cookies-only
7307 allow-popups = -filter{all-popups}
7308 +block-as-image = +block{Blocked as image.} +handle-as-image
7309 -block-as-image = -block
7311 # These aliases define combinations of actions that are useful for
7312 # certain types of sites:
7314 fragile = -block -crunch-all-cookies -filter -fast-redirects -hide-referrer
7315 shop = -crunch-all-cookies allow-popups
7317 # Allow ads for selected useful free sites:
7319 allow-ads = -block -filter{banners-by-size} -filter{banners-by-link}
7321 # Alias for specific file types that are text, but might have conflicting
7322 # MIME types. We want the browser to force these to be text documents.
7323 handle-as-text = -<link linkend="FILTER">filter</link> +-<link linkend="content-type-overwrite">content-type-overwrite{text/plain}</link> +-<link linkend="FORCE-TEXT-MODE">force-text-mode</link> -<link linkend="HIDE-CONTENT-DISPOSITION">hide-content-disposition</link></screen>
7328 Say you have accounts on some sites that you visit regularly, and
7329 you don't want to have to log in manually each time. So you'd like
7330 to allow persistent cookies for these sites. The
7331 <literal>allow-all-cookies</literal> alias defined above does exactly
7332 that, i.e. it disables crunching of cookies in any direction, and the
7333 processing of cookies to make them only temporary.
7338 { allow-all-cookies }
7342 .redhat.com</screen>
7346 Your bank is allergic to some filter, but you don't know which, so you disable them all:
7351 { -<link linkend="FILTER">filter</link> }
7352 .your-home-banking-site.com</screen>
7356 Some file types you may not want to filter for various reasons:
7361 # Technical documentation is likely to contain strings that might
7362 # erroneously get altered by the JavaScript-oriented filters:
7367 # And this stupid host sends streaming video with a wrong MIME type,
7368 # so that Privoxy thinks it is getting HTML and starts filtering:
7370 stupid-server.example.com/</screen>
7374 Example of a simple <link linkend="BLOCK">block</link> action. Say you've
7375 seen an ad on your favourite page on example.com that you want to get rid of.
7376 You have right-clicked the image, selected <quote>copy image location</quote>
7377 and pasted the URL below while removing the leading http://, into a
7378 <literal>{ +block{} }</literal> section. Note that <literal>{ +handle-as-image
7379 }</literal> need not be specified, since all URLs ending in
7380 <literal>.gif</literal> will be tagged as images by the general rules as set
7381 in default.action anyway:
7386 { +<link linkend="BLOCK">block</link>{Nasty ads.} }
7387 www.example.com/nasty-ads/sponsor\.gif
7388 another.example.net/more/junk/here/</screen>
7392 The URLs of dynamically generated banners, especially from large banner
7393 farms, often don't use the well-known image file name extensions, which
7394 makes it impossible for <application>Privoxy</application> to guess
7395 the file type just by looking at the URL.
7396 You can use the <literal>+block-as-image</literal> alias defined above for
7398 Note that objects which match this rule but then turn out NOT to be an
7399 image are typically rendered as a <quote>broken image</quote> icon by the
7400 browser. Use cautiously.
7409 ar.atwola.com/</screen>
7413 Now you noticed that the default configuration breaks Forbes Magazine,
7414 but you were too lazy to find out which action is the culprit, and you
7415 were again too lazy to give <link linkend="contact">feedback</link>, so
7416 you just used the <literal>fragile</literal> alias on the site, and
7417 -- <emphasis>whoa!</emphasis> -- it worked. The <literal>fragile</literal>
7418 aliases disables those actions that are most likely to break a site. Also,
7419 good for testing purposes to see if it is <application>Privoxy</application>
7420 that is causing the problem or not. We later find other regular sites
7421 that misbehave, and add those to our personalized list of troublemakers:
7429 .mybank.com</screen>
7433 You like the <quote>fun</quote> text replacements in <filename>default.filter</filename>,
7434 but it is disabled in the distributed actions file.
7435 So you'd like to turn it on in your private,
7436 update-safe config, once and for all:
7441 { +<link linkend="filter-fun">filter{fun}</link> }
7442 / # For ALL sites!</screen>
7446 Note that the above is not really a good idea: There are exceptions
7447 to the filters in <filename>default.action</filename> for things that
7448 really shouldn't be filtered, like code on CVS->Web interfaces. Since
7449 <filename>user.action</filename> has the last word, these exceptions
7450 won't be valid for the <quote>fun</quote> filtering specified here.
7454 You might also worry about how your favourite free websites are
7455 funded, and find that they rely on displaying banner advertisements
7456 to survive. So you might want to specifically allow banners for those
7457 sites that you feel provide value to you:
7469 Note that <literal>allow-ads</literal> has been aliased to
7470 <literal>-<link linkend="block">block</link></literal>,
7471 <literal>-<link linkend="filter-banners-by-size">filter{banners-by-size}</link></literal>, and
7472 <literal>-<link linkend="filter-banners-by-link">filter{banners-by-link}</link></literal> above.
7476 Invoke another alias here to force an over-ride of the MIME type <literal>
7477 application/x-sh</literal> which typically would open a download type
7478 dialog. In my case, I want to look at the shell script, and then I can save
7479 it should I choose to.
7489 <filename>user.action</filename> is generally the best place to define
7490 exceptions and additions to the default policies of
7491 <filename>default.action</filename>. Some actions are safe to have their
7492 default policies set here though. So let's set a default policy to have a
7493 <quote>blank</quote> image as opposed to the checkerboard pattern for
7494 <emphasis>ALL</emphasis> sites. <quote>/</quote> of course matches all URL
7500 { +<link linkend="set-image-blocker">set-image-blocker{blank}</link> }
7501 / # ALL sites</screen>
7507 <!-- ~ End section ~ -->
7511 <!-- ~ End section ~ -->
7513 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
7515 <sect1 id="filter-file">
7516 <title>Filter Files</title>
7519 On-the-fly text substitutions need
7520 to be defined in a <quote>filter file</quote>. Once defined, they
7521 can then be invoked as an <quote>action</quote>.
7525 &my-app; supports three different filter actions:
7526 <literal><link linkend="filter">filter</link></literal> to
7527 rewrite the content that is send to the client,
7528 <literal><link linkend="client-header-filter">client-header-filter</link></literal>
7529 to rewrite headers that are send by the client, and
7530 <literal><link linkend="server-header-filter">server-header-filter</link></literal>
7531 to rewrite headers that are send by the server.
7535 &my-app; also supports two tagger actions:
7536 <literal><link linkend="client-header-tagger">client-header-tagger</link></literal>
7538 <literal><link linkend="server-header-tagger">server-header-tagger</link></literal>.
7539 Taggers and filters use the same syntax in the filter files, the difference
7540 is that taggers don't modify the text they are filtering, but use a rewritten
7541 version of the filtered text as tag. The tags can then be used to change the
7542 applying actions through sections with <link linkend="tag-pattern">tag-patterns</link>.
7547 Multiple filter files can be defined through the <literal> <link
7548 linkend="filterfile">filterfile</link></literal> config directive. The filters
7549 as supplied by the developers are located in
7550 <filename>default.filter</filename>. It is recommended that any locally
7551 defined or modified filters go in a separately defined file such as
7552 <filename>user.filter</filename>.
7556 Common tasks for content filters are to eliminate common annoyances in
7557 HTML and JavaScript, such as pop-up windows,
7558 exit consoles, crippled windows without navigation tools, the
7559 infamous <BLINK> tag etc, to suppress images with certain
7560 width and height attributes (standard banner sizes or web-bugs),
7561 or just to have fun.
7565 Enabled content filters are applied to any content whose
7566 <quote>Content Type</quote> header is recognised as a sign
7567 of text-based content, with the exception of <literal>text/plain</literal>.
7568 Use the <link linkend="FORCE-TEXT-MODE">force-text-mode</link> action
7569 to also filter other content.
7573 Substitutions are made at the source level, so if you want to <quote>roll
7574 your own</quote> filters, you should first be familiar with HTML syntax,
7575 and, of course, regular expressions.
7579 Just like the <link linkend="actions-file">actions files</link>, the
7580 filter file is organized in sections, which are called <emphasis>filters</emphasis>
7581 here. Each filter consists of a heading line, that starts with one of the
7582 <emphasis>keywords</emphasis> <literal>FILTER:</literal>,
7583 <literal>CLIENT-HEADER-FILTER:</literal> or <literal>SERVER-HEADER-FILTER:</literal>
7584 followed by the filter's <emphasis>name</emphasis>, and a short (one line)
7585 <emphasis>description</emphasis> of what it does. Below that line
7586 come the <emphasis>jobs</emphasis>, i.e. lines that define the actual
7587 text substitutions. By convention, the name of a filter
7588 should describe what the filter <emphasis>eliminates</emphasis>. The
7589 comment is used in the <ulink url="http://config.privoxy.org/">web-based
7590 user interface</ulink>.
7594 Once a filter called <replaceable>name</replaceable> has been defined
7595 in the filter file, it can be invoked by using an action of the form
7596 +<literal><link linkend="filter">filter</link>{<replaceable>name</replaceable>}</literal>
7597 in any <link linkend="actions-file">actions file</link>.
7601 Filter definitions start with a header line that contains the filter
7602 type, the filter name and the filter description.
7603 A content filter header line for a filter called <quote>foo</quote> could look
7608 <screen>FILTER: foo Replace all "foo" with "bar"</screen>
7612 Below that line, and up to the next header line, come the jobs that
7613 define what text replacements the filter executes. They are specified
7614 in a syntax that imitates <ulink url="http://www.perl.org/">Perl</ulink>'s
7615 <literal>s///</literal> operator. If you are familiar with Perl, you
7616 will find this to be quite intuitive, and may want to look at the
7617 PCRS documentation for the subtle differences to Perl behaviour. Most
7618 notably, the non-standard option letter <literal>U</literal> is supported,
7619 which turns the default to ungreedy matching.
7624 <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
7625 Expressions</quote></ulink>, you might want to take a look at
7626 the <link linkend="regex">Appendix on regular expressions</link>, and
7627 see the <ulink url="http://perldoc.perl.org/perlre.html">Perl
7629 <ulink url="http://perldoc.perl.org/perlop.html">the
7630 <literal>s///</literal> operator's syntax</ulink> and <ulink
7631 url="http://perldoc.perl.org/perlre.html">Perl-style regular
7632 expressions</ulink> in general.
7633 The below examples might also help to get you started.
7637 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
7639 <sect2><title>Filter File Tutorial</title>
7641 Now, let's complete our <quote>foo</quote> content filter. We have already defined
7642 the heading, but the jobs are still missing. Since all it does is to replace
7643 <quote>foo</quote> with <quote>bar</quote>, there is only one (trivial) job
7648 <screen>s/foo/bar/</screen>
7652 But wait! Didn't the comment say that <emphasis>all</emphasis> occurrences
7653 of <quote>foo</quote> should be replaced? Our current job will only take
7654 care of the first <quote>foo</quote> on each page. For global substitution,
7655 we'll need to add the <literal>g</literal> option:
7659 <screen>s/foo/bar/g</screen>
7663 Our complete filter now looks like this:
7666 <screen>FILTER: foo Replace all "foo" with "bar"
7667 s/foo/bar/g</screen>
7671 Let's look at some real filters for more interesting examples. Here you see
7672 a filter that protects against some common annoyances that arise from JavaScript
7673 abuse. Let's look at its jobs one after the other:
7679 FILTER: js-annoyances Get rid of particularly annoying JavaScript abuse
7681 # Get rid of JavaScript referrer tracking. Test page: http://www.randomoddness.com/untitled.htm
7683 s|(<script.*)document\.referrer(.*</script>)|$1"Not Your Business!"$2|Usg</screen>
7687 Following the header line and a comment, you see the job. Note that it uses
7688 <literal>|</literal> as the delimiter instead of <literal>/</literal>, because
7689 the pattern contains a forward slash, which would otherwise have to be escaped
7690 by a backslash (<literal>\</literal>).
7694 Now, let's examine the pattern: it starts with the text <literal><script.*</literal>
7695 enclosed in parentheses. Since the dot matches any character, and <literal>*</literal>
7696 means: <quote>Match an arbitrary number of the element left of myself</quote>, this
7697 matches <quote><script</quote>, followed by <emphasis>any</emphasis> text, i.e.
7698 it matches the whole page, from the start of the first <script> tag.
7702 That's more than we want, but the pattern continues: <literal>document\.referrer</literal>
7703 matches only the exact string <quote>document.referrer</quote>. The dot needed to
7704 be <emphasis>escaped</emphasis>, i.e. preceded by a backslash, to take away its
7705 special meaning as a joker, and make it just a regular dot. So far, the meaning is:
7706 Match from the start of the first <script> tag in a the page, up to, and including,
7707 the text <quote>document.referrer</quote>, if <emphasis>both</emphasis> are present
7708 in the page (and appear in that order).
7712 But there's still more pattern to go. The next element, again enclosed in parentheses,
7713 is <literal>.*</script></literal>. You already know what <literal>.*</literal>
7714 means, so the whole pattern translates to: Match from the start of the first <script>
7715 tag in a page to the end of the last <script> tag, provided that the text
7716 <quote>document.referrer</quote> appears somewhere in between.
7720 This is still not the whole story, since we have ignored the options and the parentheses:
7721 The portions of the page matched by sub-patterns that are enclosed in parentheses, will be
7722 remembered and be available through the variables <literal>$1, $2, ...</literal> in
7723 the substitute. The <literal>U</literal> option switches to ungreedy matching, which means
7724 that the first <literal>.*</literal> in the pattern will only <quote>eat up</quote> all
7725 text in between <quote><script</quote> and the <emphasis>first</emphasis> occurrence
7726 of <quote>document.referrer</quote>, and that the second <literal>.*</literal> will
7727 only span the text up to the <emphasis>first</emphasis> <quote></script></quote>
7728 tag. Furthermore, the <literal>s</literal> option says that the match may span
7729 multiple lines in the page, and the <literal>g</literal> option again means that the
7730 substitution is global.
7734 So, to summarize, the pattern means: Match all scripts that contain the text
7735 <quote>document.referrer</quote>. Remember the parts of the script from
7736 (and including) the start tag up to (and excluding) the string
7737 <quote>document.referrer</quote> as <literal>$1</literal>, and the part following
7738 that string, up to and including the closing tag, as <literal>$2</literal>.
7742 Now the pattern is deciphered, but wasn't this about substituting things? So
7743 lets look at the substitute: <literal>$1"Not Your Business!"$2</literal> is
7744 easy to read: The text remembered as <literal>$1</literal>, followed by
7745 <literal>"Not Your Business!"</literal> (<emphasis>including</emphasis>
7746 the quotation marks!), followed by the text remembered as <literal>$2</literal>.
7747 This produces an exact copy of the original string, with the middle part
7748 (the <quote>document.referrer</quote>) replaced by <literal>"Not Your
7749 Business!"</literal>.
7753 The whole job now reads: Replace <quote>document.referrer</quote> by
7754 <literal>"Not Your Business!"</literal> wherever it appears inside a
7755 <script> tag. Note that this job won't break JavaScript syntax,
7756 since both the original and the replacement are syntactically valid
7757 string objects. The script just won't have access to the referrer
7758 information anymore.
7762 We'll show you two other jobs from the JavaScript taming department, but
7763 this time only point out the constructs of special interest:
7768 # The status bar is for displaying link targets, not pointless blahblah
7770 s/window\.status\s*=\s*(['"]).*?\1/dUmMy=1/ig</screen>
7774 <literal>\s</literal> stands for whitespace characters (space, tab, newline,
7775 carriage return, form feed), so that <literal>\s*</literal> means: <quote>zero
7776 or more whitespace</quote>. The <literal>?</literal> in <literal>.*?</literal>
7777 makes this matching of arbitrary text ungreedy. (Note that the <literal>U</literal>
7778 option is not set). The <literal>['"]</literal> construct means: <quote>a single
7779 <emphasis>or</emphasis> a double quote</quote>. Finally, <literal>\1</literal> is
7780 a back-reference to the first parenthesis just like <literal>$1</literal> above,
7781 with the difference that in the <emphasis>pattern</emphasis>, a backslash indicates
7782 a back-reference, whereas in the <emphasis>substitute</emphasis>, it's the dollar.
7786 So what does this job do? It replaces assignments of single- or double-quoted
7787 strings to the <quote>window.status</quote> object with a dummy assignment
7788 (using a variable name that is hopefully odd enough not to conflict with
7789 real variables in scripts). Thus, it catches many cases where e.g. pointless
7790 descriptions are displayed in the status bar instead of the link target when
7791 you move your mouse over links.
7796 # Kill OnUnload popups. Yummy. Test: http://www.zdnet.com/zdsubs/yahoo/tree/yfs.html
7798 s/(<body [^>]*)onunload(.*>)/$1never$2/iU</screen>
7803 <ulink url="http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html#Events-eventgroupings-htmlevents">OnUnload
7804 event binding</ulink> in the HTML DOM was a <emphasis>CRIME</emphasis>.
7805 When I close a browser window, I want it to close and die. Basta.
7806 This job replaces the <quote>onunload</quote> attribute in
7807 <quote><body></quote> tags with the dummy word <literal>never</literal>.
7808 Note that the <literal>i</literal> option makes the pattern matching
7809 case-insensitive. Also note that ungreedy matching alone doesn't always guarantee
7810 a minimal match: In the first parenthesis, we had to use <literal>[^>]*</literal>
7811 instead of <literal>.*</literal> to prevent the match from exceeding the
7812 <body> tag if it doesn't contain <quote>OnUnload</quote>, but the page's
7817 The last example is from the fun department:
7822 FILTER: fun Fun text replacements
7824 # Spice the daily news:
7826 s/microsoft(?!\.com)/MicroSuck/ig</screen>
7830 Note the <literal>(?!\.com)</literal> part (a so-called negative lookahead)
7831 in the job's pattern, which means: Don't match, if the string
7832 <quote>.com</quote> appears directly following <quote>microsoft</quote>
7833 in the page. This prevents links to microsoft.com from being trashed, while
7834 still replacing the word everywhere else.
7839 # Buzzword Bingo (example for extended regex syntax)
7841 s* industry[ -]leading \
7843 | customer[ -]focused \
7844 | market[ -]driven \
7845 | award[ -]winning # Comments are OK, too! \
7846 | high[ -]performance \
7847 | solutions[ -]based \
7851 *<font color="red"><b>BINGO!</b></font> \
7856 The <literal>x</literal> option in this job turns on extended syntax, and allows for
7857 e.g. the liberal use of (non-interpreted!) whitespace for nicer formatting.
7865 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
7867 <sect2 id="predefined-filters"><title>The Pre-defined Filters</title>
7871 Note each filter is also listed in the +filter action section above. Please
7872 keep these listings in sync.
7877 The distribution <filename>default.filter</filename> file contains a selection of
7878 pre-defined filters for your convenience:
7883 <term><emphasis>js-annoyances</emphasis></term>
7886 The purpose of this filter is to get rid of particularly annoying JavaScript abuse.
7891 replaces JavaScript references to the browser's referrer information
7892 with the string "Not Your Business!". This compliments the <literal><link
7893 linkend="hide-referrer">hide-referrer</link></literal> action on the content level.
7898 removes the bindings to the DOM's
7899 <ulink url="http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html#Events-eventgroupings-htmlevents">unload
7900 event</ulink> which we feel has no right to exist and is responsible for most <quote>exit consoles</quote>, i.e.
7901 nasty windows that pop up when you close another one.
7906 removes code that causes new windows to be opened with undesired properties, such as being
7907 full-screen, non-resizeable, without location, status or menu bar etc.
7913 Use with caution. This is an aggressive filter, and can break sites that
7914 rely heavily on JavaScript.
7920 <term><emphasis>js-events</emphasis></term>
7923 This is a very radical measure. It removes virtually all JavaScript event bindings, which
7924 means that scripts can not react to user actions such as mouse movements or clicks, window
7925 resizing etc, anymore. Use with caution!
7928 We <emphasis>strongly discourage</emphasis> using this filter as a default since it breaks
7929 many legitimate scripts. It is meant for use only on extra-nasty sites (should you really
7936 <term><emphasis>html-annoyances</emphasis></term>
7939 This filter will undo many common instances of HTML based abuse.
7942 The <literal>BLINK</literal> and <literal>MARQUEE</literal> tags
7943 are neutralized (yeah baby!), and browser windows will be created as
7944 resizeable (as of course they should be!), and will have location,
7945 scroll and menu bars -- even if specified otherwise.
7951 <term><emphasis>content-cookies</emphasis></term>
7954 Most cookies are set in the HTTP dialog, where they can be intercepted
7956 <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal>
7957 and <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>
7958 actions. But web sites increasingly make use of HTML meta tags and JavaScript
7959 to sneak cookies to the browser on the content level.
7962 This filter disables most HTML and JavaScript code that reads or sets
7963 cookies. It cannot detect all clever uses of these types of code, so it
7964 should not be relied on as an absolute fix. Use it wherever you would also
7965 use the cookie crunch actions.
7971 <term><emphasis>refresh-tags</emphasis></term>
7974 Disable any refresh tags if the interval is greater than nine seconds (so
7975 that redirections done via refresh tags are not destroyed). This is useful
7976 for dial-on-demand setups, or for those who find this HTML feature
7983 <term><emphasis>unsolicited-popups</emphasis></term>
7986 This filter attempts to prevent only <quote>unsolicited</quote> pop-up
7987 windows from opening, yet still allow pop-up windows that the user
7988 has explicitly chosen to open. It was added in version 3.0.1,
7989 as an improvement over earlier such filters.
7992 Technical note: The filter works by redefining the window.open JavaScript
7993 function to a dummy function, <literal>PrivoxyWindowOpen()</literal>,
7994 during the loading and rendering phase of each HTML page access, and
7995 restoring the function afterward.
7998 This is recommended only for browsers that cannot perform this function
7999 reliably themselves. And be aware that some sites require such windows
8000 in order to function normally. Use with caution.
8006 <term><emphasis>all-popups</emphasis></term>
8009 Attempt to prevent <emphasis>all</emphasis> pop-up windows from opening.
8010 Note this should be used with even more discretion than the above, since
8011 it is more likely to break some sites that require pop-ups for normal
8012 usage. Use with caution.
8018 <term><emphasis>img-reorder</emphasis></term>
8021 This is a helper filter that has no value if used alone. It makes the
8022 <literal>banners-by-size</literal> and <literal>banners-by-link</literal>
8023 (see below) filters more effective and should be enabled together with them.
8029 <term><emphasis>banners-by-size</emphasis></term>
8032 This filter removes image tags purely based on what size they are. Fortunately
8033 for us, many ads and banner images tend to conform to certain standardized
8034 sizes, which makes this filter quite effective for ad stripping purposes.
8037 Occasionally this filter will cause false positives on images that are not ads,
8038 but just happen to be of one of the standard banner sizes.
8041 Recommended only for those who require extreme ad blocking. The default
8042 block rules should catch 95+% of all ads <emphasis>without</emphasis> this filter enabled.
8048 <term><emphasis>banners-by-link</emphasis></term>
8051 This is an experimental filter that attempts to kill any banners if
8052 their URLs seem to point to known or suspected click trackers. It is currently
8053 not of much value and is not recommended for use by default.
8059 <term><emphasis>webbugs</emphasis></term>
8062 Webbugs are small, invisible images (technically 1X1 GIF images), that
8063 are used to track users across websites, and collect information on them.
8064 As an HTML page is loaded by the browser, an embedded image tag causes the
8065 browser to contact a third-party site, disclosing the tracking information
8066 through the requested URL and/or cookies for that third-party domain, without
8067 the user ever becoming aware of the interaction with the third-party site.
8068 HTML-ized spam also uses a similar technique to verify email addresses.
8071 This filter removes the HTML code that loads such <quote>webbugs</quote>.
8077 <term><emphasis>tiny-textforms</emphasis></term>
8080 A rather special-purpose filter that can be used to enlarge textareas (those
8081 multi-line text boxes in web forms) and turn off hard word wrap in them.
8082 It was written for the sourceforge.net tracker system where such boxes are
8083 a nuisance, but it can be handy on other sites, too.
8086 It is not recommended to use this filter as a default.
8092 <term><emphasis>jumping-windows</emphasis></term>
8095 Many consider windows that move, or resize themselves to be abusive. This filter
8096 neutralizes the related JavaScript code. Note that some sites might not display
8097 or behave as intended when using this filter. Use with caution.
8103 <term><emphasis>frameset-borders</emphasis></term>
8106 Some web designers seem to assume that everyone in the world will view their
8107 web sites using the same browser brand and version, screen resolution etc,
8108 because only that assumption could explain why they'd use static frame sizes,
8109 yet prevent their frames from being resized by the user, should they be too
8110 small to show their whole content.
8113 This filter removes the related HTML code. It should only be applied to sites
8120 <term><emphasis>demoronizer</emphasis></term>
8123 Many Microsoft products that generate HTML use non-standard extensions (read:
8124 violations) of the ISO 8859-1 aka Latin-1 character set. This can cause those
8125 HTML documents to display with errors on standard-compliant platforms.
8128 This filter translates the MS-only characters into Latin-1 equivalents.
8129 It is not necessary when using MS products, and will cause corruption of
8130 all documents that use 8-bit character sets other than Latin-1. It's mostly
8131 worthwhile for Europeans on non-MS platforms, if weird garbage characters
8132 sometimes appear on some pages, or user agents that don't correct for this on
8135 My version of Mozilla (ancient) shows litte square boxes for quote
8136 characters, and apostrophes on moronized pages. So many pages have this, I
8137 can read them fine now. HB 08/27/06
8144 <term><emphasis>shockwave-flash</emphasis></term>
8147 A filter for shockwave haters. As the name suggests, this filter strips code
8148 out of web pages that is used to embed shockwave flash objects.
8156 <term><emphasis>quicktime-kioskmode</emphasis></term>
8159 Change HTML code that embeds Quicktime objects so that kioskmode, which
8160 prevents saving, is disabled.
8166 <term><emphasis>fun</emphasis></term>
8169 Text replacements for subversive browsing fun. Make fun of your favorite
8170 Monopolist or play buzzword bingo.
8176 <term><emphasis>crude-parental</emphasis></term>
8179 A demonstration-only filter that shows how <application>Privoxy</application>
8180 can be used to delete web content on a keyword basis.
8186 <term><emphasis>ie-exploits</emphasis></term>
8189 An experimental collection of text replacements to disable malicious HTML and JavaScript
8190 code that exploits known security holes in Internet Explorer.
8193 Presently, it only protects against Nimda and a cross-site scripting bug, and
8194 would need active maintenance to provide more substantial protection.
8200 <term><emphasis>site-specifics</emphasis></term>
8203 Some web sites have very specific problems, the cure for which doesn't apply
8204 anywhere else, or could even cause damage on other sites.
8207 This is a collection of such site-specific cures which should only be applied
8208 to the sites they were intended for, which is what the supplied
8209 <filename>default.action</filename> file does. Users shouldn't need to change
8210 anything regarding this filter.
8216 <term><emphasis>google</emphasis></term>
8219 A CSS based block for Google text ads. Also removes a width limitation
8220 and the toolbar advertisement.
8226 <term><emphasis>yahoo</emphasis></term>
8229 Another CSS based block, this time for Yahoo text ads. And removes
8230 a width limitation as well.
8236 <term><emphasis>msn</emphasis></term>
8239 Another CSS based block, this time for MSN text ads. And removes
8240 tracking URLs, as well as a width limitation.
8246 <term><emphasis>blogspot</emphasis></term>
8249 Cleans up some Blogspot blogs. Read the fine print before using this one!
8252 This filter also intentionally removes some navigation stuff and sets the
8253 page width to 100%. As a result, some rounded <quote>corners</quote> would
8254 appear to early or not at all and as fixing this would require a browser
8255 that understands background-size (CSS3), they are removed instead.
8261 <term><emphasis>xml-to-html</emphasis></term>
8264 Server-header filter to change the Content-Type from xml to html.
8270 <term><emphasis>html-to-xml</emphasis></term>
8273 Server-header filter to change the Content-Type from html to xml.
8279 <term><emphasis>no-ping</emphasis></term>
8282 Removes the non-standard <literal>ping</literal> attribute from
8283 anchor and area HTML tags.
8289 <term><emphasis>hide-tor-exit-notation</emphasis></term>
8292 Client-header filter to remove the <command>Tor</command> exit node notation
8293 found in Host and Referer headers.
8296 If &my-app; and <command>Tor</command> are chained and &my-app;
8297 is configured to use socks4a, one can use <quote>http://www.example.org.foobar.exit/</quote>
8298 to access the host <quote>www.example.org</quote> through the
8299 <command>Tor</command> exit node <quote>foobar</quote>.
8302 As the HTTP client isn't aware of this notation, it treats the
8303 whole string <quote>www.example.org.foobar.exit</quote> as host and uses it
8304 for the <quote>Host</quote> and <quote>Referer</quote> headers. From the
8305 server's point of view the resulting headers are invalid and can cause problems.
8308 An invalid <quote>Referer</quote> header can trigger <quote>hot-linking</quote>
8309 protections, an invalid <quote>Host</quote> header will make it impossible for
8310 the server to find the right vhost (several domains hosted on the same IP address).
8313 This client-header filter removes the <quote>foo.exit</quote> part in those headers
8314 to prevent the mentioned problems. Note that it only modifies
8315 the HTTP headers, it doesn't make it impossible for the server
8316 to detect your <command>Tor</command> exit node based on the IP address
8317 the request is coming from.
8324 <term><emphasis> </emphasis></term>
8338 <!-- ~ End section ~ -->
8342 <!-- ~~~~~ New section ~~~~~ -->
8344 <sect1 id="templates">
8345 <title>Privoxy's Template Files</title>
8347 All <application>Privoxy</application> built-in pages, i.e. error pages such as the
8348 <ulink url="http://show-the-404-error.page"><quote>404 - No Such Domain</quote>
8349 error page</ulink>, the <ulink
8350 url="http://ads.bannerserver.example.com/nasty-ads/sponsor.html"><quote>BLOCKED</quote>
8352 and all pages of its <ulink url="http://config.privoxy.org/">web-based
8353 user interface</ulink>, are generated from <emphasis>templates</emphasis>.
8354 (<application>Privoxy</application> must be running for the above links to work as
8359 These templates are stored in a subdirectory of the <link linkend="confdir">configuration
8360 directory</link> called <filename>templates</filename>. On Unixish platforms,
8362 <ulink url="file:///etc/privoxy/templates/"><filename>/etc/privoxy/templates/</filename></ulink>.
8366 The templates are basically normal HTML files, but with place-holders (called symbols
8367 or exports), which <application>Privoxy</application> fills at run time. It
8368 is possible to edit the templates with a normal text editor, should you want
8369 to customize them. (<emphasis>Not recommended for the casual
8370 user</emphasis>). Should you create your own custom templates, you should use
8371 the <filename>config</filename> setting <link linkend="templdir">templdir</link>
8372 to specify an alternate location, so your templates do not get overwritten
8376 Note that just like in configuration files, lines starting
8377 with <literal>#</literal> are ignored when the templates are filled in.
8381 The place-holders are of the form <literal>@name@</literal>, and you will
8382 find a list of available symbols, which vary from template to template,
8383 in the comments at the start of each file. Note that these comments are not
8384 always accurate, and that it's probably best to look at the existing HTML
8385 code to find out which symbols are supported and what they are filled in with.
8389 A special application of this substitution mechanism is to make whole
8390 blocks of HTML code disappear when a specific symbol is set. We use this
8391 for many purposes, one of them being to include the beta warning in all
8392 our user interface (CGI) pages when <application>Privoxy</application>
8393 is in an alpha or beta development stage:
8398 <!-- @if-unstable-start -->
8400 ... beta warning HTML code goes here ...
8402 <!-- if-unstable-end@ --></screen>
8406 If the "unstable" symbol is set, everything in between and including
8407 <literal>@if-unstable-start</literal> and <literal>if-unstable-end@</literal>
8408 will disappear, leaving nothing but an empty comment:
8412 <screen><!-- --></screen>
8416 There's also an if-then-else construct and an <literal>#include</literal>
8417 mechanism, but you'll sure find out if you are inclined to edit the
8422 All templates refer to a style located at
8423 <ulink url="http://config.privoxy.org/send-stylesheet"><literal>http://config.privoxy.org/send-stylesheet</literal></ulink>.
8424 This is, of course, locally served by <application>Privoxy</application>
8425 and the source for it can be found and edited in the
8426 <filename>cgi-style.css</filename> template.
8431 <!-- ~ End section ~ -->
8435 <!-- ~~~~~ New section ~~~~~ -->
8437 <sect1 id="contact"><title>Contacting the Developers, Bug Reporting and Feature
8440 <!-- Include contacting.sgml boilerplate: -->
8442 <!-- end boilerplate -->
8446 <!-- ~ End section ~ -->
8449 <!-- ~~~~~ New section ~~~~~ -->
8450 <sect1 id="copyright"><title>Privoxy Copyright, License and History</title>
8452 <!-- Include copyright.sgml: -->
8454 <!-- end copyright -->
8456 <!-- ~~~~~ New section ~~~~~ -->
8457 <sect2><title>License</title>
8458 <!-- Include copyright.sgml: -->
8460 <!-- end copyright -->
8462 <!-- ~ End section ~ -->
8465 <!-- ~~~~~ New section ~~~~~ -->
8467 <sect2 id="history"><title>History</title>
8468 <!-- Include history.sgml: -->
8470 <!-- end history -->
8473 <sect2 id="authors"><title>Authors</title>
8474 <!-- Include p-authors.sgml: -->
8476 <!-- end authors -->
8481 <!-- ~ End section ~ -->
8484 <!-- ~~~~~ New section ~~~~~ -->
8485 <sect1 id="seealso"><title>See Also</title>
8486 <!-- Include seealso.sgml: -->
8488 <!-- end seealso -->
8493 <!-- ~~~~~ New section ~~~~~ -->
8494 <sect1 id="appendix"><title>Appendix</title>
8497 <!-- ~~~~~ New section ~~~~~ -->
8499 <title>Regular Expressions</title>
8501 <application>Privoxy</application> uses Perl-style <quote>regular
8502 expressions</quote> in its <link linkend="actions-file">actions
8503 files</link> and <link linkend="filter-file">filter file</link>,
8504 through the <ulink url="http://www.pcre.org/">PCRE</ulink> and
8507 <ulink url="http://www.oesterhelt.org/pcrs/">PCRS</ulink> libraries.
8509 <application>PCRS</application> libraries.
8513 If you are reading this, you probably don't understand what <quote>regular
8514 expressions</quote> are, or what they can do. So this will be a very brief
8515 introduction only. A full explanation would require a <ulink
8516 url="http://www.oreilly.com/catalog/regex/">book</ulink> ;-)
8520 Regular expressions provide a language to describe patterns that can be
8521 run against strings of characters (letter, numbers, etc), to see if they
8522 match the string or not. The patterns are themselves (sometimes complex)
8523 strings of literal characters, combined with wild-cards, and other special
8524 characters, called meta-characters. The <quote>meta-characters</quote> have
8525 special meanings and are used to build complex patterns to be matched against.
8526 Perl Compatible Regular Expressions are an especially convenient
8527 <quote>dialect</quote> of the regular expression language.
8531 To make a simple analogy, we do something similar when we use wild-card
8532 characters when listing files with the <command>dir</command> command in DOS.
8533 <literal>*.*</literal> matches all filenames. The <quote>special</quote>
8534 character here is the asterisk which matches any and all characters. We can be
8535 more specific and use <literal>?</literal> to match just individual
8536 characters. So <quote>dir file?.text</quote> would match
8537 <quote>file1.txt</quote>, <quote>file2.txt</quote>, etc. We are pattern
8538 matching, using a similar technique to <quote>regular expressions</quote>!
8542 Regular expressions do essentially the same thing, but are much, much more
8543 powerful. There are many more <quote>special characters</quote> and ways of
8544 building complex patterns however. Let's look at a few of the common ones,
8545 and then some examples:
8550 <emphasis>.</emphasis> - Matches any single character, e.g. <quote>a</quote>,
8551 <quote>A</quote>, <quote>4</quote>, <quote>:</quote>, or <quote>@</quote>.
8553 </simplelist></para>
8557 <emphasis>?</emphasis> - The preceding character or expression is matched ZERO or ONE
8560 </simplelist></para>
8564 <emphasis>+</emphasis> - The preceding character or expression is matched ONE or MORE
8567 </simplelist></para>
8571 <emphasis>*</emphasis> - The preceding character or expression is matched ZERO or MORE
8574 </simplelist></para>
8578 <emphasis>\</emphasis> - The <quote>escape</quote> character denotes that
8579 the following character should be taken literally. This is used where one of the
8580 special characters (e.g. <quote>.</quote>) needs to be taken literally and
8581 not as a special meta-character. Example: <quote>example\.com</quote>, makes
8582 sure the period is recognized only as a period (and not expanded to its
8583 meta-character meaning of any single character).
8585 </simplelist></para>
8589 <emphasis>[ ]</emphasis> - Characters enclosed in brackets will be matched if
8590 any of the enclosed characters are encountered. For instance, <quote>[0-9]</quote>
8591 matches any numeric digit (zero through nine). As an example, we can combine
8592 this with <quote>+</quote> to match any digit one of more times: <quote>[0-9]+</quote>.
8594 </simplelist></para>
8598 <emphasis>( )</emphasis> - parentheses are used to group a sub-expression,
8599 or multiple sub-expressions.
8601 </simplelist></para>
8605 <emphasis>|</emphasis> - The <quote>bar</quote> character works like an
8606 <quote>or</quote> conditional statement. A match is successful if the
8607 sub-expression on either side of <quote>|</quote> matches. As an example:
8608 <quote>/(this|that) example/</quote> uses grouping and the bar character
8609 and would match either <quote>this example</quote> or <quote>that
8610 example</quote>, and nothing else.
8612 </simplelist></para>
8615 These are just some of the ones you are likely to use when matching URLs with
8616 <application>Privoxy</application>, and is a long way from a definitive
8617 list. This is enough to get us started with a few simple examples which may
8618 be more illuminating:
8622 <emphasis><literal>/.*/banners/.*</literal></emphasis> - A simple example
8623 that uses the common combination of <quote>.</quote> and <quote>*</quote> to
8624 denote any character, zero or more times. In other words, any string at all.
8625 So we start with a literal forward slash, then our regular expression pattern
8626 (<quote>.*</quote>) another literal forward slash, the string
8627 <quote>banners</quote>, another forward slash, and lastly another
8628 <quote>.*</quote>. We are building
8629 a directory path here. This will match any file with the path that has a
8630 directory named <quote>banners</quote> in it. The <quote>.*</quote> matches
8631 any characters, and this could conceivably be more forward slashes, so it
8632 might expand into a much longer looking path. For example, this could match:
8633 <quote>/eye/hate/spammers/banners/annoy_me_please.gif</quote>, or just
8634 <quote>/banners/annoying.html</quote>, or almost an infinite number of other
8635 possible combinations, just so it has <quote>banners</quote> in the path
8640 And now something a little more complex:
8644 <emphasis><literal>/.*/adv((er)?ts?|ertis(ing|ements?))?/</literal></emphasis> -
8645 We have several literal forward slashes again (<quote>/</quote>), so we are
8646 building another expression that is a file path statement. We have another
8647 <quote>.*</quote>, so we are matching against any conceivable sub-path, just so
8648 it matches our expression. The only true literal that <emphasis>must
8649 match</emphasis> our pattern is <application>adv</application>, together with
8650 the forward slashes. What comes after the <quote>adv</quote> string is the
8655 Remember the <quote>?</quote> means the preceding expression (either a
8656 literal character or anything grouped with <quote>(...)</quote> in this case)
8657 can exist or not, since this means either zero or one match. So
8658 <quote>((er)?ts?|ertis(ing|ements?))</quote> is optional, as are the
8659 individual sub-expressions: <quote>(er)</quote>,
8660 <quote>(ing|ements?)</quote>, and the <quote>s</quote>. The <quote>|</quote>
8661 means <quote>or</quote>. We have two of those. For instance,
8662 <quote>(ing|ements?)</quote>, can expand to match either <quote>ing</quote>
8663 <emphasis>OR</emphasis> <quote>ements?</quote>. What is being done here, is an
8664 attempt at matching as many variations of <quote>advertisement</quote>, and
8665 similar, as possible. So this would expand to match just <quote>adv</quote>,
8666 or <quote>advert</quote>, or <quote>adverts</quote>, or
8667 <quote>advertising</quote>, or <quote>advertisement</quote>, or
8668 <quote>advertisements</quote>. You get the idea. But it would not match
8669 <quote>advertizements</quote> (with a <quote>z</quote>). We could fix that by
8670 changing our regular expression to:
8671 <quote>/.*/adv((er)?ts?|erti(s|z)(ing|ements?))?/</quote>, which would then match
8676 <emphasis><literal>/.*/advert[0-9]+\.(gif|jpe?g)</literal></emphasis> - Again
8677 another path statement with forward slashes. Anything in the square brackets
8678 <quote>[ ]</quote> can be matched. This is using <quote>0-9</quote> as a
8679 shorthand expression to mean any digit one through nine. It is the same as
8680 saying <quote>0123456789</quote>. So any digit matches. The <quote>+</quote>
8681 means one or more of the preceding expression must be included. The preceding
8682 expression here is what is in the square brackets -- in this case, any digit
8683 one through nine. Then, at the end, we have a grouping: <quote>(gif|jpe?g)</quote>.
8684 This includes a <quote>|</quote>, so this needs to match the expression on
8685 either side of that bar character also. A simple <quote>gif</quote> on one side, and the other
8686 side will in turn match either <quote>jpeg</quote> or <quote>jpg</quote>,
8687 since the <quote>?</quote> means the letter <quote>e</quote> is optional and
8688 can be matched once or not at all. So we are building an expression here to
8689 match image GIF or JPEG type image file. It must include the literal
8690 string <quote>advert</quote>, then one or more digits, and a <quote>.</quote>
8691 (which is now a literal, and not a special character, since it is escaped
8692 with <quote>\</quote>), and lastly either <quote>gif</quote>, or
8693 <quote>jpeg</quote>, or <quote>jpg</quote>. Some possible matches would
8694 include: <quote>//advert1.jpg</quote>,
8695 <quote>/nasty/ads/advert1234.gif</quote>,
8696 <quote>/banners/from/hell/advert99.jpg</quote>. It would not match
8697 <quote>advert1.gif</quote> (no leading slash), or
8698 <quote>/adverts232.jpg</quote> (the expression does not include an
8699 <quote>s</quote>), or <quote>/advert1.jsp</quote> (<quote>jsp</quote> is not
8700 in the expression anywhere).
8704 We are barely scratching the surface of regular expressions here so that you
8705 can understand the default <application>Privoxy</application>
8706 configuration files, and maybe use this knowledge to customize your own
8707 installation. There is much, much more that can be done with regular
8708 expressions. Now that you know enough to get started, you can learn more on
8713 More reading on Perl Compatible Regular expressions:
8714 <ulink url="http://perldoc.perl.org/perlre.html">http://perldoc.perl.org/perlre.html</ulink>
8718 For information on regular expression based substitutions and their applications
8719 in filters, please see the <link linkend="filter-file">filter file tutorial</link>
8724 <!-- ~ End section ~ -->
8727 <!-- ~~~~~ New section ~~~~~ -->
8729 <title>Privoxy's Internal Pages</title>
8732 Since <application>Privoxy</application> proxies each requested
8733 web page, it is easy for <application>Privoxy</application> to
8734 trap certain special URLs. In this way, we can talk directly to
8735 <application>Privoxy</application>, and see how it is
8736 configured, see how our rules are being applied, change these
8737 rules and other configuration options, and even turn
8738 <application>Privoxy's</application> filtering off, all with
8744 The URLs listed below are the special ones that allow direct access
8745 to <application>Privoxy</application>. Of course,
8746 <application>Privoxy</application> must be running to access these. If
8747 not, you will get a friendly error message. Internet access is not
8760 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
8764 There is a shortcut: <ulink url="http://p.p/">http://p.p/</ulink> (But it
8765 doesn't provide a fall-back to a real page, in case the request is not
8766 sent through <application>Privoxy</application>)
8772 Show information about the current configuration, including viewing and
8773 editing of actions files:
8777 <ulink url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
8784 Show the source code version numbers:
8788 <ulink url="http://config.privoxy.org/show-version">http://config.privoxy.org/show-version</ulink>
8795 Show the browser's request headers:
8799 <ulink url="http://config.privoxy.org/show-request">http://config.privoxy.org/show-request</ulink>
8806 Show which actions apply to a URL and why:
8810 <ulink url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
8817 Toggle Privoxy on or off. This feature can be turned off/on in the main
8818 <filename>config</filename> file. When toggled <quote>off</quote>, <quote>Privoxy</quote>
8819 continues to run, but only as a pass-through proxy, with no actions taking
8824 <ulink url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>
8828 Short cuts. Turn off, then on:
8832 <ulink url="http://config.privoxy.org/toggle?set=disable">http://config.privoxy.org/toggle?set=disable</ulink>
8837 <ulink url="http://config.privoxy.org/toggle?set=enable">http://config.privoxy.org/toggle?set=enable</ulink>
8846 These may be bookmarked for quick reference. See next.
8850 <sect3 id="bookmarklets">
8851 <title>Bookmarklets</title>
8853 Below are some <quote>bookmarklets</quote> to allow you to easily access a
8854 <quote>mini</quote> version of some of <application>Privoxy's</application>
8855 special pages. They are designed for MS Internet Explorer, but should work
8856 equally well in Netscape, Mozilla, and other browsers which support
8857 JavaScript. They are designed to run directly from your bookmarks - not by
8858 clicking the links below (although that should work for testing).
8861 To save them, right-click the link and choose <quote>Add to Favorites</quote>
8862 (IE) or <quote>Add Bookmark</quote> (Netscape). You will get a warning that
8863 the bookmark <quote>may not be safe</quote> - just click OK. Then you can run the
8864 Bookmarklet directly from your favorites/bookmarks. For even faster access,
8865 you can put them on the <quote>Links</quote> bar (IE) or the <quote>Personal
8866 Toolbar</quote> (Netscape), and run them with a single click.
8875 url="javascript:void(window.open('http://config.privoxy.org/toggle?mini=y&set=enabled','ijbstatus','width=250,height=100,resizable=yes,scrollbars=no,toolbar=no,location=no,directories=no,status=no,menubar=no,copyhistory=no').focus());">Privoxy - Enable</ulink>
8882 url="javascript:void(window.open('http://config.privoxy.org/toggle?mini=y&set=disabled','ijbstatus','width=250,height=100,resizable=yes,scrollbars=no,toolbar=no,location=no,directories=no,status=no,menubar=no,copyhistory=no').focus());">Privoxy - Disable</ulink>
8889 url="javascript:void(window.open('http://config.privoxy.org/toggle?mini=y&set=toggle','ijbstatus','width=250,height=100,resizable=yes,scrollbars=no,toolbar=no,location=no,directories=no,status=no,menubar=no,copyhistory=no').focus());">Privoxy - Toggle Privoxy</ulink> (Toggles between enabled and disabled)
8896 url="javascript:void(window.open('http://config.privoxy.org/toggle?mini=y','ijbstatus','width=250,height=2,resizable=yes,scrollbars=no,toolbar=no,location=no,directories=no,status=no,menubar=no,copyhistory=no').focus());">Privoxy- View Status</ulink>
8902 <ulink url="javascript:w=Math.floor(screen.width/2);h=Math.floor(screen.height*0.9);void(window.open('http://www.privoxy.org/actions/index.php?url='+escape(location.href),'Feedback','screenx='+w+',width='+w+',height='+h+',scrollbars=yes,toolbar=no,location=no,directories=no,status=no,menubar=no,copyhistory=no').focus());">Privoxy - Submit Actions File Feedback</ulink>
8908 <ulink url="javascript:void(window.open('http://config.privoxy.org/show-url-info?url='+escape(location.href),'Why').focus());">Privoxy - Why?</ulink>
8915 Credit: The site which gave us the general idea for these bookmarklets is
8916 <ulink url="http://www.bookmarklets.com/">www.bookmarklets.com</ulink>. They
8917 have more information about bookmarklets.
8926 <!-- ~~~~~ New section ~~~~~ -->
8928 <title>Chain of Events</title>
8930 Let's take a quick look at how some of <application>Privoxy's</application>
8931 core features are triggered, and the ensuing sequence of events when a web
8932 page is requested by your browser:
8939 First, your web browser requests a web page. The browser knows to send
8940 the request to <application>Privoxy</application>, which will in turn,
8941 relay the request to the remote web server after passing the following
8947 <application>Privoxy</application> traps any request for its own internal CGI
8948 pages (e.g <ulink url="http://p.p/">http://p.p/</ulink>) and sends the CGI page back to the browser.
8953 Next, <application>Privoxy</application> checks to see if the URL
8955 linkend="BLOCK"><quote>+block</quote></link> patterns. If
8956 so, the URL is then blocked, and the remote web server will not be contacted.
8957 <link linkend="HANDLE-AS-IMAGE"><quote>+handle-as-image</quote></link>
8959 <link linkend="HANDLE-AS-EMPTY-DOCUMENT"><quote>+handle-as-empty-document</quote></link>
8960 are then checked, and if there is no match, an
8961 HTML <quote>BLOCKED</quote> page is sent back to the browser. Otherwise, if
8962 it does match, an image is returned for the former, and an empty text
8963 document for the latter. The type of image would depend on the setting of
8964 <link linkend="SET-IMAGE-BLOCKER"><quote>+set-image-blocker</quote></link>
8965 (blank, checkerboard pattern, or an HTTP redirect to an image elsewhere).
8970 Untrusted URLs are blocked. If URLs are being added to the
8971 <filename>trust</filename> file, then that is done.
8976 If the URL pattern matches the <link
8977 linkend="FAST-REDIRECTS"><quote>+fast-redirects</quote></link> action,
8978 it is then processed. Unwanted parts of the requested URL are stripped.
8983 Now the rest of the client browser's request headers are processed. If any
8984 of these match any of the relevant actions (e.g. <link
8985 linkend="HIDE-USER-AGENT"><quote>+hide-user-agent</quote></link>,
8986 etc.), headers are suppressed or forged as determined by these actions and
8992 Now the web server starts sending its response back (i.e. typically a web
8998 First, the server headers are read and processed to determine, among other
8999 things, the MIME type (document type) and encoding. The headers are then
9000 filtered as determined by the
9001 <link linkend="CRUNCH-INCOMING-COOKIES"><quote>+crunch-incoming-cookies</quote></link>,
9002 <link linkend="SESSION-COOKIES-ONLY"><quote>+session-cookies-only</quote></link>,
9003 and <link linkend="DOWNGRADE-HTTP-VERSION"><quote>+downgrade-http-version</quote></link>
9009 If any <link linkend="FILTER"><quote>+filter</quote></link> action
9011 linkend="DEANIMATE-GIFS"><quote>+deanimate-gifs</quote></link>
9012 action applies (and the document type fits the action), the rest of the page is
9013 read into memory (up to a configurable limit). Then the filter rules (from
9014 <filename>default.filter</filename> and any other filter files) are
9015 processed against the buffered content. Filters are applied in the order
9016 they are specified in one of the filter files. Animated GIFs, if present,
9017 are reduced to either the first or last frame, depending on the action
9018 setting.The entire page, which is now filtered, is then sent by
9019 <application>Privoxy</application> back to your browser.
9022 If neither a <link linkend="FILTER"><quote>+filter</quote></link> action
9024 linkend="DEANIMATE-GIFS"><quote>+deanimate-gifs</quote></link>
9025 matches, then <application>Privoxy</application> passes the raw data through
9026 to the client browser as it becomes available.
9031 As the browser receives the now (possibly filtered) page content, it
9032 reads and then requests any URLs that may be embedded within the page
9033 source, e.g. ad images, stylesheets, JavaScript, other HTML documents (e.g.
9034 frames), sounds, etc. For each of these objects, the browser issues a
9035 separate request (this is easily viewable in <application>Privoxy's</application>
9036 logs). And each such request is in turn processed just as above. Note that a
9037 complex web page will have many, many such embedded URLs. If these
9038 secondary requests are to a different server, then quite possibly a very
9039 differing set of actions is triggered.
9046 NOTE: This is somewhat of a simplistic overview of what happens with each URL
9047 request. For the sake of brevity and simplicity, we have focused on
9048 <application>Privoxy's</application> core features only.
9054 <!-- ~~~~~ New section ~~~~~ -->
9055 <sect2 id="actionsanat">
9056 <title>Troubleshooting: Anatomy of an Action</title>
9059 The way <application>Privoxy</application> applies
9060 <link linkend="ACTIONS">actions</link> and <link linkend="FILTER">filters</link>
9061 to any given URL can be complex, and not always so
9062 easy to understand what is happening. And sometimes we need to be able to
9063 <emphasis>see</emphasis> just what <application>Privoxy</application> is
9064 doing. Especially, if something <application>Privoxy</application> is doing
9065 is causing us a problem inadvertently. It can be a little daunting to look at
9066 the actions and filters files themselves, since they tend to be filled with
9067 <link linkend="regex">regular expressions</link> whose consequences are not
9072 One quick test to see if <application>Privoxy</application> is causing a problem
9073 or not, is to disable it temporarily. This should be the first troubleshooting
9074 step. See <link linkend="bookmarklets">the Bookmarklets</link> section on a quick
9075 and easy way to do this (be sure to flush caches afterward!). Looking at the
9076 logs is a good idea too. (Note that both the toggle feature and logging are
9077 enabled via <filename>config</filename> file settings, and may need to be
9078 turned <quote>on</quote>.)
9081 Another easy troubleshooting step to try is if you have done any
9082 customization of your installation, revert back to the installed
9083 defaults and see if that helps. There are times the developers get complaints
9084 about one thing or another, and the problem is more related to a customized
9085 configuration issue.
9089 <application>Privoxy</application> also provides the
9090 <ulink url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
9091 page that can show us very specifically how <application>actions</application>
9092 are being applied to any given URL. This is a big help for troubleshooting.
9096 First, enter one URL (or partial URL) at the prompt, and then
9097 <application>Privoxy</application> will tell us
9098 how the current configuration will handle it. This will not
9099 help with filtering effects (i.e. the <link
9100 linkend="FILTER"><quote>+filter</quote></link> action) from
9101 one of the filter files since this is handled very
9102 differently and not so easy to trap! It also will not tell you about any other
9103 URLs that may be embedded within the URL you are testing. For instance, images
9104 such as ads are expressed as URLs within the raw page source of HTML pages. So
9105 you will only get info for the actual URL that is pasted into the prompt area
9106 -- not any sub-URLs. If you want to know about embedded URLs like ads, you
9107 will have to dig those out of the HTML source. Use your browser's <quote>View
9108 Page Source</quote> option for this. Or right click on the ad, and grab the
9113 Let's try an example, <ulink url="http://google.com">google.com</ulink>,
9114 and look at it one section at a time in a sample configuration (your real
9115 configuration may vary):
9120 Matches for http://www.google.com:
9122 In file: default.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
9124 {+change-x-forwarded-for{block}
9125 +deanimate-gifs {last}
9126 +fast-redirects {check-decoded-url}
9127 +filter {refresh-tags}
9128 +filter {img-reorder}
9129 +filter {banners-by-size}
9131 +filter {jumping-windows}
9132 +filter {ie-exploits}
9133 +hide-from-header {block}
9134 +hide-referrer {forge}
9135 +session-cookies-only
9136 +set-image-blocker {pattern}
9139 { -session-cookies-only }
9145 In file: user.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
9146 (no matches in this file)
9151 This is telling us how we have defined our
9152 <link linkend="ACTIONS"><quote>actions</quote></link>, and
9153 which ones match for our test case, <quote>google.com</quote>.
9154 Displayed is all the actions that are available to us. Remember,
9155 the <literal>+</literal> sign denotes <quote>on</quote>. <literal>-</literal>
9156 denotes <quote>off</quote>. So some are <quote>on</quote> here, but many
9157 are <quote>off</quote>. Each example we try may provide a slightly different
9158 end result, depending on our configuration directives.
9162 is for our <filename>default.action</filename> file. The large, multi-line
9163 listing, is how the actions are set to match for all URLs, i.e. our default
9164 settings. If you look at your <quote>actions</quote> file, this would be the
9165 section just below the <quote>aliases</quote> section near the top. This
9166 will apply to all URLs as signified by the single forward slash at the end
9167 of the listing -- <quote> / </quote>.
9171 But we have defined additional actions that would be exceptions to these general
9172 rules, and then we list specific URLs (or patterns) that these exceptions
9173 would apply to. Last match wins. Just below this then are two explicit
9174 matches for <quote>.google.com</quote>. The first is negating our previous
9175 cookie setting, which was for <link
9176 linkend="SESSION-COOKIES-ONLY"><quote>+session-cookies-only</quote></link>
9177 (i.e. not persistent). So we will allow persistent cookies for google, at
9178 least that is how it is in this example. The second turns
9179 <emphasis>off</emphasis> any <link
9180 linkend="FAST-REDIRECTS"><quote>+fast-redirects</quote></link>
9181 action, allowing this to take place unmolested. Note that there is a leading
9182 dot here -- <quote>.google.com</quote>. This will match any hosts and
9183 sub-domains, in the google.com domain also, such as
9184 <quote>www.google.com</quote> or <quote>mail.google.com</quote>. But it would not
9185 match <quote>www.google.de</quote>! So, apparently, we have these two actions
9186 defined as exceptions to the general rules at the top somewhere in the lower
9187 part of our <filename>default.action</filename> file, and
9188 <quote>google.com</quote> is referenced somewhere in these latter sections.
9192 Then, for our <filename>user.action</filename> file, we again have no hits.
9193 So there is nothing google-specific that we might have added to our own, local
9194 configuration. If there was, those actions would over-rule any actions from
9195 previously processed files, such as <filename>default.action</filename>.
9196 <filename>user.action</filename> typically has the last word. This is the
9197 best place to put hard and fast exceptions,
9201 And finally we pull it all together in the bottom section and summarize how
9202 <application>Privoxy</application> is applying all its <quote>actions</quote>
9203 to <quote>google.com</quote>:
9214 +change-x-forwarded-for{block}
9215 -client-header-filter{hide-tor-exit-notation}
9216 -content-type-overwrite
9217 -crunch-client-header
9218 -crunch-if-none-match
9219 -crunch-incoming-cookies
9220 -crunch-outgoing-cookies
9221 -crunch-server-header
9222 +deanimate-gifs {last}
9223 -downgrade-http-version
9226 -filter {content-cookies}
9227 -filter {all-popups}
9228 -filter {banners-by-link}
9229 -filter {tiny-textforms}
9230 -filter {frameset-borders}
9231 -filter {demoronizer}
9232 -filter {shockwave-flash}
9233 -filter {quicktime-kioskmode}
9235 -filter {crude-parental}
9236 -filter {site-specifics}
9237 -filter {js-annoyances}
9238 -filter {html-annoyances}
9239 +filter {refresh-tags}
9240 -filter {unsolicited-popups}
9241 +filter {img-reorder}
9242 +filter {banners-by-size}
9244 +filter {jumping-windows}
9245 +filter {ie-exploits}
9252 -handle-as-empty-document
9254 -hide-accept-language
9255 -hide-content-disposition
9256 +hide-from-header {block}
9257 -hide-if-modified-since
9258 +hide-referrer {forge}
9261 -overwrite-last-modified
9262 -prevent-compression
9264 -server-header-filter{xml-to-html}
9265 -server-header-filter{html-to-xml}
9266 -session-cookies-only
9267 +set-image-blocker {pattern} </screen>
9271 Notice the only difference here to the previous listing, is to
9272 <quote>fast-redirects</quote> and <quote>session-cookies-only</quote>,
9273 which are activated specifically for this site in our configuration,
9274 and thus show in the <quote>Final Results</quote>.
9278 Now another example, <quote>ad.doubleclick.net</quote>:
9284 { +block{Domains starts with "ad"} }
9287 { +block{Domain contains "ad"} }
9290 { +block{Doubleclick banner server} +handle-as-image }
9291 .[a-vx-z]*.doubleclick.net
9296 We'll just show the interesting part here - the explicit matches. It is
9297 matched three different times. Two <quote>+block{}</quote> sections,
9298 and a <quote>+block{} +handle-as-image</quote>,
9299 which is the expanded form of one of our aliases that had been defined as:
9300 <quote>+block-as-image</quote>. (<link
9301 linkend="ALIASES"><quote>Aliases</quote></link> are defined in
9302 the first section of the actions file and typically used to combine more
9307 Any one of these would have done the trick and blocked this as an unwanted
9308 image. This is unnecessarily redundant since the last case effectively
9309 would also cover the first. No point in taking chances with these guys
9310 though ;-) Note that if you want an ad or obnoxious
9311 URL to be invisible, it should be defined as <quote>ad.doubleclick.net</quote>
9312 is done here -- as both a <link
9313 linkend="BLOCK"><quote>+block{}</quote></link>
9314 <emphasis>and</emphasis> an
9315 <link linkend="HANDLE-AS-IMAGE"><quote>+handle-as-image</quote></link>.
9316 The custom alias <quote><literal>+block-as-image</literal></quote> just
9317 simplifies the process and make it more readable.
9321 One last example. Let's try <quote>http://www.example.net/adsl/HOWTO/</quote>.
9322 This one is giving us problems. We are getting a blank page. Hmmm ...
9328 Matches for http://www.example.net/adsl/HOWTO/:
9330 In file: default.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
9334 +change-x-forwarded-for{block}
9335 -client-header-filter{hide-tor-exit-notation}
9336 -content-type-overwrite
9337 -crunch-client-header
9338 -crunch-if-none-match
9339 -crunch-incoming-cookies
9340 -crunch-outgoing-cookies
9341 -crunch-server-header
9343 -downgrade-http-version
9344 +fast-redirects {check-decoded-url}
9346 -filter {content-cookies}
9347 -filter {all-popups}
9348 -filter {banners-by-link}
9349 -filter {tiny-textforms}
9350 -filter {frameset-borders}
9351 -filter {demoronizer}
9352 -filter {shockwave-flash}
9353 -filter {quicktime-kioskmode}
9355 -filter {crude-parental}
9356 -filter {site-specifics}
9357 -filter {js-annoyances}
9358 -filter {html-annoyances}
9359 +filter {refresh-tags}
9360 -filter {unsolicited-popups}
9361 +filter {img-reorder}
9362 +filter {banners-by-size}
9364 +filter {jumping-windows}
9365 +filter {ie-exploits}
9372 -handle-as-empty-document
9374 -hide-accept-language
9375 -hide-content-disposition
9376 +hide-from-header{block}
9377 +hide-referer{forge}
9379 -overwrite-last-modified
9380 +prevent-compression
9382 -server-header-filter{xml-to-html}
9383 -server-header-filter{html-to-xml}
9384 +session-cookies-only
9385 +set-image-blocker{blank} }
9388 { +block{Path contains "ads".} +handle-as-image }
9394 Ooops, the <quote>/adsl/</quote> is matching <quote>/ads</quote> in our
9395 configuration! But we did not want this at all! Now we see why we get the
9396 blank page. It is actually triggering two different actions here, and
9397 the effects are aggregated so that the URL is blocked, and &my-app; is told
9398 to treat the block as if it were an image. But this is, of course, all wrong.
9399 We could now add a new action below this (or better in our own
9400 <filename>user.action</filename> file) that explicitly
9401 <emphasis>un</emphasis> blocks (
9402 <link linkend="BLOCK"><quote>{-block}</quote></link>) paths with
9403 <quote>adsl</quote> in them (remember, last match in the configuration
9404 wins). There are various ways to handle such exceptions. Example:
9416 Now the page displays ;-)
9417 Remember to flush your browser's caches when making these kinds of changes to
9418 your configuration to insure that you get a freshly delivered page! Or, try
9419 using <literal>Shift+Reload</literal>.
9423 But now what about a situation where we get no explicit matches like
9430 { +block{Path starts with "ads".} +handle-as-image }
9436 That actually was very helpful and pointed us quickly to where the problem
9437 was. If you don't get this kind of match, then it means one of the default
9438 rules in the first section of <filename>default.action</filename> is causing
9439 the problem. This would require some guesswork, and maybe a little trial and
9440 error to isolate the offending rule. One likely cause would be one of the
9441 <link linkend="FILTER"><quote>+filter</quote></link> actions.
9442 These tend to be harder to troubleshoot.
9443 Try adding the URL for the site to one of aliases that turn off
9444 <link linkend="FILTER"><quote>+filter</quote></link>:
9452 .worldpay.com # for quietpc.com
9460 <quote><literal>{ shop }</literal></quote> is an <quote>alias</quote> that expands to
9461 <quote><literal>{ -filter -session-cookies-only }</literal></quote>.
9462 Or you could do your own exception to negate filtering:
9470 # Disable ALL filter actions for sites in this section
9478 This would turn off all filtering for these sites. This is best
9479 put in <filename>user.action</filename>, for local site
9480 exceptions. Note that when a simple domain pattern is used by itself (without
9481 the subsequent path portion), all sub-pages within that domain are included
9482 automatically in the scope of the action.
9486 Images that are inexplicably being blocked, may well be hitting the
9487 <link linkend="FILTER-BANNERS-BY-SIZE"><quote>+filter{banners-by-size}</quote></link>
9489 that images of certain sizes are ad banners (works well
9490 <emphasis>most of the time</emphasis> since these tend to be standardized).
9494 <quote><literal>{ fragile }</literal></quote> is an alias that disables most
9495 actions that are the most likely to cause trouble. This can be used as a
9496 last resort for problem sites.
9502 # Handle with care: easy to break
9504 mybank.example.com</screen>
9509 <emphasis>Remember to flush caches!</emphasis> Note that the
9510 <literal>mail.google</literal> reference lacks the TLD portion (e.g.
9511 <quote>.com</quote>). This will effectively match any TLD with
9512 <literal>google</literal> in it, such as <literal>mail.google.de.</literal>,
9516 If this still does not work, you will have to go through the remaining
9517 actions one by one to find which one(s) is causing the problem.
9526 This program is free software; you can redistribute it
9527 and/or modify it under the terms of the GNU General
9528 Public License as published by the Free Software
9529 Foundation; either version 2 of the License, or (at
9530 your option) any later version.
9532 This program is distributed in the hope that it will
9533 be useful, but WITHOUT ANY WARRANTY; without even the
9534 implied warranty of MERCHANTABILITY or FITNESS FOR A
9535 PARTICULAR PURPOSE. See the GNU General Public
9536 License for more details.
9538 The GNU General Public License should be included with
9539 this file. If not, you can view it at
9540 http://www.gnu.org/copyleft/gpl.html
9541 or write to the Free Software Foundation, Inc.,
9542 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,