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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">
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10 <!entity copyright SYSTEM "copyright.sgml">
11 <!entity license SYSTEM "license.sgml">
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13 <!entity GPLv3 SYSTEM "../../LICENSE.GPLv3">
14 <!entity p-authors SYSTEM "p-authors.sgml">
15 <!entity config SYSTEM "p-config.sgml">
16 <!entity changelog SYSTEM "changelog.sgml">
17 <!entity p-version "3.0.33">
18 <!entity p-status "UNRELEASED">
19 <!entity % p-authors-formal "INCLUDE"> <!-- include additional text, etc -->
20 <!entity % p-not-stable "INCLUDE">
21 <!entity % p-stable "IGNORE">
22 <!entity % p-text "IGNORE"> <!-- define we are not a text only doc -->
23 <!entity % p-doc "INCLUDE"> <!-- and we are a formal doc -->
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25 <!entity % user-man "IGNORE">
26 <!entity % config-file "IGNORE">
27 <!entity % p-supp-userman "IGNORE"> <!-- Omit some from supported.sgml -->
28 <!entity my-copy "©"> <!-- kludge for docbook2man -->
29 <!entity % draft "IGNORE"> <!-- WIP stuff -->
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31 <!entity my-app "<application>Privoxy</application>">
34 File : doc/source/user-manual.sgml
38 Copyright (C) 2001-2021 Privoxy Developers https://www.privoxy.org/
41 ========================================================================
42 NOTE: Please read developer-manual/documentation.html before touching
43 anything in this, or other Privoxy documentation.
44 ========================================================================
51 <title>Privoxy &p-version; User Manual</title>
55 <!-- Completely the wrong markup, but very little is allowed -->
56 <!-- in this part of an article. FIXME -->
57 <link linkend="copyright">Copyright</link> &my-copy; 2001-2021 by
58 <ulink url="https://www.privoxy.org/">Privoxy Developers</ulink>
64 Note: the following should generate a separate page, and a live link to it,
65 all nicely done. But it doesn't for some mysterious reason. Please leave
66 commented unless it can be fixed proper. For the time being, the
67 copyright/license declarations will be in their own sgml.
80 This is here to keep vim syntax file from breaking :/
81 If I knew enough to fix it, I would.
82 PLEASE DO NOT REMOVE! HB: hal@foobox.net
88 The <citetitle>Privoxy User Manual</citetitle> gives users information on how to
89 install, configure and use <ulink
90 url="https://www.privoxy.org/">Privoxy</ulink>.
93 <!-- Include privoxy.sgml boilerplate: -->
95 <!-- end privoxy.sgml -->
98 You can find the latest version of the <citetitle>Privoxy User Manual</citetitle> at <ulink
99 url="https://www.privoxy.org/user-manual/">https://www.privoxy.org/user-manual/</ulink>.
100 Please see the <link linkend="contact">Contact section</link> on how to
101 contact the developers.
108 <!-- ~~~~~ New section ~~~~~ -->
109 <sect1 label="1" id="introduction"><title>Introduction</title>
111 This documentation is included with the current &p-status; version of
112 <application>Privoxy</application>, &p-version;<![%p-not-stable;[,
113 and is mostly complete at this point. The most up to date reference for the
114 time being is still the comments in the source files and in the individual
115 configuration files. Development of a new version is currently nearing
116 completion, and includes significant changes and enhancements over
120 <!-- include only in non-stable versions -->
123 Since this is a &p-status; version, not all new features are well tested. This
124 documentation may be slightly out of sync as a result (especially with
125 <ulink url="https://www.privoxy.org/gitweb/?p=privoxy.git;a=summary">git sources</ulink>).
126 And there <emphasis>may be</emphasis> bugs, though hopefully
131 <!-- ~~~~~ New section ~~~~~ -->
132 <sect2 id="features"><title>Features</title>
134 In addition to the core
135 features of ad blocking and
136 <ulink url="https://en.wikipedia.org/wiki/Browser_cookie">cookie</ulink> management,
137 <application>Privoxy</application> provides many supplemental
138 features<![%p-not-stable;[, some of them currently under development]]>,
139 that give the end-user more control, more privacy and more freedom:
141 <!-- Include newfeatures.sgml boilerplate here: -->
143 <!-- end boilerplate -->
148 <!-- ~ End section ~ -->
151 <!-- ~~~~~ New section ~~~~~ -->
152 <sect1 id="installation"><title>Installation</title>
155 <application>Privoxy</application> is available both in convenient pre-compiled
156 packages for a wide range of operating systems, and as raw source code.
157 For most users, we recommend using the packages, which can be downloaded from our
158 <ulink url="https://sourceforge.net/projects/ijbswa/">Privoxy Project
164 On some platforms, the installer may remove previously installed versions, if
165 found. (See below for your platform). In any case <emphasis>be sure to backup
166 your old configuration if it is valuable to you.</emphasis> See the <link
167 linkend="upgradersnote">note to upgraders</link> section below.
170 <!-- ~~~~~ New section ~~~~~ -->
171 <sect2 id="installation-packages"><title>Binary Packages</title>
173 How to install the binary packages depends on your operating system:
176 <!-- XXX: The installation sections should be sorted -->
178 <!-- ~~~~~ New section ~~~~~ -->
179 <sect3 id="installation-deb"><title>Debian and Ubuntu</title>
181 DEBs can be installed with <literal>apt-get install privoxy</literal>,
182 and will use <filename>/etc/privoxy</filename> for the location of
187 <!-- ~~~~~ New section ~~~~~ -->
188 <sect3 id="installation-pack-win"><title>Windows</title>
191 Just double-click the installer, which will guide you through
192 the installation process. You will find the configuration files
193 in the same directory as you installed <application>Privoxy</application> in.
196 Version 3.0.5 beta introduced full <application>Windows</application> service
197 functionality. On Windows only, the <application>Privoxy</application>
198 program has two new command line arguments to install and uninstall
199 <application>Privoxy</application> as a <emphasis>service</emphasis>.
203 <term>Arguments:</term>
206 <replaceable class="parameter">--install</replaceable>[:<replaceable class="parameter">service_name</replaceable>]
209 <replaceable class="parameter">--uninstall</replaceable>[:<replaceable class="parameter">service_name</replaceable>]
215 After invoking <application>Privoxy</application> with
216 <command>--install</command>, you will need to bring up the
217 <application>Windows</application> service console to assign the user you
218 want <application>Privoxy</application> to run under, and whether or not you
219 want it to run whenever the system starts. You can start the
220 <application>Windows</application> services console with the following
221 command: <command>services.msc</command>. If you do not take the manual step
222 of modifying <application>Privoxy's</application> service settings, it will
223 not start. Note too that you will need to give Privoxy a user account that
224 actually exists, or it will not be permitted to
225 write to its log and configuration files.
230 <!-- ~~~~~ New section ~~~~~ -->
231 <sect3 id="installation-mac"><title>Mac OS X</title>
233 Installation instructions for the OS X platform depend upon whether
234 you downloaded a ready-built installation package (.pkg or .mpkg) or have
235 downloaded the source code.
238 <sect3 renderas="sect4" id="OS-X-install-from-package">
239 <title>Installation from ready-built package</title>
241 The downloaded file will either be a .pkg (for OS X 10.5 upwards) or a bzipped
242 .mpkg file (for OS X 10.4). The former can be double-clicked as is and the
243 installation will start; double-clicking the latter will unzip the .mpkg file
244 which can then be double-clicked to commence the installation.
247 The privoxy service will automatically start after a successful installation
248 (and thereafter every time your computer starts up) however you will need to
249 configure your web browser(s) to use it. To do so, configure them to use a
250 proxy for HTTP and HTTPS at the address 127.0.0.1:8118.
253 To prevent the privoxy service from automatically starting when your computer
254 starts up, remove or rename the file <literal>/Library/LaunchDaemons/org.ijbswa.privoxy.plist</literal>
255 (on OS X 10.5 and higher) or the folder named
256 <literal>/Library/StartupItems/Privoxy</literal> (on OS X 10.4 'Tiger').
259 To manually start or stop the privoxy service, use the scripts startPrivoxy.sh
260 and stopPrivoxy.sh supplied in /Applications/Privoxy. They must be run from an
261 administrator account, using sudo.
264 To uninstall, run /Applications/Privoxy/uninstall.command as sudo from an
265 administrator account.
268 <sect3 renderas="sect4" id="OS-X-install-from-source">
269 <title>Installation from source</title>
271 To build and install the Privoxy source code on OS X you will need to obtain
272 the macsetup module from the Privoxy Sourceforge CVS repository (refer to
273 Sourceforge help for details of how to set up a CVS client to have read-only
274 access to the repository). This module contains scripts that leverage the usual
275 open-source tools (available as part of Apple's free of charge Xcode
276 distribution or via the usual open-source software package managers for OS X
277 (MacPorts, Homebrew, Fink etc.) to build and then install the privoxy binary
278 and associated files. The macsetup module's README file contains complete
279 instructions for its use.
282 The privoxy service will automatically start after a successful installation
283 (and thereafter every time your computer starts up) however you will need to
284 configure your web browser(s) to use it. To do so, configure them to use a
285 proxy for HTTP and HTTPS at the address 127.0.0.1:8118.
288 To prevent the privoxy service from automatically starting when your computer
289 starts up, remove or rename the file <literal>/Library/LaunchDaemons/org.ijbswa.privoxy.plist</literal>
290 (on OS X 10.5 and higher) or the folder named
291 <literal>/Library/StartupItems/Privoxy</literal> (on OS X 10.4 'Tiger').
294 To manually start or stop the privoxy service, use the Privoxy Utility
295 for Mac OS X (also part of the macsetup module). This application can start
296 and stop the privoxy service and display its log and configuration files.
299 To uninstall, run the macsetup module's uninstall.sh as sudo from an
300 administrator account.
304 <!-- ~~~~~ New section ~~~~~ -->
305 <sect3 id="installation-freebsd"><title>FreeBSD</title>
308 Privoxy is part of FreeBSD's Ports Collection, you can build and install
309 it with <literal>cd /usr/ports/www/privoxy; make install clean</literal>.
315 <!-- ~~~~~ New section ~~~~~ -->
316 <sect2 id="installation-source"><title>Building from Source</title>
319 The most convenient way to obtain the <application>Privoxy</application> source
320 code is to download the source tarball from our
321 <ulink url="https://sourceforge.net/projects/ijbswa/files/Sources/">
322 project download page</ulink>,
323 or you can get the up-to-the-minute, possibly unstable, development version from
324 <ulink url="https://www.privoxy.org/">https://www.privoxy.org/</ulink>.
327 <!-- include buildsource.sgml boilerplate: -->
329 <!-- end boilerplate -->
332 <sect3 id="WINBUILD-CYGWIN"><title>Windows</title>
334 <sect4 id="WINBUILD-SETUP"><title>Setup</title>
336 Install the Cygwin utilities needed to build <application>Privoxy</application>.
337 If you have a 64 bit CPU (which most people do by now), get the
338 Cygwin setup-x86_64.exe program <ulink url="https://cygwin.com/setup-x86_64.exe">here</ulink>
339 (the .sig file is <ulink url="https://cygwin.com/setup-x86_64.exe.sig">here</ulink>).
342 Run the setup program and from View / Category select:
354 mingw64-i686-gcc-core
359 libxslt: GNOME XSLT library (runtime)
375 If you haven't already downloaded the Privoxy source code, get it now:
380 git clone https://www.privoxy.org/git/privoxy.git
384 Get the source code (.zip or .tar.gz) for tidy from
385 <ulink url="https://github.com/htacg/tidy-html5/releases">
386 https://github.com/htacg/tidy-html5/releases</ulink>,
387 unzip into <root-dir> and build the software:
391 cd tidy-html5-x.y.z/build/cmake
392 cmake ../.. -DCMAKE_BUILD_TYPE=Release -DBUILD_SHARED_LIB:BOOL=OFF -DCMAKE_INSTALL_PREFIX=/usr/local
397 If you want to be able to make a Windows release package, get the NSIS .zip file from
398 <!-- FIXME: which version(s) are known to work? -->
399 <ulink url="https://sourceforge.net/projects/nsis/files/NSIS%203/">
400 https://sourceforge.net/projects/nsis/files/NSIS%203/</ulink>
401 and extract the NSIS directory to <literal>/<root-dir>/nsis/</literal>.
402 Then edit the <filename>windows/GNUmakefile</filename> to set the location
403 of the NSIS executable - eg:
407 MAKENSIS = /<root-dir>/nsis/makensis.exe
411 Get the latest 8.x PCRE code from
412 <ulink url="https://ftp.pcre.org/pub/pcre/">PCRE
413 https://ftp.pcre.org/pub/pcre/</ulink>
414 and build the static PCRE libraries with
417 export CFLAGS="-O2 -fstack-protector-strong -D_FORTIFY_SOURCE=2"
418 export LDFLAGS="-fstack-protector-strong"
419 export CPPFLAGS="-DPCRE_STATIC"
421 ./configure --host=i686-w64-mingw32 \
422 --prefix=/usr/local/i686-w64-mingw32 \
423 --enable-utf --enable-unicode-properties \
425 --enable-newline-is-anycrlf \
428 --disable-pcregrep-libbz2 \
429 --disable-pcregrep-libz \
430 --disable-pcretest-libreadline \
431 --disable-stack-for-recursion \
432 --enable-static --disable-shared \
439 If you want to be able to have Privoxy do TLS Inspection, get the latest
440 2.16.x MBED-TLS library source code from
441 <ulink url="https://github.com/ARMmbed/mbedtls/tags">
442 https://github.com/ARMmbed/mbedtls/tags</ulink>,
443 extract the tar file into <literal><root-dir></literal>
444 and build the static libraries with
446 export WINDOWS_BUILD=1
447 # build for a Windows platform
451 export CC=i686-w64-mingw32-gcc
452 export LD=i686-w64-mingw32-gcc
453 export CFLAGS="-O2 -fstack-protector-strong -D_FORTIFY_SOURCE=2"
454 export LDFLAGS="${LDFLAGS} -fstack-protector-strong"
457 # build the libraries
463 Get the brotli library from
464 <ulink url="https://github.com/google/brotli/releases">
465 https://github.com/google/brotli/releases</ulink>
466 and build the static libraries with
469 # to create the GNU autotools files
473 export CFLAGS="-O2 -fstack-protector-strong -D_FORTIFY_SOURCE=2"
474 export LDFLAGS="${LDFLAGS} -fstack-protector-strong"
476 ./configure --host=i686-w64-mingw32 \
477 --prefix=/usr/local/i686-w64-mingw32 \
481 --disable-silent-rules \
490 <sect4 id="WINBUILD-BUILD"><title>Build</title>
493 To build just the Privoxy executable and not the whole installation package, do:
496 cd <root-dir>/privoxy
497 ./windows/MYconfigure && make
501 Privoxy uses the <ulink url="https://en.wikipedia.org/wiki/GNU_build_system">GNU Autotools</ulink>
502 for building software, so the process is:
505 autoheader # creates config.h.in
506 autoconf # uses config.h.in to create the configure shell script
507 ./configure [options] # creates GNUmakefile
508 make [options] # builds the program
512 The usual <literal>configure</literal> options for building a native Windows application under cygwin are
515 <literallayout class="Monospaced">
516 --host=i686-w64-mingw32
519 --enable-static-linking
526 You can set the <literal>CFLAGS</literal> and <literal>LDFLAGS</literal> envars before
527 running <literal>configure</literal> to set compiler and linker flags. For example:
531 $ export CFLAGS="-O2" # set gcc optimization level
532 $ export LDFLAGS="-Wl,--nxcompat" # Enable DEP
533 $ ./configure --host=i686-w64-mingw32 --enable-mingw32 --enable-zlib \
534 > --enable-static-linking --disable-pthread
535 $ make # build Privoxy
539 See the <ulink url="../developer-manual/newrelease.html#NEWRELEASE-WINDOWS">Developer's Manual</ulink>
540 for building a Windows release package.
548 <!-- ~~~~~ New section ~~~~~ -->
549 <sect2 id="installation-keepupdated"><title>Keeping your Installation Up-to-Date</title>
552 If you wish to receive an email notification whenever we release updates of
553 <application>Privoxy</application> or the actions file, <ulink
554 url="https://lists.privoxy.org/mailman/listinfo/privoxy-announce">subscribe
555 to our announce mailing list</ulink>, privoxy-announce@lists.privoxy.org.
559 In order not to lose your personal changes and adjustments when updating
560 to the latest <literal>default.action</literal> file we <emphasis>strongly
561 recommend</emphasis> that you use <literal>user.action</literal> and
562 <literal>user.filter</literal> for your local
563 customizations of <application>Privoxy</application>. See the <link
564 linkend="actions-file">Chapter on actions files</link> for details.
572 <!-- ~ End section ~ -->
574 <!-- ~~~~~ New section ~~~~~ -->
575 <sect1 id="whatsnew">
576 <title>What's New in this Release</title>
580 <!-- ~~~~~ New section ~~~~~ -->
582 <sect2 id="upgradersnote">
583 <title>Note to Upgraders</title>
586 A quick list of things to be aware of before upgrading from earlier
587 versions of <application>Privoxy</application>:
594 The recommended way to upgrade &my-app; is to backup your old
595 configuration files, install the new ones, verify that &my-app;
596 is working correctly and finally merge back your changes using
597 <application>diff</application> and maybe <application>patch</application>.
600 There are a number of new features in each &my-app; release and
601 most of them have to be explicitly enabled in the configuration
602 files. Old configuration files obviously don't do that and due
603 to syntax changes using old configuration files with a new
604 &my-app; isn't always possible anyway.
609 Note that some installers remove earlier versions completely,
610 including configuration files, therefore you should really save
611 any important configuration files!
616 On the other hand, other installers don't overwrite existing configuration
617 files, thinking you will want to do that yourself.
622 In the default configuration only fatal errors are logged now.
623 You can change that in the <link linkend="DEBUG">debug section</link>
624 of the configuration file. You may also want to enable more verbose
625 logging until you verified that the new &my-app; version is working
632 Three other config file settings are now off by default:
633 <link linkend="enable-remote-toggle">enable-remote-toggle</link>,
634 <link linkend="enable-remote-http-toggle">enable-remote-http-toggle</link>,
635 and <link linkend="enable-edit-actions">enable-edit-actions</link>.
636 If you use or want these, you will need to explicitly enable them, and
637 be aware of the security issues involved.
644 What constitutes a <quote>default</quote> configuration has changed,
645 and you may want to review which actions are <quote>on</quote> by
646 default. This is primarily a matter of emphasis, but some features
647 you may have been used to, may now be <quote>off</quote> by default.
648 There are also a number of new actions and filters you may want to
649 consider, most of which are not fully incorporated into the default
650 settings as yet (see above).
657 The default actions setting is now <literal>Cautious</literal>. Previous
658 releases had a default setting of <literal>Medium</literal>. Experienced
659 users may want to adjust this, as it is fairly conservative by &my-app;
660 standards and past practices. See <ulink
661 url="http://config.privoxy.org/edit-actions-list?f=default">
662 http://config.privoxy.org/edit-actions-list?f=default</ulink>. New users
663 should try the default settings for a while before turning up the volume.
669 The default setting has filtering turned <emphasis>off</emphasis>, which
670 subsequently means that compression is <emphasis>on</emphasis>. Remember
671 that filtering does not work on compressed pages, so if you use, or want to
672 use, filtering, you will need to force compression off. Example:
675 { +<link linkend="filter">filter</link>{google} +<link linkend="prevent-compression">prevent-compression</link> }
679 Or if you use a number of filters, or filter many sites, you may just want
680 to turn off compression for all sites in
681 <filename>default.action</filename> (or
682 <filename>user.action</filename>).
689 Also, <link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> is
690 off by default now. If you've liked this feature in the past, you may want
691 to turn it back on in <filename>user.action</filename> now.
698 Some installers may not automatically start
699 <application>Privoxy</application> after installation.
709 <!-- ~~~~~ New section ~~~~~ -->
710 <sect1 id="quickstart"><title>Quickstart to Using Privoxy</title>
716 Install <application>Privoxy</application>. See the <link
717 linkend="installation">Installation Section</link> below for platform specific
724 Advanced users and those who want to offer <application>Privoxy</application>
725 service to more than just their local machine should check the <link
726 linkend="config">main config file</link>, especially the <link
727 linkend="access-control">security-relevant</link> options. These are
734 Start <application>Privoxy</application>, if the installation program has
735 not done this already (may vary according to platform). See the section
736 <link linkend="startup">Starting <application>Privoxy</application></link>.
742 Set your browser to use <application>Privoxy</application> as HTTP and
743 HTTPS (SSL) <ulink url="https://en.wikipedia.org/wiki/Proxy_server">proxy</ulink>
744 by setting the proxy configuration for address of
745 <literal>127.0.0.1</literal> and port <literal>8118</literal>.
746 <emphasis>DO NOT</emphasis> activate proxying for <literal>FTP</literal> or
747 any protocols besides HTTP and HTTPS (SSL) unless you intend to prevent your
748 browser from using these protocols.
754 Flush your browser's disk and memory caches, to remove any cached ad images.
755 If using <application>Privoxy</application> to manage
756 <ulink url="https://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>,
757 you should remove any currently stored cookies too.
763 A default installation should provide a reasonable starting point for
764 most. There will undoubtedly be occasions where you will want to adjust the
765 configuration, but that can be dealt with as the need arises. Little
766 to no initial configuration is required in most cases, you may want
768 <ulink url="config.html#ENABLE-EDIT-ACTIONS">web-based action editor</ulink> though.
769 Be sure to read the warnings first.
772 See the <link linkend="configuration">Configuration section</link> for more
773 configuration options, and how to customize your installation.
774 You might also want to look at the <link
775 linkend="quickstart-ad-blocking">next section</link> for a quick
776 introduction to how <application>Privoxy</application> blocks ads and
783 If you experience ads that slip through, innocent images that are
784 blocked, or otherwise feel the need to fine-tune
785 <application>Privoxy's</application> behavior, take a look at the <link
786 linkend="actions-file">actions files</link>. As a quick start, you might
787 find the <link linkend="act-examples">richly commented examples</link>
788 helpful. You can also view and edit the actions files through the <ulink
789 url="http://config.privoxy.org">web-based user interface</ulink>. The
790 Appendix <quote><link linkend="actionsanat">Troubleshooting: Anatomy of an
791 Action</link></quote> has hints on how to understand and debug actions that
792 <quote>misbehave</quote>.
798 Please see the section <link linkend="contact">Contacting the
799 Developers</link> on how to report bugs, problems with websites or to get
806 Now enjoy surfing with enhanced control, comfort and privacy!
813 <!-- ~~~~~ New section ~~~~~ -->
815 <sect2 id="quickstart-ad-blocking">
816 <title>Quickstart to Ad Blocking</title>
818 NOTE: This section is deliberately redundant for those that don't
819 want to read the whole thing (which is getting lengthy).
822 Ad blocking is but one of <application>Privoxy's</application>
823 array of features. Many of these features are for the technically minded advanced
824 user. But, ad and banner blocking is surely common ground for everybody.
827 This section will provide a quick summary of ad blocking so
828 you can get up to speed quickly without having to read the more extensive
829 information provided below, though this is highly recommended.
832 First a bit of a warning ... blocking ads is much like blocking SPAM: the
833 more aggressive you are about it, the more likely you are to block
834 things that were not intended. And the more likely that some things
835 may not work as intended. So there is a trade off here. If you want
836 extreme ad free browsing, be prepared to deal with more
837 <quote>problem</quote> sites, and to spend more time adjusting the
838 configuration to solve these unintended consequences. In short, there is
839 not an easy way to eliminate <emphasis>all</emphasis> ads. Either take
840 the easy way and settle for <emphasis>most</emphasis> ads blocked with the
841 default configuration, or jump in and tweak it for your personal surfing
842 habits and preferences.
845 Secondly, a brief explanation of <application>Privoxy's </application>
846 <quote>actions</quote>. <quote>Actions</quote> in this context, are
847 the directives we use to tell <application>Privoxy</application> to perform
848 some task relating to HTTP transactions (i.e. web browsing). We tell
849 <application>Privoxy</application> to take some <quote>action</quote>. Each
850 action has a unique name and function. While there are many potential
851 <application>actions</application> in <application>Privoxy's</application>
852 arsenal, only a few are used for ad blocking. <link
853 linkend="actions">Actions</link>, and <link linkend="actions-file">action
854 configuration files</link>, are explained in depth below.
857 Actions are specified in <application>Privoxy's</application> configuration,
858 followed by one or more URLs to which the action should apply. URLs
859 can actually be URL type <link linkend="af-patterns">patterns</link> that use
860 wildcards so they can apply potentially to a range of similar URLs. The
861 actions, together with the URL patterns are called a section.
864 When you connect to a website, the full URL will either match one or more
865 of the sections as defined in <application>Privoxy's</application> configuration,
866 or not. If so, then <application>Privoxy</application> will perform the
867 respective actions. If not, then nothing special happens. Furthermore, web
868 pages may contain embedded, secondary URLs that your web browser will
869 use to load additional components of the page, as it parses the
870 original page's HTML content. An ad image for instance, is just an URL
871 embedded in the page somewhere. The image itself may be on the same server,
872 or a server somewhere else on the Internet. Complex web pages will have many
873 such embedded URLs. &my-app; can deal with each URL individually, so, for
874 instance, the main page text is not touched, but images from such-and-such
879 The most important actions for basic ad blocking are: <literal><link
880 linkend="block">block</link></literal>, <literal><link
881 linkend="handle-as-image">handle-as-image</link></literal>,
883 linkend="handle-as-empty-document">handle-as-empty-document</link></literal>,and
884 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>:
891 <literal><link linkend="block">block</link></literal> - this is perhaps
892 the single most used action, and is particularly important for ad blocking.
893 This action stops any contact between your browser and any URL patterns
894 that match this action's configuration. It can be used for blocking ads,
895 but also anything that is determined to be unwanted. By itself, it simply
896 stops any communication with the remote server and sends
897 <application>Privoxy</application>'s own built-in BLOCKED page instead to
898 let you now what has happened (with some exceptions, see below).
904 <literal><link linkend="handle-as-image">handle-as-image</link></literal> -
905 tells <application>Privoxy</application> to treat this URL as an image.
906 <application>Privoxy</application>'s default configuration already does this
907 for all common image types (e.g. GIF), but there are many situations where this
908 is not so easy to determine. So we'll force it in these cases. This is particularly
909 important for ad blocking, since only if we know that it's an image of
910 some kind, can we replace it with an image of our choosing, instead of the
911 <application>Privoxy</application> BLOCKED page (which would only result in
912 a <quote>broken image</quote> icon). There are some limitations to this
913 though. For instance, you can't just brute-force an image substitution for
914 an entire HTML page in most situations.
920 <literal><link linkend="handle-as-empty-document">handle-as-empty-document</link></literal> -
921 sends an empty document instead of <application>Privoxy's</application>
922 normal BLOCKED HTML page. This is useful for file types that are neither
923 HTML nor images, such as blocking JavaScript files.
930 linkend="set-image-blocker">set-image-blocker</link></literal> - tells
931 <application>Privoxy</application> what to display in place of an ad image that
932 has hit a block rule. For this to come into play, the URL must match a
933 <literal><link linkend="block">block</link></literal> action somewhere in the
934 configuration, <emphasis>and</emphasis>, it must also match an
935 <literal><link linkend="handle-as-image">handle-as-image</link></literal> action.
938 The configuration options on what to display instead of the ad are:
942 <emphasis>pattern</emphasis> - a checkerboard pattern, so that an ad
943 replacement is obvious. This is the default.
948 <emphasis>blank</emphasis> - A very small empty GIF image is displayed.
949 This is the so-called <quote>invisible</quote> configuration option.
954 <emphasis>http://<URL></emphasis> - A redirect to any image anywhere
955 of the user's choosing (advanced usage).
963 Advanced users will eventually want to explore &my-app;
964 <literal><link linkend="filter">filters</link></literal> as well. Filters
965 are very different from <literal><link
966 linkend="block">blocks</link></literal>.
967 A <quote>block</quote> blocks a site, page, or unwanted contented. Filters
968 are a way of filtering or modifying what is actually on the page. An example
969 filter usage: a text replacement of <quote>no-no</quote> for
970 <quote>nasty-word</quote>. That is a very simple example. This process can be
971 used for ad blocking, but it is more in the realm of advanced usage and has
972 some pitfalls to be wary off.
976 The quickest way to adjust any of these settings is with your browser through
977 the special <application>Privoxy</application> editor at <ulink
978 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
979 (shortcut: <ulink url="http://p.p/">http://p.p/show-status</ulink>). This
980 is an internal page, and does not require Internet access.
984 Note that as of <application>Privoxy</application> 3.0.7 beta the
985 action editor is disabled by default. Check the
986 <ulink url="config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions
987 section in the configuration file</ulink> to learn why and in which
988 cases it's safe to enable again.
992 If you decided to enable the action editor, select the appropriate
993 <quote>actions</quote> file, and click
994 <quote><guibutton>Edit</guibutton></quote>. It is best to put personal or
995 local preferences in <filename>user.action</filename> since this is not
996 meant to be overwritten during upgrades, and will over-ride the settings in
997 other files. Here you can insert new <quote>actions</quote>, and URLs for ad
998 blocking or other purposes, and make other adjustments to the configuration.
999 <application>Privoxy</application> will detect these changes automatically.
1003 A quick and simple step by step example:
1010 Right click on the ad image to be blocked, then select
1011 <quote><guimenuitem>Copy Link Location</guimenuitem></quote> from the
1019 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1024 Find <filename>user.action</filename> in the top section, and click
1025 on <quote><guibutton>Edit</guibutton></quote>:
1028 <!-- image of editor and actions files selections -->
1029 <figure pgwide="0" float="0"><title>Actions Files in Use</title>
1032 <imagedata fileref="files-in-use.jpg" format="jpg">
1035 <phrase>[ Screenshot of Actions Files in Use ]</phrase>
1043 You should have a section with only
1044 <literal><link linkend="block">block</link></literal> listed under
1045 <quote>Actions:</quote>.
1046 If not, click a <quote><guibutton>Insert new section below</guibutton></quote>
1047 button, and in the new section that just appeared, click the
1048 <guibutton>Edit</guibutton> button right under the word <quote>Actions:</quote>.
1049 This will bring up a list of all actions. Find
1050 <literal><link linkend="block">block</link></literal> near the top, and click
1051 in the <quote>Enabled</quote> column, then <quote><guibutton>Submit</guibutton></quote>
1052 just below the list.
1057 Now, in the <literal><link linkend="block">block</link></literal> actions section,
1058 click the <quote><guibutton>Add</guibutton></quote> button, and paste the URL the
1059 browser got from <quote><guimenuitem>Copy Link Location</guimenuitem></quote>.
1060 Remove the <literal>http://</literal> at the beginning of the URL. Then, click
1061 <quote><guibutton>Submit</guibutton></quote> (or
1062 <quote><guibutton>OK</guibutton></quote> if in a pop-up window).
1067 Now go back to the original page, and press <keycap>SHIFT-Reload</keycap>
1068 (or flush all browser caches). The image should be gone now.
1075 This is a very crude and simple example. There might be good reasons to use a
1076 wildcard pattern match to include potentially similar images from the same
1077 site. For a more extensive explanation of <quote>patterns</quote>, and
1078 the entire actions concept, see <link linkend="actions-file">the Actions
1083 For advanced users who want to hand edit their config files, you might want
1084 to now go to the <link linkend="act-examples">Actions Files Tutorial</link>.
1085 The ideas explained therein also apply to the web-based editor.
1088 There are also various
1089 <link linkend="filter">filters</link> that can be used for ad blocking
1090 (filters are a special subset of actions). These
1091 fall into the <quote>advanced</quote> usage category, and are explained in
1092 depth in later sections.
1099 <!-- ~ End section ~ -->
1102 <!-- ~~~~~ New section ~~~~~ -->
1103 <sect1 id="startup">
1104 <title>Starting Privoxy</title>
1106 Before launching <application>Privoxy</application> for the first time, you
1107 will want to configure your browser(s) to use
1108 <application>Privoxy</application> as a HTTP and HTTPS (SSL)
1109 <ulink url="https://en.wikipedia.org/wiki/Proxy_server">proxy</ulink>. The default is
1110 127.0.0.1 (or localhost) for the proxy address, and port 8118 (earlier versions
1111 used port 8000). This is the one configuration step <emphasis>that must be done
1115 Please note that <application>Privoxy</application> can only proxy HTTP and
1116 HTTPS traffic. It will not work with FTP or other protocols.
1119 <!-- image of Mozilla Proxy configuration -->
1120 <figure pgwide="0" float="0"><title>Proxy Configuration Showing
1121 Mozilla Firefox HTTP and HTTPS (SSL) Settings</title>
1124 <imagedata fileref="proxy_setup.jpg" format="jpg">
1127 <phrase>[ Screenshot of Mozilla Firefox Proxy Configuration ]</phrase>
1134 With <application>Firefox</application>, this is typically set under:
1138 <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>Network Settings</guibutton> -> <guibutton>Settings</guibutton>
1142 Or optionally on some platforms:
1146 <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>General</guibutton> -> <guibutton>Connection Settings</guibutton> -> <guibutton>Manual Proxy Configuration</guibutton>
1151 With <application>Netscape</application> (and
1152 <application>Mozilla</application>), this can be set under:
1157 <!-- Mix ascii and gui art, something for everybody -->
1158 <!-- spacing on this is tricky -->
1159 <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>Advanced</guibutton> -> <guibutton>Proxies</guibutton> -> <guibutton>HTTP Proxy</guibutton>
1163 For <application>Internet Explorer v.5-7</application>:
1167 <guibutton>Tools</guibutton> -> <guibutton>Internet Options</guibutton> -> <guibutton>Connections</guibutton> -> <guibutton>LAN Settings</guibutton>
1171 Then, check <quote>Use Proxy</quote> and fill in the appropriate info
1172 (Address: 127.0.0.1, Port: 8118). Include HTTPS (SSL), if you want HTTPS
1173 proxy support too (sometimes labeled <quote>Secure</quote>). Make sure any
1174 checkboxes like <quote>Use the same proxy server for all protocols</quote> is
1175 <emphasis>UNCHECKED</emphasis>. You want only HTTP and HTTPS (SSL)!
1178 <!-- image of IE Proxy configuration -->
1179 <figure pgwide="0" float="0"><title>Proxy Configuration Showing
1180 Internet Explorer HTTP and HTTPS (Secure) Settings</title>
1183 <imagedata fileref="proxy2.jpg" format="jpg">
1186 <phrase>[ Screenshot of IE Proxy Configuration ]</phrase>
1193 After doing this, flush your browser's disk and memory caches to force a
1194 re-reading of all pages and to get rid of any ads that may be cached. Remove
1195 any <ulink url="https://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>,
1196 if you want <application>Privoxy</application> to manage that. You are now
1197 ready to start enjoying the benefits of using
1198 <application>Privoxy</application>!
1202 <application>Privoxy</application> itself is typically started by specifying the
1203 main configuration file to be used on the command line. If no configuration
1204 file is specified on the command line, <application>Privoxy</application>
1205 will look for a file named <filename>config</filename> in the current
1206 directory. Except on Win32 where it will try <filename>config.txt</filename>.
1209 <sect2 id="start-debian">
1210 <title>Debian</title>
1212 We use a script. Note that Debian typically starts &my-app; upon booting per
1213 default. It will use the file
1214 <filename>/etc/privoxy/config</filename> as its main configuration
1218 # /etc/init.d/privoxy start
1222 <sect2 id="start-freebsd">
1223 <title>FreeBSD and ElectroBSD</title>
1225 To start <application>Privoxy</application> upon booting, add
1226 "privoxy_enable='YES'" to <filename>/etc/rc.conf</filename>.
1227 <application>Privoxy</application> will use
1228 <filename>/usr/local/etc/privoxy/config</filename> as its main
1232 If you installed <application>Privoxy</application> into a jail, the
1233 paths above are relative to the jail root.
1236 To start <application>Privoxy</application> manually, run:
1239 # service privoxy onestart
1243 <sect2 id="start-windows">
1244 <title>Windows</title>
1246 Click on the &my-app; Icon to start <application>Privoxy</application>. If no configuration file is
1247 specified on the command line, <application>Privoxy</application> will look
1248 for a file named <filename>config.txt</filename>. Note that Windows will
1249 automatically start &my-app; when the system starts if you chose that option
1253 <application>Privoxy</application> can run with full Windows service functionality.
1254 On Windows only, the &my-app; program has two new command line arguments
1255 to install and uninstall &my-app; as a service. See the
1256 <link linkend="installation-pack-win">Windows Installation
1257 instructions</link> for details.
1261 <sect2 id="start-unices">
1262 <title>Generic instructions for Unix derivates (Solaris, NetBSD, HP-UX etc.)</title>
1264 Example Unix startup command:
1267 # /usr/sbin/privoxy --user privoxy /etc/privoxy/config
1270 Note that if you installed <application>Privoxy</application> through
1271 a package manager, the package will probably contain a platform-specific
1272 script or configuration file to start <application>Privoxy</application>
1277 <sect2 id="start-macosx">
1278 <title>Mac OS X</title>
1280 The privoxy service will automatically start after a successful installation
1281 (and thereafter every time your computer starts up) however you will need to
1282 configure your web browser(s) to use it. To do so, configure them to use a
1283 proxy for HTTP and HTTPS at the address 127.0.0.1:8118.
1286 To prevent the privoxy service from automatically starting when your computer
1287 starts up, remove or rename the file <literal>/Library/LaunchDaemons/org.ijbswa.privoxy.plist</literal>
1288 (on OS X 10.5 and higher) or the folder named
1289 <literal>/Library/StartupItems/Privoxy</literal> (on OS X 10.4 'Tiger').
1292 To manually start or stop the privoxy service, use the scripts startPrivoxy.sh
1293 and stopPrivoxy.sh supplied in /Applications/Privoxy. They must be run from an
1294 administrator account, using sudo.
1302 See the section <link linkend="cmdoptions">Command line options</link> for
1306 must find a better place for this paragraph
1309 The included default configuration files should give a reasonable starting
1310 point. Most of the per site configuration is done in the
1311 <ulink url="actions-file.html"><quote>actions</quote></ulink> files. These are
1312 where various cookie actions are defined, ad and banner blocking, and other
1313 aspects of <application>Privoxy</application> configuration. There are several
1314 such files included, with varying levels of aggressiveness.
1318 You will probably want to keep an eye out for sites for which you may prefer
1319 persistent cookies, and add these to your actions configuration as needed. By
1320 default, most of these will be accepted only during the current browser
1321 session (aka <quote>session cookies</quote>), unless you add them to the
1322 configuration. If you want the browser to handle this instead, you will need
1323 to edit <filename>user.action</filename> (or through the web based interface)
1324 and disable this feature. If you use more than one browser, it would make
1325 more sense to let <application>Privoxy</application> handle this. In which
1326 case, the browser(s) should be set to accept all cookies.
1330 Another feature where you will probably want to define exceptions for trusted
1331 sites is the popup-killing (through <ulink
1332 url="actions-file.html#FILTER-POPUPS"><quote>+filter{popups}</quote></ulink>),
1333 because your favorite shopping, banking, or leisure site may need
1334 popups (explained below).
1338 <application>Privoxy</application> does not support all of the optional HTTP/1.1
1339 features yet. In the unlikely event that you experience inexplicable problems
1340 with browsers that use HTTP/1.1 per default
1341 (like <application>Mozilla</application> or recent versions of I.E.), you might
1342 try to force HTTP/1.0 compatibility. For Mozilla, look under <literal>Edit ->
1343 Preferences -> Debug -> Networking</literal>.
1344 Alternatively, set the <quote>+downgrade-http-version</quote> config option in
1345 <filename>default.action</filename> which will downgrade your browser's HTTP
1346 requests from HTTP/1.1 to HTTP/1.0 before processing them.
1350 After running <application>Privoxy</application> for a while, you can
1351 start to fine tune the configuration to suit your personal, or site,
1352 preferences and requirements. There are many, many aspects that can
1353 be customized. <quote>Actions</quote>
1354 can be adjusted by pointing your browser to
1355 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
1356 (shortcut: <ulink url="http://p.p/">http://p.p/</ulink>),
1357 and then follow the link to <quote>View & Change the Current Configuration</quote>.
1358 (This is an internal page and does not require Internet access.)
1362 In fact, various aspects of <application>Privoxy</application>
1363 configuration can be viewed from this page, including
1364 current configuration parameters, source code version numbers,
1365 the browser's request headers, and <quote>actions</quote> that apply
1366 to a given URL. In addition to the actions file
1367 editor mentioned above, <application>Privoxy</application> can also
1368 be turned <quote>on</quote> and <quote>off</quote> (toggled) from this page.
1372 If you encounter problems, try loading the page without
1373 <application>Privoxy</application>. If that helps, enter the URL where
1374 you have the problems into <ulink url="http://p.p/show-url-info">the browser
1375 based rule tracing utility</ulink>. See which rules apply and why, and
1376 then try turning them off for that site one after the other, until the problem
1377 is gone. When you have found the culprit, you might want to turn the rest on
1382 If the above paragraph sounds gibberish to you, you might want to <link
1383 linkend="actions-file">read more about the actions concept</link>
1384 or even dive deep into the <link linkend="actionsanat">Appendix
1389 If you can't get rid of the problem at all, think you've found a bug in
1390 Privoxy, want to propose a new feature or smarter rules, please see the
1391 section <link linkend="contact"><quote>Contacting the
1392 Developers</quote></link> below.
1397 <!-- ~~~~~ New section ~~~~~ -->
1398 <sect2 id="cmdoptions">
1399 <title>Command Line Options</title>
1401 <application>Privoxy</application> may be invoked with the following
1402 command-line options:
1409 <emphasis>--config-test</emphasis>
1412 Exit after loading the configuration files before binding to
1413 the listen address. The exit code signals whether or not the
1414 configuration files have been successfully loaded.
1417 If the exit code is 1, at least one of the configuration files
1418 is invalid, if it is 0, all the configuration files have been
1419 successfully loaded (but may still contain errors that can
1420 currently only be detected at run time).
1423 This option doesn't affect the log setting, combination with
1424 <emphasis>--no-daemon</emphasis> is recommended if a configured
1425 log file shouldn't be used.
1430 <emphasis>--version</emphasis>
1433 Print version info and exit. Unix only.
1438 <emphasis>--help</emphasis>
1441 Print short usage info and exit. Unix only.
1446 <emphasis>--no-daemon</emphasis>
1449 Don't become a daemon, i.e. don't fork and become process group
1450 leader, and don't detach from controlling tty. Unix only.
1455 <emphasis>--pidfile FILE</emphasis>
1458 On startup, write the process ID to <emphasis>FILE</emphasis>. Delete the
1459 <emphasis>FILE</emphasis> on exit. Failure to create or delete the
1460 <emphasis>FILE</emphasis> is non-fatal. If no <emphasis>FILE</emphasis>
1461 option is given, no PID file will be used. Unix only.
1466 <emphasis>--user USER[.GROUP]</emphasis>
1469 After (optionally) writing the PID file, assume the user ID of
1470 <emphasis>USER</emphasis>, and if included the GID of GROUP. Exit if the
1471 privileges are not sufficient to do so. Unix only.
1476 <emphasis>--chroot</emphasis>
1479 Before changing to the user ID given in the <emphasis>--user</emphasis> option,
1480 chroot to that user's home directory, i.e. make the kernel pretend to the &my-app;
1481 process that the directory tree starts there. If set up carefully, this can limit
1482 the impact of possible vulnerabilities in &my-app; to the files contained in that hierarchy.
1488 <emphasis>--pre-chroot-nslookup hostname</emphasis>
1491 Specifies a hostname (for example www.privoxy.org) to look up before doing a chroot.
1492 On some systems, initializing the resolver library involves reading config files from
1493 /etc and/or loading additional shared libraries from /lib.
1494 On these systems, doing a hostname lookup before the chroot reduces
1495 the number of files that must be copied into the chroot tree.
1498 For fastest startup speed, a good value is a hostname that is not in /etc/hosts but that
1499 your local name server (listed in /etc/resolv.conf) can resolve without recursion
1500 (that is, without having to ask any other name servers). The hostname need not exist,
1501 but if it doesn't, an error message (which can be ignored) will be output.
1507 <emphasis>configfile</emphasis>
1510 If no <emphasis>configfile</emphasis> is included on the command line,
1511 <application>Privoxy</application> will look for a file named
1512 <quote>config</quote> in the current directory (except on Win32
1513 where it will look for <quote>config.txt</quote> instead). Specify
1514 full path to avoid confusion. If no config file is found,
1515 <application>Privoxy</application> will fail to start.
1522 On <application>MS Windows</application> only there are two additional
1523 command-line options to allow <application>Privoxy</application> to install and
1524 run as a <emphasis>service</emphasis>. See the
1525 <link linkend="installation-pack-win">Window Installation section</link>
1533 <!-- ~ End section ~ -->
1536 <!-- ~~~~~ New section ~~~~~ -->
1537 <sect1 id="configuration"><title>Privoxy Configuration</title>
1539 All <application>Privoxy</application> configuration is stored
1540 in text files. These files can be edited with a text editor.
1541 Many important aspects of <application>Privoxy</application> can
1542 also be controlled easily with a web browser.
1546 <!-- ~~~~~ New section ~~~~~ -->
1548 <sect2 id="control-with-webbrowser">
1549 <title>Controlling Privoxy with Your Web Browser</title>
1551 <application>Privoxy</application>'s user interface can be reached through the special
1552 URL <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
1553 (shortcut: <ulink url="http://p.p/">http://p.p/</ulink>),
1554 which is a built-in page and works without Internet access.
1555 You will see the following section:
1558 <!-- Needs to be put in a table and colorized -->
1559 <screen><!-- want the background color that goes with screen -->
1561 <bridgehead renderas="sect2"> Privoxy Menu</bridgehead>
1564 ▪ <ulink url="http://config.privoxy.org/show-status">View & change the current configuration</ulink>
1567 ▪ <ulink url="http://config.privoxy.org/client-tags">View or toggle the tags that can be set based on the client's address</ulink>
1570 ▪ <ulink url="http://config.privoxy.org/show-request">View the request headers.</ulink>
1573 ▪ <ulink url="http://config.privoxy.org/show-url-info">Look up which actions apply to a URL and why</ulink>
1576 ▪ <ulink url="http://config.privoxy.org/toggle">Toggle Privoxy on or off</ulink>
1579 ▪ <ulink
1580 url="https://www.privoxy.org/&p-version;/user-manual/">Documentation</ulink>
1588 This should be self-explanatory. Note the first item leads to an editor for the
1589 <link linkend="actions-file">actions files</link>, which is where the ad, banner,
1590 cookie, and URL blocking magic is configured as well as other advanced features of
1591 <application>Privoxy</application>. This is an easy way to adjust various
1592 aspects of <application>Privoxy</application> configuration. The actions
1593 file, and other configuration files, are explained in detail below.
1597 <quote>Toggle Privoxy On or Off</quote> is handy for sites that might
1598 have problems with your current actions and filters. You can in fact use
1599 it as a test to see whether it is <application>Privoxy</application>
1600 causing the problem or not. <application>Privoxy</application> continues
1601 to run as a proxy in this case, but all manipulation is disabled, i.e.
1602 <application>Privoxy</application> acts like a normal forwarding proxy.
1606 Note that several of the features described above are disabled by default
1607 in <application>Privoxy</application> 3.0.7 beta and later.
1609 <ulink url="config.html">configuration file</ulink> to learn why
1610 and in which cases it's safe to enable them again.
1615 <!-- ~ End section ~ -->
1620 <!-- ~~~~~ New section ~~~~~ -->
1622 <sect2 id="confoverview">
1623 <title>Configuration Files Overview</title>
1625 For Unix, *BSD and GNU/Linux, all configuration files are located in
1626 <filename>/etc/privoxy/</filename> by default. For MS Windows
1627 these are all in the same directory as the
1628 <application>Privoxy</application> executable. <![%p-not-stable;[ The name
1629 and number of configuration files has changed from previous versions, and is
1630 subject to change as development progresses.]]>
1634 The installed defaults provide a reasonable starting point, though
1635 some settings may be aggressive by some standards. For the time being, the
1636 principle configuration files are:
1643 The <link linkend="config">main configuration file</link> is named <filename>config</filename>
1644 on GNU/Linux, Unix, BSD, and <filename>config.txt</filename>
1645 on Windows. This is a required file.
1651 <filename>match-all.action</filename> is used to define which <quote>actions</quote>
1652 relating to banner-blocking, images, pop-ups, content modification, cookie handling
1653 etc should be applied by default. It should be the first actions file loaded.
1656 <filename>default.action</filename> defines many exceptions (both positive and negative)
1657 from the default set of actions that's configured in <filename>match-all.action</filename>.
1658 It should be the second actions file loaded and shouldn't be edited by the user.
1661 Multiple actions files may be defined in <filename>config</filename>. These
1662 are processed in the order they are defined. Local customizations and locally
1663 preferred exceptions to the default policies as defined in
1664 <filename>match-all.action</filename> (which you will most probably want
1665 to define sooner or later) are best applied in <filename>user.action</filename>,
1666 where you can preserve them across upgrades. The file isn't installed by all
1667 installers, but you can easily create it yourself with a text editor.
1670 There is also a web based editor that can be accessed from
1672 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1674 url="http://p.p/show-status">http://p.p/show-status</ulink>) for the
1675 various actions files.
1681 <quote>Filter files</quote> (the <link linkend="filter-file">filter
1682 file</link>) can be used to re-write the raw page content, including
1683 viewable text as well as embedded HTML and JavaScript, and whatever else
1684 lurks on any given web page. The filtering jobs are only pre-defined here;
1685 whether to apply them or not is up to the actions files.
1686 <filename>default.filter</filename> includes various filters made
1687 available for use by the developers. Some are much more intrusive than
1688 others, and all should be used with caution. You may define additional
1689 filter files in <filename>config</filename> as you can with
1690 actions files. We suggest <filename>user.filter</filename> for any
1691 locally defined filters or customizations.
1698 The syntax of the configuration and filter files may change between different
1699 Privoxy versions, unfortunately some enhancements cost backwards compatibility.
1700 <!-- Add link to documentation-->
1704 All files use the <quote><literal>#</literal></quote> character to denote a
1705 comment (the rest of the line will be ignored) and understand line continuation
1706 through placing a backslash ("<literal>\</literal>") as the very last character
1707 in a line. If the <literal>#</literal> is preceded by a backslash, it looses
1708 its special function. Placing a <literal>#</literal> in front of an otherwise
1709 valid configuration line to prevent it from being interpreted is called "commenting
1710 out" that line. Blank lines are ignored.
1714 The actions files and filter files
1715 can use Perl style <link linkend="regex">regular expressions</link> for
1716 maximum flexibility.
1720 After making any changes, there is no need to restart
1721 <application>Privoxy</application> in order for the changes to take
1722 effect. <application>Privoxy</application> detects such changes
1723 automatically. Note, however, that it may take one or two additional
1724 requests for the change to take effect. When changing the listening address
1725 of <application>Privoxy</application>, these <quote>wake up</quote> requests
1726 must obviously be sent to the <emphasis>old</emphasis> listening address.
1731 While under development, the configuration content is subject to change.
1732 The below documentation may not be accurate by the time you read this.
1733 Also, what constitutes a <quote>default</quote> setting, may change, so
1734 please check all your configuration files on important issues.
1740 <!-- ~ End section ~ -->
1743 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
1745 <!-- **************************************************** -->
1746 <!-- Include config.sgml here -->
1747 <!-- This is where the entire config file is detailed. -->
1749 <!-- end include -->
1752 <!-- ~ End section ~ -->
1756 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
1758 <sect1 id="actions-file"><title>Actions Files</title>
1762 XXX: similar descriptions are in the Configuration Files sections.
1763 We should only describe them at one place.
1766 The actions files are used to define what <emphasis>actions</emphasis>
1767 <application>Privoxy</application> takes for which URLs, and thus determines
1768 how ad images, cookies and various other aspects of HTTP content and
1769 transactions are handled, and on which sites (or even parts thereof).
1770 There are a number of such actions, with a wide range of functionality.
1771 Each action does something a little different.
1772 These actions give us a veritable arsenal of tools with which to exert
1773 our control, preferences and independence. Actions can be combined so that
1774 their effects are aggregated when applied against a given set of URLs.
1778 are three action files included with <application>Privoxy</application> with
1784 <filename>match-all.action</filename> - is used to define which
1785 <quote>actions</quote> relating to banner-blocking, images, pop-ups,
1786 content modification, cookie handling etc should be applied by default.
1787 It should be the first actions file loaded
1792 <filename>default.action</filename> - defines many exceptions (both
1793 positive and negative) from the default set of actions that's configured
1794 in <filename>match-all.action</filename>. It is a set of rules that should
1795 work reasonably well as-is for most users. This file is only supposed to
1796 be edited by the developers. It should be the second actions file loaded.
1801 <filename>user.action</filename> - is intended to be for local site
1802 preferences and exceptions. As an example, if your ISP or your bank
1803 has specific requirements, and need special handling, this kind of
1804 thing should go here. This file will not be upgraded.
1809 <guibutton>Edit</guibutton> <guibutton>Set to Cautious</guibutton> <guibutton>Set to Medium</guibutton> <guibutton>Set to Advanced</guibutton>
1812 These have increasing levels of aggressiveness <emphasis>and have no
1813 influence on your browsing unless you select them explicitly in the
1814 editor</emphasis>. A default installation should be pre-set to
1815 <literal>Cautious</literal>. New users should try this for a while before
1816 adjusting the settings to more aggressive levels. The more aggressive
1817 the settings, then the more likelihood there is of problems such as sites
1818 not working as they should.
1821 The <guibutton>Edit</guibutton> button allows you to turn each
1822 action on/off individually for fine-tuning. The <guibutton>Cautious</guibutton>
1823 button changes the actions list to low/safe settings which will activate
1824 ad blocking and a minimal set of &my-app;'s features, and subsequently
1825 there will be less of a chance for accidental problems. The
1826 <guibutton>Medium</guibutton> button sets the list to a medium level of
1827 other features and a low level set of privacy features. The
1828 <guibutton>Advanced</guibutton> button sets the list to a high level of
1829 ad blocking and medium level of privacy. See the chart below. The latter
1830 three buttons over-ride any changes via with the
1831 <guibutton>Edit</guibutton> button. More fine-tuning can be done in the
1832 lower sections of this internal page.
1835 While the actions file editor allows to enable these settings in all
1836 actions files, they are only supposed to be enabled in the first one
1837 to make sure you don't unintentionally overrule earlier rules.
1840 The default profiles, and their associated actions, as pre-defined in
1841 <filename>default.action</filename> are:
1843 <table frame=all id="default-configurations"><title>Default Configurations</title>
1844 <tgroup cols=4 align=left colsep=1 rowsep=1>
1845 <colspec colname=c1>
1846 <colspec colname=c2>
1847 <colspec colname=c3>
1848 <colspec colname=c4>
1851 <entry>Feature</entry>
1852 <entry>Cautious</entry>
1853 <entry>Medium</entry>
1854 <entry>Advanced</entry>
1859 <!-- <entry>f1</entry> -->
1860 <!-- <entry>f2</entry> -->
1861 <!-- <entry>f3</entry> -->
1862 <!-- <entry>f4</entry> -->
1868 <entry>Ad-blocking Aggressiveness</entry>
1869 <entry>medium</entry>
1875 <entry>Ad-filtering by size</entry>
1882 <entry>Ad-filtering by link</entry>
1888 <entry>Pop-up killing</entry>
1889 <entry>blocks only</entry>
1890 <entry>blocks only</entry>
1891 <entry>blocks only</entry>
1895 <entry>Privacy Features</entry>
1897 <entry>medium</entry>
1898 <entry>medium/high</entry>
1902 <entry>Cookie handling</entry>
1904 <entry>session-only</entry>
1909 <entry>Referer forging</entry>
1916 <entry>GIF de-animation</entry>
1923 <entry>Fast redirects</entry>
1930 <entry>HTML taming</entry>
1937 <entry>JavaScript taming</entry>
1944 <entry>Web-bug killing</entry>
1951 <entry>Image tag reordering</entry>
1965 The list of actions files to be used are defined in the main configuration
1966 file, and are processed in the order they are defined (e.g.
1967 <filename>default.action</filename> is typically processed before
1968 <filename>user.action</filename>). The content of these can all be viewed and
1970 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
1971 The over-riding principle when applying actions, is that the last action that
1972 matches a given URL wins. The broadest, most general rules go first
1973 (defined in <filename>default.action</filename>),
1974 followed by any exceptions (typically also in
1975 <filename>default.action</filename>), which are then followed lastly by any
1976 local preferences (typically in <emphasis>user</emphasis><filename>.action</filename>).
1977 Generally, <filename>user.action</filename> has the last word.
1981 An actions file typically has multiple sections. If you want to use
1982 <quote>aliases</quote> in an actions file, you have to place the (optional)
1983 <link linkend="aliases">alias section</link> at the top of that file.
1984 Then comes the default set of rules which will apply universally to all
1985 sites and pages (be <emphasis>very careful</emphasis> with using such a
1986 universal set in <filename>user.action</filename> or any other actions file after
1987 <filename>default.action</filename>, because it will override the result
1988 from consulting any previous file). And then below that,
1989 exceptions to the defined universal policies. You can regard
1990 <filename>user.action</filename> as an appendix to <filename>default.action</filename>,
1991 with the advantage that it is a separate file, which makes preserving your
1992 personal settings across <application>Privoxy</application> upgrades easier.
1996 Actions can be used to block anything you want, including ads, banners, or
1997 just some obnoxious URL whose content you would rather not see. Cookies can be accepted
1998 or rejected, or accepted only during the current browser session (i.e. not
1999 written to disk), content can be modified, some JavaScripts tamed, user-tracking
2000 fooled, and much more. See below for a <link linkend="actions">complete list
2004 <!-- ~~~~~ New section ~~~~~ -->
2005 <sect2 id="right-mix">
2006 <title>Finding the Right Mix</title>
2008 Note that some <link linkend="actions">actions</link>, like cookie suppression
2009 or script disabling, may render some sites unusable that rely on these
2010 techniques to work properly. Finding the right mix of actions is not always easy and
2011 certainly a matter of personal taste. And, things can always change, requiring
2012 refinements in the configuration. In general, it can be said that the more
2013 <quote>aggressive</quote> your default settings (in the top section of the
2014 actions file) are, the more exceptions for <quote>trusted</quote> sites you
2015 will have to make later. If, for example, you want to crunch all cookies per
2016 default, you'll have to make exceptions from that rule for sites that you
2017 regularly use and that require cookies for actually useful purposes, like maybe
2018 your bank, favorite shop, or newspaper.
2022 We have tried to provide you with reasonable rules to start from in the
2023 distribution actions files. But there is no general rule of thumb on these
2024 things. There just are too many variables, and sites are constantly changing.
2025 Sooner or later you will want to change the rules (and read this chapter again :).
2029 <!-- ~~~~~ New section ~~~~~ -->
2030 <sect2 id="how-to-edit">
2031 <title>How to Edit</title>
2033 The easiest way to edit the actions files is with a browser by
2034 using our browser-based editor, which can be reached from <ulink
2035 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
2036 Note: the config file option <link
2037 linkend="enable-edit-actions">enable-edit-actions</link> must be enabled for
2038 this to work. The editor allows both fine-grained control over every single
2039 feature on a per-URL basis, and easy choosing from wholesale sets of defaults
2040 like <quote>Cautious</quote>, <quote>Medium</quote> or
2041 <quote>Advanced</quote>. Warning: the <quote>Advanced</quote> setting is more
2042 aggressive, and will be more likely to cause problems for some sites.
2043 Experienced users only!
2047 If you prefer plain text editing to GUIs, you can of course also directly edit the
2048 the actions files with your favorite text editor. Look at
2049 <filename>default.action</filename> which is richly commented with many
2055 <sect2 id="actions-apply">
2056 <title>How Actions are Applied to Requests</title>
2058 Actions files are divided into sections. There are special sections,
2059 like the <quote><link linkend="aliases">alias</link></quote> sections which will
2060 be discussed later. For now let's concentrate on regular sections: They have a
2061 heading line (often split up to multiple lines for readability) which consist
2062 of a list of actions, separated by whitespace and enclosed in curly braces.
2063 Below that, there is a list of URL and tag patterns, each on a separate line.
2067 To determine which actions apply to a request, the URL of the request is
2068 compared to all URL patterns in each <quote>action file</quote>.
2069 Every time it matches, the list of applicable actions for the request is
2070 incrementally updated, using the heading of the section in which the
2071 pattern is located. The same is done again for tags and tag patterns later on.
2075 If multiple applying sections set the same action differently,
2076 the last match wins. If not, the effects are aggregated.
2077 E.g. a URL might match a regular section with a heading line of <literal>{
2078 +<link linkend="handle-as-image">handle-as-image</link> }</literal>,
2079 then later another one with just <literal>{
2080 +<link linkend="block">block</link> }</literal>, resulting
2081 in <emphasis>both</emphasis> actions to apply. And there may well be
2082 cases where you will want to combine actions together. Such a section then
2087 { +<literal>handle-as-image</literal> +<literal>block{Banner ads.}</literal> }
2088 # Block these as if they were images. Send no block page.
2090 media.example.com/.*banners
2091 .example.com/images/ads/
2095 You can trace this process for URL patterns and any given URL by visiting <ulink
2096 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>.
2100 Examples and more detail on this is provided in the Appendix, <link linkend="ACTIONSANAT">
2101 Troubleshooting: Anatomy of an Action</link> section.
2105 <!-- ~~~~~ New section ~~~~~ -->
2106 <sect2 id="af-patterns">
2107 <title>Patterns</title>
2109 As mentioned, <application>Privoxy</application> uses <quote>patterns</quote>
2110 to determine what <emphasis>actions</emphasis> might apply to which sites and
2111 pages your browser attempts to access. These <quote>patterns</quote> use wild
2112 card type <emphasis>pattern</emphasis> matching to achieve a high degree of
2113 flexibility. This allows one expression to be expanded and potentially match
2114 against many similar patterns.
2118 Generally, an URL pattern has the form
2119 <literal><host><port>/<path></literal>, where the
2120 <literal><host></literal>, the <literal><port></literal>
2121 and the <literal><path></literal> are optional. (This is why the special
2122 <literal>/</literal> pattern matches all URLs). Note that the protocol
2123 portion of the URL pattern (e.g. <literal>http://</literal>) should
2124 <emphasis>not</emphasis> be included in the pattern. This is assumed already!
2127 The pattern matching syntax is different for the host and path parts of
2128 the URL. The host part uses a simple globbing type matching technique,
2129 while the path part uses more flexible
2130 <ulink url="https://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
2131 Expressions</quote></ulink> (POSIX 1003.2).
2134 The port part of a pattern is a decimal port number preceded by a colon
2135 (<literal>:</literal>). If the host part contains a numerical IPv6 address,
2136 it has to be put into angle brackets
2137 (<literal><</literal>, <literal>></literal>).
2142 <term><literal>www.example.com/</literal></term>
2145 is a host-only pattern and will match any request to <literal>www.example.com</literal>,
2146 regardless of which document on that server is requested. So ALL pages in
2147 this domain would be covered by the scope of this action. Note that a
2148 simple <literal>example.com</literal> is different and would NOT match.
2153 <term><literal>www.example.com</literal></term>
2156 means exactly the same. For host-only patterns, the trailing <literal>/</literal> may
2162 <term><literal>www.example.com/index.html</literal></term>
2165 matches all the documents on <literal>www.example.com</literal>
2166 whose name starts with <literal>/index.html</literal>.
2171 <term><literal>www.example.com/index.html$</literal></term>
2174 matches only the single document <literal>/index.html</literal>
2175 on <literal>www.example.com</literal>.
2180 <term><literal>/index.html$</literal></term>
2183 matches the document <literal>/index.html</literal>, regardless of the domain,
2184 i.e. on <emphasis>any</emphasis> web server anywhere.
2189 <term><literal>/</literal></term>
2192 Matches any URL because there's no requirement for either the
2193 domain or the path to match anything.
2198 <term><literal>:8000/</literal></term>
2201 Matches any URL pointing to TCP port 8000.
2206 <term><literal>10.0.0.1/</literal></term>
2209 Matches any URL with the host address <literal>10.0.0.1</literal>.
2210 (Note that the real URL uses plain brackets, not angle brackets.)
2215 <term><literal><2001:db8::1>/</literal></term>
2218 Matches any URL with the host address <literal>2001:db8::1</literal>.
2219 (Note that the real URL uses plain brackets, not angle brackets.)
2224 <term><literal>index.html</literal></term>
2227 matches nothing, since it would be interpreted as a domain name and
2228 there is no top-level domain called <literal>.html</literal>. So its
2236 <!-- ~~~~~ New section ~~~~~ -->
2237 <sect3 id="host-pattern"><title>The Host Pattern</title>
2240 The matching of the host part offers some flexible options: if the
2241 host pattern starts or ends with a dot, it becomes unanchored at that end.
2242 The host pattern is often referred to as domain pattern as it is usually
2243 used to match domain names and not IP addresses.
2249 <term><literal>.example.com</literal></term>
2252 matches any domain with first-level domain <literal>com</literal>
2253 and second-level domain <literal>example</literal>.
2254 For example <literal>www.example.com</literal>,
2255 <literal>example.com</literal> and <literal>foo.bar.baz.example.com</literal>.
2256 Note that it wouldn't match if the second-level domain was <literal>another-example</literal>.
2261 <term><literal>www.</literal></term>
2264 matches any domain that <emphasis>STARTS</emphasis> with
2265 <literal>www.</literal> (It also matches the domain
2266 <literal>www</literal> but most of the time that doesn't matter.)
2271 <term><literal>.example.</literal></term>
2274 matches any domain that <emphasis>CONTAINS</emphasis> <literal>.example.</literal>.
2275 And, by the way, also included would be any files or documents that exist
2276 within that domain since no path limitations are specified. (Correctly
2277 speaking: It matches any FQDN that contains <literal>example</literal> as
2278 a domain.) This might be <literal>www.example.com</literal>,
2279 <literal>news.example.de</literal>, or
2280 <literal>www.example.net/cgi/testing.pl</literal> for instance. All these
2288 Additionally, there are wild-cards that you can use in the domain names
2289 themselves. These work similarly to shell globbing type wild-cards:
2290 <quote>*</quote> represents zero or more arbitrary characters (this is
2292 <ulink url="https://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
2293 Expression</quote></ulink> based syntax of <quote>.*</quote>),
2294 <quote>?</quote> represents any single character (this is equivalent to the
2295 regular expression syntax of a simple <quote>.</quote>), and you can define
2296 <quote>character classes</quote> in square brackets which is similar to
2297 the same regular expression technique. All of this can be freely mixed:
2302 <term><literal>ad*.example.com</literal></term>
2305 matches <quote>adserver.example.com</quote>,
2306 <quote>ads.example.com</quote>, etc but not <quote>sfads.example.com</quote>
2311 <term><literal>*ad*.example.com</literal></term>
2314 matches all of the above, and then some.
2319 <term><literal>.?pix.com</literal></term>
2322 matches <literal>www.ipix.com</literal>,
2323 <literal>pictures.epix.com</literal>, <literal>a.b.c.d.e.upix.com</literal> etc.
2328 <term><literal>www[1-9a-ez].example.c*</literal></term>
2331 matches <literal>www1.example.com</literal>,
2332 <literal>www4.example.cc</literal>, <literal>wwwd.example.cy</literal>,
2333 <literal>wwwz.example.com</literal> etc., but <emphasis>not</emphasis>
2334 <literal>wwww.example.com</literal>.
2341 While flexible, this is not the sophistication of full regular expression based syntax.
2345 When compiled with FEATURE_PCRE_HOST_PATTERNS patterns can be prefixed with
2346 <quote>PCRE-HOST-PATTERN:</quote> in which case full regular expression
2347 (PCRE) can be used for the host pattern as well.
2352 <!-- ~ End section ~ -->
2355 <!-- ~~~~~ New section ~~~~~ -->
2356 <sect3 id="path-pattern"><title>The Path Pattern</title>
2359 <application>Privoxy</application> uses <quote>modern</quote> POSIX 1003.2
2360 <ulink url="https://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
2361 Expressions</quote></ulink> for matching the path portion (after the slash),
2362 and is thus more flexible.
2366 There is an <link linkend="regex">Appendix</link> with a brief quick-start into regular
2367 expressions, you also might want to have a look at your operating system's documentation
2368 on regular expressions (try <literal>man re_format</literal>).
2372 Note that the path pattern is automatically left-anchored at the <quote>/</quote>,
2373 i.e. it matches as if it would start with a <quote>^</quote> (regular expression speak
2374 for the beginning of a line).
2378 Please also note that matching in the path is <emphasis>CASE INSENSITIVE</emphasis>
2379 by default, but you can switch to case sensitive at any point in the pattern by using the
2380 <quote>(?-i)</quote> switch: <literal>www.example.com/(?-i)PaTtErN.*</literal> will match
2381 only documents whose path starts with <literal>PaTtErN</literal> in
2382 <emphasis>exactly</emphasis> this capitalization.
2387 <term><literal>.example.com/.*</literal></term>
2390 Is equivalent to just <quote>.example.com</quote>, since any documents
2391 within that domain are matched with or without the <quote>.*</quote>
2392 regular expression. This is redundant
2397 <term><literal>.example.com/.*/index.html$</literal></term>
2400 Will match any page in the domain of <quote>example.com</quote> that is
2401 named <quote>index.html</quote>, and that is part of some path. For
2402 example, it matches <quote>www.example.com/testing/index.html</quote> but
2403 NOT <quote>www.example.com/index.html</quote> because the regular
2404 expression called for at least two <quote>/'s</quote>, thus the path
2405 requirement. It also would match
2406 <quote>www.example.com/testing/index_html</quote>, because of the
2407 special meta-character <quote>.</quote>.
2412 <term><literal>.example.com/(.*/)?index\.html$</literal></term>
2415 This regular expression is conditional so it will match any page
2416 named <quote>index.html</quote> regardless of path which in this case can
2417 have one or more <quote>/'s</quote>. And this one must contain exactly
2418 <quote>.html</quote> (and end with that!).
2423 <term><literal>.example.com/(.*/)(ads|banners?|junk)</literal></term>
2426 This regular expression will match any path of <quote>example.com</quote>
2427 that contains any of the words <quote>ads</quote>, <quote>banner</quote>,
2428 <quote>banners</quote> (because of the <quote>?</quote>) or <quote>junk</quote>.
2429 The path does not have to end in these words, just contain them.
2430 The path has to contain at least two slashes (including the one at the beginning).
2435 <term><literal>.example.com/(.*/)(ads|banners?|junk)/.*\.(jpe?g|gif|png)$</literal></term>
2438 This is very much the same as above, except now it must end in either
2439 <quote>.jpg</quote>, <quote>.jpeg</quote>, <quote>.gif</quote> or <quote>.png</quote>. So this
2440 one is limited to common image formats.
2447 There are many, many good examples to be found in <filename>default.action</filename>,
2448 and more tutorials below in <link linkend="regex">Appendix on regular expressions</link>.
2453 <!-- ~ End section ~ -->
2456 <!-- ~~~~~ New section ~~~~~ -->
2457 <sect3 id="tag-pattern"><title>The Request Tag Pattern</title>
2460 Request tag patterns are used to change the applying actions based on the
2461 request's tags. Tags can be created based on HTTP headers with either
2462 the <link linkend="CLIENT-HEADER-TAGGER">client-header-tagger</link>
2463 or the <link linkend="SERVER-HEADER-TAGGER">server-header-tagger</link> action.
2467 Request tag patterns have to start with <quote>TAG:</quote>, so &my-app;
2468 can tell them apart from other patterns. Everything after the colon
2469 including white space, is interpreted as a regular expression with
2470 path pattern syntax, except that tag patterns aren't left-anchored
2471 automatically (&my-app; doesn't silently add a <quote>^</quote>,
2472 you have to do it yourself if you need it).
2476 To match all requests that are tagged with <quote>foo</quote>
2477 your pattern line should be <quote>TAG:^foo$</quote>,
2478 <quote>TAG:foo</quote> would work as well, but it would also
2479 match requests whose tags contain <quote>foo</quote> somewhere.
2480 <quote>TAG: foo</quote> wouldn't work as it requires white space.
2484 Sections can contain URL and request tag patterns at the same time,
2485 but request tag patterns are checked after the URL patterns and thus
2486 always overrule them, even if they are located before the URL patterns.
2490 Once a new request tag is added, Privoxy checks right away if it's matched by one
2491 of the request tag patterns and updates the action settings accordingly. As a result
2492 request tags can be used to activate other tagger actions, as long as these other
2493 taggers look for headers that haven't already be parsed.
2497 For example you could tag client requests which use the
2498 <literal>POST</literal> method,
2499 then use this tag to activate another tagger that adds a tag if cookies
2500 are sent, and then use a block action based on the cookie tag. This allows
2501 the outcome of one action, to be input into a subsequent action. However if
2502 you'd reverse the position of the described taggers, and activated the
2503 method tagger based on the cookie tagger, no method tags would be created.
2504 The method tagger would look for the request line, but at the time
2505 the cookie tag is created, the request line has already been parsed.
2509 While this is a limitation you should be aware of, this kind of
2510 indirection is seldom needed anyway and even the example doesn't
2511 make too much sense.
2516 <!-- ~~~~~ New section ~~~~~ -->
2517 <sect3 id="negative-tag-patterns"><title>The Negative Request Tag Patterns</title>
2520 To match requests that do not have a certain request tag, specify a negative tag pattern
2521 by prefixing the tag pattern line with either <quote>NO-REQUEST-TAG:</quote>
2522 or <quote>NO-RESPONSE-TAG:</quote> instead of <quote>TAG:</quote>.
2526 Negative request tag patterns created with <quote>NO-REQUEST-TAG:</quote> are checked
2527 after all client headers are scanned, the ones created with <quote>NO-RESPONSE-TAG:</quote>
2528 are checked after all server headers are scanned. In both cases all the created
2529 tags are considered.
2533 <!-- ~~~~~ New section ~~~~~ -->
2534 <sect3 id="client-tag-pattern"><title>The Client Tag Pattern</title>
2536 <!-- XXX: This section contains duplicates content from the
2537 client-specific-tag documentation. -->
2541 This is an experimental feature. The syntax is likely to change in future versions.
2546 Client tag patterns are not set based on HTTP headers but based on
2547 the client's IP address. Users can enable them themselves, but the
2548 Privoxy admin controls which tags are available and what their effect
2553 After a client-specific tag has been defined with the
2554 <link linkend="client-specific-tag">client-specific-tag</link>,
2555 directive, action sections can be activated based on the tag by using a
2556 CLIENT-TAG pattern. The CLIENT-TAG pattern is evaluated at the same priority
2557 as URL patterns, as a result the last matching pattern wins. Tags that
2558 are created based on client or server headers are evaluated later on
2559 and can overrule CLIENT-TAG and URL patterns!
2562 The tag is set for all requests that come from clients that requested
2563 it to be set. Note that "clients" are differentiated by IP address,
2564 if the IP address changes the tag has to be requested again.
2567 Clients can request tags to be set by using the CGI interface <ulink
2568 url="http://config.privoxy.org/client-tags">http://config.privoxy.org/client-tags</ulink>.
2576 # If the admin defined the client-specific-tag circumvent-blocks,
2577 # and the request comes from a client that previously requested
2578 # the tag to be set, overrule all previous +block actions that
2579 # are enabled based on URL to CLIENT-TAG patterns.
2581 CLIENT-TAG:^circumvent-blocks$
2583 # This section is not overruled because it's located after
2585 {+block{Nobody is supposed to request this.}}
2586 example.org/blocked-example-page</screen>
2592 <!-- ~ End section ~ -->
2595 <!-- ~~~~~ New section ~~~~~ -->
2597 <sect2 id="actions">
2598 <title>Actions</title>
2600 All actions are disabled by default, until they are explicitly enabled
2601 somewhere in an actions file. Actions are turned on if preceded with a
2602 <quote>+</quote>, and turned off if preceded with a <quote>-</quote>. So a
2603 <literal>+action</literal> means <quote>do that action</quote>, e.g.
2604 <literal>+block</literal> means <quote>please block URLs that match the
2605 following patterns</quote>, and <literal>-block</literal> means <quote>don't
2606 block URLs that match the following patterns, even if <literal>+block</literal>
2607 previously applied.</quote>
2611 Again, actions are invoked by placing them on a line, enclosed in curly braces and
2612 separated by whitespace, like in
2613 <literal>{+some-action -some-other-action{some-parameter}}</literal>,
2614 followed by a list of URL patterns, one per line, to which they apply.
2615 Together, the actions line and the following pattern lines make up a section
2616 of the actions file.
2620 Actions fall into three categories:
2626 Boolean, i.e the action can only be <quote>enabled</quote> or
2627 <quote>disabled</quote>. Syntax:
2630 +<replaceable class="function">name</replaceable> # enable action <replaceable class="parameter">name</replaceable>
2631 -<replaceable class="function">name</replaceable> # disable action <replaceable class="parameter">name</replaceable>
2634 Example: <literal>+handle-as-image</literal>
2641 Parameterized, where some value is required in order to enable this type of action.
2645 +<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # enable action and set parameter to <replaceable class="parameter">param</replaceable>,
2646 # overwriting parameter from previous match if necessary
2647 -<replaceable class="function">name</replaceable> # disable action. The parameter can be omitted
2650 Note that if the URL matches multiple positive forms of a parameterized action,
2651 the last match wins, i.e. the params from earlier matches are simply ignored.
2654 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>
2660 Multi-value. These look exactly like parameterized actions,
2661 but they behave differently: If the action applies multiple times to the
2662 same URL, but with different parameters, <emphasis>all</emphasis> the parameters
2663 from <emphasis>all</emphasis> matches are remembered. This is used for actions
2664 that can be executed for the same request repeatedly, like adding multiple
2665 headers, or filtering through multiple filters. Syntax:
2668 +<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # enable action and add <replaceable class="parameter">param</replaceable> to the list of parameters
2669 -<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # remove the parameter <replaceable class="parameter">param</replaceable> from the list of parameters
2670 # If it was the last one left, disable the action.
2671 <replaceable class="parameter">-name</replaceable> # disable this action completely and remove all parameters from the list
2674 Examples: <literal>+add-header{X-Fun-Header: Some text}</literal> and
2675 <literal>+filter{html-annoyances}</literal>
2682 If nothing is specified in any actions file, no <quote>actions</quote> are
2683 taken. So in this case <application>Privoxy</application> would just be a
2684 normal, non-blocking, non-filtering proxy. You must specifically enable the
2685 privacy and blocking features you need (although the provided default actions
2686 files will give a good starting point).
2690 Later defined action sections always over-ride earlier ones of the same type.
2691 So exceptions to any rules you make, should come in the latter part of the file (or
2692 in a file that is processed later when using multiple actions files such
2693 as <filename>user.action</filename>). For multi-valued actions, the actions
2694 are applied in the order they are specified. Actions files are processed in
2695 the order they are defined in <filename>config</filename> (the default
2696 installation has three actions files). It also quite possible for any given
2697 URL to match more than one <quote>pattern</quote> (because of wildcards and
2698 regular expressions), and thus to trigger more than one set of actions! Last
2702 <!-- start actions listing -->
2704 The list of valid <application>Privoxy</application> actions are:
2708 <!-- ********************************************************** -->
2709 <!-- Please note the below defined actions use id's that are -->
2710 <!-- probably linked from other places, so please don't change. -->
2712 <!-- ********************************************************** -->
2715 <!-- ~~~~~ New section ~~~~~ -->
2717 <sect3 renderas="sect4" id="add-header">
2718 <title>add-header</title>
2722 <term>Typical use:</term>
2724 <para>Confuse log analysis, custom applications</para>
2729 <term>Effect:</term>
2732 Sends a user defined HTTP header to the web server.
2739 <!-- boolean, parameterized, Multi-value -->
2741 <para>Multi-value.</para>
2746 <term>Parameter:</term>
2749 Any string value is possible. Validity of the defined HTTP headers is not checked.
2750 It is recommended that you use the <quote><literal>X-</literal></quote> prefix
2760 This action may be specified multiple times, in order to define multiple
2761 headers. This is rarely needed for the typical user. If you don't know what
2762 <quote>HTTP headers</quote> are, you definitely don't need to worry about this
2766 Headers added by this action are not modified by other actions.
2772 <term>Example usage:</term>
2774 <screen># Add a DNT ("Do not track") header to all requests,
2775 # event to those that already have one.
2777 # This is just an example, not a recommendation.
2779 # There is no reason to believe that user-tracking websites care
2780 # about the DNT header and depending on the User-Agent, adding the
2781 # header may make user-tracking easier.
2782 {+add-header{DNT: 1}}
2790 <!-- ~~~~~ New section ~~~~~ -->
2791 <sect3 renderas="sect4" id="block">
2792 <title>block</title>
2796 <term>Typical use:</term>
2798 <para>Block ads or other unwanted content</para>
2803 <term>Effect:</term>
2806 Requests for URLs to which this action applies are blocked, i.e. the
2807 requests are trapped by &my-app; and the requested URL is never retrieved,
2808 but is answered locally with a substitute page or image, as determined by
2810 linkend="handle-as-image">handle-as-image</link></literal>,
2812 linkend="set-image-blocker">set-image-blocker</link></literal>, and
2814 linkend="handle-as-empty-document">handle-as-empty-document</link></literal> actions.
2822 <!-- boolean, parameterized, Multi-value -->
2824 <para>Parameterized.</para>
2829 <term>Parameter:</term>
2831 <para>A block reason that should be given to the user.</para>
2839 <application>Privoxy</application> sends a special <quote>BLOCKED</quote> page
2840 for requests to blocked pages. This page contains the block reason given as
2841 parameter, a link to find out why the block action applies, and a click-through
2842 to the blocked content (the latter only if the force feature is available and
2846 A very important exception occurs if <emphasis>both</emphasis>
2847 <literal>block</literal> and <literal><link linkend="handle-as-image">handle-as-image</link></literal>,
2848 apply to the same request: it will then be replaced by an image. If
2849 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>
2850 (see below) also applies, the type of image will be determined by its parameter,
2851 if not, the standard checkerboard pattern is sent.
2854 It is important to understand this process, in order
2855 to understand how <application>Privoxy</application> deals with
2856 ads and other unwanted content. Blocking is a core feature, and one
2857 upon which various other features depend.
2860 The <literal><link linkend="filter">filter</link></literal>
2861 action can perform a very similar task, by <quote>blocking</quote>
2862 banner images and other content through rewriting the relevant URLs in the
2863 document's HTML source, so they don't get requested in the first place.
2864 Note that this is a totally different technique, and it's easy to confuse the two.
2870 <term>Example usage (section):</term>
2873 {+block{No nasty stuff for you.}}
2874 # Block and replace with "blocked" page
2875 .nasty-stuff.example.com
2877 {+block{Doubleclick banners.} +handle-as-image}
2878 # Block and replace with image
2882 {+block{Layered ads.} +handle-as-empty-document}
2883 # Block and then ignore
2884 adserver.example.net/.*\.js$
2894 <!-- ~~~~~ New section ~~~~~ -->
2895 <sect3 renderas="sect4" id="change-x-forwarded-for">
2896 <title>change-x-forwarded-for</title>
2900 <term>Typical use:</term>
2902 <para>Improve privacy by not forwarding the source of the request in the HTTP headers.</para>
2907 <term>Effect:</term>
2910 Deletes the <quote>X-Forwarded-For:</quote> HTTP header from the client request,
2918 <!-- Boolean, Parameterized, Multi-value -->
2920 <para>Parameterized.</para>
2925 <term>Parameter:</term>
2929 <para><quote>block</quote> to delete the header.</para>
2933 <quote>add</quote> to create the header (or append
2934 the client's IP address to an already existing one).
2945 It is safe and recommended to use <literal>block</literal>.
2948 Forwarding the source address of the request may make
2949 sense in some multi-user setups but is also a privacy risk.
2954 <term>Example usage:</term>
2956 <screen>+change-x-forwarded-for{block}</screen>
2962 <!-- ~~~~~ New section ~~~~~ -->
2963 <sect3 renderas="sect4" id="client-header-filter">
2964 <title>client-header-filter</title>
2968 <term>Typical use:</term>
2971 Rewrite or remove single client headers.
2977 <term>Effect:</term>
2980 All client headers to which this action applies are filtered on-the-fly through
2981 the specified regular expression based substitutions.
2988 <!-- boolean, parameterized, Multi-value -->
2990 <para>Multi-value.</para>
2995 <term>Parameter:</term>
2998 The name of a client-header filter, as defined in one of the
2999 <link linkend="filter-file">filter files</link>.
3008 Client-header filters are applied to each header on its own, not to
3009 all at once. This makes it easier to diagnose problems, but on the downside
3010 you can't write filters that only change header x if header y's value is z.
3011 You can do that by using tags though.
3014 Client-header filters are executed after the other header actions have finished
3015 and use their output as input.
3018 If the request URI gets changed, &my-app; will detect that and use the new
3019 one. This can be used to rewrite the request destination behind the client's
3020 back, for example to specify a Tor exit relay for certain requests.
3023 Note that to change the destination host for
3024 <link linkend="HTTPS-INSPECTION">https-inspected</link>
3025 requests a protocol and host has to be added to the URI.
3028 If <link linkend="HTTPS-INSPECTION">https inspection</link>
3029 is enabled, the protocol can be downgraded from https to http
3030 but upgrading a request from http to https is currently not
3034 After detecting a rewrite, &my-app; does not update the actions
3035 used for the request based on the new host.
3038 Please refer to the <link linkend="filter-file">filter file chapter</link>
3039 to learn which client-header filters are available by default, and how to
3047 <term>Example usage (section):</term>
3050 # Hide Tor exit notation in Host and Referer Headers
3051 {+client-header-filter{hide-tor-exit-notation}}
3060 <!-- ~~~~~ New section ~~~~~ -->
3061 <sect3 renderas="sect4" id="client-body-filter">
3062 <title>client-body-filter</title>
3066 <term>Typical use:</term>
3069 Rewrite or remove client request body.
3075 <term>Effect:</term>
3078 All request bodies to which this action applies are filtered on-the-fly through
3079 the specified regular expression based substitutions.
3086 <!-- boolean, parameterized, Multi-value -->
3088 <para>Multi-value.</para>
3093 <term>Parameter:</term>
3096 The name of a client-body filter, as defined in one of the
3097 <link linkend="filter-file">filter files</link>.
3106 Please refer to the <link linkend="filter-file">filter file chapter</link>
3107 to learn how to create your own client-body filters.
3110 The distribution <filename>default.filter</filename> file contains a selection of
3111 client-body filters for example purposes.
3114 The amount of data that can be filtered is limited by the
3115 <literal><link linkend="buffer-limit">buffer-limit</link></literal>
3116 option in the main <link linkend="config">config file</link>. The
3117 default is 4096 KB (4 Megs). Once this limit is exceeded, the whole
3118 request body is passed through unfiltered.
3124 <term>Example usage (section):</term>
3127 # Remove "test" everywhere in the request body
3128 {+client-body-filter{remove-test}}
3138 <!-- ~~~~~ New section ~~~~~ -->
3139 <sect3 renderas="sect4" id="client-header-tagger">
3140 <title>client-header-tagger</title>
3144 <term>Typical use:</term>
3147 Block requests based on their headers.
3153 <term>Effect:</term>
3156 Client headers to which this action applies are filtered on-the-fly through
3157 the specified regular expression based substitutions, the result is used as
3165 <!-- boolean, parameterized, Multi-value -->
3167 <para>Multi-value.</para>
3172 <term>Parameter:</term>
3175 The name of a client-header tagger, as defined in one of the
3176 <link linkend="filter-file">filter files</link>.
3185 Client-header taggers are applied to each header on its own,
3186 and as the header isn't modified, each tagger <quote>sees</quote>
3190 Client-header taggers are the first actions that are executed
3191 and their tags can be used to control every other action.
3197 <term>Example usage (section):</term>
3200 # Tag every request with the User-Agent header
3201 {+client-header-tagger{user-agent}}
3204 # Tagging itself doesn't change the action
3205 # settings, sections with TAG patterns do:
3207 # If it's a download agent, use a different forwarding proxy,
3208 # show the real User-Agent and make sure resume works.
3209 {+forward-override{forward-socks5 10.0.0.2:2222 .} \
3210 -hide-if-modified-since \
3211 -overwrite-last-modified \
3216 TAG:^User-Agent: NetBSD-ftp/
3217 TAG:^User-Agent: Novell ZYPP Installer
3218 TAG:^User-Agent: RPM APT-HTTP/
3219 TAG:^User-Agent: fetch libfetch/
3220 TAG:^User-Agent: Ubuntu APT-HTTP/
3221 TAG:^User-Agent: MPlayer/
3225 # Tag all requests with the Range header set
3226 {+client-header-tagger{range-requests}}
3229 # Disable filtering for the tagged requests.
3231 # With filtering enabled Privoxy would remove the Range headers
3232 # to be able to filter the whole response. The downside is that
3233 # it prevents clients from resuming downloads or skipping over
3234 # parts of multimedia files.
3235 {-filter -deanimate-gifs}
3240 # Tag all requests with the client IP address
3242 # (Technically the client IP address isn't included in the
3243 # client headers but client-header taggers can set it anyway.
3244 # For details see the tagger in default.filter)
3245 {+client-header-tagger{client-ip-address}}
3248 # Change forwarding settings for requests coming from address 10.0.0.1
3249 {+forward-override{forward-socks5 127.0.1.2:2222 .}}
3250 TAG:^IP-ADDRESS: 10\.0\.0\.1$
3259 <!-- ~~~~~ New section ~~~~~ -->
3260 <sect3 renderas="sect4" id="content-type-overwrite">
3261 <title>content-type-overwrite</title>
3265 <term>Typical use:</term>
3267 <para>Stop useless download menus from popping up, or change the browser's rendering mode</para>
3272 <term>Effect:</term>
3275 Replaces the <quote>Content-Type:</quote> HTTP server header.
3282 <!-- Boolean, Parameterized, Multi-value -->
3284 <para>Parameterized.</para>
3289 <term>Parameter:</term>
3301 The <quote>Content-Type:</quote> HTTP server header is used by the
3302 browser to decide what to do with the document. The value of this
3303 header can cause the browser to open a download menu instead of
3304 displaying the document by itself, even if the document's format is
3305 supported by the browser.
3308 The declared content type can also affect which rendering mode
3309 the browser chooses. If XHTML is delivered as <quote>text/html</quote>,
3310 many browsers treat it as yet another broken HTML document.
3311 If it is send as <quote>application/xml</quote>, browsers with
3312 XHTML support will only display it, if the syntax is correct.
3315 If you see a web site that proudly uses XHTML buttons, but sets
3316 <quote>Content-Type: text/html</quote>, you can use &my-app;
3317 to overwrite it with <quote>application/xml</quote> and validate
3318 the web master's claim inside your XHTML-supporting browser.
3319 If the syntax is incorrect, the browser will complain loudly.
3322 You can also go the opposite direction: if your browser prints
3323 error messages instead of rendering a document falsely declared
3324 as XHTML, you can overwrite the content type with
3325 <quote>text/html</quote> and have it rendered as broken HTML document.
3328 By default <literal>content-type-overwrite</literal> only replaces
3329 <quote>Content-Type:</quote> headers that look like some kind of text.
3330 If you want to overwrite it unconditionally, you have to combine it with
3331 <literal><link linkend="force-text-mode">force-text-mode</link></literal>.
3332 This limitation exists for a reason, think twice before circumventing it.
3335 Most of the time it's easier to replace this action with a custom
3336 <literal><link linkend="server-header-filter">server-header filter</link></literal>.
3337 It allows you to activate it for every document of a certain site and it will still
3338 only replace the content types you aimed at.
3341 Of course you can apply <literal>content-type-overwrite</literal>
3342 to a whole site and then make URL based exceptions, but it's a lot
3343 more work to get the same precision.
3349 <term>Example usage (sections):</term>
3351 <screen># Check if www.example.net/ really uses valid XHTML
3352 { +content-type-overwrite{application/xml} }
3355 # but leave the content type unmodified if the URL looks like a style sheet
3356 {-content-type-overwrite}
3357 www.example.net/.*\.css$
3358 www.example.net/.*style
3366 <!-- ~~~~~ New section ~~~~~ -->
3367 <sect3 renderas="sect4" id="crunch-client-header">
3371 <title>crunch-client-header</title>
3375 <term>Typical use:</term>
3377 <para>Remove a client header <application>Privoxy</application> has no dedicated action for.</para>
3382 <term>Effect:</term>
3385 Deletes every header sent by the client that contains the string the user supplied as parameter.
3392 <!-- Boolean, Parameterized, Multi-value -->
3394 <para>Parameterized.</para>
3399 <term>Parameter:</term>
3411 This action allows you to block client headers for which no dedicated
3412 <application>Privoxy</application> action exists.
3413 <application>Privoxy</application> will remove every client header that
3414 contains the string you supplied as parameter.
3417 Regular expressions are <emphasis>not supported</emphasis> and you can't
3418 use this action to block different headers in the same request, unless
3419 they contain the same string.
3422 <literal>crunch-client-header</literal> is only meant for quick tests.
3423 If you have to block several different headers, or only want to modify
3424 parts of them, you should use a
3425 <literal><link linkend="client-header-filter">client-header filter</link></literal>.
3429 Don't block any header without understanding the consequences.
3436 <term>Example usage (section):</term>
3438 <screen># Block the non-existent "Privacy-Violation:" client header
3439 { +crunch-client-header{Privacy-Violation:} }
3448 <!-- ~~~~~ New section ~~~~~ -->
3449 <sect3 renderas="sect4" id="crunch-if-none-match">
3450 <title>crunch-if-none-match</title>
3456 <term>Typical use:</term>
3458 <para>Prevent yet another way to track the user's steps between sessions.</para>
3463 <term>Effect:</term>
3466 Deletes the <quote>If-None-Match:</quote> HTTP client header.
3473 <!-- Boolean, Parameterized, Multi-value -->
3475 <para>Boolean.</para>
3480 <term>Parameter:</term>
3492 Removing the <quote>If-None-Match:</quote> HTTP client header
3493 is useful for filter testing, where you want to force a real
3494 reload instead of getting status code <quote>304</quote> which
3495 would cause the browser to use a cached copy of the page.
3498 It is also useful to make sure the header isn't used as a cookie
3499 replacement (unlikely but possible).
3502 Blocking the <quote>If-None-Match:</quote> header shouldn't cause any
3503 caching problems, as long as the <quote>If-Modified-Since:</quote> header
3504 isn't blocked or missing as well.
3507 It is recommended to use this action together with
3508 <literal><link linkend="hide-if-modified-since">hide-if-modified-since</link></literal>
3510 <literal><link linkend="overwrite-last-modified">overwrite-last-modified</link></literal>.
3516 <term>Example usage (section):</term>
3518 <screen># Let the browser revalidate cached documents but don't
3519 # allow the server to use the revalidation headers for user tracking.
3520 {+hide-if-modified-since{-60} \
3521 +overwrite-last-modified{randomize} \
3522 +crunch-if-none-match}
3531 <!-- ~~~~~ New section ~~~~~ -->
3532 <sect3 renderas="sect4" id="crunch-incoming-cookies">
3533 <title>crunch-incoming-cookies</title>
3537 <term>Typical use:</term>
3540 Prevent the web server from setting HTTP cookies on your system
3546 <term>Effect:</term>
3549 Deletes any <quote>Set-Cookie:</quote> HTTP headers from server replies.
3556 <!-- Boolean, Parameterized, Multi-value -->
3558 <para>Boolean.</para>
3563 <term>Parameter:</term>
3575 This action is only concerned with <emphasis>incoming</emphasis> HTTP cookies. For
3576 <emphasis>outgoing</emphasis> HTTP cookies, use
3577 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>.
3578 Use <emphasis>both</emphasis> to disable HTTP cookies completely.
3581 It makes <emphasis>no sense at all</emphasis> to use this action in conjunction
3582 with the <literal><link linkend="session-cookies-only">session-cookies-only</link></literal> action,
3583 since it would prevent the session cookies from being set. See also
3584 <literal><link linkend="filter-content-cookies">filter-content-cookies</link></literal>.
3590 <term>Example usage:</term>
3592 <screen>+crunch-incoming-cookies</screen>
3599 <!-- ~~~~~ New section ~~~~~ -->
3600 <sect3 renderas="sect4" id="crunch-server-header">
3601 <title>crunch-server-header</title>
3607 <term>Typical use:</term>
3609 <para>Remove a server header <application>Privoxy</application> has no dedicated action for.</para>
3614 <term>Effect:</term>
3617 Deletes every header sent by the server that contains the string the user supplied as parameter.
3624 <!-- Boolean, Parameterized, Multi-value -->
3626 <para>Parameterized.</para>
3631 <term>Parameter:</term>
3643 This action allows you to block server headers for which no dedicated
3644 <application>Privoxy</application> action exists. <application>Privoxy</application>
3645 will remove every server header that contains the string you supplied as parameter.
3648 Regular expressions are <emphasis>not supported</emphasis> and you can't
3649 use this action to block different headers in the same request, unless
3650 they contain the same string.
3653 <literal>crunch-server-header</literal> is only meant for quick tests.
3654 If you have to block several different headers, or only want to modify
3655 parts of them, you should use a custom
3656 <literal><link linkend="server-header-filter">server-header filter</link></literal>.
3660 Don't block any header without understanding the consequences.
3667 <term>Example usage (section):</term>
3669 <screen># Crunch server headers that try to prevent caching
3670 { +crunch-server-header{no-cache} }
3679 <!-- ~~~~~ New section ~~~~~ -->
3680 <sect3 renderas="sect4" id="crunch-outgoing-cookies">
3681 <title>crunch-outgoing-cookies</title>
3685 <term>Typical use:</term>
3688 Prevent the web server from reading any HTTP cookies from your system
3694 <term>Effect:</term>
3697 Deletes any <quote>Cookie:</quote> HTTP headers from client requests.
3704 <!-- Boolean, Parameterized, Multi-value -->
3706 <para>Boolean.</para>
3711 <term>Parameter:</term>
3723 This action is only concerned with <emphasis>outgoing</emphasis> HTTP cookies. For
3724 <emphasis>incoming</emphasis> HTTP cookies, use
3725 <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal>.
3726 Use <emphasis>both</emphasis> to disable HTTP cookies completely.
3729 It makes <emphasis>no sense at all</emphasis> to use this action in conjunction
3730 with the <literal><link linkend="session-cookies-only">session-cookies-only</link></literal> action,
3731 since it would prevent the session cookies from being read.
3737 <term>Example usage:</term>
3739 <screen>+crunch-outgoing-cookies</screen>
3747 <!-- ~~~~~ New section ~~~~~ -->
3748 <sect3 renderas="sect4" id="deanimate-gifs">
3749 <title>deanimate-gifs</title>
3753 <term>Typical use:</term>
3755 <para>Stop those annoying, distracting animated GIF images.</para>
3760 <term>Effect:</term>
3763 De-animate GIF animations, i.e. reduce them to their first or last image.
3770 <!-- boolean, parameterized, Multi-value -->
3772 <para>Parameterized.</para>
3777 <term>Parameter:</term>
3780 <quote>last</quote> or <quote>first</quote>
3789 This will also shrink the images considerably (in bytes, not pixels!). If
3790 the option <quote>first</quote> is given, the first frame of the animation
3791 is used as the replacement. If <quote>last</quote> is given, the last
3792 frame of the animation is used instead, which probably makes more sense for
3793 most banner animations, but also has the risk of not showing the entire
3794 last frame (if it is only a delta to an earlier frame).
3797 You can safely use this action with patterns that will also match non-GIF
3798 objects, because no attempt will be made at anything that doesn't look like
3805 <term>Example usage:</term>
3807 <screen>+deanimate-gifs{last}</screen>
3814 <!-- ~~~~~ New section ~~~~~ -->
3815 <sect3 renderas="sect4" id="delay-response">
3816 <title>delay-response</title>
3820 <term>Typical use:</term>
3822 <para>Delay responses to the client to reduce the load</para>
3827 <term>Effect:</term>
3830 Delays responses to the client by sending the response in ca. 10 byte chunks.
3837 <!-- boolean, parameterized, Multi-value -->
3839 <para>Parameterized.</para>
3844 <term>Parameter:</term>
3847 <quote>Number of milliseconds</quote>
3856 Sometimes when JavaScript code is used to fetch advertisements
3857 it doesn't respect Privoxy's blocks and retries to fetch the
3858 same resource again causing unnecessary load on the client.
3861 This action delays responses to the client and can be combined
3862 with <literal><link linkend="block">blocks</link></literal>
3863 to slow down the JavaScript code, thus reducing
3864 the load on the client.
3867 When used without <literal><link linkend="block">blocks</link></literal>
3868 the action can also be used to simulate a slow internet connection.
3874 <term>Example usage:</term>
3876 <screen>+delay-response{100}</screen>
3883 <!-- ~~~~~ New section ~~~~~ -->
3884 <sect3 renderas="sect4" id="downgrade-http-version">
3885 <title>downgrade-http-version</title>
3889 <term>Typical use:</term>
3891 <para>Work around (very rare) problems with HTTP/1.1</para>
3896 <term>Effect:</term>
3899 Downgrades HTTP/1.1 client requests and server replies to HTTP/1.0.
3906 <!-- boolean, parameterized, Multi-value -->
3908 <para>Boolean.</para>
3913 <term>Parameter:</term>
3925 This is a left-over from the time when <application>Privoxy</application>
3926 didn't support important HTTP/1.1 features well. It is left here for the
3927 unlikely case that you experience HTTP/1.1-related problems with some server
3931 Note that enabling this action is only a workaround. It should not
3932 be enabled for sites that work without it. While it shouldn't break
3933 any pages, it has an (usually negative) performance impact.
3936 If you come across a site where enabling this action helps, please report it,
3937 so the cause of the problem can be analyzed. If the problem turns out to be
3938 caused by a bug in <application>Privoxy</application> it should be
3939 fixed so the following release works without the work around.
3945 <term>Example usage (section):</term>
3947 <screen>{+downgrade-http-version}
3948 problem-host.example.com</screen>
3956 <!-- ~~~~~ New section ~~~~~ -->
3957 <sect3 renderas="sect4" id="external-filter">
3958 <title>external-filter</title>
3962 <term>Typical use:</term>
3964 <para>Modify content using a programming language of your choice.</para>
3969 <term>Effect:</term>
3972 All instances of text-based type, most notably HTML and JavaScript, to which
3973 this action applies, can be filtered on-the-fly through the specified external
3975 By default plain text documents are exempted from filtering, because web
3976 servers often use the <literal>text/plain</literal> MIME type for all files
3977 whose type they don't know.)
3984 <!-- boolean, parameterized, Multi-value -->
3986 <para>Multi-value.</para>
3991 <term>Parameter:</term>
3994 The name of an external content filter, as defined in the
3995 <link linkend="filter-file">filter file</link>.
3996 External filters can be defined in one or more files as defined by the
3997 <literal><link linkend="filterfile">filterfile</link></literal>
3998 option in the <link linkend="config">config file</link>.
4001 When used in its negative form,
4002 and without parameters, <emphasis>all</emphasis> filtering with external
4003 filters is completely disabled.
4012 External filters are scripts or programs that can modify the content in
4013 case common <literal><link linkend="filter">filters</link></literal>
4014 aren't powerful enough. With the exception that this action doesn't
4015 use pcrs-based filters, the notes in the
4016 <literal><link linkend="filter">filter</link></literal> section apply.
4020 Currently external filters are executed with &my-app;'s privileges.
4021 Only use external filters you understand and trust.
4025 This feature is experimental, the <literal><link
4026 linkend="external-filter-syntax">syntax</link></literal>
4027 may change in the future.
4034 <term>Example usage:</term>
4036 <screen>+external-filter{fancy-filter}</screen>
4042 <!-- ~~~~~ New section ~~~~~ -->
4043 <sect3 renderas="sect4" id="fast-redirects">
4044 <title>fast-redirects</title>
4048 <term>Typical use:</term>
4050 <para>Fool some click-tracking scripts and speed up indirect links.</para>
4055 <term>Effect:</term>
4058 Detects redirection URLs and redirects the browser without contacting
4059 the redirection server first.
4066 <!-- boolean, parameterized, Multi-value -->
4068 <para>Parameterized.</para>
4073 <term>Parameter:</term>
4078 <quote>simple-check</quote> to just search for the string <quote>http://</quote>
4079 to detect redirection URLs.
4084 <quote>check-decoded-url</quote> to decode URLs (if necessary) before searching
4085 for redirection URLs.
4096 Many sites, like yahoo.com, don't just link to other sites. Instead, they
4097 will link to some script on their own servers, giving the destination as a
4098 parameter, which will then redirect you to the final target. URLs
4099 resulting from this scheme typically look like:
4100 <quote>http://www.example.org/click-tracker.cgi?target=http%3a//www.example.net/</quote>.
4103 Sometimes, there are even multiple consecutive redirects encoded in the
4104 URL. These redirections via scripts make your web browsing more traceable,
4105 since the server from which you follow such a link can see where you go
4106 to. Apart from that, valuable bandwidth and time is wasted, while your
4107 browser asks the server for one redirect after the other. Plus, it feeds
4111 This feature is currently not very smart and is scheduled for improvement.
4112 If it is enabled by default, you will have to create some exceptions to
4113 this action. It can lead to failures in several ways:
4116 Not every URLs with other URLs as parameters is evil.
4117 Some sites offer a real service that requires this information to work.
4118 For example a validation service needs to know, which document to validate.
4119 <literal>fast-redirects</literal> assumes that every URL parameter that
4120 looks like another URL is a redirection target, and will always redirect to
4121 the last one. Most of the time the assumption is correct, but if it isn't,
4122 the user gets redirected anyway.
4125 Another failure occurs if the URL contains other parameters after the URL parameter.
4127 <quote>http://www.example.org/?redirect=http%3a//www.example.net/&foo=bar</quote>.
4128 contains the redirection URL <quote>http://www.example.net/</quote>,
4129 followed by another parameter. <literal>fast-redirects</literal> doesn't know that
4130 and will cause a redirect to <quote>http://www.example.net/&foo=bar</quote>.
4131 Depending on the target server configuration, the parameter will be silently ignored
4132 or lead to a <quote>page not found</quote> error. You can prevent this problem by
4133 first using the <literal><link linkend="redirect">redirect</link></literal> action
4134 to remove the last part of the URL, but it requires a little effort.
4137 To detect a redirection URL, <literal>fast-redirects</literal> only
4138 looks for the string <quote>http://</quote>, either in plain text
4139 (invalid but often used) or encoded as <quote>http%3a//</quote>.
4140 Some sites use their own URL encoding scheme, encrypt the address
4141 of the target server or replace it with a database id. In these cases
4142 <literal>fast-redirects</literal> is fooled and the request reaches the
4143 redirection server where it probably gets logged.
4149 <term>Example usage:</term>
4152 { +fast-redirects{simple-check} }
4155 { +fast-redirects{check-decoded-url} }
4156 another.example.com/testing
4165 <!-- ~~~~~ New section ~~~~~ -->
4166 <sect3 renderas="sect4" id="filter">
4167 <title>filter</title>
4171 <term>Typical use:</term>
4173 <para>Get rid of HTML and JavaScript annoyances, banner advertisements (by size),
4174 do fun text replacements, add personalized effects, etc.</para>
4179 <term>Effect:</term>
4182 All instances of text-based type, most notably HTML and JavaScript, to which
4183 this action applies, can be filtered on-the-fly through the specified regular
4184 expression based substitutions. (Note: as of version 3.0.3 plain text documents
4185 are exempted from filtering, because web servers often use the
4186 <literal>text/plain</literal> MIME type for all files whose type they don't know.)
4193 <!-- boolean, parameterized, Multi-value -->
4195 <para>Multi-value.</para>
4200 <term>Parameter:</term>
4203 The name of a content filter, as defined in the <link linkend="filter-file">filter file</link>.
4204 Filters can be defined in one or more files as defined by the
4205 <literal><link linkend="filterfile">filterfile</link></literal>
4206 option in the <link linkend="config">config file</link>.
4207 <filename>default.filter</filename> is the collection of filters
4208 supplied by the developers. Locally defined filters should go
4209 in their own file, such as <filename>user.filter</filename>.
4212 When used in its negative form,
4213 and without parameters, <emphasis>all</emphasis> filtering is completely disabled.
4222 For your convenience, there are a number of pre-defined filters available
4223 in the distribution filter file that you can use. See the examples below for
4227 Filtering requires buffering the page content, which may appear to
4228 slow down page rendering since nothing is displayed until all content has
4229 passed the filters. (The total time until the page is completely rendered
4230 doesn't change much, but it may be perceived as slower since the page is
4231 not incrementally displayed.)
4232 This effect will be more noticeable on slower connections.
4235 <quote>Rolling your own</quote>
4236 filters requires a knowledge of
4237 <ulink url="https://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
4238 Expressions</quote></ulink> and
4239 <ulink url="https://en.wikipedia.org/wiki/Html"><quote>HTML</quote></ulink>.
4240 This is very powerful feature, and potentially very intrusive.
4241 Filters should be used with caution, and where an equivalent
4242 <quote>action</quote> is not available.
4245 The amount of data that can be filtered is limited by the
4246 <literal><link linkend="buffer-limit">buffer-limit</link></literal>
4247 option in the main <link linkend="config">config file</link>. The
4248 default is 4096 KB (4 Megs). Once this limit is exceeded, the buffered
4249 data, and all pending data, is passed through unfiltered.
4252 Inappropriate MIME types, such as zipped files, are not filtered at all.
4253 (Again, only text-based types except plain text). Encrypted SSL data
4254 (from HTTPS servers) cannot be filtered either, since this would violate
4255 the integrity of the secure transaction. In some situations it might
4256 be necessary to protect certain text, like source code, from filtering
4257 by defining appropriate <literal>-filter</literal> exceptions.
4260 Compressed content can't be filtered either, but if &my-app;
4261 is compiled with zlib support and a supported compression algorithm
4262 is used (gzip or deflate), &my-app; can first decompress the content
4266 If you use a &my-app; version without zlib support, but want filtering to work on
4267 as much documents as possible, even those that would normally be sent compressed,
4268 you must use the <literal><link linkend="prevent-compression">prevent-compression</link></literal>
4269 action in conjunction with <literal>filter</literal>.
4272 Content filtering can achieve some of the same effects as the
4273 <literal><link linkend="block">block</link></literal>
4274 action, i.e. it can be used to block ads and banners. But the mechanism
4275 works quite differently. One effective use, is to block ad banners
4276 based on their size (see below), since many of these seem to be somewhat
4280 <link linkend="contact">Feedback</link> with suggestions for new or
4281 improved filters is particularly welcome!
4284 The below list has only the names and a one-line description of each
4285 predefined filter. There are <link linkend="predefined-filters">more
4286 verbose explanations</link> of what these filters do in the <link
4287 linkend="filter-file">filter file chapter</link>.
4293 <term>Example usage (with filters from the distribution <filename>default.filter</filename> file).
4294 See <link linkend="PREDEFINED-FILTERS">the Predefined Filters section</link> for
4295 more explanation on each:</term>
4298 <anchor id="filter-js-annoyances">
4300 <screen>+filter{js-annoyances} # Get rid of particularly annoying JavaScript abuse.</screen>
4302 <anchor id="filter-js-events">
4304 <screen>+filter{js-events} # Kill JavaScript event bindings and timers (Radically destructive! Only for extra nasty sites).</screen>
4306 <anchor id="filter-html-annoyances">
4308 <screen>+filter{html-annoyances} # Get rid of particularly annoying HTML abuse.</screen>
4310 <anchor id="filter-content-cookies">
4312 <screen>+filter{content-cookies} # Kill cookies that come in the HTML or JS content.</screen>
4314 <anchor id="filter-refresh-tags">
4316 <screen>+filter{refresh-tags} # Kill automatic refresh tags if refresh time is larger than 9 seconds.</screen>
4318 <anchor id="filter-unsolicited-popups">
4320 <screen>+filter{unsolicited-popups} # Disable only unsolicited pop-up windows.</screen>
4322 <anchor id="filter-all-popups">
4324 <screen>+filter{all-popups} # Kill all popups in JavaScript and HTML.</screen>
4326 <anchor id="filter-img-reorder">
4328 <screen>+filter{img-reorder} # Reorder attributes in <img> tags to make the banners-by-* filters more effective.</screen>
4330 <anchor id="filter-banners-by-size">
4332 <screen>+filter{banners-by-size} # Kill banners by size.</screen>
4334 <anchor id="filter-banners-by-link">
4336 <screen>+filter{banners-by-link} # Kill banners by their links to known clicktrackers.</screen>
4338 <anchor id="filter-webbugs">
4340 <screen>+filter{webbugs} # Squish WebBugs (1x1 invisible GIFs used for user tracking).</screen>
4342 <anchor id="filter-tiny-textforms">
4344 <screen>+filter{tiny-textforms} # Extend those tiny textareas up to 40x80 and kill the hard wrap.</screen>
4346 <anchor id="filter-jumping-windows">
4348 <screen>+filter{jumping-windows} # Prevent windows from resizing and moving themselves.</screen>
4350 <anchor id="filter-frameset-borders">
4352 <screen>+filter{frameset-borders} # Give frames a border and make them resizable.</screen>
4354 <anchor id="filter-iframes">
4356 <screen>+filter{iframes} # Removes all detected iframes. Should only be enabled for individual sites.</screen>
4358 <anchor id="filter-demoronizer">
4360 <screen>+filter{demoronizer} # Fix MS's non-standard use of standard charsets.</screen>
4362 <anchor id="filter-shockwave-flash">
4364 <screen>+filter{shockwave-flash} # Kill embedded Shockwave Flash objects.</screen>
4366 <anchor id="filter-quicktime-kioskmode">
4368 <screen>+filter{quicktime-kioskmode} # Make Quicktime movies saveable.</screen>
4370 <anchor id="filter-fun">
4372 <screen>+filter{fun} # Text replacements for subversive browsing fun!</screen>
4374 <anchor id="filter-crude-parental">
4376 <screen>+filter{crude-parental} # Crude parental filtering. Note that this filter doesn't work reliably.</screen>
4378 <anchor id="filter-ie-exploits">
4380 <screen>+filter{ie-exploits} # Disable some known Internet Explorer bug exploits.</screen>
4382 <anchor id="filter-site-specifics">
4384 <screen>+filter{site-specifics} # Cure for site-specific problems. Don't apply generally!</screen>
4386 <anchor id="filter-no-ping">
4388 <screen>+filter{no-ping} # Removes non-standard ping attributes in <a> and <area> tags.</screen>
4390 <anchor id="filter-github">
4392 <screen>+filter{github} # Removes the annoying "Sign-Up" banner and the Cookie disclaimer.</screen>
4394 <anchor id="filter-google">
4396 <screen>+filter{google} # CSS-based block for Google text ads. Also removes a width limitation and the toolbar advertisement.</screen>
4398 <anchor id="filter-imdb">
4400 <screen>+filter{imdb} # Removes some ads on IMDb.</screen>
4402 <anchor id="filter-yahoo">
4404 <screen>+filter{yahoo} # CSS-based block for Yahoo text ads. Also removes a width limitation.</screen>
4406 <anchor id="filter-msn">
4408 <screen>+filter{msn} # CSS-based block for MSN text ads. Also removes tracking URLs and a width limitation.</screen>
4410 <anchor id="filter-blogspot">
4412 <screen>+filter{blogspot} # Cleans up some Blogspot blogs. Read the fine print before using this.</screen>
4414 <anchor id="filter-sourceforge">
4416 <screen>+filter{sourceforge} # Reduces the amount of ads for proprietary software on SourceForge.</screen>
4423 <!-- ~~~~~ New section ~~~~~ -->
4424 <sect3 renderas="sect4" id="force-text-mode">
4425 <title>force-text-mode</title>
4431 <term>Typical use:</term>
4433 <para>Force <application>Privoxy</application> to treat a document as if it was in some kind of <emphasis>text</emphasis> format. </para>
4438 <term>Effect:</term>
4441 Declares a document as text, even if the <quote>Content-Type:</quote> isn't detected as such.
4448 <!-- Boolean, Parameterized, Multi-value -->
4450 <para>Boolean.</para>
4455 <term>Parameter:</term>
4467 As explained <literal><link linkend="filter">above</link></literal>,
4468 <application>Privoxy</application> tries to only filter files that are
4469 in some kind of text format. The same restrictions apply to
4470 <literal><link linkend="content-type-overwrite">content-type-overwrite</link></literal>.
4471 <literal>force-text-mode</literal> declares a document as text,
4472 without looking at the <quote>Content-Type:</quote> first.
4476 Think twice before activating this action. Filtering binary data
4477 with regular expressions can cause file damage.
4484 <term>Example usage:</term>
4495 <!-- ~~~~~ New section ~~~~~ -->
4496 <sect3 renderas="sect4" id="forward-override">
4497 <title>forward-override</title>
4503 <term>Typical use:</term>
4505 <para>Change the forwarding settings based on User-Agent or request origin</para>
4510 <term>Effect:</term>
4513 Overrules the forward directives in the configuration file.
4520 <!-- Boolean, Parameterized, Multi-value -->
4522 <para>Parameterized.</para>
4527 <term>Parameter:</term>
4531 <para><quote>forward .</quote> to use a direct connection without any additional proxies.</para>
4535 <quote>forward 127.0.0.1:8123</quote> to use the HTTP proxy listening at 127.0.0.1 port 8123.
4540 <quote>forward-socks4a 127.0.0.1:9050 .</quote> to use the socks4a proxy listening at
4541 127.0.0.1 port 9050. Replace <quote>forward-socks4a</quote> with <quote>forward-socks4</quote>
4542 to use a socks4 connection (with local DNS resolution) instead, use <quote>forward-socks5</quote>
4543 for socks5 connections (with remote DNS resolution).
4548 <quote>forward-socks4a 127.0.0.1:9050 proxy.example.org:8000</quote> to use the socks4a proxy
4549 listening at 127.0.0.1 port 9050 to reach the HTTP proxy listening at proxy.example.org port 8000.
4550 Replace <quote>forward-socks4a</quote> with <quote>forward-socks4</quote> to use a socks4 connection
4551 (with local DNS resolution) instead, use <quote>forward-socks5</quote>
4552 for socks5 connections (with remote DNS resolution).
4557 <quote>forward-webserver 127.0.0.1:80</quote> to use the HTTP
4558 server listening at 127.0.0.1 port 80 without adjusting the
4562 This makes it more convenient to use Privoxy to make
4563 existing websites available as onion services as well.
4566 Many websites serve content with hardcoded URLs and
4567 can't be easily adjusted to change the domain based
4568 on the one used by the client.
4571 Putting Privoxy between Tor and the webserver (or an stunnel
4572 that forwards to the webserver) allows to rewrite headers and
4573 content to make client and server happy at the same time.
4576 Using Privoxy for webservers that are only reachable through
4577 onion addresses and whose location is supposed to be secret
4578 is not recommended and should not be necessary anyway.
4589 This action takes parameters similar to the
4590 <link linkend="forwarding">forward</link> directives in the configuration
4591 file, but without the URL pattern. It can be used as replacement, but normally it's only
4592 used in cases where matching based on the request URL isn't sufficient.
4596 Please read the description for the <link linkend="forwarding">forward</link> directives before
4597 using this action. Forwarding to the wrong people will reduce your privacy and increase the
4598 chances of man-in-the-middle attacks.
4601 If the ports are missing or invalid, default values will be used. This might change
4602 in the future and you shouldn't rely on it. Otherwise incorrect syntax causes Privoxy
4603 to exit. Due to design limitations, invalid parameter syntax isn't detected until the
4604 action is used the first time.
4607 Use the <ulink url="http://config.privoxy.org/show-url-info">show-url-info CGI page</ulink>
4608 to verify that your forward settings do what you thought the do.
4615 <term>Example usage:</term>
4618 # Use an ssh tunnel for requests previously tagged as
4619 # <quote>User-Agent: fetch libfetch/2.0</quote> and make sure
4620 # resuming downloads continues to work.
4622 # This way you can continue to use Tor for your normal browsing,
4623 # without overloading the Tor network with your FreeBSD ports updates
4624 # or downloads of bigger files like ISOs.
4626 # Note that HTTP headers are easy to fake and therefore their
4627 # values are as (un)trustworthy as your clients and users.
4628 {+forward-override{forward-socks5 10.0.0.2:2222 .} \
4629 -hide-if-modified-since \
4630 -overwrite-last-modified \
4632 TAG:^User-Agent: fetch libfetch/2\.0$
4640 <!-- ~~~~~ New section ~~~~~ -->
4641 <sect3 renderas="sect4" id="handle-as-empty-document">
4642 <title>handle-as-empty-document</title>
4648 <term>Typical use:</term>
4650 <para>Mark URLs that should be replaced by empty documents <emphasis>if they get blocked</emphasis></para>
4655 <term>Effect:</term>
4658 This action alone doesn't do anything noticeable. It just marks URLs.
4659 If the <literal><link linkend="block">block</link></literal> action <emphasis>also applies</emphasis>,
4660 the presence or absence of this mark decides whether an HTML <quote>BLOCKED</quote>
4661 page, or an empty document will be sent to the client as a substitute for the blocked content.
4662 The <emphasis>empty</emphasis> document isn't literally empty, but actually contains a single space.
4669 <!-- Boolean, Parameterized, Multi-value -->
4671 <para>Boolean.</para>
4676 <term>Parameter:</term>
4688 Some browsers complain about syntax errors if JavaScript documents
4689 are blocked with <application>Privoxy's</application>
4690 default HTML page; this option can be used to silence them.
4691 And of course this action can also be used to eliminate the &my-app;
4692 BLOCKED message in frames.
4695 The content type for the empty document can be specified with
4696 <literal><link linkend="content-type-overwrite">content-type-overwrite{}</link></literal>,
4697 but usually this isn't necessary.
4703 <term>Example usage:</term>
4705 <screen># Block all documents on example.org that end with ".js",
4706 # but send an empty document instead of the usual HTML message.
4707 {+block{Blocked JavaScript} +handle-as-empty-document}
4716 <!-- ~~~~~ New section ~~~~~ -->
4717 <sect3 renderas="sect4" id="handle-as-image">
4718 <title>handle-as-image</title>
4722 <term>Typical use:</term>
4724 <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>
4729 <term>Effect:</term>
4732 This action alone doesn't do anything noticeable. It just marks URLs as images.
4733 If the <literal><link linkend="block">block</link></literal> action <emphasis>also applies</emphasis>,
4734 the presence or absence of this mark decides whether an HTML <quote>blocked</quote>
4735 page, or a replacement image (as determined by the <literal><link
4736 linkend="set-image-blocker">set-image-blocker</link></literal> action) will be sent to the
4737 client as a substitute for the blocked content.
4744 <!-- Boolean, Parameterized, Multi-value -->
4746 <para>Boolean.</para>
4751 <term>Parameter:</term>
4763 The below generic example section is actually part of <filename>default.action</filename>.
4764 It marks all URLs with well-known image file name extensions as images and should
4768 Users will probably only want to use the handle-as-image action in conjunction with
4769 <literal><link linkend="block">block</link></literal>, to block sources of banners, whose URLs don't
4770 reflect the file type, like in the second example section.
4773 Note that you cannot treat HTML pages as images in most cases. For instance, (in-line) ad
4774 frames require an HTML page to be sent, or they won't display properly.
4775 Forcing <literal>handle-as-image</literal> in this situation will not replace the
4776 ad frame with an image, but lead to error messages.
4782 <term>Example usage (sections):</term>
4784 <screen># Generic image extensions:
4787 /.*\.(gif|jpg|jpeg|png|bmp|ico)$
4789 # These don't look like images, but they're banners and should be
4790 # blocked as images:
4792 {+block{Nasty banners.} +handle-as-image}
4793 nasty-banner-server.example.com/junk.cgi\?output=trash
4801 <!-- ~~~~~ New section ~~~~~ -->
4802 <sect3 renderas="sect4" id="hide-accept-language">
4803 <title>hide-accept-language</title>
4809 <term>Typical use:</term>
4811 <para>Pretend to use different language settings.</para>
4816 <term>Effect:</term>
4819 Deletes or replaces the <quote>Accept-Language:</quote> HTTP header in client requests.
4826 <!-- Boolean, Parameterized, Multi-value -->
4828 <para>Parameterized.</para>
4833 <term>Parameter:</term>
4836 Keyword: <quote>block</quote>, or any user defined value.
4845 Faking the browser's language settings can be useful to make a
4846 foreign User-Agent set with
4847 <literal><link linkend="hide-user-agent">hide-user-agent</link></literal>
4851 However some sites with content in different languages check the
4852 <quote>Accept-Language:</quote> to decide which one to take by default.
4853 Sometimes it isn't possible to later switch to another language without
4854 changing the <quote>Accept-Language:</quote> header first.
4857 Therefore it's a good idea to either only change the
4858 <quote>Accept-Language:</quote> header to languages you understand,
4859 or to languages that aren't wide spread.
4862 Before setting the <quote>Accept-Language:</quote> header
4863 to a rare language, you should consider that it helps to
4864 make your requests unique and thus easier to trace.
4865 If you don't plan to change this header frequently,
4866 you should stick to a common language.
4872 <term>Example usage (section):</term>
4874 <screen># Pretend to use Canadian language settings.
4875 {+hide-accept-language{en-ca} \
4876 +hide-user-agent{Mozilla/5.0 (X11; U; OpenBSD i386; en-CA; rv:1.8.0.4) Gecko/20060628 Firefox/1.5.0.4} \
4886 <!-- ~~~~~ New section ~~~~~ -->
4887 <sect3 renderas="sect4" id="hide-content-disposition">
4888 <title>hide-content-disposition</title>
4894 <term>Typical use:</term>
4896 <para>Prevent download menus for content you prefer to view inside the browser.</para>
4901 <term>Effect:</term>
4904 Deletes or replaces the <quote>Content-Disposition:</quote> HTTP header set by some servers.
4911 <!-- Boolean, Parameterized, Multi-value -->
4913 <para>Parameterized.</para>
4918 <term>Parameter:</term>
4921 Keyword: <quote>block</quote>, or any user defined value.
4930 Some servers set the <quote>Content-Disposition:</quote> HTTP header for
4931 documents they assume you want to save locally before viewing them.
4932 The <quote>Content-Disposition:</quote> header contains the file name
4933 the browser is supposed to use by default.
4936 In most browsers that understand this header, it makes it impossible to
4937 <emphasis>just view</emphasis> the document, without downloading it first,
4938 even if it's just a simple text file or an image.
4941 Removing the <quote>Content-Disposition:</quote> header helps
4942 to prevent this annoyance, but some browsers additionally check the
4943 <quote>Content-Type:</quote> header, before they decide if they can
4944 display a document without saving it first. In these cases, you have
4945 to change this header as well, before the browser stops displaying
4949 It is also possible to change the server's file name suggestion
4950 to another one, but in most cases it isn't worth the time to set
4954 This action will probably be removed in the future,
4955 use server-header filters instead.
4961 <term>Example usage:</term>
4964 # Disarm the download link in Sourceforge's patch tracker
4966 +content-type-overwrite{text/plain} \
4967 +hide-content-disposition{block} \
4969 .sourceforge.net/tracker/download\.php
4977 <!-- ~~~~~ New section ~~~~~ -->
4978 <sect3 renderas="sect4" id="hide-if-modified-since">
4979 <title>hide-if-modified-since</title>
4985 <term>Typical use:</term>
4987 <para>Prevent yet another way to track the user's steps between sessions.</para>
4992 <term>Effect:</term>
4995 Deletes the <quote>If-Modified-Since:</quote> HTTP client header or modifies its value.
5002 <!-- Boolean, Parameterized, Multi-value -->
5004 <para>Parameterized.</para>
5009 <term>Parameter:</term>
5012 Keyword: <quote>block</quote>, or a user defined value that specifies a range of hours.
5021 Removing this header is useful for filter testing, where you want to force a real
5022 reload instead of getting status code <quote>304</quote>, which would cause the
5023 browser to use a cached copy of the page.
5026 Instead of removing the header, <literal>hide-if-modified-since</literal> can
5027 also add or subtract a random amount of time to/from the header's value.
5028 You specify a range of minutes where the random factor should be chosen from and
5029 <application>Privoxy</application> does the rest. A negative value means
5030 subtracting, a positive value adding.
5033 Randomizing the value of the <quote>If-Modified-Since:</quote> makes
5034 it less likely that the server can use the time as a cookie replacement,
5035 but you will run into caching problems if the random range is too high.
5038 It is a good idea to only use a small negative value and let
5039 <literal><link linkend="overwrite-last-modified">overwrite-last-modified</link></literal>
5040 handle the greater changes.
5043 It is also recommended to use this action together with
5044 <literal><link linkend="crunch-if-none-match">crunch-if-none-match</link></literal>,
5045 otherwise it's more or less pointless.
5051 <term>Example usage (section):</term>
5053 <screen># Let the browser revalidate but make tracking based on the time less likely.
5054 {+hide-if-modified-since{-60} \
5055 +overwrite-last-modified{randomize} \
5056 +crunch-if-none-match}
5064 <!-- ~~~~~ New section ~~~~~ -->
5065 <sect3 renderas="sect4" id="hide-from-header">
5066 <title>hide-from-header</title>
5070 <term>Typical use:</term>
5072 <para>Keep your (old and ill) browser from telling web servers your email address</para>
5077 <term>Effect:</term>
5080 Deletes any existing <quote>From:</quote> HTTP header, or replaces it with the
5088 <!-- Boolean, Parameterized, Multi-value -->
5090 <para>Parameterized.</para>
5095 <term>Parameter:</term>
5098 Keyword: <quote>block</quote>, or any user defined value.
5107 The keyword <quote>block</quote> will completely remove the header
5108 (not to be confused with the <literal><link linkend="block">block</link></literal>
5112 Alternately, you can specify any value you prefer to be sent to the web
5113 server. If you do, it is a matter of fairness not to use any address that
5114 is actually used by a real person.
5117 This action is rarely needed, as modern web browsers don't send
5118 <quote>From:</quote> headers anymore.
5124 <term>Example usage:</term>
5126 <screen>+hide-from-header{block}</screen>
5128 <screen>+hide-from-header{spam-me-senseless@sittingduck.example.com}</screen>
5135 <!-- ~~~~~ New section ~~~~~ -->
5136 <sect3 renderas="sect4" id="hide-referrer">
5137 <title>hide-referrer</title>
5138 <anchor id="hide-referer">
5141 <term>Typical use:</term>
5143 <para>Conceal which link you followed to get to a particular site</para>
5148 <term>Effect:</term>
5151 Deletes the <quote>Referer:</quote> (sic) HTTP header from the client request,
5152 or replaces it with a forged one.
5159 <!-- Boolean, Parameterized, Multi-value -->
5161 <para>Parameterized.</para>
5166 <term>Parameter:</term>
5170 <para><quote>conditional-block</quote> to delete the header completely if the host has changed.</para>
5173 <para><quote>conditional-forge</quote> to forge the header if the host has changed.</para>
5176 <para><quote>block</quote> to delete the header unconditionally.</para>
5179 <para><quote>forge</quote> to pretend to be coming from the homepage of the server we are talking to.</para>
5182 <para>Any other string to set a user defined referrer.</para>
5192 <literal>conditional-block</literal> is the only parameter,
5193 that isn't easily detected in the server's log file. If it blocks the
5194 referrer, the request will look like the visitor used a bookmark or
5195 typed in the address directly.
5198 Leaving the referrer unmodified for requests on the same host
5199 allows the server owner to see the visitor's <quote>click path</quote>,
5200 but in most cases she could also get that information by comparing
5201 other parts of the log file: for example the User-Agent if it isn't
5202 a very common one, or the user's IP address if it doesn't change between
5206 Always blocking the referrer, or using a custom one, can lead to
5207 failures on servers that check the referrer before they answer any
5208 requests, in an attempt to prevent their content from being
5209 embedded or linked to elsewhere.
5212 Both <literal>conditional-block</literal> and <literal>forge</literal>
5213 will work with referrer checks, as long as content and valid referring page
5214 are on the same host. Most of the time that's the case.
5217 <literal>hide-referer</literal> is an alternate spelling of
5218 <literal>hide-referrer</literal> and the two can be can be freely
5219 substituted with each other. (<quote>referrer</quote> is the
5220 correct English spelling, however the HTTP specification has a bug - it
5221 requires it to be spelled as <quote>referer</quote>.)
5227 <term>Example usage:</term>
5229 <screen>+hide-referrer{forge}</screen>
5231 <screen>+hide-referrer{http://www.yahoo.com/}</screen>
5238 <!-- ~~~~~ New section ~~~~~ -->
5239 <sect3 renderas="sect4" id="hide-user-agent">
5240 <title>hide-user-agent</title>
5244 <term>Typical use:</term>
5246 <para>Try to conceal your type of browser and client operating system</para>
5251 <term>Effect:</term>
5254 Replaces the value of the <quote>User-Agent:</quote> HTTP header
5255 in client requests with the specified value.
5262 <!-- Boolean, Parameterized, Multi-value -->
5264 <para>Parameterized.</para>
5269 <term>Parameter:</term>
5272 Any user-defined string.
5282 This can lead to problems on web sites that depend on looking at this header in
5283 order to customize their content for different browsers (which, by the
5284 way, is <emphasis>NOT</emphasis> the right thing to do: good web sites
5285 work browser-independently).
5289 Using this action in multi-user setups or wherever different types of
5290 browsers will access the same <application>Privoxy</application> is
5291 <emphasis>not recommended</emphasis>. In single-user, single-browser
5292 setups, you might use it to delete your OS version information from
5293 the headers, because it is an invitation to exploit known bugs for your
5294 OS. It is also occasionally useful to forge this in order to access
5295 sites that won't let you in otherwise (though there may be a good
5296 reason in some cases).
5299 More information on known user-agent strings can be found at
5300 <ulink url="http://www.user-agents.org/">http://www.user-agents.org/</ulink>
5302 <ulink url="https://en.wikipedia.org/wiki/User_agent">http://en.wikipedia.org/wiki/User_agent</ulink>.
5308 <term>Example usage:</term>
5310 <screen>+hide-user-agent{Mozilla/5.0 (X11; ElectroBSD i386; rv:78.0) Gecko/20100101 Firefox/78.0}</screen>
5317 <!-- ~~~~~ New section ~~~~~ -->
5318 <sect3 renderas="sect4" id="https-inspection">
5319 <title>https-inspection</title>
5323 <term>Typical use:</term>
5325 <para>Filter encrypted requests and responses</para>
5330 <term>Effect:</term>
5333 Encrypted requests are decrypted, filtered and forwarded encrypted.
5340 <!-- boolean, parameterized, Multi-value -->
5342 <para>Boolean.</para>
5347 <term>Parameter:</term>
5359 This action allows &my-app; to filter encrypted requests and responses.
5360 For this to work &my-app; has to generate a certificate for the web site
5361 and send it to the client which has to accept it.
5364 Before this works the directives in the
5365 <literal><ulink url="config.html#HTTPS-INSPECTION-DIRECTIVES">HTTPS inspection section</ulink></literal>
5366 of the config file have to be configured.
5369 Note that the action has to be enabled based on the CONNECT
5370 request which doesn't contain a path. Enabling it based on
5371 a pattern with path doesn't work as the path is only seen
5372 by &my-app; if the action is already enabled.
5375 This is an experimental feature.
5381 <term>Example usage (section):</term>
5383 <screen>{+https-inspection}
5384 www.example.com</screen>
5392 <!-- ~~~~~ New section ~~~~~ -->
5393 <sect3 renderas="sect4" id="ignore-certificate-errors">
5394 <title>ignore-certificate-errors</title>
5398 <term>Typical use:</term>
5400 <para>Filter encrypted requests and responses without verifying the certificate</para>
5405 <term>Effect:</term>
5408 Encrypted requests are forwarded to sites without verifying the certificate.
5415 <!-- Boolean, Parameterized, Multi-value -->
5417 <para>Boolean.</para>
5422 <term>Parameter:</term>
5435 <link linkend="HTTPS-INSPECTION"><quote>+https-inspection</quote></link>
5436 action is used &my-app; by default verifies that the remote site uses a valid
5440 If the certificate can't be validated by &my-app; the connection is aborted.
5443 This action disables the certificate check so requests to sites
5444 with certificates that can't be validated are allowed.
5447 Note that enabling this action allows Man-in-the-middle attacks.
5453 <term>Example usage:</term>
5456 {+ignore-certificate-errors}
5465 <!-- ~~~~~ New section ~~~~~ -->
5466 <sect3 renderas="sect4" id="limit-connect">
5467 <title>limit-connect</title>
5471 <term>Typical use:</term>
5473 <para>Prevent abuse of <application>Privoxy</application> as a TCP proxy relay or disable SSL for untrusted sites</para>
5478 <term>Effect:</term>
5481 Specifies to which ports HTTP CONNECT requests are allowable.
5488 <!-- Boolean, Parameterized, Multi-value -->
5490 <para>Parameterized.</para>
5495 <term>Parameter:</term>
5498 A comma-separated list of ports or port ranges (the latter using dashes, with the minimum
5499 defaulting to 0 and the maximum to 65K).
5508 By default, i.e. if no <literal>limit-connect</literal> action applies,
5509 <application>Privoxy</application> allows HTTP CONNECT requests to all
5510 ports. Use <literal>limit-connect</literal> if fine-grained control
5511 is desired for some or all destinations.
5514 The CONNECT methods exists in HTTP to allow access to secure websites
5515 (<quote>https://</quote> URLs) through proxies. It works very simply:
5516 the proxy connects to the server on the specified port, and then
5517 short-circuits its connections to the client and to the remote server.
5518 This means CONNECT-enabled proxies can be used as TCP relays very easily.
5521 <application>Privoxy</application> relays HTTPS traffic without seeing
5522 the decoded content. Websites can leverage this limitation to circumvent &my-app;'s
5523 filters. By specifying an invalid port range you can disable HTTPS entirely.
5529 <term>Example usages:</term>
5531 <!-- I had trouble getting the spacing to look right in my browser -->
5532 <!-- I probably have the wrong font setup, bollocks. -->
5533 <!-- Apparently the emphasis tag uses a proportional font no matter what -->
5534 <screen>+limit-connect{443} # Port 443 is OK.
5535 +limit-connect{80,443} # Ports 80 and 443 are OK.
5536 +limit-connect{-3, 7, 20-100, 500-} # Ports less than 3, 7, 20 to 100 and above 500 are OK.
5537 +limit-connect{-} # All ports are OK
5538 +limit-connect{,} # No HTTPS/SSL traffic is allowed</screen>
5545 <!-- ~~~~~ New section ~~~~~ -->
5546 <sect3 renderas="sect4" id="limit-cookie-lifetime">
5547 <title>limit-cookie-lifetime</title>
5551 <term>Typical use:</term>
5553 <para>Limit the lifetime of HTTP cookies to a couple of minutes or hours.</para>
5558 <term>Effect:</term>
5561 Overwrites the expires field in Set-Cookie server headers if it's above the specified limit.
5568 <!-- Boolean, Parameterized, Multi-value -->
5570 <para>Parameterized.</para>
5575 <term>Parameter:</term>
5578 The lifetime limit in minutes, or 0.
5587 This action reduces the lifetime of HTTP cookies coming from the
5588 server to the specified number of minutes, starting from the time
5589 the cookie passes Privoxy.
5592 Cookies with a lifetime below the limit are not modified.
5593 The lifetime of session cookies is set to the specified limit.
5596 The effect of this action depends on the server.
5599 In case of servers which refresh their cookies with each response
5600 (or at least frequently), the lifetime limit set by this action
5602 Thus, a session associated with the cookie continues to work with
5603 this action enabled, as long as a new request is made before the
5604 last limit set is reached.
5607 However, some servers send their cookies once, with a lifetime of several
5608 years (the year 2037 is a popular choice), and do not refresh them
5609 until a certain event in the future, for example the user logging out.
5610 In this case this action may limit the absolute lifetime of the session,
5611 even if requests are made frequently.
5614 If the parameter is <quote>0</quote>, this action behaves like
5615 <literal><link linkend="session-cookies-only">session-cookies-only</link></literal>.
5621 <term>Example usages:</term>
5623 <screen>+limit-cookie-lifetime{60}</screen>
5629 <!-- ~~~~~ New section ~~~~~ -->
5630 <sect3 renderas="sect4" id="prevent-compression">
5631 <title>prevent-compression</title>
5635 <term>Typical use:</term>
5638 Ensure that servers send the content uncompressed, so it can be
5639 passed through <literal><link linkend="filter">filter</link></literal>s.
5645 <term>Effect:</term>
5648 Removes the Accept-Encoding header which can be used to ask for compressed transfer.
5655 <!-- Boolean, Parameterized, Multi-value -->
5657 <para>Boolean.</para>
5662 <term>Parameter:</term>
5674 More and more websites send their content compressed by default, which
5675 is generally a good idea and saves bandwidth. But the <literal><link
5676 linkend="filter">filter</link></literal> and
5677 <literal><link linkend="deanimate-gifs">deanimate-gifs</link></literal>
5678 actions need access to the uncompressed data.
5681 When compiled with zlib support (available since &my-app; 3.0.7), content that should be
5682 filtered is decompressed on-the-fly and you don't have to worry about this action.
5683 If you are using an older &my-app; version, or one that hasn't been compiled with zlib
5684 support, this action can be used to convince the server to send the content uncompressed.
5687 Most text-based instances compress very well, the size is seldom decreased by less than 50%,
5688 for markup-heavy instances like news feeds saving more than 90% of the original size isn't
5692 Not using compression will therefore slow down the transfer, and you should only
5693 enable this action if you really need it. As of &my-app; 3.0.7 it's disabled in all
5694 predefined action settings.
5697 Note that some (rare) ill-configured sites don't handle requests for uncompressed
5698 documents correctly. Broken PHP applications tend to send an empty document body,
5699 some IIS versions only send the beginning of the content and some content delivery
5700 networks let the connection time out.
5701 If you enable <literal>prevent-compression</literal> per default, you might
5702 want to add exceptions for those sites. See the example for how to do that.
5708 <term>Example usage (sections):</term>
5711 # Selectively turn off compression, and enable a filter
5713 { +filter{tiny-textforms} +prevent-compression }
5714 # Match only these sites
5719 # Or instead, we could set a universal default:
5721 { +prevent-compression }
5724 # Then maybe make exceptions for broken sites:
5726 { -prevent-compression }
5736 <!-- ~~~~~ New section ~~~~~ -->
5737 <sect3 renderas="sect4" id="overwrite-last-modified">
5738 <title>overwrite-last-modified</title>
5744 <term>Typical use:</term>
5746 <para>Prevent yet another way to track the user's steps between sessions.</para>
5751 <term>Effect:</term>
5754 Deletes the <quote>Last-Modified:</quote> HTTP server header or modifies its value.
5761 <!-- Boolean, Parameterized, Multi-value -->
5763 <para>Parameterized.</para>
5768 <term>Parameter:</term>
5771 One of the keywords: <quote>block</quote>, <quote>reset-to-request-time</quote>
5772 and <quote>randomize</quote>
5781 Removing the <quote>Last-Modified:</quote> header is useful for filter
5782 testing, where you want to force a real reload instead of getting status
5783 code <quote>304</quote>, which would cause the browser to reuse the old
5784 version of the page.
5787 The <quote>randomize</quote> option overwrites the value of the
5788 <quote>Last-Modified:</quote> header with a randomly chosen time
5789 between the original value and the current time. In theory the server
5790 could send each document with a different <quote>Last-Modified:</quote>
5791 header to track visits without using cookies. <quote>Randomize</quote>
5792 makes it impossible and the browser can still revalidate cached documents.
5795 <quote>reset-to-request-time</quote> overwrites the value of the
5796 <quote>Last-Modified:</quote> header with the current time. You could use
5797 this option together with
5798 <literal><link linkend="hide-if-modified-since">hide-if-modified-since</link></literal>
5799 to further customize your random range.
5802 The preferred parameter here is <quote>randomize</quote>. It is safe
5803 to use, as long as the time settings are more or less correct.
5804 If the server sets the <quote>Last-Modified:</quote> header to the time
5805 of the request, the random range becomes zero and the value stays the same.
5806 Therefore you should later randomize it a second time with
5807 <literal><link linkend="hide-if-modified-since">hided-if-modified-since</link></literal>,
5811 It is also recommended to use this action together with
5812 <literal><link linkend="crunch-if-none-match">crunch-if-none-match</link></literal>.
5818 <term>Example usage:</term>
5821 # Let the browser revalidate without being tracked across sessions
5822 { +hide-if-modified-since{-60} \
5823 +overwrite-last-modified{randomize} \
5824 +crunch-if-none-match \
5834 <!-- ~~~~~ New section ~~~~~ -->
5835 <sect3 renderas="sect4" id="redirect">
5836 <title>redirect</title>
5842 <term>Typical use:</term>
5845 Redirect requests to other sites.
5851 <term>Effect:</term>
5854 Convinces the browser that the requested document has been moved
5855 to another location and the browser should get it from there.
5862 <!-- Boolean, Parameterized, Multi-value -->
5864 <para>Parameterized</para>
5869 <term>Parameter:</term>
5872 An absolute URL or a single pcrs command.
5881 Requests to which this action applies are answered with a
5882 HTTP redirect to URLs of your choosing. The new URL is
5883 either provided as parameter, or derived by applying a
5884 single pcrs command to the original URL.
5887 The syntax for pcrs commands is documented in the
5888 <link linkend="filter-file">filter file</link> section.
5891 Requests can't be blocked and redirected at the same time,
5892 applying this action together with
5893 <literal><link linkend="block">block</link></literal>
5894 is a configuration error. Currently the request is blocked
5895 and an error message logged, the behavior may change in the
5896 future and result in Privoxy rejecting the action file.
5899 This action can be combined with
5900 <literal><link linkend="fast-redirects">fast-redirects{check-decoded-url}</link></literal>
5901 to redirect to a decoded version of a rewritten URL.
5904 Use this action carefully, make sure not to create redirection loops
5905 and be aware that using your own redirects might make it
5906 possible to fingerprint your requests.
5909 In case of problems with your redirects, or simply to watch
5910 them working, enable <link linkend="DEBUG">debug 128</link>.
5916 <term>Example usages:</term>
5919 # Replace example.com's style sheet with another one
5920 { +redirect{http://localhost/css-replacements/example.com.css} }
5921 example.com/stylesheet\.css
5923 # Create a short, easy to remember nickname for a favorite site
5924 # (relies on the browser to accept and forward invalid URLs to &my-app;)
5925 { +redirect{https://www.privoxy.org/user-manual/actions-file.html} }
5928 # Always use the expanded view for Undeadly.org articles
5929 # (Note the $ at the end of the URL pattern to make sure
5930 # the request for the rewritten URL isn't redirected as well)
5931 {+redirect{s@$@&mode=expanded@}}
5932 undeadly.org/cgi\?action=article&sid=\d*$
5934 # Redirect Google search requests to MSN
5935 {+redirect{s@^http://[^/]*/search\?q=([^&]*).*@http://search.msn.com/results.aspx?q=$1@}}
5938 # Redirect MSN search requests to Yahoo
5939 {+redirect{s@^http://[^/]*/results\.aspx\?q=([^&]*).*@http://search.yahoo.com/search?p=$1@}}
5940 search.msn.com//results\.aspx\?q=
5942 # Redirect http://example.com/&bla=fasel&toChange=foo (and any other value but "bar")
5943 # to http://example.com/&bla=fasel&toChange=bar
5945 # The URL pattern makes sure that the following request isn't redirected again.
5946 {+redirect{s@toChange=[^&]+@toChange=bar@}}
5947 example.com/.*toChange=(?!bar)
5949 # Add a shortcut to look up illumos bugs
5950 {+redirect{s@^http://i([0-9]+)/.*@https://www.illumos.org/issues/$1@}}
5951 # Redirected URL = http://i4974/
5952 # Redirect Destination = https://www.illumos.org/issues/4974
5953 i[0-9][0-9][0-9][0-9]*/
5955 # Redirect requests for the old Tor Hidden Service of the Privoxy website to the new one
5956 {+redirect{s@^http://jvauzb4sb3bwlsnc.onion/@http://l3tczdiiwoo63iwxty4lhs6p7eaxop5micbn7vbliydgv63x5zrrrfyd.onion/@}}
5957 jvauzb4sb3bwlsnc.onion/
5959 # Redirect remote requests for this manual
5960 # to the local version delivered by Privoxy
5961 {+redirect{s@^http://www@http://config@}}
5962 www.privoxy.org/user-manual/</screen>
5970 <!-- ~~~~~ New section ~~~~~ -->
5971 <sect3 renderas="sect4" id="server-header-filter">
5972 <title>server-header-filter</title>
5976 <term>Typical use:</term>
5979 Rewrite or remove single server headers.
5985 <term>Effect:</term>
5988 All server headers to which this action applies are filtered on-the-fly
5989 through the specified regular expression based substitutions.
5996 <!-- boolean, parameterized, Multi-value -->
5998 <para>Multi-value.</para>
6003 <term>Parameter:</term>
6006 The name of a server-header filter, as defined in one of the
6007 <link linkend="filter-file">filter files</link>.
6016 Server-header filters are applied to each header on its own, not to
6017 all at once. This makes it easier to diagnose problems, but on the downside
6018 you can't write filters that only change header x if header y's value is z.
6019 You can do that by using tags though.
6022 Server-header filters are executed after the other header actions have finished
6023 and use their output as input.
6026 Please refer to the <link linkend="filter-file">filter file chapter</link>
6027 to learn which server-header filters are available by default, and how to
6034 <term>Example usage (section):</term>
6037 {+server-header-filter{html-to-xml}}
6038 example.org/xml-instance-that-is-delivered-as-html
6040 {+server-header-filter{xml-to-html}}
6041 example.org/instance-that-is-delivered-as-xml-but-is-not
6050 <!-- ~~~~~ New section ~~~~~ -->
6051 <sect3 renderas="sect4" id="server-header-tagger">
6052 <title>server-header-tagger</title>
6056 <term>Typical use:</term>
6059 Enable or disable filters based on the Content-Type header.
6065 <term>Effect:</term>
6068 Server headers to which this action applies are filtered on-the-fly through
6069 the specified regular expression based substitutions, the result is used as
6077 <!-- boolean, parameterized, Multi-value -->
6079 <para>Multi-value.</para>
6084 <term>Parameter:</term>
6087 The name of a server-header tagger, as defined in one of the
6088 <link linkend="filter-file">filter files</link>.
6097 Server-header taggers are applied to each header on its own,
6098 and as the header isn't modified, each tagger <quote>sees</quote>
6102 Server-header taggers are executed before all other header actions
6103 that modify server headers. Their tags can be used to control
6104 all of the other server-header actions, the content filters
6105 and the crunch actions (<link linkend="redirect">redirect</link>
6106 and <link linkend="block">block</link>).
6109 Obviously crunching based on tags created by server-header taggers
6110 doesn't prevent the request from showing up in the server's log file.
6117 <term>Example usage (section):</term>
6120 # Tag every request with the content type declared by the server
6121 {+server-header-tagger{content-type}}
6124 # If the response has a tag starting with 'image/' enable an external
6125 # filter that only applies to images.
6127 # Note that the filter is not available by default, it's just a
6128 # <literal><link linkend="external-filter-syntax">silly example</link></literal>.
6129 {+external-filter{rotate-image} +force-text-mode}
6139 <!-- ~~~~~ New section ~~~~~ -->
6140 <sect3 renderas="sect4" id="suppress-tag">
6141 <title>suppress-tag</title>
6145 <term>Typical use:</term>
6148 Suppress client or server tag.
6154 <term>Effect:</term>
6157 Server or client tags to which this action applies are not added to the request,
6158 thus making all actions that are specific to these request tags inactive.
6165 <!-- boolean, parameterized, Multi-value -->
6167 <para>Multi-value.</para>
6172 <term>Parameter:</term>
6175 The result tag of a server-header or client-header tagger, as defined in one of the
6176 <link linkend="filter-file">filter files</link>.
6182 <term>Example usage (section):</term>
6185 # Suppress tag produced by range-requests client-header tagger for requests coming from address 10.0.0.1
6186 {+suppress-tag{RANGE-REQUEST}}
6187 TAG:^IP-ADDRESS: 10\.0\.0\.1$
6196 <!-- ~~~~~ New section ~~~~~ -->
6197 <sect3 renderas="sect4" id="session-cookies-only">
6198 <title>session-cookies-only</title>
6202 <term>Typical use:</term>
6205 Allow only temporary <quote>session</quote> cookies (for the current
6206 browser session <emphasis>only</emphasis>).
6212 <term>Effect:</term>
6215 Deletes the <quote>expires</quote> field from <quote>Set-Cookie:</quote>
6216 server headers. Most browsers will not store such cookies permanently and
6217 forget them in between sessions.
6224 <!-- Boolean, Parameterized, Multi-value -->
6226 <para>Boolean.</para>
6231 <term>Parameter:</term>
6243 This is less strict than <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal> /
6244 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal> and allows you to browse
6245 websites that insist or rely on setting cookies, without compromising your privacy too badly.
6248 Most browsers will not permanently store cookies that have been processed by
6249 <literal>session-cookies-only</literal> and will forget about them between sessions.
6250 This makes profiling cookies useless, but won't break sites which require cookies so
6251 that you can log in for transactions. This is generally turned on for all
6252 sites, and is the recommended setting.
6255 It makes <emphasis>no sense at all</emphasis> to use <literal>session-cookies-only</literal>
6256 together with <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal> or
6257 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>. If you do, cookies
6258 will be plainly killed.
6261 Note that it is up to the browser how it handles such cookies without an <quote>expires</quote>
6262 field. If you use an exotic browser, you might want to try it out to be sure.
6265 This setting also has no effect on cookies that may have been stored
6266 previously by the browser before starting <application>Privoxy</application>.
6267 These would have to be removed manually.
6270 <application>Privoxy</application> also uses
6271 the <link linkend="filter-content-cookies">content-cookies filter</link>
6272 to block some types of cookies. Content cookies are not effected by
6273 <literal>session-cookies-only</literal>.
6279 <term>Example usage:</term>
6281 <screen>+session-cookies-only</screen>
6288 <!-- ~~~~~ New section ~~~~~ -->
6289 <sect3 renderas="sect4" id="set-image-blocker">
6290 <title>set-image-blocker</title>
6294 <term>Typical use:</term>
6296 <para>Choose the replacement for blocked images</para>
6301 <term>Effect:</term>
6304 This action alone doesn't do anything noticeable. If <emphasis>both</emphasis>
6305 <literal><link linkend="block">block</link></literal> <emphasis>and</emphasis> <literal><link
6306 linkend="handle-as-image">handle-as-image</link></literal> <emphasis>also</emphasis>
6307 apply, i.e. if the request is to be blocked as an image,
6308 <emphasis>then</emphasis> the parameter of this action decides what will be
6309 sent as a replacement.
6316 <!-- Boolean, Parameterized, Multi-value -->
6318 <para>Parameterized.</para>
6323 <term>Parameter:</term>
6328 <quote>pattern</quote> to send a built-in checkerboard pattern image. The image is visually
6329 decent, scales very well, and makes it obvious where banners were busted.
6334 <quote>blank</quote> to send a built-in transparent image. This makes banners disappear
6335 completely, but makes it hard to detect where <application>Privoxy</application> has blocked
6336 images on a given page and complicates troubleshooting if <application>Privoxy</application>
6337 has blocked innocent images, like navigation icons.
6342 <quote><replaceable class="parameter">target-url</replaceable></quote> to
6343 send a redirect to <replaceable class="parameter">target-url</replaceable>. You can redirect
6344 to any image anywhere, even in your local filesystem via <quote>file:///</quote> URL.
6345 (But note that not all browsers support redirecting to a local file system).
6348 A good application of redirects is to use special <application>Privoxy</application>-built-in
6349 URLs, which send the built-in images, as <replaceable class="parameter">target-url</replaceable>.
6350 This has the same visual effect as specifying <quote>blank</quote> or <quote>pattern</quote> in
6351 the first place, but enables your browser to cache the replacement image, instead of requesting
6352 it over and over again.
6363 The URLs for the built-in images are <quote>http://config.privoxy.org/send-banner?type=<replaceable
6364 class="parameter">type</replaceable></quote>, where <replaceable class="parameter">type</replaceable> is
6365 either <quote>blank</quote> or <quote>pattern</quote>.
6368 There is a third (advanced) type, called <quote>auto</quote>. It is <emphasis>NOT</emphasis> to be
6369 used in <literal>set-image-blocker</literal>, but meant for use from <link linkend="filter-file">filters</link>.
6370 Auto will select the type of image that would have applied to the referring page, had it been an image.
6376 <term>Example usage:</term>
6381 <screen>+set-image-blocker{pattern}</screen>
6383 Redirect to the BSD daemon:
6385 <screen>+set-image-blocker{http://www.freebsd.org/gifs/dae_up3.gif}</screen>
6387 Redirect to the built-in pattern for better caching:
6389 <screen>+set-image-blocker{http://config.privoxy.org/send-banner?type=pattern}</screen>
6396 <!-- ~~~~~ New section ~~~~~ -->
6397 <sect3 id="summary">
6398 <title>Summary</title>
6400 Note that many of these actions have the potential to cause a page to
6401 misbehave, possibly even not to display at all. There are many ways
6402 a site designer may choose to design his site, and what HTTP header
6403 content, and other criteria, he may depend on. There is no way to have hard
6404 and fast rules for all sites. See the <link
6405 linkend="ACTIONSANAT">Appendix</link> for a brief example on troubleshooting
6411 <!-- ~~~~~ New section ~~~~~ -->
6412 <sect2 id="aliases">
6413 <title>Aliases</title>
6415 Custom <quote>actions</quote>, known to <application>Privoxy</application>
6416 as <quote>aliases</quote>, can be defined by combining other actions.
6417 These can in turn be invoked just like the built-in actions.
6418 Currently, an alias name can contain any character except space, tab,
6420 <quote>{</quote> and <quote>}</quote>, but we <emphasis>strongly
6421 recommend</emphasis> that you only use <quote>a</quote> to <quote>z</quote>,
6422 <quote>0</quote> to <quote>9</quote>, <quote>+</quote>, and <quote>-</quote>.
6423 Alias names are not case sensitive, and are not required to start with a
6424 <quote>+</quote> or <quote>-</quote> sign, since they are merely textually
6428 Aliases can be used throughout the actions file, but they <emphasis>must be
6429 defined in a special section at the top of the file!</emphasis>
6430 And there can only be one such section per actions file. Each actions file may
6431 have its own alias section, and the aliases defined in it are only visible
6435 There are two main reasons to use aliases: One is to save typing for frequently
6436 used combinations of actions, the other one is a gain in flexibility: If you
6437 decide once how you want to handle shops by defining an alias called
6438 <quote>shop</quote>, you can later change your policy on shops in
6439 <emphasis>one</emphasis> place, and your changes will take effect everywhere
6440 in the actions file where the <quote>shop</quote> alias is used. Calling aliases
6441 by their purpose also makes your actions files more readable.
6444 Currently, there is one big drawback to using aliases, though:
6445 <application>Privoxy</application>'s built-in web-based action file
6446 editor honors aliases when reading the actions files, but it expands
6447 them before writing. So the effects of your aliases are of course preserved,
6448 but the aliases themselves are lost when you edit sections that use aliases
6453 Now let's define some aliases...
6457 # Useful custom aliases we can use later.
6459 # Note the (required!) section header line and that this section
6460 # must be at the top of the actions file!
6464 # These aliases just save typing later:
6465 # (Note that some already use other aliases!)
6467 +crunch-all-cookies = +<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> +<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
6468 -crunch-all-cookies = -<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> -<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
6469 +block-as-image = +block{Blocked image.} +handle-as-image
6470 allow-all-cookies = -crunch-all-cookies -<link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> -<link linkend="FILTER-CONTENT-COOKIES">filter{content-cookies}</link>
6472 # These aliases define combinations of actions
6473 # that are useful for certain types of sites:
6475 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>
6477 shop = -crunch-all-cookies -<link linkend="FILTER-ALL-POPUPS">filter{all-popups}</link>
6479 # Short names for other aliases, for really lazy people ;-)
6481 c0 = +crunch-all-cookies
6482 c1 = -crunch-all-cookies
6486 ...and put them to use. These sections would appear in the lower part of an
6487 actions file and define exceptions to the default actions (as specified further
6488 up for the <quote>/</quote> pattern):
6492 # These sites are either very complex or very keen on
6493 # user data and require minimal interference to work:
6496 .office.microsoft.com
6497 .windowsupdate.microsoft.com
6498 # Gmail is really mail.google.com, not gmail.com
6502 # Allow cookies (for setting and retrieving your customer data)
6506 .worldpay.com # for quietpc.com
6509 # These shops require pop-ups:
6511 {-filter{all-popups} -filter{unsolicited-popups}}
6517 Aliases like <quote>shop</quote> and <quote>fragile</quote> are typically used for
6518 <quote>problem</quote> sites that require more than one action to be disabled
6519 in order to function properly.
6525 <!-- ~~~~~ New section ~~~~~ -->
6526 <sect2 id="act-examples">
6527 <title>Actions Files Tutorial</title>
6529 The above chapters have shown <link linkend="actions-file">which actions files
6530 there are and how they are organized</link>, how actions are <link
6531 linkend="actions">specified</link> and <link linkend="actions-apply">applied
6532 to URLs</link>, how <link linkend="af-patterns">patterns</link> work, and how to
6533 define and use <link linkend="aliases">aliases</link>. Now, let's look at an
6534 example <filename>match-all.action</filename>, <filename>default.action</filename>
6535 and <filename>user.action</filename> file and see how all these pieces come together:
6538 <sect3 id="match-all">
6539 <title>match-all.action</title>
6541 Remember <emphasis>all actions are disabled when matching starts</emphasis>,
6542 so we have to explicitly enable the ones we want.
6546 While the <filename>match-all.action</filename> file only contains a
6547 single section, it is probably the most important one. It has only one
6548 pattern, <quote><literal>/</literal></quote>, but this pattern
6549 <link linkend="af-patterns">matches all URLs</link>. Therefore, the set of
6550 actions used in this <quote>default</quote> section <emphasis>will
6551 be applied to all requests as a start</emphasis>. It can be partly or
6552 wholly overridden by other actions files like <filename>default.action</filename>
6553 and <filename>user.action</filename>, but it will still be largely responsible
6554 for your overall browsing experience.
6558 Again, at the start of matching, all actions are disabled, so there is
6559 no need to disable any actions here. (Remember: a <quote>+</quote>
6560 preceding the action name enables the action, a <quote>-</quote> disables!).
6561 Also note how this long line has been made more readable by splitting it into
6562 multiple lines with line continuation.
6567 +<link linkend="CHANGE-X-FORWARDED-FOR">change-x-forwarded-for{block}</link> \
6568 +<link linkend="HIDE-FROM-HEADER">hide-from-header{block}</link> \
6569 +<link linkend="SET-IMAGE-BLOCKER">set-image-blocker{pattern}</link> \
6575 The default behavior is now set.
6579 <sect3 id="default-action">
6580 <title>default.action</title>
6583 If you aren't a developer, there's no need for you to edit the
6584 <filename>default.action</filename> file. It is maintained by
6585 the &my-app; developers and if you disagree with some of the
6586 sections, you should overrule them in your <filename>user.action</filename>.
6590 Understanding the <filename>default.action</filename> file can
6591 help you with your <filename>user.action</filename>, though.
6595 The first section in this file is a special section for internal use
6596 that prevents older &my-app; versions from reading the file:
6600 ##########################################################################
6601 # Settings -- Don't change! For internal Privoxy use ONLY.
6602 ##########################################################################
6604 for-privoxy-version=3.0.11</screen>
6607 After that comes the (optional) alias section. We'll use the example
6608 section from the above <link linkend="aliases">chapter on aliases</link>,
6609 that also explains why and how aliases are used:
6613 ##########################################################################
6615 ##########################################################################
6618 # These aliases just save typing later:
6619 # (Note that some already use other aliases!)
6621 +crunch-all-cookies = +<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> +<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
6622 -crunch-all-cookies = -<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> -<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
6623 +block-as-image = +block{Blocked image.} +handle-as-image
6624 mercy-for-cookies = -crunch-all-cookies -<link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> -<link linkend="FILTER-CONTENT-COOKIES">filter{content-cookies}</link>
6626 # These aliases define combinations of actions
6627 # that are useful for certain types of sites:
6629 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>
6630 shop = -crunch-all-cookies -<link linkend="FILTER-ALL-POPUPS">filter{all-popups}</link></screen>
6633 The first of our specialized sections is concerned with <quote>fragile</quote>
6634 sites, i.e. sites that require minimum interference, because they are either
6635 very complex or very keen on tracking you (and have mechanisms in place that
6636 make them unusable for people who avoid being tracked). We will use
6637 our pre-defined <literal>fragile</literal> alias instead of stating the list
6638 of actions explicitly:
6642 ##########################################################################
6643 # Exceptions for sites that'll break under the default action set:
6644 ##########################################################################
6646 # "Fragile" Use a minimum set of actions for these sites (see alias above):
6649 .office.microsoft.com # surprise, surprise!
6650 .windowsupdate.microsoft.com
6651 mail.google.com</screen>
6654 Shopping sites are not as fragile, but they typically
6655 require cookies to log in, and pop-up windows for shopping
6656 carts or item details. Again, we'll use a pre-defined alias:
6664 .worldpay.com # for quietpc.com
6666 .scan.co.uk</screen>
6669 The <literal><link linkend="FAST-REDIRECTS">fast-redirects</link></literal>
6670 action, which may have been enabled in <filename>match-all.action</filename>,
6671 breaks some sites. So disable it for popular sites where we know it misbehaves:
6675 { -<link linkend="FAST-REDIRECTS">fast-redirects</link> }
6679 .altavista.com/.*(like|url|link):http
6680 .altavista.com/trans.*urltext=http
6681 .nytimes.com</screen>
6684 It is important that <application>Privoxy</application> knows which
6685 URLs belong to images, so that <emphasis>if</emphasis> they are to
6686 be blocked, a substitute image can be sent, rather than an HTML page.
6687 Contacting the remote site to find out is not an option, since it
6688 would destroy the loading time advantage of banner blocking, and it
6689 would feed the advertisers information about you. We can mark any
6690 URL as an image with the <literal><link
6691 linkend="handle-as-image">handle-as-image</link></literal> action,
6692 and marking all URLs that end in a known image file extension is a
6697 ##########################################################################
6699 ##########################################################################
6701 # Define which file types will be treated as images, in case they get
6702 # blocked further down this file:
6704 { +<link linkend="HANDLE-AS-IMAGE">handle-as-image</link> }
6705 /.*\.(gif|jpe?g|png|bmp|ico)$</screen>
6708 And then there are known banner sources. They often use scripts to
6709 generate the banners, so it won't be visible from the URL that the
6710 request is for an image. Hence we block them <emphasis>and</emphasis>
6711 mark them as images in one go, with the help of our
6712 <literal>+block-as-image</literal> alias defined above. (We could of
6713 course just as well use <literal>+<link linkend="block">block</link>
6714 +<link linkend="handle-as-image">handle-as-image</link></literal> here.)
6715 Remember that the type of the replacement image is chosen by the
6716 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>
6717 action. Since all URLs have matched the default section with its
6718 <literal>+<link linkend="set-image-blocker">set-image-blocker</link>{pattern}</literal>
6719 action before, it still applies and needn't be repeated:
6723 # Known ad generators:
6728 .ad.*.doubleclick.net
6729 .a.yimg.com/(?:(?!/i/).)*$
6730 .a[0-9].yimg.com/(?:(?!/i/).)*$
6735 One of the most important jobs of <application>Privoxy</application>
6736 is to block banners. Many of these can be <quote>blocked</quote>
6737 by the <literal><link linkend="filter">filter</link>{banners-by-size}</literal>
6738 action, which we enabled above, and which deletes the references to banner
6739 images from the pages while they are loaded, so the browser doesn't request
6740 them anymore, and hence they don't need to be blocked here. But this naturally
6741 doesn't catch all banners, and some people choose not to use filters, so we
6742 need a comprehensive list of patterns for banner URLs here, and apply the
6743 <literal><link linkend="block">block</link></literal> action to them.
6746 First comes many generic patterns, which do most of the work, by
6747 matching typical domain and path name components of banners. Then comes
6748 a list of individual patterns for specific sites, which is omitted here
6749 to keep the example short:
6753 ##########################################################################
6754 # Block these fine banners:
6755 ##########################################################################
6756 { <link linkend="BLOCK">+block{Banner ads.}</link> }
6764 /.*count(er)?\.(pl|cgi|exe|dll|asp|php[34]?)
6765 /(?:.*/)?(publicite|werbung|rekla(ma|me|am)|annonse|maino(kset|nta|s)?)/
6767 # Site-specific patterns (abbreviated):
6769 .hitbox.com</screen>
6772 It's quite remarkable how many advertisers actually call their banner
6773 servers ads.<replaceable>company</replaceable>.com, or call the directory
6774 in which the banners are stored literally <quote>banners</quote>. So the above
6775 generic patterns are surprisingly effective.
6778 But being very generic, they necessarily also catch URLs that we don't want
6779 to block. The pattern <literal>.*ads.</literal> e.g. catches
6780 <quote>nasty-<emphasis>ads</emphasis>.nasty-corp.com</quote> as intended,
6781 but also <quote>downlo<emphasis>ads</emphasis>.sourcefroge.net</quote> or
6782 <quote><emphasis>ads</emphasis>l.some-provider.net.</quote> So here come some
6783 well-known exceptions to the <literal>+<link linkend="BLOCK">block</link></literal>
6787 Note that these are exceptions to exceptions from the default! Consider the URL
6788 <quote>downloads.sourcefroge.net</quote>: Initially, all actions are deactivated,
6789 so it wouldn't get blocked. Then comes the defaults section, which matches the
6790 URL, but just deactivates the <literal><link linkend="BLOCK">block</link></literal>
6791 action once again. Then it matches <literal>.*ads.</literal>, an exception to the
6792 general non-blocking policy, and suddenly
6793 <literal><link linkend="BLOCK">+block</link></literal> applies. And now, it'll match
6794 <literal>.*loads.</literal>, where <literal><link linkend="BLOCK">-block</link></literal>
6795 applies, so (unless it matches <emphasis>again</emphasis> further down) it ends up
6796 with no <literal><link linkend="BLOCK">block</link></literal> action applying.
6800 ##########################################################################
6801 # Save some innocent victims of the above generic block patterns:
6802 ##########################################################################
6806 { -<link linkend="BLOCK">block</link> }
6807 adv[io]*. # (for advogato.org and advice.*)
6808 adsl. # (has nothing to do with ads)
6809 adobe. # (has nothing to do with ads either)
6810 ad[ud]*. # (adult.* and add.*)
6811 .edu # (universities don't host banners (yet!))
6812 .*loads. # (downloads, uploads etc)
6820 www.globalintersec.com/adv # (adv = advanced)
6821 www.ugu.com/sui/ugu/adv</screen>
6824 Filtering source code can have nasty side effects,
6825 so make an exception for our friends at sourceforge.net,
6826 and all paths with <quote>cvs</quote> in them. Note that
6827 <literal>-<link linkend="FILTER">filter</link></literal>
6828 disables <emphasis>all</emphasis> filters in one fell swoop!
6832 # Don't filter code!
6834 { -<link linkend="FILTER">filter</link> }
6839 .sourceforge.net</screen>
6842 The actual <filename>default.action</filename> is of course much more
6843 comprehensive, but we hope this example made clear how it works.
6848 <sect3 id="user-action"><title>user.action</title>
6851 So far we are painting with a broad brush by setting general policies,
6852 which would be a reasonable starting point for many people. Now,
6853 you might want to be more specific and have customized rules that
6854 are more suitable to your personal habits and preferences. These would
6855 be for narrowly defined situations like your ISP or your bank, and should
6856 be placed in <filename>user.action</filename>, which is parsed after all other
6857 actions files and hence has the last word, over-riding any previously
6858 defined actions. <filename>user.action</filename> is also a
6859 <emphasis>safe</emphasis> place for your personal settings, since
6860 <filename>default.action</filename> is actively maintained by the
6861 <application>Privoxy</application> developers and you'll probably want
6862 to install updated versions from time to time.
6866 So let's look at a few examples of things that one might typically do in
6867 <filename>user.action</filename>:
6871 <!-- brief sample user.action here -->
6874 # My user.action file. <fred@example.com></screen>
6877 As <link linkend="aliases">aliases</link> are local to the actions
6878 file that they are defined in, you can't use the ones from
6879 <filename>default.action</filename>, unless you repeat them here:
6883 # Aliases are local to the file they are defined in.
6884 # (Re-)define aliases for this file:
6888 # These aliases just save typing later, and the alias names should
6889 # be self explanatory.
6891 +crunch-all-cookies = +crunch-incoming-cookies +crunch-outgoing-cookies
6892 -crunch-all-cookies = -crunch-incoming-cookies -crunch-outgoing-cookies
6893 allow-all-cookies = -crunch-all-cookies -session-cookies-only
6894 allow-popups = -filter{all-popups}
6895 +block-as-image = +block{Blocked as image.} +handle-as-image
6896 -block-as-image = -block
6898 # These aliases define combinations of actions that are useful for
6899 # certain types of sites:
6901 fragile = -block -crunch-all-cookies -filter -fast-redirects -hide-referrer
6902 shop = -crunch-all-cookies allow-popups
6904 # Allow ads for selected useful free sites:
6906 allow-ads = -block -filter{banners-by-size} -filter{banners-by-link}
6908 # Alias for specific file types that are text, but might have conflicting
6909 # MIME types. We want the browser to force these to be text documents.
6910 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>
6913 Say you have accounts on some sites that you visit regularly, and
6914 you don't want to have to log in manually each time. So you'd like
6915 to allow persistent cookies for these sites. The
6916 <literal>allow-all-cookies</literal> alias defined above does exactly
6917 that, i.e. it disables crunching of cookies in any direction, and the
6918 processing of cookies to make them only temporary.
6922 { allow-all-cookies }
6930 Your bank is allergic to some filter, but you don't know which, so you disable them all:
6934 { -<link linkend="FILTER">filter</link> }
6935 .your-home-banking-site.com
6939 Some file types you may not want to filter for various reasons:
6943 # Technical documentation is likely to contain strings that might
6944 # erroneously get altered by the JavaScript-oriented filters:
6949 # And this stupid host sends streaming video with a wrong MIME type,
6950 # so that Privoxy thinks it is getting HTML and starts filtering:
6952 stupid-server.example.com/</screen>
6955 Example of a simple <link linkend="BLOCK">block</link> action. Say you've
6956 seen an ad on your favourite page on example.com that you want to get rid of.
6957 You have right-clicked the image, selected <quote>copy image location</quote>
6958 and pasted the URL below while removing the leading http://, into a
6959 <literal>{ +block{} }</literal> section. Note that <literal>{ +handle-as-image
6960 }</literal> need not be specified, since all URLs ending in
6961 <literal>.gif</literal> will be tagged as images by the general rules as set
6962 in default.action anyway:
6966 { +<link linkend="BLOCK">block</link>{Nasty ads.} }
6967 www.example.com/nasty-ads/sponsor\.gif
6968 another.example.net/more/junk/here/
6972 The URLs of dynamically generated banners, especially from large banner
6973 farms, often don't use the well-known image file name extensions, which
6974 makes it impossible for <application>Privoxy</application> to guess
6975 the file type just by looking at the URL.
6976 You can use the <literal>+block-as-image</literal> alias defined above for
6978 Note that objects which match this rule but then turn out NOT to be an
6979 image are typically rendered as a <quote>broken image</quote> icon by the
6980 browser. Use cautiously.
6992 Now you noticed that the default configuration breaks Forbes Magazine,
6993 but you were too lazy to find out which action is the culprit, and you
6994 were again too lazy to give <link linkend="contact">feedback</link>, so
6995 you just used the <literal>fragile</literal> alias on the site, and
6996 -- <emphasis>whoa!</emphasis> -- it worked. The <literal>fragile</literal>
6997 aliases disables those actions that are most likely to break a site. Also,
6998 good for testing purposes to see if it is <application>Privoxy</application>
6999 that is causing the problem or not. We later find other regular sites
7000 that misbehave, and add those to our personalized list of troublemakers:
7011 You like the <quote>fun</quote> text replacements in <filename>default.filter</filename>,
7012 but it is disabled in the distributed actions file.
7013 So you'd like to turn it on in your private,
7014 update-safe config, once and for all:
7018 { +<link linkend="filter-fun">filter{fun}</link> }
7023 Note that the above is not really a good idea: There are exceptions
7024 to the filters in <filename>default.action</filename> for things that
7025 really shouldn't be filtered, like code on CVS->Web interfaces. Since
7026 <filename>user.action</filename> has the last word, these exceptions
7027 won't be valid for the <quote>fun</quote> filtering specified here.
7031 You might also worry about how your favourite free websites are
7032 funded, and find that they rely on displaying banner advertisements
7033 to survive. So you might want to specifically allow banners for those
7034 sites that you feel provide value to you:
7045 Note that <literal>allow-ads</literal> has been aliased to
7046 <literal>-<link linkend="block">block</link></literal>,
7047 <literal>-<link linkend="filter-banners-by-size">filter{banners-by-size}</link></literal>, and
7048 <literal>-<link linkend="filter-banners-by-link">filter{banners-by-link}</link></literal> above.
7052 Invoke another alias here to force an over-ride of the MIME type <literal>
7053 application/x-sh</literal> which typically would open a download type
7054 dialog. In my case, I want to look at the shell script, and then I can save
7055 it should I choose to.
7064 <filename>user.action</filename> is generally the best place to define
7065 exceptions and additions to the default policies of
7066 <filename>default.action</filename>. Some actions are safe to have their
7067 default policies set here though. So let's set a default policy to have a
7068 <quote>blank</quote> image as opposed to the checkerboard pattern for
7069 <emphasis>ALL</emphasis> sites. <quote>/</quote> of course matches all URL
7074 { +<link linkend="set-image-blocker">set-image-blocker{blank}</link> }
7075 / # ALL sites</screen>
7080 <!-- ~ End section ~ -->
7084 <!-- ~ End section ~ -->
7086 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
7088 <sect1 id="filter-file">
7089 <title>Filter Files</title>
7092 On-the-fly text substitutions need
7093 to be defined in a <quote>filter file</quote>. Once defined, they
7094 can then be invoked as an <quote>action</quote>.
7098 &my-app; supports four different pcrs-based filter actions:
7099 <literal><link linkend="filter">filter</link></literal> to
7100 rewrite the content that is send to the client,
7101 <literal><link linkend="client-header-filter">client-header-filter</link></literal>
7102 to rewrite headers that are send by the client,
7103 <literal><link linkend="server-header-filter">server-header-filter</link></literal>
7104 to rewrite headers that are send by the server, and
7105 <literal><link linkend="client-body-filter">client-body-filter</link></literal>
7106 to rewrite client request body.
7110 &my-app; also supports two tagger actions:
7111 <literal><link linkend="client-header-tagger">client-header-tagger</link></literal>
7113 <literal><link linkend="server-header-tagger">server-header-tagger</link></literal>.
7114 Taggers and filters use the same syntax in the filter files, the difference
7115 is that taggers don't modify the text they are filtering, but use a rewritten
7116 version of the filtered text as tag. The tags can then be used to change the
7117 applying actions through sections with <link linkend="tag-pattern">tag-patterns</link>.
7121 Finally &my-app; supports the
7122 <literal><link linkend="external-filter">external-filter</link></literal> action
7123 to enable <literal><link linkend="external-filter-syntax">external filters</link></literal>
7124 written in proper programming languages.
7129 Multiple filter files can be defined through the <literal> <link
7130 linkend="filterfile">filterfile</link></literal> config directive. The filters
7131 as supplied by the developers are located in
7132 <filename>default.filter</filename>. It is recommended that any locally
7133 defined or modified filters go in a separately defined file such as
7134 <filename>user.filter</filename>.
7138 Common tasks for content filters are to eliminate common annoyances in
7139 HTML and JavaScript, such as pop-up windows,
7140 exit consoles, crippled windows without navigation tools, the
7141 infamous <BLINK> tag etc, to suppress images with certain
7142 width and height attributes (standard banner sizes or web-bugs),
7143 or just to have fun.
7147 Enabled content filters are applied to any content whose
7148 <quote>Content Type</quote> header is recognised as a sign
7149 of text-based content, with the exception of <literal>text/plain</literal>.
7150 Use the <link linkend="FORCE-TEXT-MODE">force-text-mode</link> action
7151 to also filter other content.
7155 Substitutions are made at the source level, so if you want to <quote>roll
7156 your own</quote> filters, you should first be familiar with HTML syntax,
7157 and, of course, regular expressions.
7161 Just like the <link linkend="actions-file">actions files</link>, the
7162 filter file is organized in sections, which are called <emphasis>filters</emphasis>
7163 here. Each filter consists of a heading line, that starts with one of the
7164 <emphasis>keywords</emphasis> <literal>FILTER:</literal>,
7165 <literal>CLIENT-HEADER-FILTER:</literal>, <literal>SERVER-HEADER-FILTER:</literal> or
7166 <literal>CLIENT-BODY-FILTER:</literal>
7167 followed by the filter's <emphasis>name</emphasis>, and a short (one line)
7168 <emphasis>description</emphasis> of what it does. Below that line
7169 come the <emphasis>jobs</emphasis>, i.e. lines that define the actual
7170 text substitutions. By convention, the name of a filter
7171 should describe what the filter <emphasis>eliminates</emphasis>. The
7172 comment is used in the <ulink url="http://config.privoxy.org/">web-based
7173 user interface</ulink>.
7177 Once a filter called <replaceable>name</replaceable> has been defined
7178 in the filter file, it can be invoked by using an action of the form
7179 +<literal><link linkend="filter">filter</link>{<replaceable>name</replaceable>}</literal>
7180 in any <link linkend="actions-file">actions file</link>.
7184 Filter definitions start with a header line that contains the filter
7185 type, the filter name and the filter description.
7186 A content filter header line for a filter called <quote>foo</quote> could look
7190 <screen>FILTER: foo Replace all "foo" with "bar"</screen>
7193 Below that line, and up to the next header line, come the jobs that
7194 define what text replacements the filter executes. They are specified
7195 in a syntax that imitates <ulink url="http://www.perl.org/">Perl</ulink>'s
7196 <literal>s///</literal> operator. If you are familiar with Perl, you
7197 will find this to be quite intuitive, and may want to look at the
7198 PCRS documentation for the subtle differences to Perl behaviour.
7202 Most notably, the non-standard option letter <literal>U</literal> is supported,
7203 which turns the default to ungreedy matching (add <literal>?</literal> to
7204 quantifiers to turn them greedy again).
7208 The non-standard option letter <literal>D</literal> (dynamic) allows
7209 to use the variables $host, $origin (the IP address the request came from),
7210 $path, $url and $listen-address (the address on which Privoxy accepted the
7211 client request. Example: 127.0.0.1:8118).
7212 They will be replaced with the value they refer to before the filter
7217 Note that '$' is a bad choice for a delimiter in a dynamic filter as you
7218 might end up with unintended variables if you use a variable name
7219 directly after the delimiter. Variables will be resolved without
7220 escaping anything, therefore you also have to be careful not to chose
7221 delimiters that appear in the replacement text. For example '<' should
7222 be save, while '?' will sooner or later cause conflicts with $url.
7226 The non-standard option letter <literal>T</literal> (trivial) prevents
7227 parsing for backreferences in the substitute. Use it if you want to include
7228 text like '$&' in your substitute without quoting.
7233 <ulink url="https://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
7234 Expressions</quote></ulink>, you might want to take a look at
7235 the <link linkend="regex">Appendix on regular expressions</link>, and
7236 see the <ulink url="http://perldoc.perl.org/perlre.html">Perl
7238 <ulink url="http://perldoc.perl.org/perlop.html">the
7239 <literal>s///</literal> operator's syntax</ulink> and <ulink
7240 url="http://perldoc.perl.org/perlre.html">Perl-style regular
7241 expressions</ulink> in general.
7242 The below examples might also help to get you started.
7246 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
7248 <sect2 id="filter-file-tut"><title>Filter File Tutorial</title>
7250 Now, let's complete our <quote>foo</quote> content filter. We have already defined
7251 the heading, but the jobs are still missing. Since all it does is to replace
7252 <quote>foo</quote> with <quote>bar</quote>, there is only one (trivial) job
7256 <screen>s/foo/bar/</screen>
7259 But wait! Didn't the comment say that <emphasis>all</emphasis> occurrences
7260 of <quote>foo</quote> should be replaced? Our current job will only take
7261 care of the first <quote>foo</quote> on each page. For global substitution,
7262 we'll need to add the <literal>g</literal> option:
7265 <screen>s/foo/bar/g</screen>
7268 Our complete filter now looks like this:
7271 <screen>FILTER: foo Replace all "foo" with "bar"
7272 s/foo/bar/g</screen>
7275 Let's look at some real filters for more interesting examples. Here you see
7276 a filter that protects against some common annoyances that arise from JavaScript
7277 abuse. Let's look at its jobs one after the other:
7282 FILTER: js-annoyances Get rid of particularly annoying JavaScript abuse
7284 # Get rid of JavaScript referrer tracking. Test page: http://www.randomoddness.com/untitled.htm
7286 s|(<script.*)document\.referrer(.*</script>)|$1"Not Your Business!"$2|Usg</screen>
7289 Following the header line and a comment, you see the job. Note that it uses
7290 <literal>|</literal> as the delimiter instead of <literal>/</literal>, because
7291 the pattern contains a forward slash, which would otherwise have to be escaped
7292 by a backslash (<literal>\</literal>).
7296 Now, let's examine the pattern: it starts with the text <literal><script.*</literal>
7297 enclosed in parentheses. Since the dot matches any character, and <literal>*</literal>
7298 means: <quote>Match an arbitrary number of the element left of myself</quote>, this
7299 matches <quote><script</quote>, followed by <emphasis>any</emphasis> text, i.e.
7300 it matches the whole page, from the start of the first <script> tag.
7304 That's more than we want, but the pattern continues: <literal>document\.referrer</literal>
7305 matches only the exact string <quote>document.referrer</quote>. The dot needed to
7306 be <emphasis>escaped</emphasis>, i.e. preceded by a backslash, to take away its
7307 special meaning as a joker, and make it just a regular dot. So far, the meaning is:
7308 Match from the start of the first <script> tag in a the page, up to, and including,
7309 the text <quote>document.referrer</quote>, if <emphasis>both</emphasis> are present
7310 in the page (and appear in that order).
7314 But there's still more pattern to go. The next element, again enclosed in parentheses,
7315 is <literal>.*</script></literal>. You already know what <literal>.*</literal>
7316 means, so the whole pattern translates to: Match from the start of the first <script>
7317 tag in a page to the end of the last <script> tag, provided that the text
7318 <quote>document.referrer</quote> appears somewhere in between.
7322 This is still not the whole story, since we have ignored the options and the parentheses:
7323 The portions of the page matched by sub-patterns that are enclosed in parentheses, will be
7324 remembered and be available through the variables <literal>$1, $2, ...</literal> in
7325 the substitute. The <literal>U</literal> option switches to ungreedy matching, which means
7326 that the first <literal>.*</literal> in the pattern will only <quote>eat up</quote> all
7327 text in between <quote><script</quote> and the <emphasis>first</emphasis> occurrence
7328 of <quote>document.referrer</quote>, and that the second <literal>.*</literal> will
7329 only span the text up to the <emphasis>first</emphasis> <quote></script></quote>
7330 tag. Furthermore, the <literal>s</literal> option says that the match may span
7331 multiple lines in the page, and the <literal>g</literal> option again means that the
7332 substitution is global.
7336 So, to summarize, the pattern means: Match all scripts that contain the text
7337 <quote>document.referrer</quote>. Remember the parts of the script from
7338 (and including) the start tag up to (and excluding) the string
7339 <quote>document.referrer</quote> as <literal>$1</literal>, and the part following
7340 that string, up to and including the closing tag, as <literal>$2</literal>.
7344 Now the pattern is deciphered, but wasn't this about substituting things? So
7345 lets look at the substitute: <literal>$1"Not Your Business!"$2</literal> is
7346 easy to read: The text remembered as <literal>$1</literal>, followed by
7347 <literal>"Not Your Business!"</literal> (<emphasis>including</emphasis>
7348 the quotation marks!), followed by the text remembered as <literal>$2</literal>.
7349 This produces an exact copy of the original string, with the middle part
7350 (the <quote>document.referrer</quote>) replaced by <literal>"Not Your
7351 Business!"</literal>.
7355 The whole job now reads: Replace <quote>document.referrer</quote> by
7356 <literal>"Not Your Business!"</literal> wherever it appears inside a
7357 <script> tag. Note that this job won't break JavaScript syntax,
7358 since both the original and the replacement are syntactically valid
7359 string objects. The script just won't have access to the referrer
7360 information anymore.
7364 We'll show you two other jobs from the JavaScript taming department, but
7365 this time only point out the constructs of special interest:
7369 # The status bar is for displaying link targets, not pointless blahblah
7371 s/window\.status\s*=\s*(['"]).*?\1/dUmMy=1/ig</screen>
7374 <literal>\s</literal> stands for whitespace characters (space, tab, newline,
7375 carriage return, form feed), so that <literal>\s*</literal> means: <quote>zero
7376 or more whitespace</quote>. The <literal>?</literal> in <literal>.*?</literal>
7377 makes this matching of arbitrary text ungreedy. (Note that the <literal>U</literal>
7378 option is not set). The <literal>['"]</literal> construct means: <quote>a single
7379 <emphasis>or</emphasis> a double quote</quote>. Finally, <literal>\1</literal> is
7380 a back-reference to the first parenthesis just like <literal>$1</literal> above,
7381 with the difference that in the <emphasis>pattern</emphasis>, a backslash indicates
7382 a back-reference, whereas in the <emphasis>substitute</emphasis>, it's the dollar.
7386 So what does this job do? It replaces assignments of single- or double-quoted
7387 strings to the <quote>window.status</quote> object with a dummy assignment
7388 (using a variable name that is hopefully odd enough not to conflict with
7389 real variables in scripts). Thus, it catches many cases where e.g. pointless
7390 descriptions are displayed in the status bar instead of the link target when
7391 you move your mouse over links.
7395 # Kill OnUnload popups. Yummy. Test: http://www.zdnet.com/zdsubs/yahoo/tree/yfs.html
7397 s/(<body [^>]*)onunload(.*>)/$1never$2/iU</screen>
7401 <ulink url="http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html#Events-eventgroupings-htmlevents">OnUnload
7402 event binding</ulink> in the HTML DOM was a <emphasis>CRIME</emphasis>.
7403 When I close a browser window, I want it to close and die. Basta.
7404 This job replaces the <quote>onunload</quote> attribute in
7405 <quote><body></quote> tags with the dummy word <literal>never</literal>.
7406 Note that the <literal>i</literal> option makes the pattern matching
7407 case-insensitive. Also note that ungreedy matching alone doesn't always guarantee
7408 a minimal match: In the first parenthesis, we had to use <literal>[^>]*</literal>
7409 instead of <literal>.*</literal> to prevent the match from exceeding the
7410 <body> tag if it doesn't contain <quote>OnUnload</quote>, but the page's
7415 The last example is from the fun department:
7419 FILTER: fun Fun text replacements
7421 # Spice the daily news:
7423 s/microsoft(?!\.com)/MicroSuck/ig</screen>
7426 Note the <literal>(?!\.com)</literal> part (a so-called negative lookahead)
7427 in the job's pattern, which means: Don't match, if the string
7428 <quote>.com</quote> appears directly following <quote>microsoft</quote>
7429 in the page. This prevents links to microsoft.com from being trashed, while
7430 still replacing the word everywhere else.
7434 # Buzzword Bingo (example for extended regex syntax)
7436 s* industry[ -]leading \
7438 | customer[ -]focused \
7439 | market[ -]driven \
7440 | award[ -]winning # Comments are OK, too! \
7441 | high[ -]performance \
7442 | solutions[ -]based \
7446 *<font color="red"><b>BINGO!</b></font> \
7450 The <literal>x</literal> option in this job turns on extended syntax, and allows for
7451 e.g. the liberal use of (non-interpreted!) whitespace for nicer formatting.
7459 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
7461 <sect2 id="predefined-filters"><title>The Pre-defined Filters</title>
7465 Note each filter is also listed in the +filter action section above. Please
7466 keep these listings in sync.
7471 The distribution <filename>default.filter</filename> file contains a selection of
7472 pre-defined filters for your convenience:
7477 <term><emphasis>js-annoyances</emphasis></term>
7480 The purpose of this filter is to get rid of particularly annoying JavaScript abuse.
7486 replaces JavaScript references to the browser's referrer information
7487 with the string "Not Your Business!". This compliments the <literal><link
7488 linkend="hide-referrer">hide-referrer</link></literal> action on the content level.
7493 removes the bindings to the DOM's
7494 <ulink url="http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html#Events-eventgroupings-htmlevents">unload
7495 event</ulink> which we feel has no right to exist and is responsible for most <quote>exit consoles</quote>, i.e.
7496 nasty windows that pop up when you close another one.
7501 removes code that causes new windows to be opened with undesired properties, such as being
7502 full-screen, non-resizeable, without location, status or menu bar etc.
7507 Use with caution. This is an aggressive filter, and can break sites that
7508 rely heavily on JavaScript.
7514 <term><emphasis>js-events</emphasis></term>
7517 This is a very radical measure. It removes virtually all JavaScript event bindings, which
7518 means that scripts can not react to user actions such as mouse movements or clicks, window
7519 resizing etc, anymore. Use with caution!
7522 We <emphasis>strongly discourage</emphasis> using this filter as a default since it breaks
7523 many legitimate scripts. It is meant for use only on extra-nasty sites (should you really
7530 <term><emphasis>html-annoyances</emphasis></term>
7533 This filter will undo many common instances of HTML based abuse.
7536 The <literal>BLINK</literal> and <literal>MARQUEE</literal> tags
7537 are neutralized (yeah baby!), and browser windows will be created as
7538 resizeable (as of course they should be!), and will have location,
7539 scroll and menu bars -- even if specified otherwise.
7545 <term><emphasis>content-cookies</emphasis></term>
7548 Most cookies are set in the HTTP dialog, where they can be intercepted
7550 <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal>
7551 and <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>
7552 actions. But web sites increasingly make use of HTML meta tags and JavaScript
7553 to sneak cookies to the browser on the content level.
7556 This filter disables most HTML and JavaScript code that reads or sets
7557 cookies. It cannot detect all clever uses of these types of code, so it
7558 should not be relied on as an absolute fix. Use it wherever you would also
7559 use the cookie crunch actions.
7565 <term><emphasis>refresh-tags</emphasis></term>
7568 Disable any refresh tags if the interval is greater than nine seconds (so
7569 that redirections done via refresh tags are not destroyed). This is useful
7570 for dial-on-demand setups, or for those who find this HTML feature
7577 <term><emphasis>unsolicited-popups</emphasis></term>
7580 This filter attempts to prevent only <quote>unsolicited</quote> pop-up
7581 windows from opening, yet still allow pop-up windows that the user
7582 has explicitly chosen to open. It was added in version 3.0.1,
7583 as an improvement over earlier such filters.
7586 Technical note: The filter works by redefining the window.open JavaScript
7587 function to a dummy function, <literal>PrivoxyWindowOpen()</literal>,
7588 during the loading and rendering phase of each HTML page access, and
7589 restoring the function afterward.
7592 This is recommended only for browsers that cannot perform this function
7593 reliably themselves. And be aware that some sites require such windows
7594 in order to function normally. Use with caution.
7600 <term><emphasis>all-popups</emphasis></term>
7603 Attempt to prevent <emphasis>all</emphasis> pop-up windows from opening.
7604 Note this should be used with even more discretion than the above, since
7605 it is more likely to break some sites that require pop-ups for normal
7606 usage. Use with caution.
7612 <term><emphasis>img-reorder</emphasis></term>
7615 This is a helper filter that has no value if used alone. It makes the
7616 <literal>banners-by-size</literal> and <literal>banners-by-link</literal>
7617 (see below) filters more effective and should be enabled together with them.
7623 <term><emphasis>banners-by-size</emphasis></term>
7626 This filter removes image tags purely based on what size they are. Fortunately
7627 for us, many ads and banner images tend to conform to certain standardized
7628 sizes, which makes this filter quite effective for ad stripping purposes.
7631 Occasionally this filter will cause false positives on images that are not ads,
7632 but just happen to be of one of the standard banner sizes.
7635 Recommended only for those who require extreme ad blocking. The default
7636 block rules should catch 95+% of all ads <emphasis>without</emphasis> this filter enabled.
7642 <term><emphasis>banners-by-link</emphasis></term>
7645 This is an experimental filter that attempts to kill any banners if
7646 their URLs seem to point to known or suspected click trackers. It is currently
7647 not of much value and is not recommended for use by default.
7653 <term><emphasis>webbugs</emphasis></term>
7656 Webbugs are small, invisible images (technically 1X1 GIF images), that
7657 are used to track users across websites, and collect information on them.
7658 As an HTML page is loaded by the browser, an embedded image tag causes the
7659 browser to contact a third-party site, disclosing the tracking information
7660 through the requested URL and/or cookies for that third-party domain, without
7661 the user ever becoming aware of the interaction with the third-party site.
7662 HTML-ized spam also uses a similar technique to verify email addresses.
7665 This filter removes the HTML code that loads such <quote>webbugs</quote>.
7671 <term><emphasis>tiny-textforms</emphasis></term>
7674 A rather special-purpose filter that can be used to enlarge textareas (those
7675 multi-line text boxes in web forms) and turn off hard word wrap in them.
7676 It was written for the sourceforge.net tracker system where such boxes are
7677 a nuisance, but it can be handy on other sites, too.
7680 It is not recommended to use this filter as a default.
7686 <term><emphasis>jumping-windows</emphasis></term>
7689 Many consider windows that move, or resize themselves to be abusive. This filter
7690 neutralizes the related JavaScript code. Note that some sites might not display
7691 or behave as intended when using this filter. Use with caution.
7697 <term><emphasis>frameset-borders</emphasis></term>
7700 Some web designers seem to assume that everyone in the world will view their
7701 web sites using the same browser brand and version, screen resolution etc,
7702 because only that assumption could explain why they'd use static frame sizes,
7703 yet prevent their frames from being resized by the user, should they be too
7704 small to show their whole content.
7707 This filter removes the related HTML code. It should only be applied to sites
7714 <term><emphasis>demoronizer</emphasis></term>
7717 Many Microsoft products that generate HTML use non-standard extensions (read:
7718 violations) of the ISO 8859-1 aka Latin-1 character set. This can cause those
7719 HTML documents to display with errors on standard-compliant platforms.
7722 This filter translates the MS-only characters into Latin-1 equivalents.
7723 It is not necessary when using MS products, and will cause corruption of
7724 all documents that use 8-bit character sets other than Latin-1. It's mostly
7725 worthwhile for Europeans on non-MS platforms, if weird garbage characters
7726 sometimes appear on some pages, or user agents that don't correct for this on
7729 My version of Mozilla (ancient) shows little square boxes for quote
7730 characters, and apostrophes on moronized pages. So many pages have this, I
7731 can read them fine now. HB 08/27/06
7738 <term><emphasis>shockwave-flash</emphasis></term>
7741 A filter for shockwave haters. As the name suggests, this filter strips code
7742 out of web pages that is used to embed shockwave flash objects.
7750 <term><emphasis>quicktime-kioskmode</emphasis></term>
7753 Change HTML code that embeds Quicktime objects so that kioskmode, which
7754 prevents saving, is disabled.
7760 <term><emphasis>fun</emphasis></term>
7763 Text replacements for subversive browsing fun. Make fun of your favorite
7764 Monopolist or play buzzword bingo.
7770 <term><emphasis>crude-parental</emphasis></term>
7773 A demonstration-only filter that shows how <application>Privoxy</application>
7774 can be used to delete web content on a keyword basis.
7780 <term><emphasis>ie-exploits</emphasis></term>
7783 An experimental collection of text replacements to disable malicious HTML and JavaScript
7784 code that exploits known security holes in Internet Explorer.
7787 Presently, it only protects against Nimda and a cross-site scripting bug, and
7788 would need active maintenance to provide more substantial protection.
7794 <term><emphasis>site-specifics</emphasis></term>
7797 Some web sites have very specific problems, the cure for which doesn't apply
7798 anywhere else, or could even cause damage on other sites.
7801 This is a collection of such site-specific cures which should only be applied
7802 to the sites they were intended for, which is what the supplied
7803 <filename>default.action</filename> file does. Users shouldn't need to change
7804 anything regarding this filter.
7810 <term><emphasis>google</emphasis></term>
7813 A CSS based block for Google text ads. Also removes a width limitation
7814 and the toolbar advertisement.
7820 <term><emphasis>yahoo</emphasis></term>
7823 Another CSS based block, this time for Yahoo text ads. And removes
7824 a width limitation as well.
7830 <term><emphasis>msn</emphasis></term>
7833 Another CSS based block, this time for MSN text ads. And removes
7834 tracking URLs, as well as a width limitation.
7840 <term><emphasis>blogspot</emphasis></term>
7843 Cleans up some Blogspot blogs. Read the fine print before using this one!
7846 This filter also intentionally removes some navigation stuff and sets the
7847 page width to 100%. As a result, some rounded <quote>corners</quote> would
7848 appear to early or not at all and as fixing this would require a browser
7849 that understands background-size (CSS3), they are removed instead.
7855 <term><emphasis>xml-to-html</emphasis></term>
7858 Server-header filter to change the Content-Type from xml to html.
7864 <term><emphasis>html-to-xml</emphasis></term>
7867 Server-header filter to change the Content-Type from html to xml.
7873 <term><emphasis>no-ping</emphasis></term>
7876 Removes the non-standard <literal>ping</literal> attribute from
7877 anchor and area HTML tags.
7883 <term><emphasis>hide-tor-exit-notation</emphasis></term>
7886 Client-header filter to remove the <command>Tor</command> exit node notation
7887 found in Host and Referer headers.
7890 If &my-app; and <command>Tor</command> are chained and &my-app;
7891 is configured to use socks4a, one can use <quote>http://www.example.org.foobar.exit/</quote>
7892 to access the host <quote>www.example.org</quote> through the
7893 <command>Tor</command> exit node <quote>foobar</quote>.
7896 As the HTTP client isn't aware of this notation, it treats the
7897 whole string <quote>www.example.org.foobar.exit</quote> as host and uses it
7898 for the <quote>Host</quote> and <quote>Referer</quote> headers. From the
7899 server's point of view the resulting headers are invalid and can cause problems.
7902 An invalid <quote>Referer</quote> header can trigger <quote>hot-linking</quote>
7903 protections, an invalid <quote>Host</quote> header will make it impossible for
7904 the server to find the right vhost (several domains hosted on the same IP address).
7907 This client-header filter removes the <quote>foo.exit</quote> part in those headers
7908 to prevent the mentioned problems. Note that it only modifies
7909 the HTTP headers, it doesn't make it impossible for the server
7910 to detect your <command>Tor</command> exit node based on the IP address
7911 the request is coming from.
7918 <term><emphasis> </emphasis></term>
7931 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
7932 <sect2 id="external-filter-syntax"><title>External filter syntax</title>
7934 External filters are scripts or programs that can modify the content in
7935 case common <literal><link linkend="filter">filters</link></literal>
7936 aren't powerful enough.
7939 External filters can be written in any language the platform &my-app; runs
7943 They are controlled with the
7944 <literal><link linkend="external-filter">external-filter</link></literal> action
7945 and have to be defined in the <literal><link linkend="filterfile">filterfile</link></literal>
7949 The header looks like any other filter, but instead of pcrs jobs, external
7950 filters contain a single job which can be a program or a shell script (which
7951 may call other scripts or programs).
7954 External filters read the content from STDIN and write the rewritten
7956 The environment variables PRIVOXY_URL, PRIVOXY_PATH, PRIVOXY_HOST,
7957 PRIVOXY_ORIGIN, PRIVOXY_LISTEN_ADDRESS can be used to get some details
7958 about the client request.
7961 &my-app; will temporary store the content to filter in the
7962 <literal><link linkend="temporary-directory">temporary-directory</link></literal>.
7966 EXTERNAL-FILTER: cat Pointless example filter that doesn't actually modify the content
7969 # Incorrect reimplementation of the filter above in POSIX shell.
7971 # Note that it's a single job that spans multiple lines, the line
7972 # breaks are not passed to the shell, thus the semicolons are required.
7974 # If the script isn't trivial, it is recommended to put it into an external file.
7976 # In general, writing external filters entirely in POSIX shell is not
7977 # considered a good idea.
7978 EXTERNAL-FILTER: cat2 Pointless example filter that despite its name may actually modify the content
7984 EXTERNAL-FILTER: rotate-image Rotate an image by 180 degree. Test filter with limited value.
7985 /usr/local/bin/convert - -rotate 180 -
7987 EXTERNAL-FILTER: citation-needed Adds a "[citation needed]" tag to an image. The coordinates may need adjustment.
7988 /usr/local/bin/convert - -pointsize 16 -fill white -annotate +17+418 "[citation needed]" -
7993 Currently external filters are executed with &my-app;'s privileges!
7994 Only use external filters you understand and trust.
7998 External filters are experimental and the syntax may change in the future.
8004 <!-- ~ End section ~ -->
8008 <!-- ~~~~~ New section ~~~~~ -->
8010 <sect1 id="templates">
8011 <title>Privoxy's Template Files</title>
8013 All <application>Privoxy</application> built-in pages, i.e. error pages such as the
8014 <ulink url="http://show-the-404-error.page"><quote>404 - No Such Domain</quote>
8015 error page</ulink>, the <ulink
8016 url="http://ads.bannerserver.example.com/nasty-ads/sponsor.html"><quote>BLOCKED</quote>
8018 and all pages of its <ulink url="http://config.privoxy.org/">web-based
8019 user interface</ulink>, are generated from <emphasis>templates</emphasis>.
8020 (<application>Privoxy</application> must be running for the above links to work as
8025 These templates are stored in a subdirectory of the <link linkend="confdir">configuration
8026 directory</link> called <filename>templates</filename>. On Unixish platforms,
8028 <ulink url="file:///etc/privoxy/templates/"><filename>/etc/privoxy/templates/</filename></ulink>.
8032 The templates are basically normal HTML files, but with place-holders (called symbols
8033 or exports), which <application>Privoxy</application> fills at run time. It
8034 is possible to edit the templates with a normal text editor, should you want
8035 to customize them. (<emphasis>Not recommended for the casual
8036 user</emphasis>). Should you create your own custom templates, you should use
8037 the <filename>config</filename> setting <link linkend="templdir">templdir</link>
8038 to specify an alternate location, so your templates do not get overwritten
8042 Note that just like in configuration files, lines starting
8043 with <literal>#</literal> are ignored when the templates are filled in.
8047 The place-holders are of the form <literal>@name@</literal>, and you will
8048 find a list of available symbols, which vary from template to template,
8049 in the comments at the start of each file. Note that these comments are not
8050 always accurate, and that it's probably best to look at the existing HTML
8051 code to find out which symbols are supported and what they are filled in with.
8055 A special application of this substitution mechanism is to make whole
8056 blocks of HTML code disappear when a specific symbol is set. We use this
8057 for many purposes, one of them being to include the beta warning in all
8058 our user interface (CGI) pages when <application>Privoxy</application>
8059 is in an alpha or beta development stage:
8063 <!-- @if-unstable-start -->
8065 ... beta warning HTML code goes here ...
8067 <!-- if-unstable-end@ --></screen>
8070 If the "unstable" symbol is set, everything in between and including
8071 <literal>@if-unstable-start</literal> and <literal>if-unstable-end@</literal>
8072 will disappear, leaving nothing but an empty comment:
8075 <screen><!-- --></screen>
8078 There's also an if-then-else construct and an <literal>#include</literal>
8079 mechanism, but you'll sure find out if you are inclined to edit the
8084 All templates refer to a style located at
8085 <ulink url="http://config.privoxy.org/send-stylesheet"><literal>http://config.privoxy.org/send-stylesheet</literal></ulink>.
8086 This is, of course, locally served by <application>Privoxy</application>
8087 and the source for it can be found and edited in the
8088 <filename>cgi-style.css</filename> template.
8093 <!-- ~ End section ~ -->
8097 <!-- ~~~~~ New section ~~~~~ -->
8099 <sect1 id="contact"><title>Contacting the Developers, Bug Reporting and Feature
8102 <!-- Include contacting.sgml boilerplate: -->
8104 <!-- end boilerplate -->
8108 <!-- ~ End section ~ -->
8111 <!-- ~~~~~ New section ~~~~~ -->
8112 <sect1 id="copyright"><title>Privoxy Copyright, License and History</title>
8114 <!-- Include copyright.sgml: -->
8116 <!-- end copyright -->
8119 <application>Privoxy</application> is free software; you can
8120 redistribute and/or modify its source code under the terms
8121 of the <citetitle>GNU General Public License</citetitle>
8122 as published by the Free Software Foundation, either version 2
8123 of the license, or (at your option) any later version.
8127 The same is true for <application>Privoxy</application> binaries
8128 unless they are linked with a
8129 <ulink url="https://tls.mbed.org/">mbed TLS</ulink> version
8130 that is licensed under the Apache 2.0 license in which
8131 case you can redistribute and/or modify the <application>Privoxy</application>
8132 binaries under the terms of the <citetitle>GNU General Public License</citetitle>
8133 as published by the Free Software Foundation, either version 3
8134 of the license, or (at your option) any later version.
8138 Both licenses are included in the next section.
8141 <!-- ~~~~~ New section ~~~~~ -->
8142 <sect2 id="license"><title>License</title>
8144 <sect3 id="gplv2"><title>GNU General Public License version 2</title>
8145 <literallayout class="Monospaced"><![ RCDATA [ &GPLv2; ]]></literallayout>
8148 <sect3 id="gplv3"><title>GNU General Public License version 3</title>
8149 <literallayout class="Monospaced"><![ RCDATA [ &GPLv3; ]]></literallayout>
8152 <sect3 id="third-party-licenses"><title>Third-party licenses and copyrights</title>
8154 Privoxy depends on a couple of third-party libraries which have seperate licenses.
8155 Please refer to the third-party websites for up-to-date license and copyright
8159 Privoxy depends on <ulink url="https://pcre.org/">pcre</ulink>.
8162 When compiled with FEATURE_BROTLI (optional), Privoxy depends on
8163 <ulink url="https://www.brotli.org/">brotli</ulink>.
8166 When compiled with FEATURE_HTTPS_INSPECTION (optional),
8167 Privoxy depends on a TLS library. The supported libraries are
8168 <ulink url="https://www.openssl.org/">LibreSSL</ulink>,
8169 <ulink url="https://tls.mbed.org/">mbed TLS</ulink> and
8170 <ulink url="https://www.openssl.org/">OpenSSL</ulink>.
8173 When compiled with FEATURE_ZLIB (optional),
8174 Privoxy depends on <ulink url="https://zlib.net/">zlib</ulink>.
8179 <!-- ~ End section ~ -->
8182 <!-- ~~~~~ New section ~~~~~ -->
8184 <sect2 id="history"><title>History</title>
8185 <!-- Include history.sgml: -->
8187 <!-- end history -->
8190 <sect2 id="authors"><title>Authors</title>
8191 <!-- Include p-authors.sgml: -->
8193 <!-- end authors -->
8198 <!-- ~ End section ~ -->
8201 <!-- ~~~~~ New section ~~~~~ -->
8202 <sect1 id="seealso"><title>See Also</title>
8203 <!-- Include seealso.sgml: -->
8205 <!-- end seealso -->
8210 <!-- ~~~~~ New section ~~~~~ -->
8211 <sect1 id="appendix"><title>Appendix</title>
8214 <!-- ~~~~~ New section ~~~~~ -->
8216 <title>Regular Expressions</title>
8218 <application>Privoxy</application> uses Perl-style <quote>regular
8219 expressions</quote> in its <link linkend="actions-file">actions
8220 files</link> and <link linkend="filter-file">filter file</link>,
8221 through the <ulink url="http://www.pcre.org/">PCRE</ulink> and
8224 <ulink url="http://www.oesterhelt.org/pcrs/">PCRS</ulink> libraries.
8226 <application>PCRS</application> libraries.
8230 If you are reading this, you probably don't understand what <quote>regular
8231 expressions</quote> are, or what they can do. So this will be a very brief
8232 introduction only. A full explanation would require a <ulink
8233 url="http://www.oreilly.com/catalog/regex/">book</ulink> ;-)
8237 Regular expressions provide a language to describe patterns that can be
8238 run against strings of characters (letter, numbers, etc), to see if they
8239 match the string or not. The patterns are themselves (sometimes complex)
8240 strings of literal characters, combined with wild-cards, and other special
8241 characters, called meta-characters. The <quote>meta-characters</quote> have
8242 special meanings and are used to build complex patterns to be matched against.
8243 Perl Compatible Regular Expressions are an especially convenient
8244 <quote>dialect</quote> of the regular expression language.
8248 To make a simple analogy, we do something similar when we use wild-card
8249 characters when listing files with the <command>dir</command> command in DOS.
8250 <literal>*.*</literal> matches all filenames. The <quote>special</quote>
8251 character here is the asterisk which matches any and all characters. We can be
8252 more specific and use <literal>?</literal> to match just individual
8253 characters. So <quote>dir file?.text</quote> would match
8254 <quote>file1.txt</quote>, <quote>file2.txt</quote>, etc. We are pattern
8255 matching, using a similar technique to <quote>regular expressions</quote>!
8259 Regular expressions do essentially the same thing, but are much, much more
8260 powerful. There are many more <quote>special characters</quote> and ways of
8261 building complex patterns however. Let's look at a few of the common ones,
8262 and then some examples:
8267 <emphasis>.</emphasis> - Matches any single character, e.g. <quote>a</quote>,
8268 <quote>A</quote>, <quote>4</quote>, <quote>:</quote>, or <quote>@</quote>.
8274 <emphasis>?</emphasis> - The preceding character or expression is matched ZERO or ONE
8281 <emphasis>+</emphasis> - The preceding character or expression is matched ONE or MORE
8288 <emphasis>*</emphasis> - The preceding character or expression is matched ZERO or MORE
8295 <emphasis>\</emphasis> - The <quote>escape</quote> character denotes that
8296 the following character should be taken literally. This is used where one of the
8297 special characters (e.g. <quote>.</quote>) needs to be taken literally and
8298 not as a special meta-character. Example: <quote>example\.com</quote>, makes
8299 sure the period is recognized only as a period (and not expanded to its
8300 meta-character meaning of any single character).
8306 <emphasis>[ ]</emphasis> - Characters enclosed in brackets will be matched if
8307 any of the enclosed characters are encountered. For instance, <quote>[0-9]</quote>
8308 matches any numeric digit (zero through nine). As an example, we can combine
8309 this with <quote>+</quote> to match any digit one of more times: <quote>[0-9]+</quote>.
8315 <emphasis>( )</emphasis> - parentheses are used to group a sub-expression,
8316 or multiple sub-expressions.
8322 <emphasis>|</emphasis> - The <quote>bar</quote> character works like an
8323 <quote>or</quote> conditional statement. A match is successful if the
8324 sub-expression on either side of <quote>|</quote> matches. As an example:
8325 <quote>/(this|that) example/</quote> uses grouping and the bar character
8326 and would match either <quote>this example</quote> or <quote>that
8327 example</quote>, and nothing else.
8332 These are just some of the ones you are likely to use when matching URLs with
8333 <application>Privoxy</application>, and is a long way from a definitive
8334 list. This is enough to get us started with a few simple examples which may
8335 be more illuminating:
8339 <emphasis><literal>/.*/banners/.*</literal></emphasis> - A simple example
8340 that uses the common combination of <quote>.</quote> and <quote>*</quote> to
8341 denote any character, zero or more times. In other words, any string at all.
8342 So we start with a literal forward slash, then our regular expression pattern
8343 (<quote>.*</quote>) another literal forward slash, the string
8344 <quote>banners</quote>, another forward slash, and lastly another
8345 <quote>.*</quote>. We are building
8346 a directory path here. This will match any file with the path that has a
8347 directory named <quote>banners</quote> in it. The <quote>.*</quote> matches
8348 any characters, and this could conceivably be more forward slashes, so it
8349 might expand into a much longer looking path. For example, this could match:
8350 <quote>/eye/hate/spammers/banners/annoy_me_please.gif</quote>, or just
8351 <quote>/banners/annoying.html</quote>, or almost an infinite number of other
8352 possible combinations, just so it has <quote>banners</quote> in the path
8357 And now something a little more complex:
8361 <emphasis><literal>/.*/adv((er)?ts?|ertis(ing|ements?))?/</literal></emphasis> -
8362 We have several literal forward slashes again (<quote>/</quote>), so we are
8363 building another expression that is a file path statement. We have another
8364 <quote>.*</quote>, so we are matching against any conceivable sub-path, just so
8365 it matches our expression. The only true literal that <emphasis>must
8366 match</emphasis> our pattern is <application>adv</application>, together with
8367 the forward slashes. What comes after the <quote>adv</quote> string is the
8372 Remember the <quote>?</quote> means the preceding expression (either a
8373 literal character or anything grouped with <quote>(...)</quote> in this case)
8374 can exist or not, since this means either zero or one match. So
8375 <quote>((er)?ts?|ertis(ing|ements?))</quote> is optional, as are the
8376 individual sub-expressions: <quote>(er)</quote>,
8377 <quote>(ing|ements?)</quote>, and the <quote>s</quote>. The <quote>|</quote>
8378 means <quote>or</quote>. We have two of those. For instance,
8379 <quote>(ing|ements?)</quote>, can expand to match either <quote>ing</quote>
8380 <emphasis>OR</emphasis> <quote>ements?</quote>. What is being done here, is an
8381 attempt at matching as many variations of <quote>advertisement</quote>, and
8382 similar, as possible. So this would expand to match just <quote>adv</quote>,
8383 or <quote>advert</quote>, or <quote>adverts</quote>, or
8384 <quote>advertising</quote>, or <quote>advertisement</quote>, or
8385 <quote>advertisements</quote>. You get the idea. But it would not match
8386 <quote>advertizements</quote> (with a <quote>z</quote>). We could fix that by
8387 changing our regular expression to:
8388 <quote>/.*/adv((er)?ts?|erti(s|z)(ing|ements?))?/</quote>, which would then match
8393 <emphasis><literal>/.*/advert[0-9]+\.(gif|jpe?g)</literal></emphasis> - Again
8394 another path statement with forward slashes. Anything in the square brackets
8395 <quote>[ ]</quote> can be matched. This is using <quote>0-9</quote> as a
8396 shorthand expression to mean any digit one through nine. It is the same as
8397 saying <quote>0123456789</quote>. So any digit matches. The <quote>+</quote>
8398 means one or more of the preceding expression must be included. The preceding
8399 expression here is what is in the square brackets -- in this case, any digit
8400 one through nine. Then, at the end, we have a grouping: <quote>(gif|jpe?g)</quote>.
8401 This includes a <quote>|</quote>, so this needs to match the expression on
8402 either side of that bar character also. A simple <quote>gif</quote> on one side, and the other
8403 side will in turn match either <quote>jpeg</quote> or <quote>jpg</quote>,
8404 since the <quote>?</quote> means the letter <quote>e</quote> is optional and
8405 can be matched once or not at all. So we are building an expression here to
8406 match image GIF or JPEG type image file. It must include the literal
8407 string <quote>advert</quote>, then one or more digits, and a <quote>.</quote>
8408 (which is now a literal, and not a special character, since it is escaped
8409 with <quote>\</quote>), and lastly either <quote>gif</quote>, or
8410 <quote>jpeg</quote>, or <quote>jpg</quote>. Some possible matches would
8411 include: <quote>//advert1.jpg</quote>,
8412 <quote>/nasty/ads/advert1234.gif</quote>,
8413 <quote>/banners/from/hell/advert99.jpg</quote>. It would not match
8414 <quote>advert1.gif</quote> (no leading slash), or
8415 <quote>/adverts232.jpg</quote> (the expression does not include an
8416 <quote>s</quote>), or <quote>/advert1.jsp</quote> (<quote>jsp</quote> is not
8417 in the expression anywhere).
8421 We are barely scratching the surface of regular expressions here so that you
8422 can understand the default <application>Privoxy</application>
8423 configuration files, and maybe use this knowledge to customize your own
8424 installation. There is much, much more that can be done with regular
8425 expressions. Now that you know enough to get started, you can learn more on
8430 More reading on Perl Compatible Regular expressions:
8431 <ulink url="http://perldoc.perl.org/perlre.html">http://perldoc.perl.org/perlre.html</ulink>
8435 For information on regular expression based substitutions and their applications
8436 in filters, please see the <link linkend="filter-file">filter file tutorial</link>
8441 <!-- ~ End section ~ -->
8444 <!-- ~~~~~ New section ~~~~~ -->
8445 <sect2 id="internal-pages">
8446 <title>Privoxy's Internal Pages</title>
8449 Since <application>Privoxy</application> proxies each requested
8450 web page, it is easy for <application>Privoxy</application> to
8451 trap certain special URLs. In this way, we can talk directly to
8452 <application>Privoxy</application>, and see how it is
8453 configured, see how our rules are being applied, change these
8454 rules and other configuration options, and even turn
8455 <application>Privoxy's</application> filtering off, all with
8460 The URLs listed below are the special ones that allow direct access
8461 to <application>Privoxy</application>. Of course,
8462 <application>Privoxy</application> must be running to access these. If
8463 not, you will get a friendly error message. Internet access is not
8475 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
8479 There is a shortcut: <ulink url="http://p.p/">http://p.p/</ulink> (But it
8480 doesn't provide a fall-back to a real page, in case the request is not
8481 sent through <application>Privoxy</application>)
8487 View and toggle client tags:
8491 <ulink url="http://config.privoxy.org/client-tags">http://config.privoxy.org/client-tags</ulink>
8498 Show information about the current configuration, including viewing and
8499 editing of actions files:
8503 <ulink url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
8510 Show the browser's request headers:
8514 <ulink url="http://config.privoxy.org/show-request">http://config.privoxy.org/show-request</ulink>
8521 Show which actions apply to a URL and why:
8525 <ulink url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
8532 Toggle Privoxy on or off. This feature can be turned off/on in the main
8533 <filename>config</filename> file. When toggled <quote>off</quote>, <quote>Privoxy</quote>
8534 continues to run, but only as a pass-through proxy, with no actions taking
8539 <ulink url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>
8543 Short cuts. Turn off, then on:
8547 <ulink url="http://config.privoxy.org/toggle?set=disable">http://config.privoxy.org/toggle?set=disable</ulink>
8552 <ulink url="http://config.privoxy.org/toggle?set=enable">http://config.privoxy.org/toggle?set=enable</ulink>
8562 <!-- ~~~~~ New section ~~~~~ -->
8564 <title>Chain of Events</title>
8566 Let's take a quick look at how some of <application>Privoxy's</application>
8567 core features are triggered, and the ensuing sequence of events when a web
8568 page is requested by your browser:
8574 First, your web browser requests a web page. The browser knows to send
8575 the request to <application>Privoxy</application>, which will in turn,
8576 relay the request to the remote web server after passing the following
8582 <application>Privoxy</application> traps any request for its own internal CGI
8583 pages (e.g <ulink url="http://p.p/">http://p.p/</ulink>) and sends the CGI page back to the browser.
8588 Next, <application>Privoxy</application> checks to see if the URL
8590 linkend="BLOCK"><quote>+block</quote></link> patterns. If
8591 so, the URL is then blocked, and the remote web server will not be contacted.
8592 <link linkend="HANDLE-AS-IMAGE"><quote>+handle-as-image</quote></link>
8594 <link linkend="HANDLE-AS-EMPTY-DOCUMENT"><quote>+handle-as-empty-document</quote></link>
8595 are then checked, and if there is no match, an
8596 HTML <quote>BLOCKED</quote> page is sent back to the browser. Otherwise, if
8597 it does match, an image is returned for the former, and an empty text
8598 document for the latter. The type of image would depend on the setting of
8599 <link linkend="SET-IMAGE-BLOCKER"><quote>+set-image-blocker</quote></link>
8600 (blank, checkerboard pattern, or an HTTP redirect to an image elsewhere).
8605 Untrusted URLs are blocked. If URLs are being added to the
8606 <filename>trust</filename> file, then that is done.
8611 If the URL pattern matches the <link
8612 linkend="FAST-REDIRECTS"><quote>+fast-redirects</quote></link> action,
8613 it is then processed. Unwanted parts of the requested URL are stripped.
8618 Now the rest of the client browser's request headers are processed. If any
8619 of these match any of the relevant actions (e.g. <link
8620 linkend="HIDE-USER-AGENT"><quote>+hide-user-agent</quote></link>,
8621 etc.), headers are suppressed or forged as determined by these actions and
8627 Now the web server starts sending its response back (i.e. typically a web
8633 First, the server headers are read and processed to determine, among other
8634 things, the MIME type (document type) and encoding. The headers are then
8635 filtered as determined by the
8636 <link linkend="CRUNCH-INCOMING-COOKIES"><quote>+crunch-incoming-cookies</quote></link>,
8637 <link linkend="SESSION-COOKIES-ONLY"><quote>+session-cookies-only</quote></link>,
8638 and <link linkend="DOWNGRADE-HTTP-VERSION"><quote>+downgrade-http-version</quote></link>
8644 If any <link linkend="FILTER"><quote>+filter</quote></link> action
8646 linkend="DEANIMATE-GIFS"><quote>+deanimate-gifs</quote></link>
8647 action applies (and the document type fits the action), the rest of the page is
8648 read into memory (up to a configurable limit). Then the filter rules (from
8649 <filename>default.filter</filename> and any other filter files) are
8650 processed against the buffered content. Filters are applied in the order
8651 they are specified in one of the filter files. Animated GIFs, if present,
8652 are reduced to either the first or last frame, depending on the action
8653 setting.The entire page, which is now filtered, is then sent by
8654 <application>Privoxy</application> back to your browser.
8657 If neither a <link linkend="FILTER"><quote>+filter</quote></link> action
8659 linkend="DEANIMATE-GIFS"><quote>+deanimate-gifs</quote></link>
8660 matches, then <application>Privoxy</application> passes the raw data through
8661 to the client browser as it becomes available.
8666 As the browser receives the now (possibly filtered) page content, it
8667 reads and then requests any URLs that may be embedded within the page
8668 source, e.g. ad images, stylesheets, JavaScript, other HTML documents (e.g.
8669 frames), sounds, etc. For each of these objects, the browser issues a
8670 separate request (this is easily viewable in <application>Privoxy's</application>
8671 logs). And each such request is in turn processed just as above. Note that a
8672 complex web page will have many, many such embedded URLs. If these
8673 secondary requests are to a different server, then quite possibly a very
8674 differing set of actions is triggered.
8681 NOTE: This is somewhat of a simplistic overview of what happens with each URL
8682 request. For the sake of brevity and simplicity, we have focused on
8683 <application>Privoxy's</application> core features only.
8689 <!-- ~~~~~ New section ~~~~~ -->
8690 <sect2 id="actionsanat">
8691 <title>Troubleshooting: Anatomy of an Action</title>
8694 The way <application>Privoxy</application> applies
8695 <link linkend="ACTIONS">actions</link> and <link linkend="FILTER">filters</link>
8696 to any given URL can be complex, and not always so
8697 easy to understand what is happening. And sometimes we need to be able to
8698 <emphasis>see</emphasis> just what <application>Privoxy</application> is
8699 doing. Especially, if something <application>Privoxy</application> is doing
8700 is causing us a problem inadvertently. It can be a little daunting to look at
8701 the actions and filters files themselves, since they tend to be filled with
8702 <link linkend="regex">regular expressions</link> whose consequences are not
8707 One quick test to see if <application>Privoxy</application> is causing a problem
8708 or not, is to disable it temporarily. This should be the first troubleshooting
8709 step (be sure to flush caches afterward!). Looking at the
8710 logs is a good idea too. (Note that both the toggle feature and logging are
8711 enabled via <filename>config</filename> file settings, and may need to be
8712 turned <quote>on</quote>.)
8715 Another easy troubleshooting step to try is if you have done any
8716 customization of your installation, revert back to the installed
8717 defaults and see if that helps. There are times the developers get complaints
8718 about one thing or another, and the problem is more related to a customized
8719 configuration issue.
8723 <application>Privoxy</application> also provides the
8724 <ulink url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
8725 page that can show us very specifically how <application>actions</application>
8726 are being applied to any given URL. This is a big help for troubleshooting.
8730 First, enter one URL (or partial URL) at the prompt, and then
8731 <application>Privoxy</application> will tell us
8732 how the current configuration will handle it. This will not
8733 help with filtering effects (i.e. the <link
8734 linkend="FILTER"><quote>+filter</quote></link> action) from
8735 one of the filter files since this is handled very
8736 differently and not so easy to trap! It also will not tell you about any other
8737 URLs that may be embedded within the URL you are testing. For instance, images
8738 such as ads are expressed as URLs within the raw page source of HTML pages. So
8739 you will only get info for the actual URL that is pasted into the prompt area
8740 -- not any sub-URLs. If you want to know about embedded URLs like ads, you
8741 will have to dig those out of the HTML source. Use your browser's <quote>View
8742 Page Source</quote> option for this. Or right click on the ad, and grab the
8747 Let's try an example, <ulink url="http://google.com">google.com</ulink>,
8748 and look at it one section at a time in a sample configuration (your real
8749 configuration may vary):
8753 Matches for http://www.google.com:
8755 In file: default.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
8757 {+change-x-forwarded-for{block}
8758 +deanimate-gifs {last}
8759 +fast-redirects {check-decoded-url}
8760 +filter {refresh-tags}
8761 +filter {img-reorder}
8762 +filter {banners-by-size}
8764 +filter {jumping-windows}
8765 +filter {ie-exploits}
8766 +hide-from-header {block}
8767 +hide-referrer {forge}
8768 +session-cookies-only
8769 +set-image-blocker {pattern} }
8772 { -session-cookies-only }
8778 In file: user.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
8779 (no matches in this file)
8783 This is telling us how we have defined our
8784 <link linkend="ACTIONS"><quote>actions</quote></link>, and
8785 which ones match for our test case, <quote>google.com</quote>.
8786 Displayed is all the actions that are available to us. Remember,
8787 the <literal>+</literal> sign denotes <quote>on</quote>. <literal>-</literal>
8788 denotes <quote>off</quote>. So some are <quote>on</quote> here, but many
8789 are <quote>off</quote>. Each example we try may provide a slightly different
8790 end result, depending on our configuration directives.
8794 is for our <filename>default.action</filename> file. The large, multi-line
8795 listing, is how the actions are set to match for all URLs, i.e. our default
8796 settings. If you look at your <quote>actions</quote> file, this would be the
8797 section just below the <quote>aliases</quote> section near the top. This
8798 will apply to all URLs as signified by the single forward slash at the end
8799 of the listing -- <quote> / </quote>.
8803 But we have defined additional actions that would be exceptions to these general
8804 rules, and then we list specific URLs (or patterns) that these exceptions
8805 would apply to. Last match wins. Just below this then are two explicit
8806 matches for <quote>.google.com</quote>. The first is negating our previous
8807 cookie setting, which was for <link
8808 linkend="SESSION-COOKIES-ONLY"><quote>+session-cookies-only</quote></link>
8809 (i.e. not persistent). So we will allow persistent cookies for google, at
8810 least that is how it is in this example. The second turns
8811 <emphasis>off</emphasis> any <link
8812 linkend="FAST-REDIRECTS"><quote>+fast-redirects</quote></link>
8813 action, allowing this to take place unmolested. Note that there is a leading
8814 dot here -- <quote>.google.com</quote>. This will match any hosts and
8815 sub-domains, in the google.com domain also, such as
8816 <quote>www.google.com</quote> or <quote>mail.google.com</quote>. But it would not
8817 match <quote>www.google.de</quote>! So, apparently, we have these two actions
8818 defined as exceptions to the general rules at the top somewhere in the lower
8819 part of our <filename>default.action</filename> file, and
8820 <quote>google.com</quote> is referenced somewhere in these latter sections.
8824 Then, for our <filename>user.action</filename> file, we again have no hits.
8825 So there is nothing google-specific that we might have added to our own, local
8826 configuration. If there was, those actions would over-rule any actions from
8827 previously processed files, such as <filename>default.action</filename>.
8828 <filename>user.action</filename> typically has the last word. This is the
8829 best place to put hard and fast exceptions,
8833 And finally we pull it all together in the bottom section and summarize how
8834 <application>Privoxy</application> is applying all its <quote>actions</quote>
8835 to <quote>google.com</quote>:
8843 +change-x-forwarded-for{block}
8844 -client-header-filter{hide-tor-exit-notation}
8845 -content-type-overwrite
8846 -crunch-client-header
8847 -crunch-if-none-match
8848 -crunch-incoming-cookies
8849 -crunch-outgoing-cookies
8850 -crunch-server-header
8851 +deanimate-gifs {last}
8852 -downgrade-http-version
8855 -filter {content-cookies}
8856 -filter {all-popups}
8857 -filter {banners-by-link}
8858 -filter {tiny-textforms}
8859 -filter {frameset-borders}
8860 -filter {demoronizer}
8861 -filter {shockwave-flash}
8862 -filter {quicktime-kioskmode}
8864 -filter {crude-parental}
8865 -filter {site-specifics}
8866 -filter {js-annoyances}
8867 -filter {html-annoyances}
8868 +filter {refresh-tags}
8869 -filter {unsolicited-popups}
8870 +filter {img-reorder}
8871 +filter {banners-by-size}
8873 +filter {jumping-windows}
8874 +filter {ie-exploits}
8881 -handle-as-empty-document
8883 -hide-accept-language
8884 -hide-content-disposition
8885 +hide-from-header {block}
8886 -hide-if-modified-since
8887 +hide-referrer {forge}
8890 -overwrite-last-modified
8891 -prevent-compression
8893 -server-header-filter{xml-to-html}
8894 -server-header-filter{html-to-xml}
8895 -session-cookies-only
8896 +set-image-blocker {pattern}
8900 Notice the only difference here to the previous listing, is to
8901 <quote>fast-redirects</quote> and <quote>session-cookies-only</quote>,
8902 which are activated specifically for this site in our configuration,
8903 and thus show in the <quote>Final Results</quote>.
8907 Now another example, <quote>ad.doubleclick.net</quote>:
8911 { +block{Domains starts with "ad"} }
8914 { +block{Domain contains "ad"} }
8917 { +block{Doubleclick banner server} +handle-as-image }
8918 .[a-vx-z]*.doubleclick.net
8922 We'll just show the interesting part here - the explicit matches. It is
8923 matched three different times. Two <quote>+block{}</quote> sections,
8924 and a <quote>+block{} +handle-as-image</quote>,
8925 which is the expanded form of one of our aliases that had been defined as:
8926 <quote>+block-as-image</quote>. (<link
8927 linkend="ALIASES"><quote>Aliases</quote></link> are defined in
8928 the first section of the actions file and typically used to combine more
8933 Any one of these would have done the trick and blocked this as an unwanted
8934 image. This is unnecessarily redundant since the last case effectively
8935 would also cover the first. No point in taking chances with these guys
8936 though ;-) Note that if you want an ad or obnoxious
8937 URL to be invisible, it should be defined as <quote>ad.doubleclick.net</quote>
8938 is done here -- as both a <link
8939 linkend="BLOCK"><quote>+block{}</quote></link>
8940 <emphasis>and</emphasis> an
8941 <link linkend="HANDLE-AS-IMAGE"><quote>+handle-as-image</quote></link>.
8942 The custom alias <quote><literal>+block-as-image</literal></quote> just
8943 simplifies the process and make it more readable.
8947 One last example. Let's try <quote>http://www.example.net/adsl/HOWTO/</quote>.
8948 This one is giving us problems. We are getting a blank page. Hmmm ...
8952 Matches for http://www.example.net/adsl/HOWTO/:
8954 In file: default.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
8958 +change-x-forwarded-for{block}
8959 -client-header-filter{hide-tor-exit-notation}
8960 -content-type-overwrite
8961 -crunch-client-header
8962 -crunch-if-none-match
8963 -crunch-incoming-cookies
8964 -crunch-outgoing-cookies
8965 -crunch-server-header
8967 -downgrade-http-version
8968 +fast-redirects {check-decoded-url}
8970 -filter {content-cookies}
8971 -filter {all-popups}
8972 -filter {banners-by-link}
8973 -filter {tiny-textforms}
8974 -filter {frameset-borders}
8975 -filter {demoronizer}
8976 -filter {shockwave-flash}
8977 -filter {quicktime-kioskmode}
8979 -filter {crude-parental}
8980 -filter {site-specifics}
8981 -filter {js-annoyances}
8982 -filter {html-annoyances}
8983 +filter {refresh-tags}
8984 -filter {unsolicited-popups}
8985 +filter {img-reorder}
8986 +filter {banners-by-size}
8988 +filter {jumping-windows}
8989 +filter {ie-exploits}
8996 -handle-as-empty-document
8998 -hide-accept-language
8999 -hide-content-disposition
9000 +hide-from-header{block}
9001 +hide-referer{forge}
9003 -overwrite-last-modified
9004 +prevent-compression
9006 -server-header-filter{xml-to-html}
9007 -server-header-filter{html-to-xml}
9008 +session-cookies-only
9009 +set-image-blocker{blank} }
9012 { +block{Path contains "ads".} +handle-as-image }
9017 Ooops, the <quote>/adsl/</quote> is matching <quote>/ads</quote> in our
9018 configuration! But we did not want this at all! Now we see why we get the
9019 blank page. It is actually triggering two different actions here, and
9020 the effects are aggregated so that the URL is blocked, and &my-app; is told
9021 to treat the block as if it were an image. But this is, of course, all wrong.
9022 We could now add a new action below this (or better in our own
9023 <filename>user.action</filename> file) that explicitly
9024 <emphasis>un</emphasis> blocks (
9025 <link linkend="BLOCK"><quote>{-block}</quote></link>) paths with
9026 <quote>adsl</quote> in them (remember, last match in the configuration
9027 wins). There are various ways to handle such exceptions. Example:
9036 Now the page displays ;-)
9037 Remember to flush your browser's caches when making these kinds of changes to
9038 your configuration to insure that you get a freshly delivered page! Or, try
9039 using <literal>Shift+Reload</literal>.
9043 But now what about a situation where we get no explicit matches like
9048 { +block{Path starts with "ads".} +handle-as-image }
9053 That actually was very helpful and pointed us quickly to where the problem
9054 was. If you don't get this kind of match, then it means one of the default
9055 rules in the first section of <filename>default.action</filename> is causing
9056 the problem. This would require some guesswork, and maybe a little trial and
9057 error to isolate the offending rule. One likely cause would be one of the
9058 <link linkend="FILTER"><quote>+filter</quote></link> actions.
9059 These tend to be harder to troubleshoot.
9060 Try adding the URL for the site to one of aliases that turn off
9061 <link linkend="FILTER"><quote>+filter</quote></link>:
9067 .worldpay.com # for quietpc.com
9074 <quote><literal>{ shop }</literal></quote> is an <quote>alias</quote> that expands to
9075 <quote><literal>{ -filter -session-cookies-only }</literal></quote>.
9076 Or you could do your own exception to negate filtering:
9081 # Disable ALL filter actions for sites in this section
9088 This would turn off all filtering for these sites. This is best
9089 put in <filename>user.action</filename>, for local site
9090 exceptions. Note that when a simple domain pattern is used by itself (without
9091 the subsequent path portion), all sub-pages within that domain are included
9092 automatically in the scope of the action.
9096 Images that are inexplicably being blocked, may well be hitting the
9097 <link linkend="FILTER-BANNERS-BY-SIZE"><quote>+filter{banners-by-size}</quote></link>
9099 that images of certain sizes are ad banners (works well
9100 <emphasis>most of the time</emphasis> since these tend to be standardized).
9104 <quote><literal>{ fragile }</literal></quote> is an alias that disables most
9105 actions that are the most likely to cause trouble. This can be used as a
9106 last resort for problem sites.
9111 # Handle with care: easy to break
9118 <emphasis>Remember to flush caches!</emphasis> Note that the
9119 <literal>mail.google</literal> reference lacks the TLD portion (e.g.
9120 <quote>.com</quote>). This will effectively match any TLD with
9121 <literal>google</literal> in it, such as <literal>mail.google.de.</literal>,
9125 If this still does not work, you will have to go through the remaining
9126 actions one by one to find which one(s) is causing the problem.
9135 This program is free software; you can redistribute it
9136 and/or modify it under the terms of the GNU General
9137 Public License as published by the Free Software
9138 Foundation; either version 2 of the License, or (at
9139 your option) any later version.
9141 This program is distributed in the hope that it will
9142 be useful, but WITHOUT ANY WARRANTY; without even the
9143 implied warranty of MERCHANTABILITY or FITNESS FOR A
9144 PARTICULAR PURPOSE. See the GNU General Public
9145 License for more details.
9147 The GNU General Public License should be included with
9148 this file. If not, you can view it at
9149 http://www.gnu.org/copyleft/gpl.html
9150 or write to the Free Software Foundation, Inc.,
9151 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,