1 <!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook V3.1//EN" [
2 <!entity % dummy "IGNORE">
3 <!entity supported SYSTEM "supported.sgml">
4 <!entity newfeatures SYSTEM "newfeatures.sgml">
5 <!entity p-intro SYSTEM "privoxy.sgml">
6 <!entity seealso SYSTEM "seealso.sgml">
7 <!entity buildsource SYSTEM "buildsource.sgml">
8 <!entity contacting SYSTEM "contacting.sgml">
9 <!entity history SYSTEM "history.sgml">
10 <!entity copyright SYSTEM "copyright.sgml">
11 <!entity license SYSTEM "license.sgml">
12 <!entity GPLv2 SYSTEM "../../LICENSE">
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 -->
24 <!entity % p-readme "IGNORE">
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 -->
30 <!entity % seealso-extra "INCLUDE"> <!-- extra stuff from seealso.sgml -->
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 --disable-dynamic-pcre
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> }
678 Or if you use a number of filters, or filter many sites, you may just want
679 to turn off compression for all sites in
680 <filename>default.action</filename> (or
681 <filename>user.action</filename>).
688 Also, <link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> is
689 off by default now. If you've liked this feature in the past, you may want
690 to turn it back on in <filename>user.action</filename> now.
697 Some installers may not automatically start
698 <application>Privoxy</application> after installation.
708 <!-- ~~~~~ New section ~~~~~ -->
709 <sect1 id="quickstart"><title>Quickstart to Using Privoxy</title>
715 Install <application>Privoxy</application>. See the <link
716 linkend="installation">Installation Section</link> below for platform specific
723 Advanced users and those who want to offer <application>Privoxy</application>
724 service to more than just their local machine should check the <link
725 linkend="config">main config file</link>, especially the <link
726 linkend="access-control">security-relevant</link> options. These are
733 Start <application>Privoxy</application>, if the installation program has
734 not done this already (may vary according to platform). See the section
735 <link linkend="startup">Starting <application>Privoxy</application></link>.
741 Set your browser to use <application>Privoxy</application> as HTTP and
742 HTTPS (SSL) <ulink url="https://en.wikipedia.org/wiki/Proxy_server">proxy</ulink>
743 by setting the proxy configuration for address of
744 <literal>127.0.0.1</literal> and port <literal>8118</literal>.
745 <emphasis>DO NOT</emphasis> activate proxying for <literal>FTP</literal> or
746 any protocols besides HTTP and HTTPS (SSL) unless you intend to prevent your
747 browser from using these protocols.
753 Flush your browser's disk and memory caches, to remove any cached ad images.
754 If using <application>Privoxy</application> to manage
755 <ulink url="https://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>,
756 you should remove any currently stored cookies too.
762 A default installation should provide a reasonable starting point for
763 most. There will undoubtedly be occasions where you will want to adjust the
764 configuration, but that can be dealt with as the need arises. Little
765 to no initial configuration is required in most cases, you may want
767 <ulink url="config.html#ENABLE-EDIT-ACTIONS">web-based action editor</ulink> though.
768 Be sure to read the warnings first.
771 See the <link linkend="configuration">Configuration section</link> for more
772 configuration options, and how to customize your installation.
773 You might also want to look at the <link
774 linkend="quickstart-ad-blocking">next section</link> for a quick
775 introduction to how <application>Privoxy</application> blocks ads and
782 If you experience ads that slip through, innocent images that are
783 blocked, or otherwise feel the need to fine-tune
784 <application>Privoxy's</application> behavior, take a look at the <link
785 linkend="actions-file">actions files</link>. As a quick start, you might
786 find the <link linkend="act-examples">richly commented examples</link>
787 helpful. You can also view and edit the actions files through the <ulink
788 url="http://config.privoxy.org">web-based user interface</ulink>. The
789 Appendix <quote><link linkend="actionsanat">Troubleshooting: Anatomy of an
790 Action</link></quote> has hints on how to understand and debug actions that
791 <quote>misbehave</quote>.
797 Please see the section <link linkend="contact">Contacting the
798 Developers</link> on how to report bugs, problems with websites or to get
805 Now enjoy surfing with enhanced control, comfort and privacy!
812 <!-- ~~~~~ New section ~~~~~ -->
814 <sect2 id="quickstart-ad-blocking">
815 <title>Quickstart to Ad Blocking</title>
817 NOTE: This section is deliberately redundant for those that don't
818 want to read the whole thing (which is getting lengthy).
821 Ad blocking is but one of <application>Privoxy's</application>
822 array of features. Many of these features are for the technically minded advanced
823 user. But, ad and banner blocking is surely common ground for everybody.
826 This section will provide a quick summary of ad blocking so
827 you can get up to speed quickly without having to read the more extensive
828 information provided below, though this is highly recommended.
831 First a bit of a warning ... blocking ads is much like blocking SPAM: the
832 more aggressive you are about it, the more likely you are to block
833 things that were not intended. And the more likely that some things
834 may not work as intended. So there is a trade off here. If you want
835 extreme ad free browsing, be prepared to deal with more
836 <quote>problem</quote> sites, and to spend more time adjusting the
837 configuration to solve these unintended consequences. In short, there is
838 not an easy way to eliminate <emphasis>all</emphasis> ads. Either take
839 the easy way and settle for <emphasis>most</emphasis> ads blocked with the
840 default configuration, or jump in and tweak it for your personal surfing
841 habits and preferences.
844 Secondly, a brief explanation of <application>Privoxy's </application>
845 <quote>actions</quote>. <quote>Actions</quote> in this context, are
846 the directives we use to tell <application>Privoxy</application> to perform
847 some task relating to HTTP transactions (i.e. web browsing). We tell
848 <application>Privoxy</application> to take some <quote>action</quote>. Each
849 action has a unique name and function. While there are many potential
850 <application>actions</application> in <application>Privoxy's</application>
851 arsenal, only a few are used for ad blocking. <link
852 linkend="actions">Actions</link>, and <link linkend="actions-file">action
853 configuration files</link>, are explained in depth below.
856 Actions are specified in <application>Privoxy's</application> configuration,
857 followed by one or more URLs to which the action should apply. URLs
858 can actually be URL type <link linkend="af-patterns">patterns</link> that use
859 wildcards so they can apply potentially to a range of similar URLs. The
860 actions, together with the URL patterns are called a section.
863 When you connect to a website, the full URL will either match one or more
864 of the sections as defined in <application>Privoxy's</application> configuration,
865 or not. If so, then <application>Privoxy</application> will perform the
866 respective actions. If not, then nothing special happens. Furthermore, web
867 pages may contain embedded, secondary URLs that your web browser will
868 use to load additional components of the page, as it parses the
869 original page's HTML content. An ad image for instance, is just an URL
870 embedded in the page somewhere. The image itself may be on the same server,
871 or a server somewhere else on the Internet. Complex web pages will have many
872 such embedded URLs. &my-app; can deal with each URL individually, so, for
873 instance, the main page text is not touched, but images from such-and-such
878 The most important actions for basic ad blocking are: <literal><link
879 linkend="block">block</link></literal>, <literal><link
880 linkend="handle-as-image">handle-as-image</link></literal>,
882 linkend="handle-as-empty-document">handle-as-empty-document</link></literal>,and
883 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>:
890 <literal><link linkend="block">block</link></literal> - this is perhaps
891 the single most used action, and is particularly important for ad blocking.
892 This action stops any contact between your browser and any URL patterns
893 that match this action's configuration. It can be used for blocking ads,
894 but also anything that is determined to be unwanted. By itself, it simply
895 stops any communication with the remote server and sends
896 <application>Privoxy</application>'s own built-in BLOCKED page instead to
897 let you now what has happened (with some exceptions, see below).
903 <literal><link linkend="handle-as-image">handle-as-image</link></literal> -
904 tells <application>Privoxy</application> to treat this URL as an image.
905 <application>Privoxy</application>'s default configuration already does this
906 for all common image types (e.g. GIF), but there are many situations where this
907 is not so easy to determine. So we'll force it in these cases. This is particularly
908 important for ad blocking, since only if we know that it's an image of
909 some kind, can we replace it with an image of our choosing, instead of the
910 <application>Privoxy</application> BLOCKED page (which would only result in
911 a <quote>broken image</quote> icon). There are some limitations to this
912 though. For instance, you can't just brute-force an image substitution for
913 an entire HTML page in most situations.
919 <literal><link linkend="handle-as-empty-document">handle-as-empty-document</link></literal> -
920 sends an empty document instead of <application>Privoxy's</application>
921 normal BLOCKED HTML page. This is useful for file types that are neither
922 HTML nor images, such as blocking JavaScript files.
929 linkend="set-image-blocker">set-image-blocker</link></literal> - tells
930 <application>Privoxy</application> what to display in place of an ad image that
931 has hit a block rule. For this to come into play, the URL must match a
932 <literal><link linkend="block">block</link></literal> action somewhere in the
933 configuration, <emphasis>and</emphasis>, it must also match an
934 <literal><link linkend="handle-as-image">handle-as-image</link></literal> action.
937 The configuration options on what to display instead of the ad are:
941 <emphasis>pattern</emphasis> - a checkerboard pattern, so that an ad
942 replacement is obvious. This is the default.
947 <emphasis>blank</emphasis> - A very small empty GIF image is displayed.
948 This is the so-called <quote>invisible</quote> configuration option.
953 <emphasis>http://<URL></emphasis> - A redirect to any image anywhere
954 of the user's choosing (advanced usage).
962 Advanced users will eventually want to explore &my-app;
963 <literal><link linkend="filter">filters</link></literal> as well. Filters
964 are very different from <literal><link
965 linkend="block">blocks</link></literal>.
966 A <quote>block</quote> blocks a site, page, or unwanted contented. Filters
967 are a way of filtering or modifying what is actually on the page. An example
968 filter usage: a text replacement of <quote>no-no</quote> for
969 <quote>nasty-word</quote>. That is a very simple example. This process can be
970 used for ad blocking, but it is more in the realm of advanced usage and has
971 some pitfalls to be wary off.
975 The quickest way to adjust any of these settings is with your browser through
976 the special <application>Privoxy</application> editor at <ulink
977 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
978 (shortcut: <ulink url="http://p.p/">http://p.p/show-status</ulink>). This
979 is an internal page, and does not require Internet access.
983 Note that as of <application>Privoxy</application> 3.0.7 beta the
984 action editor is disabled by default. Check the
985 <ulink url="config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions
986 section in the configuration file</ulink> to learn why and in which
987 cases it's safe to enable again.
991 If you decided to enable the action editor, select the appropriate
992 <quote>actions</quote> file, and click
993 <quote><guibutton>Edit</guibutton></quote>. It is best to put personal or
994 local preferences in <filename>user.action</filename> since this is not
995 meant to be overwritten during upgrades, and will over-ride the settings in
996 other files. Here you can insert new <quote>actions</quote>, and URLs for ad
997 blocking or other purposes, and make other adjustments to the configuration.
998 <application>Privoxy</application> will detect these changes automatically.
1002 A quick and simple step by step example:
1009 Right click on the ad image to be blocked, then select
1010 <quote><guimenuitem>Copy Link Location</guimenuitem></quote> from the
1018 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1023 Find <filename>user.action</filename> in the top section, and click
1024 on <quote><guibutton>Edit</guibutton></quote>:
1027 <!-- image of editor and actions files selections -->
1028 <figure pgwide="0" float="0"><title>Actions Files in Use</title>
1031 <imagedata fileref="files-in-use.jpg" format="jpg">
1034 <phrase>[ Screenshot of Actions Files in Use ]</phrase>
1042 You should have a section with only
1043 <literal><link linkend="block">block</link></literal> listed under
1044 <quote>Actions:</quote>.
1045 If not, click a <quote><guibutton>Insert new section below</guibutton></quote>
1046 button, and in the new section that just appeared, click the
1047 <guibutton>Edit</guibutton> button right under the word <quote>Actions:</quote>.
1048 This will bring up a list of all actions. Find
1049 <literal><link linkend="block">block</link></literal> near the top, and click
1050 in the <quote>Enabled</quote> column, then <quote><guibutton>Submit</guibutton></quote>
1051 just below the list.
1056 Now, in the <literal><link linkend="block">block</link></literal> actions section,
1057 click the <quote><guibutton>Add</guibutton></quote> button, and paste the URL the
1058 browser got from <quote><guimenuitem>Copy Link Location</guimenuitem></quote>.
1059 Remove the <literal>http://</literal> at the beginning of the URL. Then, click
1060 <quote><guibutton>Submit</guibutton></quote> (or
1061 <quote><guibutton>OK</guibutton></quote> if in a pop-up window).
1066 Now go back to the original page, and press <keycap>SHIFT-Reload</keycap>
1067 (or flush all browser caches). The image should be gone now.
1074 This is a very crude and simple example. There might be good reasons to use a
1075 wildcard pattern match to include potentially similar images from the same
1076 site. For a more extensive explanation of <quote>patterns</quote>, and
1077 the entire actions concept, see <link linkend="actions-file">the Actions
1082 For advanced users who want to hand edit their config files, you might want
1083 to now go to the <link linkend="act-examples">Actions Files Tutorial</link>.
1084 The ideas explained therein also apply to the web-based editor.
1087 There are also various
1088 <link linkend="filter">filters</link> that can be used for ad blocking
1089 (filters are a special subset of actions). These
1090 fall into the <quote>advanced</quote> usage category, and are explained in
1091 depth in later sections.
1098 <!-- ~ End section ~ -->
1101 <!-- ~~~~~ New section ~~~~~ -->
1102 <sect1 id="startup">
1103 <title>Starting Privoxy</title>
1105 Before launching <application>Privoxy</application> for the first time, you
1106 will want to configure your browser(s) to use
1107 <application>Privoxy</application> as a HTTP and HTTPS (SSL)
1108 <ulink url="https://en.wikipedia.org/wiki/Proxy_server">proxy</ulink>. The default is
1109 127.0.0.1 (or localhost) for the proxy address, and port 8118 (earlier versions
1110 used port 8000). This is the one configuration step <emphasis>that must be done
1114 Please note that <application>Privoxy</application> can only proxy HTTP and
1115 HTTPS traffic. It will not work with FTP or other protocols.
1118 <!-- image of Mozilla Proxy configuration -->
1119 <figure pgwide="0" float="0"><title>Proxy Configuration Showing
1120 Mozilla Firefox HTTP and HTTPS (SSL) Settings</title>
1123 <imagedata fileref="proxy_setup.jpg" format="jpg">
1126 <phrase>[ Screenshot of Mozilla Firefox Proxy Configuration ]</phrase>
1133 With <application>Firefox</application>, this is typically set under:
1137 <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>Network Settings</guibutton> -> <guibutton>Settings</guibutton>
1141 Or optionally on some platforms:
1145 <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>General</guibutton> -> <guibutton>Connection Settings</guibutton> -> <guibutton>Manual Proxy Configuration</guibutton>
1150 With <application>Netscape</application> (and
1151 <application>Mozilla</application>), this can be set under:
1156 <!-- Mix ascii and gui art, something for everybody -->
1157 <!-- spacing on this is tricky -->
1158 <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>Advanced</guibutton> -> <guibutton>Proxies</guibutton> -> <guibutton>HTTP Proxy</guibutton>
1162 For <application>Internet Explorer v.5-7</application>:
1166 <guibutton>Tools</guibutton> -> <guibutton>Internet Options</guibutton> -> <guibutton>Connections</guibutton> -> <guibutton>LAN Settings</guibutton>
1170 Then, check <quote>Use Proxy</quote> and fill in the appropriate info
1171 (Address: 127.0.0.1, Port: 8118). Include HTTPS (SSL), if you want HTTPS
1172 proxy support too (sometimes labeled <quote>Secure</quote>). Make sure any
1173 checkboxes like <quote>Use the same proxy server for all protocols</quote> is
1174 <emphasis>UNCHECKED</emphasis>. You want only HTTP and HTTPS (SSL)!
1177 <!-- image of IE Proxy configuration -->
1178 <figure pgwide="0" float="0"><title>Proxy Configuration Showing
1179 Internet Explorer HTTP and HTTPS (Secure) Settings</title>
1182 <imagedata fileref="proxy2.jpg" format="jpg">
1185 <phrase>[ Screenshot of IE Proxy Configuration ]</phrase>
1192 After doing this, flush your browser's disk and memory caches to force a
1193 re-reading of all pages and to get rid of any ads that may be cached. Remove
1194 any <ulink url="https://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>,
1195 if you want <application>Privoxy</application> to manage that. You are now
1196 ready to start enjoying the benefits of using
1197 <application>Privoxy</application>!
1201 <application>Privoxy</application> itself is typically started by specifying the
1202 main configuration file to be used on the command line. If no configuration
1203 file is specified on the command line, <application>Privoxy</application>
1204 will look for a file named <filename>config</filename> in the current
1205 directory. Except on Win32 where it will try <filename>config.txt</filename>.
1208 <sect2 id="start-debian">
1209 <title>Debian</title>
1211 We use a script. Note that Debian typically starts &my-app; upon booting per
1212 default. It will use the file
1213 <filename>/etc/privoxy/config</filename> as its main configuration
1217 # /etc/init.d/privoxy start
1221 <sect2 id="start-freebsd">
1222 <title>FreeBSD and ElectroBSD</title>
1224 To start <application>Privoxy</application> upon booting, add
1225 "privoxy_enable='YES'" to <filename>/etc/rc.conf</filename>.
1226 <application>Privoxy</application> will use
1227 <filename>/usr/local/etc/privoxy/config</filename> as its main
1231 If you installed <application>Privoxy</application> into a jail, the
1232 paths above are relative to the jail root.
1235 To start <application>Privoxy</application> manually, run:
1238 # service privoxy onestart
1242 <sect2 id="start-windows">
1243 <title>Windows</title>
1245 Click on the &my-app; Icon to start <application>Privoxy</application>. If no configuration file is
1246 specified on the command line, <application>Privoxy</application> will look
1247 for a file named <filename>config.txt</filename>. Note that Windows will
1248 automatically start &my-app; when the system starts if you chose that option
1252 <application>Privoxy</application> can run with full Windows service functionality.
1253 On Windows only, the &my-app; program has two new command line arguments
1254 to install and uninstall &my-app; as a service. See the
1255 <link linkend="installation-pack-win">Windows Installation
1256 instructions</link> for details.
1260 <sect2 id="start-unices">
1261 <title>Generic instructions for Unix derivates (Solaris, NetBSD, HP-UX etc.)</title>
1263 Example Unix startup command:
1266 # /usr/sbin/privoxy --user privoxy /etc/privoxy/config
1269 Note that if you installed <application>Privoxy</application> through
1270 a package manager, the package will probably contain a platform-specific
1271 script or configuration file to start <application>Privoxy</application>
1276 <sect2 id="start-macosx">
1277 <title>Mac OS X</title>
1279 The privoxy service will automatically start after a successful installation
1280 (and thereafter every time your computer starts up) however you will need to
1281 configure your web browser(s) to use it. To do so, configure them to use a
1282 proxy for HTTP and HTTPS at the address 127.0.0.1:8118.
1285 To prevent the privoxy service from automatically starting when your computer
1286 starts up, remove or rename the file <literal>/Library/LaunchDaemons/org.ijbswa.privoxy.plist</literal>
1287 (on OS X 10.5 and higher) or the folder named
1288 <literal>/Library/StartupItems/Privoxy</literal> (on OS X 10.4 'Tiger').
1291 To manually start or stop the privoxy service, use the scripts startPrivoxy.sh
1292 and stopPrivoxy.sh supplied in /Applications/Privoxy. They must be run from an
1293 administrator account, using sudo.
1301 See the section <link linkend="cmdoptions">Command line options</link> for
1305 must find a better place for this paragraph
1308 The included default configuration files should give a reasonable starting
1309 point. Most of the per site configuration is done in the
1310 <ulink url="actions-file.html"><quote>actions</quote></ulink> files. These are
1311 where various cookie actions are defined, ad and banner blocking, and other
1312 aspects of <application>Privoxy</application> configuration. There are several
1313 such files included, with varying levels of aggressiveness.
1317 You will probably want to keep an eye out for sites for which you may prefer
1318 persistent cookies, and add these to your actions configuration as needed. By
1319 default, most of these will be accepted only during the current browser
1320 session (aka <quote>session cookies</quote>), unless you add them to the
1321 configuration. If you want the browser to handle this instead, you will need
1322 to edit <filename>user.action</filename> (or through the web based interface)
1323 and disable this feature. If you use more than one browser, it would make
1324 more sense to let <application>Privoxy</application> handle this. In which
1325 case, the browser(s) should be set to accept all cookies.
1329 Another feature where you will probably want to define exceptions for trusted
1330 sites is the popup-killing (through <ulink
1331 url="actions-file.html#FILTER-POPUPS"><quote>+filter{popups}</quote></ulink>),
1332 because your favorite shopping, banking, or leisure site may need
1333 popups (explained below).
1337 <application>Privoxy</application> does not support all of the optional HTTP/1.1
1338 features yet. In the unlikely event that you experience inexplicable problems
1339 with browsers that use HTTP/1.1 per default
1340 (like <application>Mozilla</application> or recent versions of I.E.), you might
1341 try to force HTTP/1.0 compatibility. For Mozilla, look under <literal>Edit ->
1342 Preferences -> Debug -> Networking</literal>.
1343 Alternatively, set the <quote>+downgrade-http-version</quote> config option in
1344 <filename>default.action</filename> which will downgrade your browser's HTTP
1345 requests from HTTP/1.1 to HTTP/1.0 before processing them.
1349 After running <application>Privoxy</application> for a while, you can
1350 start to fine tune the configuration to suit your personal, or site,
1351 preferences and requirements. There are many, many aspects that can
1352 be customized. <quote>Actions</quote>
1353 can be adjusted by pointing your browser to
1354 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
1355 (shortcut: <ulink url="http://p.p/">http://p.p/</ulink>),
1356 and then follow the link to <quote>View & Change the Current Configuration</quote>.
1357 (This is an internal page and does not require Internet access.)
1361 In fact, various aspects of <application>Privoxy</application>
1362 configuration can be viewed from this page, including
1363 current configuration parameters, source code version numbers,
1364 the browser's request headers, and <quote>actions</quote> that apply
1365 to a given URL. In addition to the actions file
1366 editor mentioned above, <application>Privoxy</application> can also
1367 be turned <quote>on</quote> and <quote>off</quote> (toggled) from this page.
1371 If you encounter problems, try loading the page without
1372 <application>Privoxy</application>. If that helps, enter the URL where
1373 you have the problems into <ulink url="http://p.p/show-url-info">the browser
1374 based rule tracing utility</ulink>. See which rules apply and why, and
1375 then try turning them off for that site one after the other, until the problem
1376 is gone. When you have found the culprit, you might want to turn the rest on
1381 If the above paragraph sounds gibberish to you, you might want to <link
1382 linkend="actions-file">read more about the actions concept</link>
1383 or even dive deep into the <link linkend="actionsanat">Appendix
1388 If you can't get rid of the problem at all, think you've found a bug in
1389 Privoxy, want to propose a new feature or smarter rules, please see the
1390 section <link linkend="contact"><quote>Contacting the
1391 Developers</quote></link> below.
1396 <!-- ~~~~~ New section ~~~~~ -->
1397 <sect2 id="cmdoptions">
1398 <title>Command Line Options</title>
1400 <application>Privoxy</application> may be invoked with the following
1401 command-line options:
1408 <emphasis>--config-test</emphasis>
1411 Exit after loading the configuration files before binding to
1412 the listen address. The exit code signals whether or not the
1413 configuration files have been successfully loaded.
1416 If the exit code is 1, at least one of the configuration files
1417 is invalid, if it is 0, all the configuration files have been
1418 successfully loaded (but may still contain errors that can
1419 currently only be detected at run time).
1422 This option doesn't affect the log setting, combination with
1423 <emphasis>--no-daemon</emphasis> is recommended if a configured
1424 log file shouldn't be used.
1429 <emphasis>--version</emphasis>
1432 Print version info and exit. Unix only.
1437 <emphasis>--help</emphasis>
1440 Print short usage info and exit. Unix only.
1445 <emphasis>--no-daemon</emphasis>
1448 Don't become a daemon, i.e. don't fork and become process group
1449 leader, and don't detach from controlling tty. Unix only.
1454 <emphasis>--pidfile FILE</emphasis>
1457 On startup, write the process ID to <emphasis>FILE</emphasis>. Delete the
1458 <emphasis>FILE</emphasis> on exit. Failure to create or delete the
1459 <emphasis>FILE</emphasis> is non-fatal. If no <emphasis>FILE</emphasis>
1460 option is given, no PID file will be used. Unix only.
1465 <emphasis>--user USER[.GROUP]</emphasis>
1468 After (optionally) writing the PID file, assume the user ID of
1469 <emphasis>USER</emphasis>, and if included the GID of GROUP. Exit if the
1470 privileges are not sufficient to do so. Unix only.
1475 <emphasis>--chroot</emphasis>
1478 Before changing to the user ID given in the <emphasis>--user</emphasis> option,
1479 chroot to that user's home directory, i.e. make the kernel pretend to the &my-app;
1480 process that the directory tree starts there. If set up carefully, this can limit
1481 the impact of possible vulnerabilities in &my-app; to the files contained in that hierarchy.
1487 <emphasis>--pre-chroot-nslookup hostname</emphasis>
1490 Specifies a hostname (for example www.privoxy.org) to look up before doing a chroot.
1491 On some systems, initializing the resolver library involves reading config files from
1492 /etc and/or loading additional shared libraries from /lib.
1493 On these systems, doing a hostname lookup before the chroot reduces
1494 the number of files that must be copied into the chroot tree.
1497 For fastest startup speed, a good value is a hostname that is not in /etc/hosts but that
1498 your local name server (listed in /etc/resolv.conf) can resolve without recursion
1499 (that is, without having to ask any other name servers). The hostname need not exist,
1500 but if it doesn't, an error message (which can be ignored) will be output.
1506 <emphasis>configfile</emphasis>
1509 If no <emphasis>configfile</emphasis> is included on the command line,
1510 <application>Privoxy</application> will look for a file named
1511 <quote>config</quote> in the current directory (except on Win32
1512 where it will look for <quote>config.txt</quote> instead). Specify
1513 full path to avoid confusion. If no config file is found,
1514 <application>Privoxy</application> will fail to start.
1521 On <application>MS Windows</application> only there are two additional
1522 command-line options to allow <application>Privoxy</application> to install and
1523 run as a <emphasis>service</emphasis>. See the
1524 <link linkend="installation-pack-win">Window Installation section</link>
1532 <!-- ~ End section ~ -->
1535 <!-- ~~~~~ New section ~~~~~ -->
1536 <sect1 id="configuration"><title>Privoxy Configuration</title>
1538 All <application>Privoxy</application> configuration is stored
1539 in text files. These files can be edited with a text editor.
1540 Many important aspects of <application>Privoxy</application> can
1541 also be controlled easily with a web browser.
1545 <!-- ~~~~~ New section ~~~~~ -->
1547 <sect2 id="control-with-webbrowser">
1548 <title>Controlling Privoxy with Your Web Browser</title>
1550 <application>Privoxy</application>'s user interface can be reached through the special
1551 URL <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
1552 (shortcut: <ulink url="http://p.p/">http://p.p/</ulink>),
1553 which is a built-in page and works without Internet access.
1554 You will see the following section:
1557 <!-- Needs to be put in a table and colorized -->
1558 <screen><!-- want the background color that goes with screen -->
1560 <bridgehead renderas="sect2"> Privoxy Menu</bridgehead>
1563 ▪ <ulink url="http://config.privoxy.org/show-status">View & change the current configuration</ulink>
1566 ▪ <ulink url="http://config.privoxy.org/client-tags">View or toggle the tags that can be set based on the client's address</ulink>
1569 ▪ <ulink url="http://config.privoxy.org/show-request">View the request headers.</ulink>
1572 ▪ <ulink url="http://config.privoxy.org/show-url-info">Look up which actions apply to a URL and why</ulink>
1575 ▪ <ulink url="http://config.privoxy.org/toggle">Toggle Privoxy on or off</ulink>
1578 ▪ <ulink
1579 url="https://www.privoxy.org/&p-version;/user-manual/">Documentation</ulink>
1587 This should be self-explanatory. Note the first item leads to an editor for the
1588 <link linkend="actions-file">actions files</link>, which is where the ad, banner,
1589 cookie, and URL blocking magic is configured as well as other advanced features of
1590 <application>Privoxy</application>. This is an easy way to adjust various
1591 aspects of <application>Privoxy</application> configuration. The actions
1592 file, and other configuration files, are explained in detail below.
1596 <quote>Toggle Privoxy On or Off</quote> is handy for sites that might
1597 have problems with your current actions and filters. You can in fact use
1598 it as a test to see whether it is <application>Privoxy</application>
1599 causing the problem or not. <application>Privoxy</application> continues
1600 to run as a proxy in this case, but all manipulation is disabled, i.e.
1601 <application>Privoxy</application> acts like a normal forwarding proxy.
1605 Note that several of the features described above are disabled by default
1606 in <application>Privoxy</application> 3.0.7 beta and later.
1608 <ulink url="config.html">configuration file</ulink> to learn why
1609 and in which cases it's safe to enable them again.
1614 <!-- ~ End section ~ -->
1619 <!-- ~~~~~ New section ~~~~~ -->
1621 <sect2 id="confoverview">
1622 <title>Configuration Files Overview</title>
1624 For Unix, *BSD and GNU/Linux, all configuration files are located in
1625 <filename>/etc/privoxy/</filename> by default. For MS Windows
1626 these are all in the same directory as the
1627 <application>Privoxy</application> executable. <![%p-not-stable;[ The name
1628 and number of configuration files has changed from previous versions, and is
1629 subject to change as development progresses.]]>
1633 The installed defaults provide a reasonable starting point, though
1634 some settings may be aggressive by some standards. For the time being, the
1635 principle configuration files are:
1642 The <link linkend="config">main configuration file</link> is named <filename>config</filename>
1643 on GNU/Linux, Unix, BSD, and <filename>config.txt</filename>
1644 on Windows. This is a required file.
1650 <filename>match-all.action</filename> is used to define which <quote>actions</quote>
1651 relating to banner-blocking, images, pop-ups, content modification, cookie handling
1652 etc should be applied by default. It should be the first actions file loaded.
1655 <filename>default.action</filename> defines many exceptions (both positive and negative)
1656 from the default set of actions that's configured in <filename>match-all.action</filename>.
1657 It should be the second actions file loaded and shouldn't be edited by the user.
1660 Multiple actions files may be defined in <filename>config</filename>. These
1661 are processed in the order they are defined. Local customizations and locally
1662 preferred exceptions to the default policies as defined in
1663 <filename>match-all.action</filename> (which you will most probably want
1664 to define sooner or later) are best applied in <filename>user.action</filename>,
1665 where you can preserve them across upgrades. The file isn't installed by all
1666 installers, but you can easily create it yourself with a text editor.
1669 There is also a web based editor that can be accessed from
1671 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
1673 url="http://p.p/show-status">http://p.p/show-status</ulink>) for the
1674 various actions files.
1680 <quote>Filter files</quote> (the <link linkend="filter-file">filter
1681 file</link>) can be used to re-write the raw page content, including
1682 viewable text as well as embedded HTML and JavaScript, and whatever else
1683 lurks on any given web page. The filtering jobs are only pre-defined here;
1684 whether to apply them or not is up to the actions files.
1685 <filename>default.filter</filename> includes various filters made
1686 available for use by the developers. Some are much more intrusive than
1687 others, and all should be used with caution. You may define additional
1688 filter files in <filename>config</filename> as you can with
1689 actions files. We suggest <filename>user.filter</filename> for any
1690 locally defined filters or customizations.
1697 The syntax of the configuration and filter files may change between different
1698 Privoxy versions, unfortunately some enhancements cost backwards compatibility.
1699 <!-- Add link to documentation-->
1703 All files use the <quote><literal>#</literal></quote> character to denote a
1704 comment (the rest of the line will be ignored) and understand line continuation
1705 through placing a backslash ("<literal>\</literal>") as the very last character
1706 in a line. If the <literal>#</literal> is preceded by a backslash, it looses
1707 its special function. Placing a <literal>#</literal> in front of an otherwise
1708 valid configuration line to prevent it from being interpreted is called "commenting
1709 out" that line. Blank lines are ignored.
1713 The actions files and filter files
1714 can use Perl style <link linkend="regex">regular expressions</link> for
1715 maximum flexibility.
1719 After making any changes, there is no need to restart
1720 <application>Privoxy</application> in order for the changes to take
1721 effect. <application>Privoxy</application> detects such changes
1722 automatically. Note, however, that it may take one or two additional
1723 requests for the change to take effect. When changing the listening address
1724 of <application>Privoxy</application>, these <quote>wake up</quote> requests
1725 must obviously be sent to the <emphasis>old</emphasis> listening address.
1730 While under development, the configuration content is subject to change.
1731 The below documentation may not be accurate by the time you read this.
1732 Also, what constitutes a <quote>default</quote> setting, may change, so
1733 please check all your configuration files on important issues.
1739 <!-- ~ End section ~ -->
1742 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
1744 <!-- **************************************************** -->
1745 <!-- Include config.sgml here -->
1746 <!-- This is where the entire config file is detailed. -->
1748 <!-- end include -->
1751 <!-- ~ End section ~ -->
1755 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
1757 <sect1 id="actions-file"><title>Actions Files</title>
1761 XXX: similar descriptions are in the Configuration Files sections.
1762 We should only describe them at one place.
1765 The actions files are used to define what <emphasis>actions</emphasis>
1766 <application>Privoxy</application> takes for which URLs, and thus determines
1767 how ad images, cookies and various other aspects of HTTP content and
1768 transactions are handled, and on which sites (or even parts thereof).
1769 There are a number of such actions, with a wide range of functionality.
1770 Each action does something a little different.
1771 These actions give us a veritable arsenal of tools with which to exert
1772 our control, preferences and independence. Actions can be combined so that
1773 their effects are aggregated when applied against a given set of URLs.
1777 are three action files included with <application>Privoxy</application> with
1783 <filename>match-all.action</filename> - is used to define which
1784 <quote>actions</quote> relating to banner-blocking, images, pop-ups,
1785 content modification, cookie handling etc should be applied by default.
1786 It should be the first actions file loaded
1791 <filename>default.action</filename> - defines many exceptions (both
1792 positive and negative) from the default set of actions that's configured
1793 in <filename>match-all.action</filename>. It is a set of rules that should
1794 work reasonably well as-is for most users. This file is only supposed to
1795 be edited by the developers. It should be the second actions file loaded.
1800 <filename>user.action</filename> - is intended to be for local site
1801 preferences and exceptions. As an example, if your ISP or your bank
1802 has specific requirements, and need special handling, this kind of
1803 thing should go here. This file will not be upgraded.
1808 <guibutton>Edit</guibutton> <guibutton>Set to Cautious</guibutton> <guibutton>Set to Medium</guibutton> <guibutton>Set to Advanced</guibutton>
1811 These have increasing levels of aggressiveness <emphasis>and have no
1812 influence on your browsing unless you select them explicitly in the
1813 editor</emphasis>. A default installation should be pre-set to
1814 <literal>Cautious</literal>. New users should try this for a while before
1815 adjusting the settings to more aggressive levels. The more aggressive
1816 the settings, then the more likelihood there is of problems such as sites
1817 not working as they should.
1820 The <guibutton>Edit</guibutton> button allows you to turn each
1821 action on/off individually for fine-tuning. The <guibutton>Cautious</guibutton>
1822 button changes the actions list to low/safe settings which will activate
1823 ad blocking and a minimal set of &my-app;'s features, and subsequently
1824 there will be less of a chance for accidental problems. The
1825 <guibutton>Medium</guibutton> button sets the list to a medium level of
1826 other features and a low level set of privacy features. The
1827 <guibutton>Advanced</guibutton> button sets the list to a high level of
1828 ad blocking and medium level of privacy. See the chart below. The latter
1829 three buttons over-ride any changes via with the
1830 <guibutton>Edit</guibutton> button. More fine-tuning can be done in the
1831 lower sections of this internal page.
1834 While the actions file editor allows to enable these settings in all
1835 actions files, they are only supposed to be enabled in the first one
1836 to make sure you don't unintentionally overrule earlier rules.
1839 The default profiles, and their associated actions, as pre-defined in
1840 <filename>default.action</filename> are:
1842 <table frame=all id="default-configurations"><title>Default Configurations</title>
1843 <tgroup cols=4 align=left colsep=1 rowsep=1>
1844 <colspec colname=c1>
1845 <colspec colname=c2>
1846 <colspec colname=c3>
1847 <colspec colname=c4>
1850 <entry>Feature</entry>
1851 <entry>Cautious</entry>
1852 <entry>Medium</entry>
1853 <entry>Advanced</entry>
1858 <!-- <entry>f1</entry> -->
1859 <!-- <entry>f2</entry> -->
1860 <!-- <entry>f3</entry> -->
1861 <!-- <entry>f4</entry> -->
1867 <entry>Ad-blocking Aggressiveness</entry>
1868 <entry>medium</entry>
1874 <entry>Ad-filtering by size</entry>
1881 <entry>Ad-filtering by link</entry>
1887 <entry>Pop-up killing</entry>
1888 <entry>blocks only</entry>
1889 <entry>blocks only</entry>
1890 <entry>blocks only</entry>
1894 <entry>Privacy Features</entry>
1896 <entry>medium</entry>
1897 <entry>medium/high</entry>
1901 <entry>Cookie handling</entry>
1903 <entry>session-only</entry>
1908 <entry>Referer forging</entry>
1915 <entry>GIF de-animation</entry>
1922 <entry>Fast redirects</entry>
1929 <entry>HTML taming</entry>
1936 <entry>JavaScript taming</entry>
1943 <entry>Web-bug killing</entry>
1950 <entry>Image tag reordering</entry>
1964 The list of actions files to be used are defined in the main configuration
1965 file, and are processed in the order they are defined (e.g.
1966 <filename>default.action</filename> is typically processed before
1967 <filename>user.action</filename>). The content of these can all be viewed and
1969 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
1970 The over-riding principle when applying actions, is that the last action that
1971 matches a given URL wins. The broadest, most general rules go first
1972 (defined in <filename>default.action</filename>),
1973 followed by any exceptions (typically also in
1974 <filename>default.action</filename>), which are then followed lastly by any
1975 local preferences (typically in <emphasis>user</emphasis><filename>.action</filename>).
1976 Generally, <filename>user.action</filename> has the last word.
1980 An actions file typically has multiple sections. If you want to use
1981 <quote>aliases</quote> in an actions file, you have to place the (optional)
1982 <link linkend="aliases">alias section</link> at the top of that file.
1983 Then comes the default set of rules which will apply universally to all
1984 sites and pages (be <emphasis>very careful</emphasis> with using such a
1985 universal set in <filename>user.action</filename> or any other actions file after
1986 <filename>default.action</filename>, because it will override the result
1987 from consulting any previous file). And then below that,
1988 exceptions to the defined universal policies. You can regard
1989 <filename>user.action</filename> as an appendix to <filename>default.action</filename>,
1990 with the advantage that it is a separate file, which makes preserving your
1991 personal settings across <application>Privoxy</application> upgrades easier.
1995 Actions can be used to block anything you want, including ads, banners, or
1996 just some obnoxious URL whose content you would rather not see. Cookies can be accepted
1997 or rejected, or accepted only during the current browser session (i.e. not
1998 written to disk), content can be modified, some JavaScripts tamed, user-tracking
1999 fooled, and much more. See below for a <link linkend="actions">complete list
2003 <!-- ~~~~~ New section ~~~~~ -->
2004 <sect2 id="right-mix">
2005 <title>Finding the Right Mix</title>
2007 Note that some <link linkend="actions">actions</link>, like cookie suppression
2008 or script disabling, may render some sites unusable that rely on these
2009 techniques to work properly. Finding the right mix of actions is not always easy and
2010 certainly a matter of personal taste. And, things can always change, requiring
2011 refinements in the configuration. In general, it can be said that the more
2012 <quote>aggressive</quote> your default settings (in the top section of the
2013 actions file) are, the more exceptions for <quote>trusted</quote> sites you
2014 will have to make later. If, for example, you want to crunch all cookies per
2015 default, you'll have to make exceptions from that rule for sites that you
2016 regularly use and that require cookies for actually useful purposes, like maybe
2017 your bank, favorite shop, or newspaper.
2021 We have tried to provide you with reasonable rules to start from in the
2022 distribution actions files. But there is no general rule of thumb on these
2023 things. There just are too many variables, and sites are constantly changing.
2024 Sooner or later you will want to change the rules (and read this chapter again :).
2028 <!-- ~~~~~ New section ~~~~~ -->
2029 <sect2 id="how-to-edit">
2030 <title>How to Edit</title>
2032 The easiest way to edit the actions files is with a browser by
2033 using our browser-based editor, which can be reached from <ulink
2034 url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
2035 Note: the config file option <link
2036 linkend="enable-edit-actions">enable-edit-actions</link> must be enabled for
2037 this to work. The editor allows both fine-grained control over every single
2038 feature on a per-URL basis, and easy choosing from wholesale sets of defaults
2039 like <quote>Cautious</quote>, <quote>Medium</quote> or
2040 <quote>Advanced</quote>. Warning: the <quote>Advanced</quote> setting is more
2041 aggressive, and will be more likely to cause problems for some sites.
2042 Experienced users only!
2046 If you prefer plain text editing to GUIs, you can of course also directly edit the
2047 the actions files with your favorite text editor. Look at
2048 <filename>default.action</filename> which is richly commented with many
2054 <sect2 id="actions-apply">
2055 <title>How Actions are Applied to Requests</title>
2057 Actions files are divided into sections. There are special sections,
2058 like the <quote><link linkend="aliases">alias</link></quote> sections which will
2059 be discussed later. For now let's concentrate on regular sections: They have a
2060 heading line (often split up to multiple lines for readability) which consist
2061 of a list of actions, separated by whitespace and enclosed in curly braces.
2062 Below that, there is a list of URL and tag patterns, each on a separate line.
2066 To determine which actions apply to a request, the URL of the request is
2067 compared to all URL patterns in each <quote>action file</quote>.
2068 Every time it matches, the list of applicable actions for the request is
2069 incrementally updated, using the heading of the section in which the
2070 pattern is located. The same is done again for tags and tag patterns later on.
2074 If multiple applying sections set the same action differently,
2075 the last match wins. If not, the effects are aggregated.
2076 E.g. a URL might match a regular section with a heading line of <literal>{
2077 +<link linkend="handle-as-image">handle-as-image</link> }</literal>,
2078 then later another one with just <literal>{
2079 +<link linkend="block">block</link> }</literal>, resulting
2080 in <emphasis>both</emphasis> actions to apply. And there may well be
2081 cases where you will want to combine actions together. Such a section then
2086 { +<literal>handle-as-image</literal> +<literal>block{Banner ads.}</literal> }
2087 # Block these as if they were images. Send no block page.
2089 media.example.com/.*banners
2090 .example.com/images/ads/</screen>
2093 You can trace this process for URL patterns and any given URL by visiting <ulink
2094 url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>.
2098 Examples and more detail on this is provided in the Appendix, <link linkend="ACTIONSANAT">
2099 Troubleshooting: Anatomy of an Action</link> section.
2103 <!-- ~~~~~ New section ~~~~~ -->
2104 <sect2 id="af-patterns">
2105 <title>Patterns</title>
2107 As mentioned, <application>Privoxy</application> uses <quote>patterns</quote>
2108 to determine what <emphasis>actions</emphasis> might apply to which sites and
2109 pages your browser attempts to access. These <quote>patterns</quote> use wild
2110 card type <emphasis>pattern</emphasis> matching to achieve a high degree of
2111 flexibility. This allows one expression to be expanded and potentially match
2112 against many similar patterns.
2116 Generally, an URL pattern has the form
2117 <literal><host><port>/<path></literal>, where the
2118 <literal><host></literal>, the <literal><port></literal>
2119 and the <literal><path></literal> are optional. (This is why the special
2120 <literal>/</literal> pattern matches all URLs). Note that the protocol
2121 portion of the URL pattern (e.g. <literal>http://</literal>) should
2122 <emphasis>not</emphasis> be included in the pattern. This is assumed already!
2125 The pattern matching syntax is different for the host and path parts of
2126 the URL. The host part uses a simple globbing type matching technique,
2127 while the path part uses more flexible
2128 <ulink url="https://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
2129 Expressions</quote></ulink> (POSIX 1003.2).
2132 The port part of a pattern is a decimal port number preceded by a colon
2133 (<literal>:</literal>). If the host part contains a numerical IPv6 address,
2134 it has to be put into angle brackets
2135 (<literal><</literal>, <literal>></literal>).
2140 <term><literal>www.example.com/</literal></term>
2143 is a host-only pattern and will match any request to <literal>www.example.com</literal>,
2144 regardless of which document on that server is requested. So ALL pages in
2145 this domain would be covered by the scope of this action. Note that a
2146 simple <literal>example.com</literal> is different and would NOT match.
2151 <term><literal>www.example.com</literal></term>
2154 means exactly the same. For host-only patterns, the trailing <literal>/</literal> may
2160 <term><literal>www.example.com/index.html</literal></term>
2163 matches all the documents on <literal>www.example.com</literal>
2164 whose name starts with <literal>/index.html</literal>.
2169 <term><literal>www.example.com/index.html$</literal></term>
2172 matches only the single document <literal>/index.html</literal>
2173 on <literal>www.example.com</literal>.
2178 <term><literal>/index.html$</literal></term>
2181 matches the document <literal>/index.html</literal>, regardless of the domain,
2182 i.e. on <emphasis>any</emphasis> web server anywhere.
2187 <term><literal>/</literal></term>
2190 Matches any URL because there's no requirement for either the
2191 domain or the path to match anything.
2196 <term><literal>:8000/</literal></term>
2199 Matches any URL pointing to TCP port 8000.
2204 <term><literal>10.0.0.1/</literal></term>
2207 Matches any URL with the host address <literal>10.0.0.1</literal>.
2208 (Note that the real URL uses plain brackets, not angle brackets.)
2213 <term><literal><2001:db8::1>/</literal></term>
2216 Matches any URL with the host address <literal>2001:db8::1</literal>.
2217 (Note that the real URL uses plain brackets, not angle brackets.)
2222 <term><literal>index.html</literal></term>
2225 matches nothing, since it would be interpreted as a domain name and
2226 there is no top-level domain called <literal>.html</literal>. So its
2234 <!-- ~~~~~ New section ~~~~~ -->
2235 <sect3 id="host-pattern"><title>The Host Pattern</title>
2238 The matching of the host part offers some flexible options: if the
2239 host pattern starts or ends with a dot, it becomes unanchored at that end.
2240 The host pattern is often referred to as domain pattern as it is usually
2241 used to match domain names and not IP addresses.
2247 <term><literal>.example.com</literal></term>
2250 matches any domain with first-level domain <literal>com</literal>
2251 and second-level domain <literal>example</literal>.
2252 For example <literal>www.example.com</literal>,
2253 <literal>example.com</literal> and <literal>foo.bar.baz.example.com</literal>.
2254 Note that it wouldn't match if the second-level domain was <literal>another-example</literal>.
2259 <term><literal>www.</literal></term>
2262 matches any domain that <emphasis>STARTS</emphasis> with
2263 <literal>www.</literal> (It also matches the domain
2264 <literal>www</literal> but most of the time that doesn't matter.)
2269 <term><literal>.example.</literal></term>
2272 matches any domain that <emphasis>CONTAINS</emphasis> <literal>.example.</literal>.
2273 And, by the way, also included would be any files or documents that exist
2274 within that domain since no path limitations are specified. (Correctly
2275 speaking: It matches any FQDN that contains <literal>example</literal> as
2276 a domain.) This might be <literal>www.example.com</literal>,
2277 <literal>news.example.de</literal>, or
2278 <literal>www.example.net/cgi/testing.pl</literal> for instance. All these
2286 Additionally, there are wild-cards that you can use in the domain names
2287 themselves. These work similarly to shell globbing type wild-cards:
2288 <quote>*</quote> represents zero or more arbitrary characters (this is
2290 <ulink url="https://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
2291 Expression</quote></ulink> based syntax of <quote>.*</quote>),
2292 <quote>?</quote> represents any single character (this is equivalent to the
2293 regular expression syntax of a simple <quote>.</quote>), and you can define
2294 <quote>character classes</quote> in square brackets which is similar to
2295 the same regular expression technique. All of this can be freely mixed:
2300 <term><literal>ad*.example.com</literal></term>
2303 matches <quote>adserver.example.com</quote>,
2304 <quote>ads.example.com</quote>, etc but not <quote>sfads.example.com</quote>
2309 <term><literal>*ad*.example.com</literal></term>
2312 matches all of the above, and then some.
2317 <term><literal>.?pix.com</literal></term>
2320 matches <literal>www.ipix.com</literal>,
2321 <literal>pictures.epix.com</literal>, <literal>a.b.c.d.e.upix.com</literal> etc.
2326 <term><literal>www[1-9a-ez].example.c*</literal></term>
2329 matches <literal>www1.example.com</literal>,
2330 <literal>www4.example.cc</literal>, <literal>wwwd.example.cy</literal>,
2331 <literal>wwwz.example.com</literal> etc., but <emphasis>not</emphasis>
2332 <literal>wwww.example.com</literal>.
2339 While flexible, this is not the sophistication of full regular expression based syntax.
2343 When compiled with FEATURE_PCRE_HOST_PATTERNS patterns can be prefixed with
2344 <quote>PCRE-HOST-PATTERN:</quote> in which case full regular expression
2345 (PCRE) can be used for the host pattern as well.
2350 <!-- ~ End section ~ -->
2353 <!-- ~~~~~ New section ~~~~~ -->
2354 <sect3 id="path-pattern"><title>The Path Pattern</title>
2357 <application>Privoxy</application> uses <quote>modern</quote> POSIX 1003.2
2358 <ulink url="https://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
2359 Expressions</quote></ulink> for matching the path portion (after the slash),
2360 and is thus more flexible.
2364 There is an <link linkend="regex">Appendix</link> with a brief quick-start into regular
2365 expressions, you also might want to have a look at your operating system's documentation
2366 on regular expressions (try <literal>man re_format</literal>).
2370 Note that the path pattern is automatically left-anchored at the <quote>/</quote>,
2371 i.e. it matches as if it would start with a <quote>^</quote> (regular expression speak
2372 for the beginning of a line).
2376 Please also note that matching in the path is <emphasis>CASE INSENSITIVE</emphasis>
2377 by default, but you can switch to case sensitive at any point in the pattern by using the
2378 <quote>(?-i)</quote> switch: <literal>www.example.com/(?-i)PaTtErN.*</literal> will match
2379 only documents whose path starts with <literal>PaTtErN</literal> in
2380 <emphasis>exactly</emphasis> this capitalization.
2385 <term><literal>.example.com/.*</literal></term>
2388 Is equivalent to just <quote>.example.com</quote>, since any documents
2389 within that domain are matched with or without the <quote>.*</quote>
2390 regular expression. This is redundant
2395 <term><literal>.example.com/.*/index.html$</literal></term>
2398 Will match any page in the domain of <quote>example.com</quote> that is
2399 named <quote>index.html</quote>, and that is part of some path. For
2400 example, it matches <quote>www.example.com/testing/index.html</quote> but
2401 NOT <quote>www.example.com/index.html</quote> because the regular
2402 expression called for at least two <quote>/'s</quote>, thus the path
2403 requirement. It also would match
2404 <quote>www.example.com/testing/index_html</quote>, because of the
2405 special meta-character <quote>.</quote>.
2410 <term><literal>.example.com/(.*/)?index\.html$</literal></term>
2413 This regular expression is conditional so it will match any page
2414 named <quote>index.html</quote> regardless of path which in this case can
2415 have one or more <quote>/'s</quote>. And this one must contain exactly
2416 <quote>.html</quote> (and end with that!).
2421 <term><literal>.example.com/(.*/)(ads|banners?|junk)</literal></term>
2424 This regular expression will match any path of <quote>example.com</quote>
2425 that contains any of the words <quote>ads</quote>, <quote>banner</quote>,
2426 <quote>banners</quote> (because of the <quote>?</quote>) or <quote>junk</quote>.
2427 The path does not have to end in these words, just contain them.
2428 The path has to contain at least two slashes (including the one at the beginning).
2433 <term><literal>.example.com/(.*/)(ads|banners?|junk)/.*\.(jpe?g|gif|png)$</literal></term>
2436 This is very much the same as above, except now it must end in either
2437 <quote>.jpg</quote>, <quote>.jpeg</quote>, <quote>.gif</quote> or <quote>.png</quote>. So this
2438 one is limited to common image formats.
2445 There are many, many good examples to be found in <filename>default.action</filename>,
2446 and more tutorials below in <link linkend="regex">Appendix on regular expressions</link>.
2451 <!-- ~ End section ~ -->
2454 <!-- ~~~~~ New section ~~~~~ -->
2455 <sect3 id="tag-pattern"><title>The Request Tag Pattern</title>
2458 Request tag patterns are used to change the applying actions based on the
2459 request's tags. Tags can be created based on HTTP headers with either
2460 the <link linkend="CLIENT-HEADER-TAGGER">client-header-tagger</link>
2461 or the <link linkend="SERVER-HEADER-TAGGER">server-header-tagger</link> action.
2465 Request tag patterns have to start with <quote>TAG:</quote>, so &my-app;
2466 can tell them apart from other patterns. Everything after the colon
2467 including white space, is interpreted as a regular expression with
2468 path pattern syntax, except that tag patterns aren't left-anchored
2469 automatically (&my-app; doesn't silently add a <quote>^</quote>,
2470 you have to do it yourself if you need it).
2474 To match all requests that are tagged with <quote>foo</quote>
2475 your pattern line should be <quote>TAG:^foo$</quote>,
2476 <quote>TAG:foo</quote> would work as well, but it would also
2477 match requests whose tags contain <quote>foo</quote> somewhere.
2478 <quote>TAG: foo</quote> wouldn't work as it requires white space.
2482 Sections can contain URL and request tag patterns at the same time,
2483 but request tag patterns are checked after the URL patterns and thus
2484 always overrule them, even if they are located before the URL patterns.
2488 Once a new request tag is added, Privoxy checks right away if it's matched by one
2489 of the request tag patterns and updates the action settings accordingly. As a result
2490 request tags can be used to activate other tagger actions, as long as these other
2491 taggers look for headers that haven't already be parsed.
2495 For example you could tag client requests which use the
2496 <literal>POST</literal> method,
2497 then use this tag to activate another tagger that adds a tag if cookies
2498 are sent, and then use a block action based on the cookie tag. This allows
2499 the outcome of one action, to be input into a subsequent action. However if
2500 you'd reverse the position of the described taggers, and activated the
2501 method tagger based on the cookie tagger, no method tags would be created.
2502 The method tagger would look for the request line, but at the time
2503 the cookie tag is created, the request line has already been parsed.
2507 While this is a limitation you should be aware of, this kind of
2508 indirection is seldom needed anyway and even the example doesn't
2509 make too much sense.
2514 <!-- ~~~~~ New section ~~~~~ -->
2515 <sect3 id="negative-tag-patterns"><title>The Negative Request Tag Patterns</title>
2518 To match requests that do not have a certain request tag, specify a negative tag pattern
2519 by prefixing the tag pattern line with either <quote>NO-REQUEST-TAG:</quote>
2520 or <quote>NO-RESPONSE-TAG:</quote> instead of <quote>TAG:</quote>.
2524 Negative request tag patterns created with <quote>NO-REQUEST-TAG:</quote> are checked
2525 after all client headers are scanned, the ones created with <quote>NO-RESPONSE-TAG:</quote>
2526 are checked after all server headers are scanned. In both cases all the created
2527 tags are considered.
2531 <!-- ~~~~~ New section ~~~~~ -->
2532 <sect3 id="client-tag-pattern"><title>The Client Tag Pattern</title>
2534 <!-- XXX: This section contains duplicates content from the
2535 client-specific-tag documentation. -->
2539 This is an experimental feature. The syntax is likely to change in future versions.
2544 Client tag patterns are not set based on HTTP headers but based on
2545 the client's IP address. Users can enable them themselves, but the
2546 Privoxy admin controls which tags are available and what their effect
2551 After a client-specific tag has been defined with the
2552 <link linkend="client-specific-tag">client-specific-tag</link>,
2553 directive, action sections can be activated based on the tag by using a
2554 CLIENT-TAG pattern. The CLIENT-TAG pattern is evaluated at the same priority
2555 as URL patterns, as a result the last matching pattern wins. Tags that
2556 are created based on client or server headers are evaluated later on
2557 and can overrule CLIENT-TAG and URL patterns!
2560 The tag is set for all requests that come from clients that requested
2561 it to be set. Note that "clients" are differentiated by IP address,
2562 if the IP address changes the tag has to be requested again.
2565 Clients can request tags to be set by using the CGI interface <ulink
2566 url="http://config.privoxy.org/client-tags">http://config.privoxy.org/client-tags</ulink>.
2574 # If the admin defined the client-specific-tag circumvent-blocks,
2575 # and the request comes from a client that previously requested
2576 # the tag to be set, overrule all previous +block actions that
2577 # are enabled based on URL to CLIENT-TAG patterns.
2579 CLIENT-TAG:^circumvent-blocks$
2581 # This section is not overruled because it's located after
2583 {+block{Nobody is supposed to request this.}}
2584 example.org/blocked-example-page</screen>
2590 <!-- ~ End section ~ -->
2593 <!-- ~~~~~ New section ~~~~~ -->
2595 <sect2 id="actions">
2596 <title>Actions</title>
2598 All actions are disabled by default, until they are explicitly enabled
2599 somewhere in an actions file. Actions are turned on if preceded with a
2600 <quote>+</quote>, and turned off if preceded with a <quote>-</quote>. So a
2601 <literal>+action</literal> means <quote>do that action</quote>, e.g.
2602 <literal>+block</literal> means <quote>please block URLs that match the
2603 following patterns</quote>, and <literal>-block</literal> means <quote>don't
2604 block URLs that match the following patterns, even if <literal>+block</literal>
2605 previously applied.</quote>
2609 Again, actions are invoked by placing them on a line, enclosed in curly braces and
2610 separated by whitespace, like in
2611 <literal>{+some-action -some-other-action{some-parameter}}</literal>,
2612 followed by a list of URL patterns, one per line, to which they apply.
2613 Together, the actions line and the following pattern lines make up a section
2614 of the actions file.
2618 Actions fall into three categories:
2624 Boolean, i.e the action can only be <quote>enabled</quote> or
2625 <quote>disabled</quote>. Syntax:
2628 +<replaceable class="function">name</replaceable> # enable action <replaceable class="parameter">name</replaceable>
2629 -<replaceable class="function">name</replaceable> # disable action <replaceable class="parameter">name</replaceable></screen>
2631 Example: <literal>+handle-as-image</literal>
2638 Parameterized, where some value is required in order to enable this type of action.
2642 +<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # enable action and set parameter to <replaceable class="parameter">param</replaceable>,
2643 # overwriting parameter from previous match if necessary
2644 -<replaceable class="function">name</replaceable> # disable action. The parameter can be omitted</screen>
2646 Note that if the URL matches multiple positive forms of a parameterized action,
2647 the last match wins, i.e. the params from earlier matches are simply ignored.
2650 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>
2656 Multi-value. These look exactly like parameterized actions,
2657 but they behave differently: If the action applies multiple times to the
2658 same URL, but with different parameters, <emphasis>all</emphasis> the parameters
2659 from <emphasis>all</emphasis> matches are remembered. This is used for actions
2660 that can be executed for the same request repeatedly, like adding multiple
2661 headers, or filtering through multiple filters. Syntax:
2664 +<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # enable action and add <replaceable class="parameter">param</replaceable> to the list of parameters
2665 -<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # remove the parameter <replaceable class="parameter">param</replaceable> from the list of parameters
2666 # If it was the last one left, disable the action.
2667 <replaceable class="parameter">-name</replaceable> # disable this action completely and remove all parameters from the list</screen>
2669 Examples: <literal>+add-header{X-Fun-Header: Some text}</literal> and
2670 <literal>+filter{html-annoyances}</literal>
2677 If nothing is specified in any actions file, no <quote>actions</quote> are
2678 taken. So in this case <application>Privoxy</application> would just be a
2679 normal, non-blocking, non-filtering proxy. You must specifically enable the
2680 privacy and blocking features you need (although the provided default actions
2681 files will give a good starting point).
2685 Later defined action sections always over-ride earlier ones of the same type.
2686 So exceptions to any rules you make, should come in the latter part of the file (or
2687 in a file that is processed later when using multiple actions files such
2688 as <filename>user.action</filename>). For multi-valued actions, the actions
2689 are applied in the order they are specified. Actions files are processed in
2690 the order they are defined in <filename>config</filename> (the default
2691 installation has three actions files). It also quite possible for any given
2692 URL to match more than one <quote>pattern</quote> (because of wildcards and
2693 regular expressions), and thus to trigger more than one set of actions! Last
2697 <!-- start actions listing -->
2699 The list of valid <application>Privoxy</application> actions are:
2703 <!-- ********************************************************** -->
2704 <!-- Please note the below defined actions use id's that are -->
2705 <!-- probably linked from other places, so please don't change. -->
2707 <!-- ********************************************************** -->
2710 <!-- ~~~~~ New section ~~~~~ -->
2712 <sect3 renderas="sect4" id="add-header">
2713 <title>add-header</title>
2717 <term>Typical use:</term>
2719 <para>Confuse log analysis, custom applications</para>
2724 <term>Effect:</term>
2727 Sends a user defined HTTP header to the web server.
2734 <!-- boolean, parameterized, Multi-value -->
2736 <para>Multi-value.</para>
2741 <term>Parameter:</term>
2744 Any string value is possible. Validity of the defined HTTP headers is not checked.
2745 It is recommended that you use the <quote><literal>X-</literal></quote> prefix
2755 This action may be specified multiple times, in order to define multiple
2756 headers. This is rarely needed for the typical user. If you don't know what
2757 <quote>HTTP headers</quote> are, you definitely don't need to worry about this
2761 Headers added by this action are not modified by other actions.
2767 <term>Example usage:</term>
2769 <screen># Add a DNT ("Do not track") header to all requests,
2770 # event to those that already have one.
2772 # This is just an example, not a recommendation.
2774 # There is no reason to believe that user-tracking websites care
2775 # about the DNT header and depending on the User-Agent, adding the
2776 # header may make user-tracking easier.
2777 {+add-header{DNT: 1}}
2785 <!-- ~~~~~ New section ~~~~~ -->
2786 <sect3 renderas="sect4" id="block">
2787 <title>block</title>
2791 <term>Typical use:</term>
2793 <para>Block ads or other unwanted content</para>
2798 <term>Effect:</term>
2801 Requests for URLs to which this action applies are blocked, i.e. the
2802 requests are trapped by &my-app; and the requested URL is never retrieved,
2803 but is answered locally with a substitute page or image, as determined by
2805 linkend="handle-as-image">handle-as-image</link></literal>,
2807 linkend="set-image-blocker">set-image-blocker</link></literal>, and
2809 linkend="handle-as-empty-document">handle-as-empty-document</link></literal> actions.
2817 <!-- boolean, parameterized, Multi-value -->
2819 <para>Parameterized.</para>
2824 <term>Parameter:</term>
2826 <para>A block reason that should be given to the user.</para>
2834 <application>Privoxy</application> sends a special <quote>BLOCKED</quote> page
2835 for requests to blocked pages. This page contains the block reason given as
2836 parameter, a link to find out why the block action applies, and a click-through
2837 to the blocked content (the latter only if the force feature is available and
2841 A very important exception occurs if <emphasis>both</emphasis>
2842 <literal>block</literal> and <literal><link linkend="handle-as-image">handle-as-image</link></literal>,
2843 apply to the same request: it will then be replaced by an image. If
2844 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>
2845 (see below) also applies, the type of image will be determined by its parameter,
2846 if not, the standard checkerboard pattern is sent.
2849 It is important to understand this process, in order
2850 to understand how <application>Privoxy</application> deals with
2851 ads and other unwanted content. Blocking is a core feature, and one
2852 upon which various other features depend.
2855 The <literal><link linkend="filter">filter</link></literal>
2856 action can perform a very similar task, by <quote>blocking</quote>
2857 banner images and other content through rewriting the relevant URLs in the
2858 document's HTML source, so they don't get requested in the first place.
2859 Note that this is a totally different technique, and it's easy to confuse the two.
2865 <term>Example usage (section):</term>
2867 <screen>{+block{No nasty stuff for you.}}
2868 # Block and replace with "blocked" page
2869 .nasty-stuff.example.com
2871 {+block{Doubleclick banners.} +handle-as-image}
2872 # Block and replace with image
2876 {+block{Layered ads.} +handle-as-empty-document}
2877 # Block and then ignore
2878 adserver.example.net/.*\.js$</screen>
2887 <!-- ~~~~~ New section ~~~~~ -->
2888 <sect3 renderas="sect4" id="change-x-forwarded-for">
2889 <title>change-x-forwarded-for</title>
2893 <term>Typical use:</term>
2895 <para>Improve privacy by not forwarding the source of the request in the HTTP headers.</para>
2900 <term>Effect:</term>
2903 Deletes the <quote>X-Forwarded-For:</quote> HTTP header from the client request,
2911 <!-- Boolean, Parameterized, Multi-value -->
2913 <para>Parameterized.</para>
2918 <term>Parameter:</term>
2922 <para><quote>block</quote> to delete the header.</para>
2926 <quote>add</quote> to create the header (or append
2927 the client's IP address to an already existing one).
2938 It is safe and recommended to use <literal>block</literal>.
2941 Forwarding the source address of the request may make
2942 sense in some multi-user setups but is also a privacy risk.
2947 <term>Example usage:</term>
2949 <screen>+change-x-forwarded-for{block}</screen>
2955 <!-- ~~~~~ New section ~~~~~ -->
2956 <sect3 renderas="sect4" id="client-header-filter">
2957 <title>client-header-filter</title>
2961 <term>Typical use:</term>
2964 Rewrite or remove single client headers.
2970 <term>Effect:</term>
2973 All client headers to which this action applies are filtered on-the-fly through
2974 the specified regular expression based substitutions.
2981 <!-- boolean, parameterized, Multi-value -->
2983 <para>Multi-value.</para>
2988 <term>Parameter:</term>
2991 The name of a client-header filter, as defined in one of the
2992 <link linkend="filter-file">filter files</link>.
3001 Client-header filters are applied to each header on its own, not to
3002 all at once. This makes it easier to diagnose problems, but on the downside
3003 you can't write filters that only change header x if header y's value is z.
3004 You can do that by using tags though.
3007 Client-header filters are executed after the other header actions have finished
3008 and use their output as input.
3011 If the request URI gets changed, &my-app; will detect that and use the new
3012 one. This can be used to rewrite the request destination behind the client's
3013 back, for example to specify a Tor exit relay for certain requests.
3016 Note that to change the destination host for
3017 <link linkend="HTTPS-INSPECTION">https-inspected</link>
3018 requests a protocol and host has to be added to the URI.
3021 If <link linkend="HTTPS-INSPECTION">https inspection</link>
3022 is enabled, the protocol can be downgraded from https to http
3023 but upgrading a request from http to https is currently not
3027 After detecting a rewrite, &my-app; does not update the actions
3028 used for the request based on the new host.
3031 Please refer to the <link linkend="filter-file">filter file chapter</link>
3032 to learn which client-header filters are available by default, and how to
3040 <term>Example usage (section):</term>
3043 # Hide Tor exit notation in Host and Referer Headers
3044 {+client-header-filter{hide-tor-exit-notation}}
3053 <!-- ~~~~~ New section ~~~~~ -->
3054 <sect3 renderas="sect4" id="client-body-filter">
3055 <title>client-body-filter</title>
3059 <term>Typical use:</term>
3062 Rewrite or remove client request body.
3068 <term>Effect:</term>
3071 All request bodies to which this action applies are filtered on-the-fly through
3072 the specified regular expression based substitutions.
3079 <!-- boolean, parameterized, Multi-value -->
3081 <para>Multi-value.</para>
3086 <term>Parameter:</term>
3089 The name of a client-body filter, as defined in one of the
3090 <link linkend="filter-file">filter files</link>.
3099 Please refer to the <link linkend="filter-file">filter file chapter</link>
3100 to learn how to create your own client-body filters.
3103 The distribution <filename>default.filter</filename> file contains a selection of
3104 client-body filters for example purposes.
3107 The amount of data that can be filtered is limited by the
3108 <literal><link linkend="buffer-limit">buffer-limit</link></literal>
3109 option in the main <link linkend="config">config file</link>. The
3110 default is 4096 KB (4 Megs). Once this limit is exceeded, the whole
3111 request body is passed through unfiltered.
3117 <term>Example usage (section):</term>
3120 # Remove "test" everywhere in the request body
3121 {+client-body-filter{remove-test}}
3131 <!-- ~~~~~ New section ~~~~~ -->
3132 <sect3 renderas="sect4" id="client-header-tagger">
3133 <title>client-header-tagger</title>
3137 <term>Typical use:</term>
3140 Block requests based on their headers.
3146 <term>Effect:</term>
3149 Client headers to which this action applies are filtered on-the-fly through
3150 the specified regular expression based substitutions, the result is used as
3158 <!-- boolean, parameterized, Multi-value -->
3160 <para>Multi-value.</para>
3165 <term>Parameter:</term>
3168 The name of a client-header tagger, as defined in one of the
3169 <link linkend="filter-file">filter files</link>.
3178 Client-header taggers are applied to each header on its own,
3179 and as the header isn't modified, each tagger <quote>sees</quote>
3183 Client-header taggers are the first actions that are executed
3184 and their tags can be used to control every other action.
3190 <term>Example usage (section):</term>
3193 # Tag every request with the User-Agent header
3194 {+client-header-tagger{user-agent}}
3197 # Tagging itself doesn't change the action
3198 # settings, sections with TAG patterns do:
3200 # If it's a download agent, use a different forwarding proxy,
3201 # show the real User-Agent and make sure resume works.
3202 {+forward-override{forward-socks5 10.0.0.2:2222 .} \
3203 -hide-if-modified-since \
3204 -overwrite-last-modified \
3209 TAG:^User-Agent: NetBSD-ftp/
3210 TAG:^User-Agent: Novell ZYPP Installer
3211 TAG:^User-Agent: RPM APT-HTTP/
3212 TAG:^User-Agent: fetch libfetch/
3213 TAG:^User-Agent: Ubuntu APT-HTTP/
3214 TAG:^User-Agent: MPlayer/
3218 # Tag all requests with the Range header set
3219 {+client-header-tagger{range-requests}}
3222 # Disable filtering for the tagged requests.
3224 # With filtering enabled Privoxy would remove the Range headers
3225 # to be able to filter the whole response. The downside is that
3226 # it prevents clients from resuming downloads or skipping over
3227 # parts of multimedia files.
3228 {-filter -deanimate-gifs}
3233 # Tag all requests with the client IP address
3235 # (Technically the client IP address isn't included in the
3236 # client headers but client-header taggers can set it anyway.
3237 # For details see the tagger in default.filter)
3238 {+client-header-tagger{client-ip-address}}
3241 # Change forwarding settings for requests coming from address 10.0.0.1
3242 {+forward-override{forward-socks5 127.0.1.2:2222 .}}
3243 TAG:^IP-ADDRESS: 10\.0\.0\.1$
3252 <!-- ~~~~~ New section ~~~~~ -->
3253 <sect3 renderas="sect4" id="content-type-overwrite">
3254 <title>content-type-overwrite</title>
3258 <term>Typical use:</term>
3260 <para>Stop useless download menus from popping up, or change the browser's rendering mode</para>
3265 <term>Effect:</term>
3268 Replaces the <quote>Content-Type:</quote> HTTP server header.
3275 <!-- Boolean, Parameterized, Multi-value -->
3277 <para>Parameterized.</para>
3282 <term>Parameter:</term>
3294 The <quote>Content-Type:</quote> HTTP server header is used by the
3295 browser to decide what to do with the document. The value of this
3296 header can cause the browser to open a download menu instead of
3297 displaying the document by itself, even if the document's format is
3298 supported by the browser.
3301 The declared content type can also affect which rendering mode
3302 the browser chooses. If XHTML is delivered as <quote>text/html</quote>,
3303 many browsers treat it as yet another broken HTML document.
3304 If it is send as <quote>application/xml</quote>, browsers with
3305 XHTML support will only display it, if the syntax is correct.
3308 If you see a web site that proudly uses XHTML buttons, but sets
3309 <quote>Content-Type: text/html</quote>, you can use &my-app;
3310 to overwrite it with <quote>application/xml</quote> and validate
3311 the web master's claim inside your XHTML-supporting browser.
3312 If the syntax is incorrect, the browser will complain loudly.
3315 You can also go the opposite direction: if your browser prints
3316 error messages instead of rendering a document falsely declared
3317 as XHTML, you can overwrite the content type with
3318 <quote>text/html</quote> and have it rendered as broken HTML document.
3321 By default <literal>content-type-overwrite</literal> only replaces
3322 <quote>Content-Type:</quote> headers that look like some kind of text.
3323 If you want to overwrite it unconditionally, you have to combine it with
3324 <literal><link linkend="force-text-mode">force-text-mode</link></literal>.
3325 This limitation exists for a reason, think twice before circumventing it.
3328 Most of the time it's easier to replace this action with a custom
3329 <literal><link linkend="server-header-filter">server-header filter</link></literal>.
3330 It allows you to activate it for every document of a certain site and it will still
3331 only replace the content types you aimed at.
3334 Of course you can apply <literal>content-type-overwrite</literal>
3335 to a whole site and then make URL based exceptions, but it's a lot
3336 more work to get the same precision.
3342 <term>Example usage (sections):</term>
3344 <screen># Check if www.example.net/ really uses valid XHTML
3345 { +content-type-overwrite{application/xml} }
3348 # but leave the content type unmodified if the URL looks like a style sheet
3349 {-content-type-overwrite}
3350 www.example.net/.*\.css$
3351 www.example.net/.*style
3359 <!-- ~~~~~ New section ~~~~~ -->
3360 <sect3 renderas="sect4" id="crunch-client-header">
3364 <title>crunch-client-header</title>
3368 <term>Typical use:</term>
3370 <para>Remove a client header <application>Privoxy</application> has no dedicated action for.</para>
3375 <term>Effect:</term>
3378 Deletes every header sent by the client that contains the string the user supplied as parameter.
3385 <!-- Boolean, Parameterized, Multi-value -->
3387 <para>Parameterized.</para>
3392 <term>Parameter:</term>
3404 This action allows you to block client headers for which no dedicated
3405 <application>Privoxy</application> action exists.
3406 <application>Privoxy</application> will remove every client header that
3407 contains the string you supplied as parameter.
3410 Regular expressions are <emphasis>not supported</emphasis> and you can't
3411 use this action to block different headers in the same request, unless
3412 they contain the same string.
3415 <literal>crunch-client-header</literal> is only meant for quick tests.
3416 If you have to block several different headers, or only want to modify
3417 parts of them, you should use a
3418 <literal><link linkend="client-header-filter">client-header filter</link></literal>.
3422 Don't block any header without understanding the consequences.
3429 <term>Example usage (section):</term>
3431 <screen># Block the non-existent "Privacy-Violation:" client header
3432 { +crunch-client-header{Privacy-Violation:} }
3441 <!-- ~~~~~ New section ~~~~~ -->
3442 <sect3 renderas="sect4" id="crunch-if-none-match">
3443 <title>crunch-if-none-match</title>
3449 <term>Typical use:</term>
3451 <para>Prevent yet another way to track the user's steps between sessions.</para>
3456 <term>Effect:</term>
3459 Deletes the <quote>If-None-Match:</quote> HTTP client header.
3466 <!-- Boolean, Parameterized, Multi-value -->
3468 <para>Boolean.</para>
3473 <term>Parameter:</term>
3485 Removing the <quote>If-None-Match:</quote> HTTP client header
3486 is useful for filter testing, where you want to force a real
3487 reload instead of getting status code <quote>304</quote> which
3488 would cause the browser to use a cached copy of the page.
3491 It is also useful to make sure the header isn't used as a cookie
3492 replacement (unlikely but possible).
3495 Blocking the <quote>If-None-Match:</quote> header shouldn't cause any
3496 caching problems, as long as the <quote>If-Modified-Since:</quote> header
3497 isn't blocked or missing as well.
3500 It is recommended to use this action together with
3501 <literal><link linkend="hide-if-modified-since">hide-if-modified-since</link></literal>
3503 <literal><link linkend="overwrite-last-modified">overwrite-last-modified</link></literal>.
3509 <term>Example usage (section):</term>
3511 <screen># Let the browser revalidate cached documents but don't
3512 # allow the server to use the revalidation headers for user tracking.
3513 {+hide-if-modified-since{-60} \
3514 +overwrite-last-modified{randomize} \
3515 +crunch-if-none-match}
3524 <!-- ~~~~~ New section ~~~~~ -->
3525 <sect3 renderas="sect4" id="crunch-incoming-cookies">
3526 <title>crunch-incoming-cookies</title>
3530 <term>Typical use:</term>
3533 Prevent the web server from setting HTTP cookies on your system
3539 <term>Effect:</term>
3542 Deletes any <quote>Set-Cookie:</quote> HTTP headers from server replies.
3549 <!-- Boolean, Parameterized, Multi-value -->
3551 <para>Boolean.</para>
3556 <term>Parameter:</term>
3568 This action is only concerned with <emphasis>incoming</emphasis> HTTP cookies. For
3569 <emphasis>outgoing</emphasis> HTTP cookies, use
3570 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>.
3571 Use <emphasis>both</emphasis> to disable HTTP cookies completely.
3574 It makes <emphasis>no sense at all</emphasis> to use this action in conjunction
3575 with the <literal><link linkend="session-cookies-only">session-cookies-only</link></literal> action,
3576 since it would prevent the session cookies from being set. See also
3577 <literal><link linkend="filter-content-cookies">filter-content-cookies</link></literal>.
3583 <term>Example usage:</term>
3585 <screen>+crunch-incoming-cookies</screen>
3592 <!-- ~~~~~ New section ~~~~~ -->
3593 <sect3 renderas="sect4" id="crunch-server-header">
3594 <title>crunch-server-header</title>
3600 <term>Typical use:</term>
3602 <para>Remove a server header <application>Privoxy</application> has no dedicated action for.</para>
3607 <term>Effect:</term>
3610 Deletes every header sent by the server that contains the string the user supplied as parameter.
3617 <!-- Boolean, Parameterized, Multi-value -->
3619 <para>Parameterized.</para>
3624 <term>Parameter:</term>
3636 This action allows you to block server headers for which no dedicated
3637 <application>Privoxy</application> action exists. <application>Privoxy</application>
3638 will remove every server header that contains the string you supplied as parameter.
3641 Regular expressions are <emphasis>not supported</emphasis> and you can't
3642 use this action to block different headers in the same request, unless
3643 they contain the same string.
3646 <literal>crunch-server-header</literal> is only meant for quick tests.
3647 If you have to block several different headers, or only want to modify
3648 parts of them, you should use a custom
3649 <literal><link linkend="server-header-filter">server-header filter</link></literal>.
3653 Don't block any header without understanding the consequences.
3660 <term>Example usage (section):</term>
3662 <screen># Crunch server headers that try to prevent caching
3663 { +crunch-server-header{no-cache} }
3672 <!-- ~~~~~ New section ~~~~~ -->
3673 <sect3 renderas="sect4" id="crunch-outgoing-cookies">
3674 <title>crunch-outgoing-cookies</title>
3678 <term>Typical use:</term>
3681 Prevent the web server from reading any HTTP cookies from your system
3687 <term>Effect:</term>
3690 Deletes any <quote>Cookie:</quote> HTTP headers from client requests.
3697 <!-- Boolean, Parameterized, Multi-value -->
3699 <para>Boolean.</para>
3704 <term>Parameter:</term>
3716 This action is only concerned with <emphasis>outgoing</emphasis> HTTP cookies. For
3717 <emphasis>incoming</emphasis> HTTP cookies, use
3718 <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal>.
3719 Use <emphasis>both</emphasis> to disable HTTP cookies completely.
3722 It makes <emphasis>no sense at all</emphasis> to use this action in conjunction
3723 with the <literal><link linkend="session-cookies-only">session-cookies-only</link></literal> action,
3724 since it would prevent the session cookies from being read.
3730 <term>Example usage:</term>
3732 <screen>+crunch-outgoing-cookies</screen>
3740 <!-- ~~~~~ New section ~~~~~ -->
3741 <sect3 renderas="sect4" id="deanimate-gifs">
3742 <title>deanimate-gifs</title>
3746 <term>Typical use:</term>
3748 <para>Stop those annoying, distracting animated GIF images.</para>
3753 <term>Effect:</term>
3756 De-animate GIF animations, i.e. reduce them to their first or last image.
3763 <!-- boolean, parameterized, Multi-value -->
3765 <para>Parameterized.</para>
3770 <term>Parameter:</term>
3773 <quote>last</quote> or <quote>first</quote>
3782 This will also shrink the images considerably (in bytes, not pixels!). If
3783 the option <quote>first</quote> is given, the first frame of the animation
3784 is used as the replacement. If <quote>last</quote> is given, the last
3785 frame of the animation is used instead, which probably makes more sense for
3786 most banner animations, but also has the risk of not showing the entire
3787 last frame (if it is only a delta to an earlier frame).
3790 You can safely use this action with patterns that will also match non-GIF
3791 objects, because no attempt will be made at anything that doesn't look like
3798 <term>Example usage:</term>
3800 <screen>+deanimate-gifs{last}</screen>
3807 <!-- ~~~~~ New section ~~~~~ -->
3808 <sect3 renderas="sect4" id="delay-response">
3809 <title>delay-response</title>
3813 <term>Typical use:</term>
3815 <para>Delay responses to the client to reduce the load</para>
3820 <term>Effect:</term>
3823 Delays responses to the client by sending the response in ca. 10 byte chunks.
3830 <!-- boolean, parameterized, Multi-value -->
3832 <para>Parameterized.</para>
3837 <term>Parameter:</term>
3840 <quote>Number of milliseconds</quote>
3849 Sometimes when JavaScript code is used to fetch advertisements
3850 it doesn't respect Privoxy's blocks and retries to fetch the
3851 same resource again causing unnecessary load on the client.
3854 This action delays responses to the client and can be combined
3855 with <literal><link linkend="block">blocks</link></literal>
3856 to slow down the JavaScript code, thus reducing
3857 the load on the client.
3860 When used without <literal><link linkend="block">blocks</link></literal>
3861 the action can also be used to simulate a slow internet connection.
3867 <term>Example usage:</term>
3869 <screen>+delay-response{100}</screen>
3876 <!-- ~~~~~ New section ~~~~~ -->
3877 <sect3 renderas="sect4" id="downgrade-http-version">
3878 <title>downgrade-http-version</title>
3882 <term>Typical use:</term>
3884 <para>Work around (very rare) problems with HTTP/1.1</para>
3889 <term>Effect:</term>
3892 Downgrades HTTP/1.1 client requests and server replies to HTTP/1.0.
3899 <!-- boolean, parameterized, Multi-value -->
3901 <para>Boolean.</para>
3906 <term>Parameter:</term>
3918 This is a left-over from the time when <application>Privoxy</application>
3919 didn't support important HTTP/1.1 features well. It is left here for the
3920 unlikely case that you experience HTTP/1.1-related problems with some server
3924 Note that enabling this action is only a workaround. It should not
3925 be enabled for sites that work without it. While it shouldn't break
3926 any pages, it has an (usually negative) performance impact.
3929 If you come across a site where enabling this action helps, please report it,
3930 so the cause of the problem can be analyzed. If the problem turns out to be
3931 caused by a bug in <application>Privoxy</application> it should be
3932 fixed so the following release works without the work around.
3938 <term>Example usage (section):</term>
3940 <screen>{+downgrade-http-version}
3941 problem-host.example.com</screen>
3949 <!-- ~~~~~ New section ~~~~~ -->
3950 <sect3 renderas="sect4" id="external-filter">
3951 <title>external-filter</title>
3955 <term>Typical use:</term>
3957 <para>Modify content using a programming language of your choice.</para>
3962 <term>Effect:</term>
3965 All instances of text-based type, most notably HTML and JavaScript, to which
3966 this action applies, can be filtered on-the-fly through the specified external
3968 By default plain text documents are exempted from filtering, because web
3969 servers often use the <literal>text/plain</literal> MIME type for all files
3970 whose type they don't know.)
3977 <!-- boolean, parameterized, Multi-value -->
3979 <para>Multi-value.</para>
3984 <term>Parameter:</term>
3987 The name of an external content filter, as defined in the
3988 <link linkend="filter-file">filter file</link>.
3989 External filters can be defined in one or more files as defined by the
3990 <literal><link linkend="filterfile">filterfile</link></literal>
3991 option in the <link linkend="config">config file</link>.
3994 When used in its negative form,
3995 and without parameters, <emphasis>all</emphasis> filtering with external
3996 filters is completely disabled.
4005 External filters are scripts or programs that can modify the content in
4006 case common <literal><link linkend="filter">filters</link></literal>
4007 aren't powerful enough. With the exception that this action doesn't
4008 use pcrs-based filters, the notes in the
4009 <literal><link linkend="filter">filter</link></literal> section apply.
4013 Currently external filters are executed with &my-app;'s privileges.
4014 Only use external filters you understand and trust.
4018 This feature is experimental, the <literal><link
4019 linkend="external-filter-syntax">syntax</link></literal>
4020 may change in the future.
4027 <term>Example usage:</term>
4029 <screen>+external-filter{fancy-filter}</screen>
4035 <!-- ~~~~~ New section ~~~~~ -->
4036 <sect3 renderas="sect4" id="fast-redirects">
4037 <title>fast-redirects</title>
4041 <term>Typical use:</term>
4043 <para>Fool some click-tracking scripts and speed up indirect links.</para>
4048 <term>Effect:</term>
4051 Detects redirection URLs and redirects the browser without contacting
4052 the redirection server first.
4059 <!-- boolean, parameterized, Multi-value -->
4061 <para>Parameterized.</para>
4066 <term>Parameter:</term>
4071 <quote>simple-check</quote> to just search for the string <quote>http://</quote>
4072 to detect redirection URLs.
4077 <quote>check-decoded-url</quote> to decode URLs (if necessary) before searching
4078 for redirection URLs.
4089 Many sites, like yahoo.com, don't just link to other sites. Instead, they
4090 will link to some script on their own servers, giving the destination as a
4091 parameter, which will then redirect you to the final target. URLs
4092 resulting from this scheme typically look like:
4093 <quote>http://www.example.org/click-tracker.cgi?target=http%3a//www.example.net/</quote>.
4096 Sometimes, there are even multiple consecutive redirects encoded in the
4097 URL. These redirections via scripts make your web browsing more traceable,
4098 since the server from which you follow such a link can see where you go
4099 to. Apart from that, valuable bandwidth and time is wasted, while your
4100 browser asks the server for one redirect after the other. Plus, it feeds
4104 This feature is currently not very smart and is scheduled for improvement.
4105 If it is enabled by default, you will have to create some exceptions to
4106 this action. It can lead to failures in several ways:
4109 Not every URLs with other URLs as parameters is evil.
4110 Some sites offer a real service that requires this information to work.
4111 For example a validation service needs to know, which document to validate.
4112 <literal>fast-redirects</literal> assumes that every URL parameter that
4113 looks like another URL is a redirection target, and will always redirect to
4114 the last one. Most of the time the assumption is correct, but if it isn't,
4115 the user gets redirected anyway.
4118 Another failure occurs if the URL contains other parameters after the URL parameter.
4120 <quote>http://www.example.org/?redirect=http%3a//www.example.net/&foo=bar</quote>.
4121 contains the redirection URL <quote>http://www.example.net/</quote>,
4122 followed by another parameter. <literal>fast-redirects</literal> doesn't know that
4123 and will cause a redirect to <quote>http://www.example.net/&foo=bar</quote>.
4124 Depending on the target server configuration, the parameter will be silently ignored
4125 or lead to a <quote>page not found</quote> error. You can prevent this problem by
4126 first using the <literal><link linkend="redirect">redirect</link></literal> action
4127 to remove the last part of the URL, but it requires a little effort.
4130 To detect a redirection URL, <literal>fast-redirects</literal> only
4131 looks for the string <quote>http://</quote>, either in plain text
4132 (invalid but often used) or encoded as <quote>http%3a//</quote>.
4133 Some sites use their own URL encoding scheme, encrypt the address
4134 of the target server or replace it with a database id. In these cases
4135 <literal>fast-redirects</literal> is fooled and the request reaches the
4136 redirection server where it probably gets logged.
4142 <term>Example usage:</term>
4145 { +fast-redirects{simple-check} }
4148 { +fast-redirects{check-decoded-url} }
4149 another.example.com/testing</screen>
4157 <!-- ~~~~~ New section ~~~~~ -->
4158 <sect3 renderas="sect4" id="filter">
4159 <title>filter</title>
4163 <term>Typical use:</term>
4165 <para>Get rid of HTML and JavaScript annoyances, banner advertisements (by size),
4166 do fun text replacements, add personalized effects, etc.</para>
4171 <term>Effect:</term>
4174 All instances of text-based type, most notably HTML and JavaScript, to which
4175 this action applies, can be filtered on-the-fly through the specified regular
4176 expression based substitutions. (Note: as of version 3.0.3 plain text documents
4177 are exempted from filtering, because web servers often use the
4178 <literal>text/plain</literal> MIME type for all files whose type they don't know.)
4185 <!-- boolean, parameterized, Multi-value -->
4187 <para>Multi-value.</para>
4192 <term>Parameter:</term>
4195 The name of a content filter, as defined in the <link linkend="filter-file">filter file</link>.
4196 Filters can be defined in one or more files as defined by the
4197 <literal><link linkend="filterfile">filterfile</link></literal>
4198 option in the <link linkend="config">config file</link>.
4199 <filename>default.filter</filename> is the collection of filters
4200 supplied by the developers. Locally defined filters should go
4201 in their own file, such as <filename>user.filter</filename>.
4204 When used in its negative form,
4205 and without parameters, <emphasis>all</emphasis> filtering is completely disabled.
4214 For your convenience, there are a number of pre-defined filters available
4215 in the distribution filter file that you can use. See the examples below for
4219 Filtering requires buffering the page content, which may appear to
4220 slow down page rendering since nothing is displayed until all content has
4221 passed the filters. (The total time until the page is completely rendered
4222 doesn't change much, but it may be perceived as slower since the page is
4223 not incrementally displayed.)
4224 This effect will be more noticeable on slower connections.
4227 <quote>Rolling your own</quote>
4228 filters requires a knowledge of
4229 <ulink url="https://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
4230 Expressions</quote></ulink> and
4231 <ulink url="https://en.wikipedia.org/wiki/Html"><quote>HTML</quote></ulink>.
4232 This is very powerful feature, and potentially very intrusive.
4233 Filters should be used with caution, and where an equivalent
4234 <quote>action</quote> is not available.
4237 The amount of data that can be filtered is limited by the
4238 <literal><link linkend="buffer-limit">buffer-limit</link></literal>
4239 option in the main <link linkend="config">config file</link>. The
4240 default is 4096 KB (4 Megs). Once this limit is exceeded, the buffered
4241 data, and all pending data, is passed through unfiltered.
4244 Inappropriate MIME types, such as zipped files, are not filtered at all.
4245 (Again, only text-based types except plain text). Encrypted SSL data
4246 (from HTTPS servers) cannot be filtered either, since this would violate
4247 the integrity of the secure transaction. In some situations it might
4248 be necessary to protect certain text, like source code, from filtering
4249 by defining appropriate <literal>-filter</literal> exceptions.
4252 Compressed content can't be filtered either, but if &my-app;
4253 is compiled with zlib support and a supported compression algorithm
4254 is used (gzip or deflate), &my-app; can first decompress the content
4258 If you use a &my-app; version without zlib support, but want filtering to work on
4259 as much documents as possible, even those that would normally be sent compressed,
4260 you must use the <literal><link linkend="prevent-compression">prevent-compression</link></literal>
4261 action in conjunction with <literal>filter</literal>.
4264 Content filtering can achieve some of the same effects as the
4265 <literal><link linkend="block">block</link></literal>
4266 action, i.e. it can be used to block ads and banners. But the mechanism
4267 works quite differently. One effective use, is to block ad banners
4268 based on their size (see below), since many of these seem to be somewhat
4272 <link linkend="contact">Feedback</link> with suggestions for new or
4273 improved filters is particularly welcome!
4276 The below list has only the names and a one-line description of each
4277 predefined filter. There are <link linkend="predefined-filters">more
4278 verbose explanations</link> of what these filters do in the <link
4279 linkend="filter-file">filter file chapter</link>.
4285 <term>Example usage (with filters from the distribution <filename>default.filter</filename> file).
4286 See <link linkend="PREDEFINED-FILTERS">the Predefined Filters section</link> for
4287 more explanation on each:</term>
4290 <anchor id="filter-js-annoyances">
4292 <screen>+filter{js-annoyances} # Get rid of particularly annoying JavaScript abuse.</screen>
4294 <anchor id="filter-js-events">
4296 <screen>+filter{js-events} # Kill JavaScript event bindings and timers (Radically destructive! Only for extra nasty sites).</screen>
4298 <anchor id="filter-html-annoyances">
4300 <screen>+filter{html-annoyances} # Get rid of particularly annoying HTML abuse.</screen>
4302 <anchor id="filter-content-cookies">
4304 <screen>+filter{content-cookies} # Kill cookies that come in the HTML or JS content.</screen>
4306 <anchor id="filter-refresh-tags">
4308 <screen>+filter{refresh-tags} # Kill automatic refresh tags if refresh time is larger than 9 seconds.</screen>
4310 <anchor id="filter-unsolicited-popups">
4312 <screen>+filter{unsolicited-popups} # Disable only unsolicited pop-up windows.</screen>
4314 <anchor id="filter-all-popups">
4316 <screen>+filter{all-popups} # Kill all popups in JavaScript and HTML.</screen>
4318 <anchor id="filter-img-reorder">
4320 <screen>+filter{img-reorder} # Reorder attributes in <img> tags to make the banners-by-* filters more effective.</screen>
4322 <anchor id="filter-banners-by-size">
4324 <screen>+filter{banners-by-size} # Kill banners by size.</screen>
4326 <anchor id="filter-banners-by-link">
4328 <screen>+filter{banners-by-link} # Kill banners by their links to known clicktrackers.</screen>
4330 <anchor id="filter-webbugs">
4332 <screen>+filter{webbugs} # Squish WebBugs (1x1 invisible GIFs used for user tracking).</screen>
4334 <anchor id="filter-tiny-textforms">
4336 <screen>+filter{tiny-textforms} # Extend those tiny textareas up to 40x80 and kill the hard wrap.</screen>
4338 <anchor id="filter-jumping-windows">
4340 <screen>+filter{jumping-windows} # Prevent windows from resizing and moving themselves.</screen>
4342 <anchor id="filter-frameset-borders">
4344 <screen>+filter{frameset-borders} # Give frames a border and make them resizable.</screen>
4346 <anchor id="filter-iframes">
4348 <screen>+filter{iframes} # Removes all detected iframes. Should only be enabled for individual sites.</screen>
4350 <anchor id="filter-demoronizer">
4352 <screen>+filter{demoronizer} # Fix MS's non-standard use of standard charsets.</screen>
4354 <anchor id="filter-shockwave-flash">
4356 <screen>+filter{shockwave-flash} # Kill embedded Shockwave Flash objects.</screen>
4358 <anchor id="filter-quicktime-kioskmode">
4360 <screen>+filter{quicktime-kioskmode} # Make Quicktime movies saveable.</screen>
4362 <anchor id="filter-fun">
4364 <screen>+filter{fun} # Text replacements for subversive browsing fun!</screen>
4366 <anchor id="filter-crude-parental">
4368 <screen>+filter{crude-parental} # Crude parental filtering. Note that this filter doesn't work reliably.</screen>
4370 <anchor id="filter-ie-exploits">
4372 <screen>+filter{ie-exploits} # Disable some known Internet Explorer bug exploits.</screen>
4374 <anchor id="filter-site-specifics">
4376 <screen>+filter{site-specifics} # Cure for site-specific problems. Don't apply generally!</screen>
4378 <anchor id="filter-no-ping">
4380 <screen>+filter{no-ping} # Removes non-standard ping attributes in <a> and <area> tags.</screen>
4382 <anchor id="filter-github">
4384 <screen>+filter{github} # Removes the annoying "Sign-Up" banner and the Cookie disclaimer.</screen>
4386 <anchor id="filter-google">
4388 <screen>+filter{google} # CSS-based block for Google text ads. Also removes a width limitation and the toolbar advertisement.</screen>
4390 <anchor id="filter-imdb">
4392 <screen>+filter{imdb} # Removes some ads on IMDb.</screen>
4394 <anchor id="filter-yahoo">
4396 <screen>+filter{yahoo} # CSS-based block for Yahoo text ads. Also removes a width limitation.</screen>
4398 <anchor id="filter-msn">
4400 <screen>+filter{msn} # CSS-based block for MSN text ads. Also removes tracking URLs and a width limitation.</screen>
4402 <anchor id="filter-blogspot">
4404 <screen>+filter{blogspot} # Cleans up some Blogspot blogs. Read the fine print before using this.</screen>
4406 <anchor id="filter-sourceforge">
4408 <screen>+filter{sourceforge} # Reduces the amount of ads for proprietary software on SourceForge.</screen>
4415 <!-- ~~~~~ New section ~~~~~ -->
4416 <sect3 renderas="sect4" id="force-text-mode">
4417 <title>force-text-mode</title>
4423 <term>Typical use:</term>
4425 <para>Force <application>Privoxy</application> to treat a document as if it was in some kind of <emphasis>text</emphasis> format. </para>
4430 <term>Effect:</term>
4433 Declares a document as text, even if the <quote>Content-Type:</quote> isn't detected as such.
4440 <!-- Boolean, Parameterized, Multi-value -->
4442 <para>Boolean.</para>
4447 <term>Parameter:</term>
4459 As explained <literal><link linkend="filter">above</link></literal>,
4460 <application>Privoxy</application> tries to only filter files that are
4461 in some kind of text format. The same restrictions apply to
4462 <literal><link linkend="content-type-overwrite">content-type-overwrite</link></literal>.
4463 <literal>force-text-mode</literal> declares a document as text,
4464 without looking at the <quote>Content-Type:</quote> first.
4468 Think twice before activating this action. Filtering binary data
4469 with regular expressions can cause file damage.
4476 <term>Example usage:</term>
4487 <!-- ~~~~~ New section ~~~~~ -->
4488 <sect3 renderas="sect4" id="forward-override">
4489 <title>forward-override</title>
4495 <term>Typical use:</term>
4497 <para>Change the forwarding settings based on User-Agent or request origin</para>
4502 <term>Effect:</term>
4505 Overrules the forward directives in the configuration file.
4512 <!-- Boolean, Parameterized, Multi-value -->
4514 <para>Parameterized.</para>
4519 <term>Parameter:</term>
4523 <para><quote>forward .</quote> to use a direct connection without any additional proxies.</para>
4527 <quote>forward 127.0.0.1:8123</quote> to use the HTTP proxy listening at 127.0.0.1 port 8123.
4532 <quote>forward-socks4a 127.0.0.1:9050 .</quote> to use the socks4a proxy listening at
4533 127.0.0.1 port 9050. Replace <quote>forward-socks4a</quote> with <quote>forward-socks4</quote>
4534 to use a socks4 connection (with local DNS resolution) instead, use <quote>forward-socks5</quote>
4535 for socks5 connections (with remote DNS resolution).
4540 <quote>forward-socks4a 127.0.0.1:9050 proxy.example.org:8000</quote> to use the socks4a proxy
4541 listening at 127.0.0.1 port 9050 to reach the HTTP proxy listening at proxy.example.org port 8000.
4542 Replace <quote>forward-socks4a</quote> with <quote>forward-socks4</quote> to use a socks4 connection
4543 (with local DNS resolution) instead, use <quote>forward-socks5</quote>
4544 for socks5 connections (with remote DNS resolution).
4549 <quote>forward-webserver 127.0.0.1:80</quote> to use the HTTP
4550 server listening at 127.0.0.1 port 80 without adjusting the
4554 This makes it more convenient to use Privoxy to make
4555 existing websites available as onion services as well.
4558 Many websites serve content with hardcoded URLs and
4559 can't be easily adjusted to change the domain based
4560 on the one used by the client.
4563 Putting Privoxy between Tor and the webserver (or an stunnel
4564 that forwards to the webserver) allows to rewrite headers and
4565 content to make client and server happy at the same time.
4568 Using Privoxy for webservers that are only reachable through
4569 onion addresses and whose location is supposed to be secret
4570 is not recommended and should not be necessary anyway.
4581 This action takes parameters similar to the
4582 <link linkend="forwarding">forward</link> directives in the configuration
4583 file, but without the URL pattern. It can be used as replacement, but normally it's only
4584 used in cases where matching based on the request URL isn't sufficient.
4588 Please read the description for the <link linkend="forwarding">forward</link> directives before
4589 using this action. Forwarding to the wrong people will reduce your privacy and increase the
4590 chances of man-in-the-middle attacks.
4593 If the ports are missing or invalid, default values will be used. This might change
4594 in the future and you shouldn't rely on it. Otherwise incorrect syntax causes Privoxy
4595 to exit. Due to design limitations, invalid parameter syntax isn't detected until the
4596 action is used the first time.
4599 Use the <ulink url="http://config.privoxy.org/show-url-info">show-url-info CGI page</ulink>
4600 to verify that your forward settings do what you thought the do.
4607 <term>Example usage:</term>
4610 # Use an ssh tunnel for requests previously tagged as
4611 # <quote>User-Agent: fetch libfetch/2.0</quote> and make sure
4612 # resuming downloads continues to work.
4614 # This way you can continue to use Tor for your normal browsing,
4615 # without overloading the Tor network with your FreeBSD ports updates
4616 # or downloads of bigger files like ISOs.
4618 # Note that HTTP headers are easy to fake and therefore their
4619 # values are as (un)trustworthy as your clients and users.
4620 {+forward-override{forward-socks5 10.0.0.2:2222 .} \
4621 -hide-if-modified-since \
4622 -overwrite-last-modified \
4624 TAG:^User-Agent: fetch libfetch/2\.0$
4632 <!-- ~~~~~ New section ~~~~~ -->
4633 <sect3 renderas="sect4" id="handle-as-empty-document">
4634 <title>handle-as-empty-document</title>
4640 <term>Typical use:</term>
4642 <para>Mark URLs that should be replaced by empty documents <emphasis>if they get blocked</emphasis></para>
4647 <term>Effect:</term>
4650 This action alone doesn't do anything noticeable. It just marks URLs.
4651 If the <literal><link linkend="block">block</link></literal> action <emphasis>also applies</emphasis>,
4652 the presence or absence of this mark decides whether an HTML <quote>BLOCKED</quote>
4653 page, or an empty document will be sent to the client as a substitute for the blocked content.
4654 The <emphasis>empty</emphasis> document isn't literally empty, but actually contains a single space.
4661 <!-- Boolean, Parameterized, Multi-value -->
4663 <para>Boolean.</para>
4668 <term>Parameter:</term>
4680 Some browsers complain about syntax errors if JavaScript documents
4681 are blocked with <application>Privoxy's</application>
4682 default HTML page; this option can be used to silence them.
4683 And of course this action can also be used to eliminate the &my-app;
4684 BLOCKED message in frames.
4687 The content type for the empty document can be specified with
4688 <literal><link linkend="content-type-overwrite">content-type-overwrite{}</link></literal>,
4689 but usually this isn't necessary.
4695 <term>Example usage:</term>
4697 <screen># Block all documents on example.org that end with ".js",
4698 # but send an empty document instead of the usual HTML message.
4699 {+block{Blocked JavaScript} +handle-as-empty-document}
4708 <!-- ~~~~~ New section ~~~~~ -->
4709 <sect3 renderas="sect4" id="handle-as-image">
4710 <title>handle-as-image</title>
4714 <term>Typical use:</term>
4716 <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>
4721 <term>Effect:</term>
4724 This action alone doesn't do anything noticeable. It just marks URLs as images.
4725 If the <literal><link linkend="block">block</link></literal> action <emphasis>also applies</emphasis>,
4726 the presence or absence of this mark decides whether an HTML <quote>blocked</quote>
4727 page, or a replacement image (as determined by the <literal><link
4728 linkend="set-image-blocker">set-image-blocker</link></literal> action) will be sent to the
4729 client as a substitute for the blocked content.
4736 <!-- Boolean, Parameterized, Multi-value -->
4738 <para>Boolean.</para>
4743 <term>Parameter:</term>
4755 The below generic example section is actually part of <filename>default.action</filename>.
4756 It marks all URLs with well-known image file name extensions as images and should
4760 Users will probably only want to use the handle-as-image action in conjunction with
4761 <literal><link linkend="block">block</link></literal>, to block sources of banners, whose URLs don't
4762 reflect the file type, like in the second example section.
4765 Note that you cannot treat HTML pages as images in most cases. For instance, (in-line) ad
4766 frames require an HTML page to be sent, or they won't display properly.
4767 Forcing <literal>handle-as-image</literal> in this situation will not replace the
4768 ad frame with an image, but lead to error messages.
4774 <term>Example usage (sections):</term>
4776 <screen># Generic image extensions:
4779 /.*\.(gif|jpg|jpeg|png|bmp|ico)$
4781 # These don't look like images, but they're banners and should be
4782 # blocked as images:
4784 {+block{Nasty banners.} +handle-as-image}
4785 nasty-banner-server.example.com/junk.cgi\?output=trash
4793 <!-- ~~~~~ New section ~~~~~ -->
4794 <sect3 renderas="sect4" id="hide-accept-language">
4795 <title>hide-accept-language</title>
4801 <term>Typical use:</term>
4803 <para>Pretend to use different language settings.</para>
4808 <term>Effect:</term>
4811 Deletes or replaces the <quote>Accept-Language:</quote> HTTP header in client requests.
4818 <!-- Boolean, Parameterized, Multi-value -->
4820 <para>Parameterized.</para>
4825 <term>Parameter:</term>
4828 Keyword: <quote>block</quote>, or any user defined value.
4837 Faking the browser's language settings can be useful to make a
4838 foreign User-Agent set with
4839 <literal><link linkend="hide-user-agent">hide-user-agent</link></literal>
4843 However some sites with content in different languages check the
4844 <quote>Accept-Language:</quote> to decide which one to take by default.
4845 Sometimes it isn't possible to later switch to another language without
4846 changing the <quote>Accept-Language:</quote> header first.
4849 Therefore it's a good idea to either only change the
4850 <quote>Accept-Language:</quote> header to languages you understand,
4851 or to languages that aren't wide spread.
4854 Before setting the <quote>Accept-Language:</quote> header
4855 to a rare language, you should consider that it helps to
4856 make your requests unique and thus easier to trace.
4857 If you don't plan to change this header frequently,
4858 you should stick to a common language.
4864 <term>Example usage (section):</term>
4866 <screen># Pretend to use Canadian language settings.
4867 {+hide-accept-language{en-ca} \
4868 +hide-user-agent{Mozilla/5.0 (X11; U; OpenBSD i386; en-CA; rv:1.8.0.4) Gecko/20060628 Firefox/1.5.0.4} \
4878 <!-- ~~~~~ New section ~~~~~ -->
4879 <sect3 renderas="sect4" id="hide-content-disposition">
4880 <title>hide-content-disposition</title>
4886 <term>Typical use:</term>
4888 <para>Prevent download menus for content you prefer to view inside the browser.</para>
4893 <term>Effect:</term>
4896 Deletes or replaces the <quote>Content-Disposition:</quote> HTTP header set by some servers.
4903 <!-- Boolean, Parameterized, Multi-value -->
4905 <para>Parameterized.</para>
4910 <term>Parameter:</term>
4913 Keyword: <quote>block</quote>, or any user defined value.
4922 Some servers set the <quote>Content-Disposition:</quote> HTTP header for
4923 documents they assume you want to save locally before viewing them.
4924 The <quote>Content-Disposition:</quote> header contains the file name
4925 the browser is supposed to use by default.
4928 In most browsers that understand this header, it makes it impossible to
4929 <emphasis>just view</emphasis> the document, without downloading it first,
4930 even if it's just a simple text file or an image.
4933 Removing the <quote>Content-Disposition:</quote> header helps
4934 to prevent this annoyance, but some browsers additionally check the
4935 <quote>Content-Type:</quote> header, before they decide if they can
4936 display a document without saving it first. In these cases, you have
4937 to change this header as well, before the browser stops displaying
4941 It is also possible to change the server's file name suggestion
4942 to another one, but in most cases it isn't worth the time to set
4946 This action will probably be removed in the future,
4947 use server-header filters instead.
4953 <term>Example usage:</term>
4955 <screen># Disarm the download link in Sourceforge's patch tracker
4957 +content-type-overwrite{text/plain}\
4958 +hide-content-disposition{block} }
4959 .sourceforge.net/tracker/download\.php</screen>
4966 <!-- ~~~~~ New section ~~~~~ -->
4967 <sect3 renderas="sect4" id="hide-if-modified-since">
4968 <title>hide-if-modified-since</title>
4974 <term>Typical use:</term>
4976 <para>Prevent yet another way to track the user's steps between sessions.</para>
4981 <term>Effect:</term>
4984 Deletes the <quote>If-Modified-Since:</quote> HTTP client header or modifies its value.
4991 <!-- Boolean, Parameterized, Multi-value -->
4993 <para>Parameterized.</para>
4998 <term>Parameter:</term>
5001 Keyword: <quote>block</quote>, or a user defined value that specifies a range of hours.
5010 Removing this header is useful for filter testing, where you want to force a real
5011 reload instead of getting status code <quote>304</quote>, which would cause the
5012 browser to use a cached copy of the page.
5015 Instead of removing the header, <literal>hide-if-modified-since</literal> can
5016 also add or subtract a random amount of time to/from the header's value.
5017 You specify a range of minutes where the random factor should be chosen from and
5018 <application>Privoxy</application> does the rest. A negative value means
5019 subtracting, a positive value adding.
5022 Randomizing the value of the <quote>If-Modified-Since:</quote> makes
5023 it less likely that the server can use the time as a cookie replacement,
5024 but you will run into caching problems if the random range is too high.
5027 It is a good idea to only use a small negative value and let
5028 <literal><link linkend="overwrite-last-modified">overwrite-last-modified</link></literal>
5029 handle the greater changes.
5032 It is also recommended to use this action together with
5033 <literal><link linkend="crunch-if-none-match">crunch-if-none-match</link></literal>,
5034 otherwise it's more or less pointless.
5040 <term>Example usage (section):</term>
5042 <screen># Let the browser revalidate but make tracking based on the time less likely.
5043 {+hide-if-modified-since{-60} \
5044 +overwrite-last-modified{randomize} \
5045 +crunch-if-none-match}
5053 <!-- ~~~~~ New section ~~~~~ -->
5054 <sect3 renderas="sect4" id="hide-from-header">
5055 <title>hide-from-header</title>
5059 <term>Typical use:</term>
5061 <para>Keep your (old and ill) browser from telling web servers your email address</para>
5066 <term>Effect:</term>
5069 Deletes any existing <quote>From:</quote> HTTP header, or replaces it with the
5077 <!-- Boolean, Parameterized, Multi-value -->
5079 <para>Parameterized.</para>
5084 <term>Parameter:</term>
5087 Keyword: <quote>block</quote>, or any user defined value.
5096 The keyword <quote>block</quote> will completely remove the header
5097 (not to be confused with the <literal><link linkend="block">block</link></literal>
5101 Alternately, you can specify any value you prefer to be sent to the web
5102 server. If you do, it is a matter of fairness not to use any address that
5103 is actually used by a real person.
5106 This action is rarely needed, as modern web browsers don't send
5107 <quote>From:</quote> headers anymore.
5113 <term>Example usage:</term>
5115 <screen>+hide-from-header{block}</screen>
5117 <screen>+hide-from-header{spam-me-senseless@sittingduck.example.com}</screen>
5124 <!-- ~~~~~ New section ~~~~~ -->
5125 <sect3 renderas="sect4" id="hide-referrer">
5126 <title>hide-referrer</title>
5127 <anchor id="hide-referer">
5130 <term>Typical use:</term>
5132 <para>Conceal which link you followed to get to a particular site</para>
5137 <term>Effect:</term>
5140 Deletes the <quote>Referer:</quote> (sic) HTTP header from the client request,
5141 or replaces it with a forged one.
5148 <!-- Boolean, Parameterized, Multi-value -->
5150 <para>Parameterized.</para>
5155 <term>Parameter:</term>
5159 <para><quote>conditional-block</quote> to delete the header completely if the host has changed.</para>
5162 <para><quote>conditional-forge</quote> to forge the header if the host has changed.</para>
5165 <para><quote>block</quote> to delete the header unconditionally.</para>
5168 <para><quote>forge</quote> to pretend to be coming from the homepage of the server we are talking to.</para>
5171 <para>Any other string to set a user defined referrer.</para>
5181 <literal>conditional-block</literal> is the only parameter,
5182 that isn't easily detected in the server's log file. If it blocks the
5183 referrer, the request will look like the visitor used a bookmark or
5184 typed in the address directly.
5187 Leaving the referrer unmodified for requests on the same host
5188 allows the server owner to see the visitor's <quote>click path</quote>,
5189 but in most cases she could also get that information by comparing
5190 other parts of the log file: for example the User-Agent if it isn't
5191 a very common one, or the user's IP address if it doesn't change between
5195 Always blocking the referrer, or using a custom one, can lead to
5196 failures on servers that check the referrer before they answer any
5197 requests, in an attempt to prevent their content from being
5198 embedded or linked to elsewhere.
5201 Both <literal>conditional-block</literal> and <literal>forge</literal>
5202 will work with referrer checks, as long as content and valid referring page
5203 are on the same host. Most of the time that's the case.
5206 <literal>hide-referer</literal> is an alternate spelling of
5207 <literal>hide-referrer</literal> and the two can be can be freely
5208 substituted with each other. (<quote>referrer</quote> is the
5209 correct English spelling, however the HTTP specification has a bug - it
5210 requires it to be spelled as <quote>referer</quote>.)
5216 <term>Example usage:</term>
5218 <screen>+hide-referrer{forge}</screen>
5220 <screen>+hide-referrer{http://www.yahoo.com/}</screen>
5227 <!-- ~~~~~ New section ~~~~~ -->
5228 <sect3 renderas="sect4" id="hide-user-agent">
5229 <title>hide-user-agent</title>
5233 <term>Typical use:</term>
5235 <para>Try to conceal your type of browser and client operating system</para>
5240 <term>Effect:</term>
5243 Replaces the value of the <quote>User-Agent:</quote> HTTP header
5244 in client requests with the specified value.
5251 <!-- Boolean, Parameterized, Multi-value -->
5253 <para>Parameterized.</para>
5258 <term>Parameter:</term>
5261 Any user-defined string.
5271 This can lead to problems on web sites that depend on looking at this header in
5272 order to customize their content for different browsers (which, by the
5273 way, is <emphasis>NOT</emphasis> the right thing to do: good web sites
5274 work browser-independently).
5278 Using this action in multi-user setups or wherever different types of
5279 browsers will access the same <application>Privoxy</application> is
5280 <emphasis>not recommended</emphasis>. In single-user, single-browser
5281 setups, you might use it to delete your OS version information from
5282 the headers, because it is an invitation to exploit known bugs for your
5283 OS. It is also occasionally useful to forge this in order to access
5284 sites that won't let you in otherwise (though there may be a good
5285 reason in some cases).
5288 More information on known user-agent strings can be found at
5289 <ulink url="http://www.user-agents.org/">http://www.user-agents.org/</ulink>
5291 <ulink url="https://en.wikipedia.org/wiki/User_agent">http://en.wikipedia.org/wiki/User_agent</ulink>.
5297 <term>Example usage:</term>
5299 <screen>+hide-user-agent{Mozilla/5.0 (X11; ElectroBSD i386; rv:78.0) Gecko/20100101 Firefox/78.0}</screen>
5306 <!-- ~~~~~ New section ~~~~~ -->
5307 <sect3 renderas="sect4" id="https-inspection">
5308 <title>https-inspection</title>
5312 <term>Typical use:</term>
5314 <para>Filter encrypted requests and responses</para>
5319 <term>Effect:</term>
5322 Encrypted requests are decrypted, filtered and forwarded encrypted.
5329 <!-- boolean, parameterized, Multi-value -->
5331 <para>Boolean.</para>
5336 <term>Parameter:</term>
5348 This action allows &my-app; to filter encrypted requests and responses.
5349 For this to work &my-app; has to generate a certificate and send it
5350 to the client which has to accept it.
5353 Before this works the directives in the
5354 <literal><ulink url="config.html#HTTPS-INSPECTION-DIRECTIVES">HTTPS inspection section</ulink></literal>
5355 of the config file have to be configured.
5358 Note that the action has to be enabled based on the CONNECT
5359 request which doesn't contain a path. Enabling it based on
5360 a pattern with path doesn't work as the path is only seen
5361 by &my-app; if the action is already enabled.
5364 This is an experimental feature.
5370 <term>Example usage (section):</term>
5372 <screen>{+https-inspection}
5373 www.example.com</screen>
5381 <!-- ~~~~~ New section ~~~~~ -->
5382 <sect3 renderas="sect4" id="ignore-certificate-errors">
5383 <title>ignore-certificate-errors</title>
5387 <term>Typical use:</term>
5389 <para>Filter encrypted requests and responses without verifying the certificate</para>
5394 <term>Effect:</term>
5397 Encrypted requests are forwarded to sites without verifying the certificate.
5404 <!-- Boolean, Parameterized, Multi-value -->
5406 <para>Boolean.</para>
5411 <term>Parameter:</term>
5424 <link linkend="HTTPS-INSPECTION"><quote>+https-inspection</quote></link>
5425 action is used &my-app; by default verifies that the remote site uses a valid
5429 If the certificate can't be validated by &my-app; the connection is aborted.
5432 This action disables the certificate check so requests to sites
5433 with certificates that can't be validated are allowed.
5436 Note that enabling this action allows Man-in-the-middle attacks.
5442 <term>Example usage:</term>
5445 {+ignore-certificate-errors}
5454 <!-- ~~~~~ New section ~~~~~ -->
5455 <sect3 renderas="sect4" id="limit-connect">
5456 <title>limit-connect</title>
5460 <term>Typical use:</term>
5462 <para>Prevent abuse of <application>Privoxy</application> as a TCP proxy relay or disable SSL for untrusted sites</para>
5467 <term>Effect:</term>
5470 Specifies to which ports HTTP CONNECT requests are allowable.
5477 <!-- Boolean, Parameterized, Multi-value -->
5479 <para>Parameterized.</para>
5484 <term>Parameter:</term>
5487 A comma-separated list of ports or port ranges (the latter using dashes, with the minimum
5488 defaulting to 0 and the maximum to 65K).
5497 By default, i.e. if no <literal>limit-connect</literal> action applies,
5498 <application>Privoxy</application> allows HTTP CONNECT requests to all
5499 ports. Use <literal>limit-connect</literal> if fine-grained control
5500 is desired for some or all destinations.
5503 The CONNECT methods exists in HTTP to allow access to secure websites
5504 (<quote>https://</quote> URLs) through proxies. It works very simply:
5505 the proxy connects to the server on the specified port, and then
5506 short-circuits its connections to the client and to the remote server.
5507 This means CONNECT-enabled proxies can be used as TCP relays very easily.
5510 <application>Privoxy</application> relays HTTPS traffic without seeing
5511 the decoded content. Websites can leverage this limitation to circumvent &my-app;'s
5512 filters. By specifying an invalid port range you can disable HTTPS entirely.
5518 <term>Example usages:</term>
5520 <!-- I had trouble getting the spacing to look right in my browser -->
5521 <!-- I probably have the wrong font setup, bollocks. -->
5522 <!-- Apparently the emphasis tag uses a proportional font no matter what -->
5523 <screen>+limit-connect{443} # Port 443 is OK.
5524 +limit-connect{80,443} # Ports 80 and 443 are OK.
5525 +limit-connect{-3, 7, 20-100, 500-} # Ports less than 3, 7, 20 to 100 and above 500 are OK.
5526 +limit-connect{-} # All ports are OK
5527 +limit-connect{,} # No HTTPS/SSL traffic is allowed</screen>
5534 <!-- ~~~~~ New section ~~~~~ -->
5535 <sect3 renderas="sect4" id="limit-cookie-lifetime">
5536 <title>limit-cookie-lifetime</title>
5540 <term>Typical use:</term>
5542 <para>Limit the lifetime of HTTP cookies to a couple of minutes or hours.</para>
5547 <term>Effect:</term>
5550 Overwrites the expires field in Set-Cookie server headers if it's above the specified limit.
5557 <!-- Boolean, Parameterized, Multi-value -->
5559 <para>Parameterized.</para>
5564 <term>Parameter:</term>
5567 The lifetime limit in minutes, or 0.
5576 This action reduces the lifetime of HTTP cookies coming from the
5577 server to the specified number of minutes, starting from the time
5578 the cookie passes Privoxy.
5581 Cookies with a lifetime below the limit are not modified.
5582 The lifetime of session cookies is set to the specified limit.
5585 The effect of this action depends on the server.
5588 In case of servers which refresh their cookies with each response
5589 (or at least frequently), the lifetime limit set by this action
5591 Thus, a session associated with the cookie continues to work with
5592 this action enabled, as long as a new request is made before the
5593 last limit set is reached.
5596 However, some servers send their cookies once, with a lifetime of several
5597 years (the year 2037 is a popular choice), and do not refresh them
5598 until a certain event in the future, for example the user logging out.
5599 In this case this action may limit the absolute lifetime of the session,
5600 even if requests are made frequently.
5603 If the parameter is <quote>0</quote>, this action behaves like
5604 <literal><link linkend="session-cookies-only">session-cookies-only</link></literal>.
5610 <term>Example usages:</term>
5612 <screen>+limit-cookie-lifetime{60}</screen>
5618 <!-- ~~~~~ New section ~~~~~ -->
5619 <sect3 renderas="sect4" id="prevent-compression">
5620 <title>prevent-compression</title>
5624 <term>Typical use:</term>
5627 Ensure that servers send the content uncompressed, so it can be
5628 passed through <literal><link linkend="filter">filter</link></literal>s.
5634 <term>Effect:</term>
5637 Removes the Accept-Encoding header which can be used to ask for compressed transfer.
5644 <!-- Boolean, Parameterized, Multi-value -->
5646 <para>Boolean.</para>
5651 <term>Parameter:</term>
5663 More and more websites send their content compressed by default, which
5664 is generally a good idea and saves bandwidth. But the <literal><link
5665 linkend="filter">filter</link></literal> and
5666 <literal><link linkend="deanimate-gifs">deanimate-gifs</link></literal>
5667 actions need access to the uncompressed data.
5670 When compiled with zlib support (available since &my-app; 3.0.7), content that should be
5671 filtered is decompressed on-the-fly and you don't have to worry about this action.
5672 If you are using an older &my-app; version, or one that hasn't been compiled with zlib
5673 support, this action can be used to convince the server to send the content uncompressed.
5676 Most text-based instances compress very well, the size is seldom decreased by less than 50%,
5677 for markup-heavy instances like news feeds saving more than 90% of the original size isn't
5681 Not using compression will therefore slow down the transfer, and you should only
5682 enable this action if you really need it. As of &my-app; 3.0.7 it's disabled in all
5683 predefined action settings.
5686 Note that some (rare) ill-configured sites don't handle requests for uncompressed
5687 documents correctly. Broken PHP applications tend to send an empty document body,
5688 some IIS versions only send the beginning of the content and some content delivery
5689 networks let the connection time out.
5690 If you enable <literal>prevent-compression</literal> per default, you might
5691 want to add exceptions for those sites. See the example for how to do that.
5697 <term>Example usage (sections):</term>
5700 # Selectively turn off compression, and enable a filter
5702 { +filter{tiny-textforms} +prevent-compression }
5703 # Match only these sites
5708 # Or instead, we could set a universal default:
5710 { +prevent-compression }
5713 # Then maybe make exceptions for broken sites:
5715 { -prevent-compression }
5716 .compusa.com/</screen>
5724 <!-- ~~~~~ New section ~~~~~ -->
5725 <sect3 renderas="sect4" id="overwrite-last-modified">
5726 <title>overwrite-last-modified</title>
5732 <term>Typical use:</term>
5734 <para>Prevent yet another way to track the user's steps between sessions.</para>
5739 <term>Effect:</term>
5742 Deletes the <quote>Last-Modified:</quote> HTTP server header or modifies its value.
5749 <!-- Boolean, Parameterized, Multi-value -->
5751 <para>Parameterized.</para>
5756 <term>Parameter:</term>
5759 One of the keywords: <quote>block</quote>, <quote>reset-to-request-time</quote>
5760 and <quote>randomize</quote>
5769 Removing the <quote>Last-Modified:</quote> header is useful for filter
5770 testing, where you want to force a real reload instead of getting status
5771 code <quote>304</quote>, which would cause the browser to reuse the old
5772 version of the page.
5775 The <quote>randomize</quote> option overwrites the value of the
5776 <quote>Last-Modified:</quote> header with a randomly chosen time
5777 between the original value and the current time. In theory the server
5778 could send each document with a different <quote>Last-Modified:</quote>
5779 header to track visits without using cookies. <quote>Randomize</quote>
5780 makes it impossible and the browser can still revalidate cached documents.
5783 <quote>reset-to-request-time</quote> overwrites the value of the
5784 <quote>Last-Modified:</quote> header with the current time. You could use
5785 this option together with
5786 <literal><link linkend="hide-if-modified-since">hide-if-modified-since</link></literal>
5787 to further customize your random range.
5790 The preferred parameter here is <quote>randomize</quote>. It is safe
5791 to use, as long as the time settings are more or less correct.
5792 If the server sets the <quote>Last-Modified:</quote> header to the time
5793 of the request, the random range becomes zero and the value stays the same.
5794 Therefore you should later randomize it a second time with
5795 <literal><link linkend="hide-if-modified-since">hided-if-modified-since</link></literal>,
5799 It is also recommended to use this action together with
5800 <literal><link linkend="crunch-if-none-match">crunch-if-none-match</link></literal>.
5806 <term>Example usage:</term>
5808 <screen># Let the browser revalidate without being tracked across sessions
5809 { +hide-if-modified-since{-60} \
5810 +overwrite-last-modified{randomize} \
5811 +crunch-if-none-match}
5819 <!-- ~~~~~ New section ~~~~~ -->
5820 <sect3 renderas="sect4" id="redirect">
5821 <title>redirect</title>
5827 <term>Typical use:</term>
5830 Redirect requests to other sites.
5836 <term>Effect:</term>
5839 Convinces the browser that the requested document has been moved
5840 to another location and the browser should get it from there.
5847 <!-- Boolean, Parameterized, Multi-value -->
5849 <para>Parameterized</para>
5854 <term>Parameter:</term>
5857 An absolute URL or a single pcrs command.
5866 Requests to which this action applies are answered with a
5867 HTTP redirect to URLs of your choosing. The new URL is
5868 either provided as parameter, or derived by applying a
5869 single pcrs command to the original URL.
5872 The syntax for pcrs commands is documented in the
5873 <link linkend="filter-file">filter file</link> section.
5876 Requests can't be blocked and redirected at the same time,
5877 applying this action together with
5878 <literal><link linkend="block">block</link></literal>
5879 is a configuration error. Currently the request is blocked
5880 and an error message logged, the behavior may change in the
5881 future and result in Privoxy rejecting the action file.
5884 This action can be combined with
5885 <literal><link linkend="fast-redirects">fast-redirects{check-decoded-url}</link></literal>
5886 to redirect to a decoded version of a rewritten URL.
5889 Use this action carefully, make sure not to create redirection loops
5890 and be aware that using your own redirects might make it
5891 possible to fingerprint your requests.
5894 In case of problems with your redirects, or simply to watch
5895 them working, enable <link linkend="DEBUG">debug 128</link>.
5901 <term>Example usages:</term>
5903 <screen># Replace example.com's style sheet with another one
5904 { +redirect{http://localhost/css-replacements/example.com.css} }
5905 example.com/stylesheet\.css
5907 # Create a short, easy to remember nickname for a favorite site
5908 # (relies on the browser to accept and forward invalid URLs to &my-app;)
5909 { +redirect{https://www.privoxy.org/user-manual/actions-file.html} }
5912 # Always use the expanded view for Undeadly.org articles
5913 # (Note the $ at the end of the URL pattern to make sure
5914 # the request for the rewritten URL isn't redirected as well)
5915 {+redirect{s@$@&mode=expanded@}}
5916 undeadly.org/cgi\?action=article&sid=\d*$
5918 # Redirect Google search requests to MSN
5919 {+redirect{s@^http://[^/]*/search\?q=([^&]*).*@http://search.msn.com/results.aspx?q=$1@}}
5922 # Redirect MSN search requests to Yahoo
5923 {+redirect{s@^http://[^/]*/results\.aspx\?q=([^&]*).*@http://search.yahoo.com/search?p=$1@}}
5924 search.msn.com//results\.aspx\?q=
5926 # Redirect http://example.com/&bla=fasel&toChange=foo (and any other value but "bar")
5927 # to http://example.com/&bla=fasel&toChange=bar
5929 # The URL pattern makes sure that the following request isn't redirected again.
5930 {+redirect{s@toChange=[^&]+@toChange=bar@}}
5931 example.com/.*toChange=(?!bar)
5933 # Add a shortcut to look up illumos bugs
5934 {+redirect{s@^http://i([0-9]+)/.*@https://www.illumos.org/issues/$1@}}
5935 # Redirected URL = http://i4974/
5936 # Redirect Destination = https://www.illumos.org/issues/4974
5937 i[0-9][0-9][0-9][0-9]*/
5939 # Redirect requests for the old Tor Hidden Service of the Privoxy website to the new one
5940 {+redirect{s@^http://jvauzb4sb3bwlsnc.onion/@http://l3tczdiiwoo63iwxty4lhs6p7eaxop5micbn7vbliydgv63x5zrrrfyd.onion/@}}
5941 jvauzb4sb3bwlsnc.onion/
5943 # Redirect remote requests for this manual
5944 # to the local version delivered by Privoxy
5945 {+redirect{s@^http://www@http://config@}}
5946 www.privoxy.org/user-manual/</screen>
5954 <!-- ~~~~~ New section ~~~~~ -->
5955 <sect3 renderas="sect4" id="server-header-filter">
5956 <title>server-header-filter</title>
5960 <term>Typical use:</term>
5963 Rewrite or remove single server headers.
5969 <term>Effect:</term>
5972 All server headers to which this action applies are filtered on-the-fly
5973 through the specified regular expression based substitutions.
5980 <!-- boolean, parameterized, Multi-value -->
5982 <para>Multi-value.</para>
5987 <term>Parameter:</term>
5990 The name of a server-header filter, as defined in one of the
5991 <link linkend="filter-file">filter files</link>.
6000 Server-header filters are applied to each header on its own, not to
6001 all at once. This makes it easier to diagnose problems, but on the downside
6002 you can't write filters that only change header x if header y's value is z.
6003 You can do that by using tags though.
6006 Server-header filters are executed after the other header actions have finished
6007 and use their output as input.
6010 Please refer to the <link linkend="filter-file">filter file chapter</link>
6011 to learn which server-header filters are available by default, and how to
6018 <term>Example usage (section):</term>
6021 {+server-header-filter{html-to-xml}}
6022 example.org/xml-instance-that-is-delivered-as-html
6024 {+server-header-filter{xml-to-html}}
6025 example.org/instance-that-is-delivered-as-xml-but-is-not
6034 <!-- ~~~~~ New section ~~~~~ -->
6035 <sect3 renderas="sect4" id="server-header-tagger">
6036 <title>server-header-tagger</title>
6040 <term>Typical use:</term>
6043 Enable or disable filters based on the Content-Type header.
6049 <term>Effect:</term>
6052 Server headers to which this action applies are filtered on-the-fly through
6053 the specified regular expression based substitutions, the result is used as
6061 <!-- boolean, parameterized, Multi-value -->
6063 <para>Multi-value.</para>
6068 <term>Parameter:</term>
6071 The name of a server-header tagger, as defined in one of the
6072 <link linkend="filter-file">filter files</link>.
6081 Server-header taggers are applied to each header on its own,
6082 and as the header isn't modified, each tagger <quote>sees</quote>
6086 Server-header taggers are executed before all other header actions
6087 that modify server headers. Their tags can be used to control
6088 all of the other server-header actions, the content filters
6089 and the crunch actions (<link linkend="redirect">redirect</link>
6090 and <link linkend="block">block</link>).
6093 Obviously crunching based on tags created by server-header taggers
6094 doesn't prevent the request from showing up in the server's log file.
6101 <term>Example usage (section):</term>
6104 # Tag every request with the content type declared by the server
6105 {+server-header-tagger{content-type}}
6108 # If the response has a tag starting with 'image/' enable an external
6109 # filter that only applies to images.
6111 # Note that the filter is not available by default, it's just a
6112 # <literal><link linkend="external-filter-syntax">silly example</link></literal>.
6113 {+external-filter{rotate-image} +force-text-mode}
6123 <!-- ~~~~~ New section ~~~~~ -->
6124 <sect3 renderas="sect4" id="suppress-tag">
6125 <title>suppress-tag</title>
6129 <term>Typical use:</term>
6132 Suppress client or server tag.
6138 <term>Effect:</term>
6141 Server or client tags to which this action applies are not added to the request,
6142 thus making all actions that are specific to these request tags inactive.
6149 <!-- boolean, parameterized, Multi-value -->
6151 <para>Multi-value.</para>
6156 <term>Parameter:</term>
6159 The result tag of a server-header or client-header tagger, as defined in one of the
6160 <link linkend="filter-file">filter files</link>.
6166 <term>Example usage (section):</term>
6169 # Suppress tag produced by range-requests client-header tagger for requests coming from address 10.0.0.1
6170 {+suppress-tag{RANGE-REQUEST}}
6171 TAG:^IP-ADDRESS: 10\.0\.0\.1$
6180 <!-- ~~~~~ New section ~~~~~ -->
6181 <sect3 renderas="sect4" id="session-cookies-only">
6182 <title>session-cookies-only</title>
6186 <term>Typical use:</term>
6189 Allow only temporary <quote>session</quote> cookies (for the current
6190 browser session <emphasis>only</emphasis>).
6196 <term>Effect:</term>
6199 Deletes the <quote>expires</quote> field from <quote>Set-Cookie:</quote>
6200 server headers. Most browsers will not store such cookies permanently and
6201 forget them in between sessions.
6208 <!-- Boolean, Parameterized, Multi-value -->
6210 <para>Boolean.</para>
6215 <term>Parameter:</term>
6227 This is less strict than <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal> /
6228 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal> and allows you to browse
6229 websites that insist or rely on setting cookies, without compromising your privacy too badly.
6232 Most browsers will not permanently store cookies that have been processed by
6233 <literal>session-cookies-only</literal> and will forget about them between sessions.
6234 This makes profiling cookies useless, but won't break sites which require cookies so
6235 that you can log in for transactions. This is generally turned on for all
6236 sites, and is the recommended setting.
6239 It makes <emphasis>no sense at all</emphasis> to use <literal>session-cookies-only</literal>
6240 together with <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal> or
6241 <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>. If you do, cookies
6242 will be plainly killed.
6245 Note that it is up to the browser how it handles such cookies without an <quote>expires</quote>
6246 field. If you use an exotic browser, you might want to try it out to be sure.
6249 This setting also has no effect on cookies that may have been stored
6250 previously by the browser before starting <application>Privoxy</application>.
6251 These would have to be removed manually.
6254 <application>Privoxy</application> also uses
6255 the <link linkend="filter-content-cookies">content-cookies filter</link>
6256 to block some types of cookies. Content cookies are not effected by
6257 <literal>session-cookies-only</literal>.
6263 <term>Example usage:</term>
6265 <screen>+session-cookies-only</screen>
6272 <!-- ~~~~~ New section ~~~~~ -->
6273 <sect3 renderas="sect4" id="set-image-blocker">
6274 <title>set-image-blocker</title>
6278 <term>Typical use:</term>
6280 <para>Choose the replacement for blocked images</para>
6285 <term>Effect:</term>
6288 This action alone doesn't do anything noticeable. If <emphasis>both</emphasis>
6289 <literal><link linkend="block">block</link></literal> <emphasis>and</emphasis> <literal><link
6290 linkend="handle-as-image">handle-as-image</link></literal> <emphasis>also</emphasis>
6291 apply, i.e. if the request is to be blocked as an image,
6292 <emphasis>then</emphasis> the parameter of this action decides what will be
6293 sent as a replacement.
6300 <!-- Boolean, Parameterized, Multi-value -->
6302 <para>Parameterized.</para>
6307 <term>Parameter:</term>
6312 <quote>pattern</quote> to send a built-in checkerboard pattern image. The image is visually
6313 decent, scales very well, and makes it obvious where banners were busted.
6318 <quote>blank</quote> to send a built-in transparent image. This makes banners disappear
6319 completely, but makes it hard to detect where <application>Privoxy</application> has blocked
6320 images on a given page and complicates troubleshooting if <application>Privoxy</application>
6321 has blocked innocent images, like navigation icons.
6326 <quote><replaceable class="parameter">target-url</replaceable></quote> to
6327 send a redirect to <replaceable class="parameter">target-url</replaceable>. You can redirect
6328 to any image anywhere, even in your local filesystem via <quote>file:///</quote> URL.
6329 (But note that not all browsers support redirecting to a local file system).
6332 A good application of redirects is to use special <application>Privoxy</application>-built-in
6333 URLs, which send the built-in images, as <replaceable class="parameter">target-url</replaceable>.
6334 This has the same visual effect as specifying <quote>blank</quote> or <quote>pattern</quote> in
6335 the first place, but enables your browser to cache the replacement image, instead of requesting
6336 it over and over again.
6347 The URLs for the built-in images are <quote>http://config.privoxy.org/send-banner?type=<replaceable
6348 class="parameter">type</replaceable></quote>, where <replaceable class="parameter">type</replaceable> is
6349 either <quote>blank</quote> or <quote>pattern</quote>.
6352 There is a third (advanced) type, called <quote>auto</quote>. It is <emphasis>NOT</emphasis> to be
6353 used in <literal>set-image-blocker</literal>, but meant for use from <link linkend="filter-file">filters</link>.
6354 Auto will select the type of image that would have applied to the referring page, had it been an image.
6360 <term>Example usage:</term>
6365 <screen>+set-image-blocker{pattern}</screen>
6367 Redirect to the BSD daemon:
6369 <screen>+set-image-blocker{http://www.freebsd.org/gifs/dae_up3.gif}</screen>
6371 Redirect to the built-in pattern for better caching:
6373 <screen>+set-image-blocker{http://config.privoxy.org/send-banner?type=pattern}</screen>
6380 <!-- ~~~~~ New section ~~~~~ -->
6381 <sect3 id="summary">
6382 <title>Summary</title>
6384 Note that many of these actions have the potential to cause a page to
6385 misbehave, possibly even not to display at all. There are many ways
6386 a site designer may choose to design his site, and what HTTP header
6387 content, and other criteria, he may depend on. There is no way to have hard
6388 and fast rules for all sites. See the <link
6389 linkend="ACTIONSANAT">Appendix</link> for a brief example on troubleshooting
6395 <!-- ~~~~~ New section ~~~~~ -->
6396 <sect2 id="aliases">
6397 <title>Aliases</title>
6399 Custom <quote>actions</quote>, known to <application>Privoxy</application>
6400 as <quote>aliases</quote>, can be defined by combining other actions.
6401 These can in turn be invoked just like the built-in actions.
6402 Currently, an alias name can contain any character except space, tab,
6404 <quote>{</quote> and <quote>}</quote>, but we <emphasis>strongly
6405 recommend</emphasis> that you only use <quote>a</quote> to <quote>z</quote>,
6406 <quote>0</quote> to <quote>9</quote>, <quote>+</quote>, and <quote>-</quote>.
6407 Alias names are not case sensitive, and are not required to start with a
6408 <quote>+</quote> or <quote>-</quote> sign, since they are merely textually
6412 Aliases can be used throughout the actions file, but they <emphasis>must be
6413 defined in a special section at the top of the file!</emphasis>
6414 And there can only be one such section per actions file. Each actions file may
6415 have its own alias section, and the aliases defined in it are only visible
6419 There are two main reasons to use aliases: One is to save typing for frequently
6420 used combinations of actions, the other one is a gain in flexibility: If you
6421 decide once how you want to handle shops by defining an alias called
6422 <quote>shop</quote>, you can later change your policy on shops in
6423 <emphasis>one</emphasis> place, and your changes will take effect everywhere
6424 in the actions file where the <quote>shop</quote> alias is used. Calling aliases
6425 by their purpose also makes your actions files more readable.
6428 Currently, there is one big drawback to using aliases, though:
6429 <application>Privoxy</application>'s built-in web-based action file
6430 editor honors aliases when reading the actions files, but it expands
6431 them before writing. So the effects of your aliases are of course preserved,
6432 but the aliases themselves are lost when you edit sections that use aliases
6437 Now let's define some aliases...
6441 # Useful custom aliases we can use later.
6443 # Note the (required!) section header line and that this section
6444 # must be at the top of the actions file!
6448 # These aliases just save typing later:
6449 # (Note that some already use other aliases!)
6451 +crunch-all-cookies = +<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> +<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
6452 -crunch-all-cookies = -<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> -<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
6453 +block-as-image = +block{Blocked image.} +handle-as-image
6454 allow-all-cookies = -crunch-all-cookies -<link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> -<link linkend="FILTER-CONTENT-COOKIES">filter{content-cookies}</link>
6456 # These aliases define combinations of actions
6457 # that are useful for certain types of sites:
6459 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>
6461 shop = -crunch-all-cookies -<link linkend="FILTER-ALL-POPUPS">filter{all-popups}</link>
6463 # Short names for other aliases, for really lazy people ;-)
6465 c0 = +crunch-all-cookies
6466 c1 = -crunch-all-cookies</screen>
6469 ...and put them to use. These sections would appear in the lower part of an
6470 actions file and define exceptions to the default actions (as specified further
6471 up for the <quote>/</quote> pattern):
6475 # These sites are either very complex or very keen on
6476 # user data and require minimal interference to work:
6479 .office.microsoft.com
6480 .windowsupdate.microsoft.com
6481 # Gmail is really mail.google.com, not gmail.com
6485 # Allow cookies (for setting and retrieving your customer data)
6489 .worldpay.com # for quietpc.com
6492 # These shops require pop-ups:
6494 {-filter{all-popups} -filter{unsolicited-popups}}
6496 .overclockers.co.uk</screen>
6499 Aliases like <quote>shop</quote> and <quote>fragile</quote> are typically used for
6500 <quote>problem</quote> sites that require more than one action to be disabled
6501 in order to function properly.
6507 <!-- ~~~~~ New section ~~~~~ -->
6508 <sect2 id="act-examples">
6509 <title>Actions Files Tutorial</title>
6511 The above chapters have shown <link linkend="actions-file">which actions files
6512 there are and how they are organized</link>, how actions are <link
6513 linkend="actions">specified</link> and <link linkend="actions-apply">applied
6514 to URLs</link>, how <link linkend="af-patterns">patterns</link> work, and how to
6515 define and use <link linkend="aliases">aliases</link>. Now, let's look at an
6516 example <filename>match-all.action</filename>, <filename>default.action</filename>
6517 and <filename>user.action</filename> file and see how all these pieces come together:
6520 <sect3 id="match-all">
6521 <title>match-all.action</title>
6523 Remember <emphasis>all actions are disabled when matching starts</emphasis>,
6524 so we have to explicitly enable the ones we want.
6528 While the <filename>match-all.action</filename> file only contains a
6529 single section, it is probably the most important one. It has only one
6530 pattern, <quote><literal>/</literal></quote>, but this pattern
6531 <link linkend="af-patterns">matches all URLs</link>. Therefore, the set of
6532 actions used in this <quote>default</quote> section <emphasis>will
6533 be applied to all requests as a start</emphasis>. It can be partly or
6534 wholly overridden by other actions files like <filename>default.action</filename>
6535 and <filename>user.action</filename>, but it will still be largely responsible
6536 for your overall browsing experience.
6540 Again, at the start of matching, all actions are disabled, so there is
6541 no need to disable any actions here. (Remember: a <quote>+</quote>
6542 preceding the action name enables the action, a <quote>-</quote> disables!).
6543 Also note how this long line has been made more readable by splitting it into
6544 multiple lines with line continuation.
6549 +<link linkend="CHANGE-X-FORWARDED-FOR">change-x-forwarded-for{block}</link> \
6550 +<link linkend="HIDE-FROM-HEADER">hide-from-header{block}</link> \
6551 +<link linkend="SET-IMAGE-BLOCKER">set-image-blocker{pattern}</link> \
6557 The default behavior is now set.
6561 <sect3 id="default-action">
6562 <title>default.action</title>
6565 If you aren't a developer, there's no need for you to edit the
6566 <filename>default.action</filename> file. It is maintained by
6567 the &my-app; developers and if you disagree with some of the
6568 sections, you should overrule them in your <filename>user.action</filename>.
6572 Understanding the <filename>default.action</filename> file can
6573 help you with your <filename>user.action</filename>, though.
6577 The first section in this file is a special section for internal use
6578 that prevents older &my-app; versions from reading the file:
6582 ##########################################################################
6583 # Settings -- Don't change! For internal Privoxy use ONLY.
6584 ##########################################################################
6586 for-privoxy-version=3.0.11</screen>
6589 After that comes the (optional) alias section. We'll use the example
6590 section from the above <link linkend="aliases">chapter on aliases</link>,
6591 that also explains why and how aliases are used:
6595 ##########################################################################
6597 ##########################################################################
6600 # These aliases just save typing later:
6601 # (Note that some already use other aliases!)
6603 +crunch-all-cookies = +<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> +<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
6604 -crunch-all-cookies = -<link linkend="CRUNCH-INCOMING-COOKIES">crunch-incoming-cookies</link> -<link linkend="CRUNCH-OUTGOING-COOKIES">crunch-outgoing-cookies</link>
6605 +block-as-image = +block{Blocked image.} +handle-as-image
6606 mercy-for-cookies = -crunch-all-cookies -<link linkend="SESSION-COOKIES-ONLY">session-cookies-only</link> -<link linkend="FILTER-CONTENT-COOKIES">filter{content-cookies}</link>
6608 # These aliases define combinations of actions
6609 # that are useful for certain types of sites:
6611 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>
6612 shop = -crunch-all-cookies -<link linkend="FILTER-ALL-POPUPS">filter{all-popups}</link></screen>
6615 The first of our specialized sections is concerned with <quote>fragile</quote>
6616 sites, i.e. sites that require minimum interference, because they are either
6617 very complex or very keen on tracking you (and have mechanisms in place that
6618 make them unusable for people who avoid being tracked). We will use
6619 our pre-defined <literal>fragile</literal> alias instead of stating the list
6620 of actions explicitly:
6624 ##########################################################################
6625 # Exceptions for sites that'll break under the default action set:
6626 ##########################################################################
6628 # "Fragile" Use a minimum set of actions for these sites (see alias above):
6631 .office.microsoft.com # surprise, surprise!
6632 .windowsupdate.microsoft.com
6633 mail.google.com</screen>
6636 Shopping sites are not as fragile, but they typically
6637 require cookies to log in, and pop-up windows for shopping
6638 carts or item details. Again, we'll use a pre-defined alias:
6646 .worldpay.com # for quietpc.com
6648 .scan.co.uk</screen>
6651 The <literal><link linkend="FAST-REDIRECTS">fast-redirects</link></literal>
6652 action, which may have been enabled in <filename>match-all.action</filename>,
6653 breaks some sites. So disable it for popular sites where we know it misbehaves:
6657 { -<link linkend="FAST-REDIRECTS">fast-redirects</link> }
6661 .altavista.com/.*(like|url|link):http
6662 .altavista.com/trans.*urltext=http
6663 .nytimes.com</screen>
6666 It is important that <application>Privoxy</application> knows which
6667 URLs belong to images, so that <emphasis>if</emphasis> they are to
6668 be blocked, a substitute image can be sent, rather than an HTML page.
6669 Contacting the remote site to find out is not an option, since it
6670 would destroy the loading time advantage of banner blocking, and it
6671 would feed the advertisers information about you. We can mark any
6672 URL as an image with the <literal><link
6673 linkend="handle-as-image">handle-as-image</link></literal> action,
6674 and marking all URLs that end in a known image file extension is a
6679 ##########################################################################
6681 ##########################################################################
6683 # Define which file types will be treated as images, in case they get
6684 # blocked further down this file:
6686 { +<link linkend="HANDLE-AS-IMAGE">handle-as-image</link> }
6687 /.*\.(gif|jpe?g|png|bmp|ico)$</screen>
6690 And then there are known banner sources. They often use scripts to
6691 generate the banners, so it won't be visible from the URL that the
6692 request is for an image. Hence we block them <emphasis>and</emphasis>
6693 mark them as images in one go, with the help of our
6694 <literal>+block-as-image</literal> alias defined above. (We could of
6695 course just as well use <literal>+<link linkend="block">block</link>
6696 +<link linkend="handle-as-image">handle-as-image</link></literal> here.)
6697 Remember that the type of the replacement image is chosen by the
6698 <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>
6699 action. Since all URLs have matched the default section with its
6700 <literal>+<link linkend="set-image-blocker">set-image-blocker</link>{pattern}</literal>
6701 action before, it still applies and needn't be repeated:
6705 # Known ad generators:
6710 .ad.*.doubleclick.net
6711 .a.yimg.com/(?:(?!/i/).)*$
6712 .a[0-9].yimg.com/(?:(?!/i/).)*$
6717 One of the most important jobs of <application>Privoxy</application>
6718 is to block banners. Many of these can be <quote>blocked</quote>
6719 by the <literal><link linkend="filter">filter</link>{banners-by-size}</literal>
6720 action, which we enabled above, and which deletes the references to banner
6721 images from the pages while they are loaded, so the browser doesn't request
6722 them anymore, and hence they don't need to be blocked here. But this naturally
6723 doesn't catch all banners, and some people choose not to use filters, so we
6724 need a comprehensive list of patterns for banner URLs here, and apply the
6725 <literal><link linkend="block">block</link></literal> action to them.
6728 First comes many generic patterns, which do most of the work, by
6729 matching typical domain and path name components of banners. Then comes
6730 a list of individual patterns for specific sites, which is omitted here
6731 to keep the example short:
6735 ##########################################################################
6736 # Block these fine banners:
6737 ##########################################################################
6738 { <link linkend="BLOCK">+block{Banner ads.}</link> }
6746 /.*count(er)?\.(pl|cgi|exe|dll|asp|php[34]?)
6747 /(?:.*/)?(publicite|werbung|rekla(ma|me|am)|annonse|maino(kset|nta|s)?)/
6749 # Site-specific patterns (abbreviated):
6751 .hitbox.com</screen>
6754 It's quite remarkable how many advertisers actually call their banner
6755 servers ads.<replaceable>company</replaceable>.com, or call the directory
6756 in which the banners are stored literally <quote>banners</quote>. So the above
6757 generic patterns are surprisingly effective.
6760 But being very generic, they necessarily also catch URLs that we don't want
6761 to block. The pattern <literal>.*ads.</literal> e.g. catches
6762 <quote>nasty-<emphasis>ads</emphasis>.nasty-corp.com</quote> as intended,
6763 but also <quote>downlo<emphasis>ads</emphasis>.sourcefroge.net</quote> or
6764 <quote><emphasis>ads</emphasis>l.some-provider.net.</quote> So here come some
6765 well-known exceptions to the <literal>+<link linkend="BLOCK">block</link></literal>
6769 Note that these are exceptions to exceptions from the default! Consider the URL
6770 <quote>downloads.sourcefroge.net</quote>: Initially, all actions are deactivated,
6771 so it wouldn't get blocked. Then comes the defaults section, which matches the
6772 URL, but just deactivates the <literal><link linkend="BLOCK">block</link></literal>
6773 action once again. Then it matches <literal>.*ads.</literal>, an exception to the
6774 general non-blocking policy, and suddenly
6775 <literal><link linkend="BLOCK">+block</link></literal> applies. And now, it'll match
6776 <literal>.*loads.</literal>, where <literal><link linkend="BLOCK">-block</link></literal>
6777 applies, so (unless it matches <emphasis>again</emphasis> further down) it ends up
6778 with no <literal><link linkend="BLOCK">block</link></literal> action applying.
6782 ##########################################################################
6783 # Save some innocent victims of the above generic block patterns:
6784 ##########################################################################
6788 { -<link linkend="BLOCK">block</link> }
6789 adv[io]*. # (for advogato.org and advice.*)
6790 adsl. # (has nothing to do with ads)
6791 adobe. # (has nothing to do with ads either)
6792 ad[ud]*. # (adult.* and add.*)
6793 .edu # (universities don't host banners (yet!))
6794 .*loads. # (downloads, uploads etc)
6802 www.globalintersec.com/adv # (adv = advanced)
6803 www.ugu.com/sui/ugu/adv</screen>
6806 Filtering source code can have nasty side effects,
6807 so make an exception for our friends at sourceforge.net,
6808 and all paths with <quote>cvs</quote> in them. Note that
6809 <literal>-<link linkend="FILTER">filter</link></literal>
6810 disables <emphasis>all</emphasis> filters in one fell swoop!
6814 # Don't filter code!
6816 { -<link linkend="FILTER">filter</link> }
6821 .sourceforge.net</screen>
6824 The actual <filename>default.action</filename> is of course much more
6825 comprehensive, but we hope this example made clear how it works.
6830 <sect3 id="user-action"><title>user.action</title>
6833 So far we are painting with a broad brush by setting general policies,
6834 which would be a reasonable starting point for many people. Now,
6835 you might want to be more specific and have customized rules that
6836 are more suitable to your personal habits and preferences. These would
6837 be for narrowly defined situations like your ISP or your bank, and should
6838 be placed in <filename>user.action</filename>, which is parsed after all other
6839 actions files and hence has the last word, over-riding any previously
6840 defined actions. <filename>user.action</filename> is also a
6841 <emphasis>safe</emphasis> place for your personal settings, since
6842 <filename>default.action</filename> is actively maintained by the
6843 <application>Privoxy</application> developers and you'll probably want
6844 to install updated versions from time to time.
6848 So let's look at a few examples of things that one might typically do in
6849 <filename>user.action</filename>:
6853 <!-- brief sample user.action here -->
6856 # My user.action file. <fred@example.com></screen>
6859 As <link linkend="aliases">aliases</link> are local to the actions
6860 file that they are defined in, you can't use the ones from
6861 <filename>default.action</filename>, unless you repeat them here:
6865 # Aliases are local to the file they are defined in.
6866 # (Re-)define aliases for this file:
6870 # These aliases just save typing later, and the alias names should
6871 # be self explanatory.
6873 +crunch-all-cookies = +crunch-incoming-cookies +crunch-outgoing-cookies
6874 -crunch-all-cookies = -crunch-incoming-cookies -crunch-outgoing-cookies
6875 allow-all-cookies = -crunch-all-cookies -session-cookies-only
6876 allow-popups = -filter{all-popups}
6877 +block-as-image = +block{Blocked as image.} +handle-as-image
6878 -block-as-image = -block
6880 # These aliases define combinations of actions that are useful for
6881 # certain types of sites:
6883 fragile = -block -crunch-all-cookies -filter -fast-redirects -hide-referrer
6884 shop = -crunch-all-cookies allow-popups
6886 # Allow ads for selected useful free sites:
6888 allow-ads = -block -filter{banners-by-size} -filter{banners-by-link}
6890 # Alias for specific file types that are text, but might have conflicting
6891 # MIME types. We want the browser to force these to be text documents.
6892 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>
6895 Say you have accounts on some sites that you visit regularly, and
6896 you don't want to have to log in manually each time. So you'd like
6897 to allow persistent cookies for these sites. The
6898 <literal>allow-all-cookies</literal> alias defined above does exactly
6899 that, i.e. it disables crunching of cookies in any direction, and the
6900 processing of cookies to make them only temporary.
6904 { allow-all-cookies }
6908 .redhat.com</screen>
6911 Your bank is allergic to some filter, but you don't know which, so you disable them all:
6915 { -<link linkend="FILTER">filter</link> }
6916 .your-home-banking-site.com</screen>
6919 Some file types you may not want to filter for various reasons:
6923 # Technical documentation is likely to contain strings that might
6924 # erroneously get altered by the JavaScript-oriented filters:
6929 # And this stupid host sends streaming video with a wrong MIME type,
6930 # so that Privoxy thinks it is getting HTML and starts filtering:
6932 stupid-server.example.com/</screen>
6935 Example of a simple <link linkend="BLOCK">block</link> action. Say you've
6936 seen an ad on your favourite page on example.com that you want to get rid of.
6937 You have right-clicked the image, selected <quote>copy image location</quote>
6938 and pasted the URL below while removing the leading http://, into a
6939 <literal>{ +block{} }</literal> section. Note that <literal>{ +handle-as-image
6940 }</literal> need not be specified, since all URLs ending in
6941 <literal>.gif</literal> will be tagged as images by the general rules as set
6942 in default.action anyway:
6946 { +<link linkend="BLOCK">block</link>{Nasty ads.} }
6947 www.example.com/nasty-ads/sponsor\.gif
6948 another.example.net/more/junk/here/</screen>
6951 The URLs of dynamically generated banners, especially from large banner
6952 farms, often don't use the well-known image file name extensions, which
6953 makes it impossible for <application>Privoxy</application> to guess
6954 the file type just by looking at the URL.
6955 You can use the <literal>+block-as-image</literal> alias defined above for
6957 Note that objects which match this rule but then turn out NOT to be an
6958 image are typically rendered as a <quote>broken image</quote> icon by the
6959 browser. Use cautiously.
6967 ar.atwola.com/</screen>
6970 Now you noticed that the default configuration breaks Forbes Magazine,
6971 but you were too lazy to find out which action is the culprit, and you
6972 were again too lazy to give <link linkend="contact">feedback</link>, so
6973 you just used the <literal>fragile</literal> alias on the site, and
6974 -- <emphasis>whoa!</emphasis> -- it worked. The <literal>fragile</literal>
6975 aliases disables those actions that are most likely to break a site. Also,
6976 good for testing purposes to see if it is <application>Privoxy</application>
6977 that is causing the problem or not. We later find other regular sites
6978 that misbehave, and add those to our personalized list of troublemakers:
6985 .mybank.com</screen>
6988 You like the <quote>fun</quote> text replacements in <filename>default.filter</filename>,
6989 but it is disabled in the distributed actions file.
6990 So you'd like to turn it on in your private,
6991 update-safe config, once and for all:
6995 { +<link linkend="filter-fun">filter{fun}</link> }
6996 / # For ALL sites!</screen>
6999 Note that the above is not really a good idea: There are exceptions
7000 to the filters in <filename>default.action</filename> for things that
7001 really shouldn't be filtered, like code on CVS->Web interfaces. Since
7002 <filename>user.action</filename> has the last word, these exceptions
7003 won't be valid for the <quote>fun</quote> filtering specified here.
7007 You might also worry about how your favourite free websites are
7008 funded, and find that they rely on displaying banner advertisements
7009 to survive. So you might want to specifically allow banners for those
7010 sites that you feel provide value to you:
7020 Note that <literal>allow-ads</literal> has been aliased to
7021 <literal>-<link linkend="block">block</link></literal>,
7022 <literal>-<link linkend="filter-banners-by-size">filter{banners-by-size}</link></literal>, and
7023 <literal>-<link linkend="filter-banners-by-link">filter{banners-by-link}</link></literal> above.
7027 Invoke another alias here to force an over-ride of the MIME type <literal>
7028 application/x-sh</literal> which typically would open a download type
7029 dialog. In my case, I want to look at the shell script, and then I can save
7030 it should I choose to.
7038 <filename>user.action</filename> is generally the best place to define
7039 exceptions and additions to the default policies of
7040 <filename>default.action</filename>. Some actions are safe to have their
7041 default policies set here though. So let's set a default policy to have a
7042 <quote>blank</quote> image as opposed to the checkerboard pattern for
7043 <emphasis>ALL</emphasis> sites. <quote>/</quote> of course matches all URL
7048 { +<link linkend="set-image-blocker">set-image-blocker{blank}</link> }
7049 / # ALL sites</screen>
7054 <!-- ~ End section ~ -->
7058 <!-- ~ End section ~ -->
7060 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
7062 <sect1 id="filter-file">
7063 <title>Filter Files</title>
7066 On-the-fly text substitutions need
7067 to be defined in a <quote>filter file</quote>. Once defined, they
7068 can then be invoked as an <quote>action</quote>.
7072 &my-app; supports four different pcrs-based filter actions:
7073 <literal><link linkend="filter">filter</link></literal> to
7074 rewrite the content that is send to the client,
7075 <literal><link linkend="client-header-filter">client-header-filter</link></literal>
7076 to rewrite headers that are send by the client,
7077 <literal><link linkend="server-header-filter">server-header-filter</link></literal>
7078 to rewrite headers that are send by the server, and
7079 <literal><link linkend="client-body-filter">client-body-filter</link></literal>
7080 to rewrite client request body.
7084 &my-app; also supports two tagger actions:
7085 <literal><link linkend="client-header-tagger">client-header-tagger</link></literal>
7087 <literal><link linkend="server-header-tagger">server-header-tagger</link></literal>.
7088 Taggers and filters use the same syntax in the filter files, the difference
7089 is that taggers don't modify the text they are filtering, but use a rewritten
7090 version of the filtered text as tag. The tags can then be used to change the
7091 applying actions through sections with <link linkend="tag-pattern">tag-patterns</link>.
7095 Finally &my-app; supports the
7096 <literal><link linkend="external-filter">external-filter</link></literal> action
7097 to enable <literal><link linkend="external-filter-syntax">external filters</link></literal>
7098 written in proper programming languages.
7103 Multiple filter files can be defined through the <literal> <link
7104 linkend="filterfile">filterfile</link></literal> config directive. The filters
7105 as supplied by the developers are located in
7106 <filename>default.filter</filename>. It is recommended that any locally
7107 defined or modified filters go in a separately defined file such as
7108 <filename>user.filter</filename>.
7112 Common tasks for content filters are to eliminate common annoyances in
7113 HTML and JavaScript, such as pop-up windows,
7114 exit consoles, crippled windows without navigation tools, the
7115 infamous <BLINK> tag etc, to suppress images with certain
7116 width and height attributes (standard banner sizes or web-bugs),
7117 or just to have fun.
7121 Enabled content filters are applied to any content whose
7122 <quote>Content Type</quote> header is recognised as a sign
7123 of text-based content, with the exception of <literal>text/plain</literal>.
7124 Use the <link linkend="FORCE-TEXT-MODE">force-text-mode</link> action
7125 to also filter other content.
7129 Substitutions are made at the source level, so if you want to <quote>roll
7130 your own</quote> filters, you should first be familiar with HTML syntax,
7131 and, of course, regular expressions.
7135 Just like the <link linkend="actions-file">actions files</link>, the
7136 filter file is organized in sections, which are called <emphasis>filters</emphasis>
7137 here. Each filter consists of a heading line, that starts with one of the
7138 <emphasis>keywords</emphasis> <literal>FILTER:</literal>,
7139 <literal>CLIENT-HEADER-FILTER:</literal>, <literal>SERVER-HEADER-FILTER:</literal> or
7140 <literal>CLIENT-BODY-FILTER:</literal>
7141 followed by the filter's <emphasis>name</emphasis>, and a short (one line)
7142 <emphasis>description</emphasis> of what it does. Below that line
7143 come the <emphasis>jobs</emphasis>, i.e. lines that define the actual
7144 text substitutions. By convention, the name of a filter
7145 should describe what the filter <emphasis>eliminates</emphasis>. The
7146 comment is used in the <ulink url="http://config.privoxy.org/">web-based
7147 user interface</ulink>.
7151 Once a filter called <replaceable>name</replaceable> has been defined
7152 in the filter file, it can be invoked by using an action of the form
7153 +<literal><link linkend="filter">filter</link>{<replaceable>name</replaceable>}</literal>
7154 in any <link linkend="actions-file">actions file</link>.
7158 Filter definitions start with a header line that contains the filter
7159 type, the filter name and the filter description.
7160 A content filter header line for a filter called <quote>foo</quote> could look
7164 <screen>FILTER: foo Replace all "foo" with "bar"</screen>
7167 Below that line, and up to the next header line, come the jobs that
7168 define what text replacements the filter executes. They are specified
7169 in a syntax that imitates <ulink url="http://www.perl.org/">Perl</ulink>'s
7170 <literal>s///</literal> operator. If you are familiar with Perl, you
7171 will find this to be quite intuitive, and may want to look at the
7172 PCRS documentation for the subtle differences to Perl behaviour.
7176 Most notably, the non-standard option letter <literal>U</literal> is supported,
7177 which turns the default to ungreedy matching (add <literal>?</literal> to
7178 quantifiers to turn them greedy again).
7182 The non-standard option letter <literal>D</literal> (dynamic) allows
7183 to use the variables $host, $origin (the IP address the request came from),
7184 $path, $url and $listen-address (the address on which Privoxy accepted the
7185 client request. Example: 127.0.0.1:8118).
7186 They will be replaced with the value they refer to before the filter
7191 Note that '$' is a bad choice for a delimiter in a dynamic filter as you
7192 might end up with unintended variables if you use a variable name
7193 directly after the delimiter. Variables will be resolved without
7194 escaping anything, therefore you also have to be careful not to chose
7195 delimiters that appear in the replacement text. For example '<' should
7196 be save, while '?' will sooner or later cause conflicts with $url.
7200 The non-standard option letter <literal>T</literal> (trivial) prevents
7201 parsing for backreferences in the substitute. Use it if you want to include
7202 text like '$&' in your substitute without quoting.
7207 <ulink url="https://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
7208 Expressions</quote></ulink>, you might want to take a look at
7209 the <link linkend="regex">Appendix on regular expressions</link>, and
7210 see the <ulink url="http://perldoc.perl.org/perlre.html">Perl
7212 <ulink url="http://perldoc.perl.org/perlop.html">the
7213 <literal>s///</literal> operator's syntax</ulink> and <ulink
7214 url="http://perldoc.perl.org/perlre.html">Perl-style regular
7215 expressions</ulink> in general.
7216 The below examples might also help to get you started.
7220 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
7222 <sect2 id="filter-file-tut"><title>Filter File Tutorial</title>
7224 Now, let's complete our <quote>foo</quote> content filter. We have already defined
7225 the heading, but the jobs are still missing. Since all it does is to replace
7226 <quote>foo</quote> with <quote>bar</quote>, there is only one (trivial) job
7230 <screen>s/foo/bar/</screen>
7233 But wait! Didn't the comment say that <emphasis>all</emphasis> occurrences
7234 of <quote>foo</quote> should be replaced? Our current job will only take
7235 care of the first <quote>foo</quote> on each page. For global substitution,
7236 we'll need to add the <literal>g</literal> option:
7239 <screen>s/foo/bar/g</screen>
7242 Our complete filter now looks like this:
7245 <screen>FILTER: foo Replace all "foo" with "bar"
7246 s/foo/bar/g</screen>
7249 Let's look at some real filters for more interesting examples. Here you see
7250 a filter that protects against some common annoyances that arise from JavaScript
7251 abuse. Let's look at its jobs one after the other:
7256 FILTER: js-annoyances Get rid of particularly annoying JavaScript abuse
7258 # Get rid of JavaScript referrer tracking. Test page: http://www.randomoddness.com/untitled.htm
7260 s|(<script.*)document\.referrer(.*</script>)|$1"Not Your Business!"$2|Usg</screen>
7263 Following the header line and a comment, you see the job. Note that it uses
7264 <literal>|</literal> as the delimiter instead of <literal>/</literal>, because
7265 the pattern contains a forward slash, which would otherwise have to be escaped
7266 by a backslash (<literal>\</literal>).
7270 Now, let's examine the pattern: it starts with the text <literal><script.*</literal>
7271 enclosed in parentheses. Since the dot matches any character, and <literal>*</literal>
7272 means: <quote>Match an arbitrary number of the element left of myself</quote>, this
7273 matches <quote><script</quote>, followed by <emphasis>any</emphasis> text, i.e.
7274 it matches the whole page, from the start of the first <script> tag.
7278 That's more than we want, but the pattern continues: <literal>document\.referrer</literal>
7279 matches only the exact string <quote>document.referrer</quote>. The dot needed to
7280 be <emphasis>escaped</emphasis>, i.e. preceded by a backslash, to take away its
7281 special meaning as a joker, and make it just a regular dot. So far, the meaning is:
7282 Match from the start of the first <script> tag in a the page, up to, and including,
7283 the text <quote>document.referrer</quote>, if <emphasis>both</emphasis> are present
7284 in the page (and appear in that order).
7288 But there's still more pattern to go. The next element, again enclosed in parentheses,
7289 is <literal>.*</script></literal>. You already know what <literal>.*</literal>
7290 means, so the whole pattern translates to: Match from the start of the first <script>
7291 tag in a page to the end of the last <script> tag, provided that the text
7292 <quote>document.referrer</quote> appears somewhere in between.
7296 This is still not the whole story, since we have ignored the options and the parentheses:
7297 The portions of the page matched by sub-patterns that are enclosed in parentheses, will be
7298 remembered and be available through the variables <literal>$1, $2, ...</literal> in
7299 the substitute. The <literal>U</literal> option switches to ungreedy matching, which means
7300 that the first <literal>.*</literal> in the pattern will only <quote>eat up</quote> all
7301 text in between <quote><script</quote> and the <emphasis>first</emphasis> occurrence
7302 of <quote>document.referrer</quote>, and that the second <literal>.*</literal> will
7303 only span the text up to the <emphasis>first</emphasis> <quote></script></quote>
7304 tag. Furthermore, the <literal>s</literal> option says that the match may span
7305 multiple lines in the page, and the <literal>g</literal> option again means that the
7306 substitution is global.
7310 So, to summarize, the pattern means: Match all scripts that contain the text
7311 <quote>document.referrer</quote>. Remember the parts of the script from
7312 (and including) the start tag up to (and excluding) the string
7313 <quote>document.referrer</quote> as <literal>$1</literal>, and the part following
7314 that string, up to and including the closing tag, as <literal>$2</literal>.
7318 Now the pattern is deciphered, but wasn't this about substituting things? So
7319 lets look at the substitute: <literal>$1"Not Your Business!"$2</literal> is
7320 easy to read: The text remembered as <literal>$1</literal>, followed by
7321 <literal>"Not Your Business!"</literal> (<emphasis>including</emphasis>
7322 the quotation marks!), followed by the text remembered as <literal>$2</literal>.
7323 This produces an exact copy of the original string, with the middle part
7324 (the <quote>document.referrer</quote>) replaced by <literal>"Not Your
7325 Business!"</literal>.
7329 The whole job now reads: Replace <quote>document.referrer</quote> by
7330 <literal>"Not Your Business!"</literal> wherever it appears inside a
7331 <script> tag. Note that this job won't break JavaScript syntax,
7332 since both the original and the replacement are syntactically valid
7333 string objects. The script just won't have access to the referrer
7334 information anymore.
7338 We'll show you two other jobs from the JavaScript taming department, but
7339 this time only point out the constructs of special interest:
7343 # The status bar is for displaying link targets, not pointless blahblah
7345 s/window\.status\s*=\s*(['"]).*?\1/dUmMy=1/ig</screen>
7348 <literal>\s</literal> stands for whitespace characters (space, tab, newline,
7349 carriage return, form feed), so that <literal>\s*</literal> means: <quote>zero
7350 or more whitespace</quote>. The <literal>?</literal> in <literal>.*?</literal>
7351 makes this matching of arbitrary text ungreedy. (Note that the <literal>U</literal>
7352 option is not set). The <literal>['"]</literal> construct means: <quote>a single
7353 <emphasis>or</emphasis> a double quote</quote>. Finally, <literal>\1</literal> is
7354 a back-reference to the first parenthesis just like <literal>$1</literal> above,
7355 with the difference that in the <emphasis>pattern</emphasis>, a backslash indicates
7356 a back-reference, whereas in the <emphasis>substitute</emphasis>, it's the dollar.
7360 So what does this job do? It replaces assignments of single- or double-quoted
7361 strings to the <quote>window.status</quote> object with a dummy assignment
7362 (using a variable name that is hopefully odd enough not to conflict with
7363 real variables in scripts). Thus, it catches many cases where e.g. pointless
7364 descriptions are displayed in the status bar instead of the link target when
7365 you move your mouse over links.
7369 # Kill OnUnload popups. Yummy. Test: http://www.zdnet.com/zdsubs/yahoo/tree/yfs.html
7371 s/(<body [^>]*)onunload(.*>)/$1never$2/iU</screen>
7375 <ulink url="http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html#Events-eventgroupings-htmlevents">OnUnload
7376 event binding</ulink> in the HTML DOM was a <emphasis>CRIME</emphasis>.
7377 When I close a browser window, I want it to close and die. Basta.
7378 This job replaces the <quote>onunload</quote> attribute in
7379 <quote><body></quote> tags with the dummy word <literal>never</literal>.
7380 Note that the <literal>i</literal> option makes the pattern matching
7381 case-insensitive. Also note that ungreedy matching alone doesn't always guarantee
7382 a minimal match: In the first parenthesis, we had to use <literal>[^>]*</literal>
7383 instead of <literal>.*</literal> to prevent the match from exceeding the
7384 <body> tag if it doesn't contain <quote>OnUnload</quote>, but the page's
7389 The last example is from the fun department:
7393 FILTER: fun Fun text replacements
7395 # Spice the daily news:
7397 s/microsoft(?!\.com)/MicroSuck/ig</screen>
7400 Note the <literal>(?!\.com)</literal> part (a so-called negative lookahead)
7401 in the job's pattern, which means: Don't match, if the string
7402 <quote>.com</quote> appears directly following <quote>microsoft</quote>
7403 in the page. This prevents links to microsoft.com from being trashed, while
7404 still replacing the word everywhere else.
7408 # Buzzword Bingo (example for extended regex syntax)
7410 s* industry[ -]leading \
7412 | customer[ -]focused \
7413 | market[ -]driven \
7414 | award[ -]winning # Comments are OK, too! \
7415 | high[ -]performance \
7416 | solutions[ -]based \
7420 *<font color="red"><b>BINGO!</b></font> \
7424 The <literal>x</literal> option in this job turns on extended syntax, and allows for
7425 e.g. the liberal use of (non-interpreted!) whitespace for nicer formatting.
7433 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
7435 <sect2 id="predefined-filters"><title>The Pre-defined Filters</title>
7439 Note each filter is also listed in the +filter action section above. Please
7440 keep these listings in sync.
7445 The distribution <filename>default.filter</filename> file contains a selection of
7446 pre-defined filters for your convenience:
7451 <term><emphasis>js-annoyances</emphasis></term>
7454 The purpose of this filter is to get rid of particularly annoying JavaScript abuse.
7460 replaces JavaScript references to the browser's referrer information
7461 with the string "Not Your Business!". This compliments the <literal><link
7462 linkend="hide-referrer">hide-referrer</link></literal> action on the content level.
7467 removes the bindings to the DOM's
7468 <ulink url="http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/events.html#Events-eventgroupings-htmlevents">unload
7469 event</ulink> which we feel has no right to exist and is responsible for most <quote>exit consoles</quote>, i.e.
7470 nasty windows that pop up when you close another one.
7475 removes code that causes new windows to be opened with undesired properties, such as being
7476 full-screen, non-resizeable, without location, status or menu bar etc.
7481 Use with caution. This is an aggressive filter, and can break sites that
7482 rely heavily on JavaScript.
7488 <term><emphasis>js-events</emphasis></term>
7491 This is a very radical measure. It removes virtually all JavaScript event bindings, which
7492 means that scripts can not react to user actions such as mouse movements or clicks, window
7493 resizing etc, anymore. Use with caution!
7496 We <emphasis>strongly discourage</emphasis> using this filter as a default since it breaks
7497 many legitimate scripts. It is meant for use only on extra-nasty sites (should you really
7504 <term><emphasis>html-annoyances</emphasis></term>
7507 This filter will undo many common instances of HTML based abuse.
7510 The <literal>BLINK</literal> and <literal>MARQUEE</literal> tags
7511 are neutralized (yeah baby!), and browser windows will be created as
7512 resizeable (as of course they should be!), and will have location,
7513 scroll and menu bars -- even if specified otherwise.
7519 <term><emphasis>content-cookies</emphasis></term>
7522 Most cookies are set in the HTTP dialog, where they can be intercepted
7524 <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal>
7525 and <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>
7526 actions. But web sites increasingly make use of HTML meta tags and JavaScript
7527 to sneak cookies to the browser on the content level.
7530 This filter disables most HTML and JavaScript code that reads or sets
7531 cookies. It cannot detect all clever uses of these types of code, so it
7532 should not be relied on as an absolute fix. Use it wherever you would also
7533 use the cookie crunch actions.
7539 <term><emphasis>refresh-tags</emphasis></term>
7542 Disable any refresh tags if the interval is greater than nine seconds (so
7543 that redirections done via refresh tags are not destroyed). This is useful
7544 for dial-on-demand setups, or for those who find this HTML feature
7551 <term><emphasis>unsolicited-popups</emphasis></term>
7554 This filter attempts to prevent only <quote>unsolicited</quote> pop-up
7555 windows from opening, yet still allow pop-up windows that the user
7556 has explicitly chosen to open. It was added in version 3.0.1,
7557 as an improvement over earlier such filters.
7560 Technical note: The filter works by redefining the window.open JavaScript
7561 function to a dummy function, <literal>PrivoxyWindowOpen()</literal>,
7562 during the loading and rendering phase of each HTML page access, and
7563 restoring the function afterward.
7566 This is recommended only for browsers that cannot perform this function
7567 reliably themselves. And be aware that some sites require such windows
7568 in order to function normally. Use with caution.
7574 <term><emphasis>all-popups</emphasis></term>
7577 Attempt to prevent <emphasis>all</emphasis> pop-up windows from opening.
7578 Note this should be used with even more discretion than the above, since
7579 it is more likely to break some sites that require pop-ups for normal
7580 usage. Use with caution.
7586 <term><emphasis>img-reorder</emphasis></term>
7589 This is a helper filter that has no value if used alone. It makes the
7590 <literal>banners-by-size</literal> and <literal>banners-by-link</literal>
7591 (see below) filters more effective and should be enabled together with them.
7597 <term><emphasis>banners-by-size</emphasis></term>
7600 This filter removes image tags purely based on what size they are. Fortunately
7601 for us, many ads and banner images tend to conform to certain standardized
7602 sizes, which makes this filter quite effective for ad stripping purposes.
7605 Occasionally this filter will cause false positives on images that are not ads,
7606 but just happen to be of one of the standard banner sizes.
7609 Recommended only for those who require extreme ad blocking. The default
7610 block rules should catch 95+% of all ads <emphasis>without</emphasis> this filter enabled.
7616 <term><emphasis>banners-by-link</emphasis></term>
7619 This is an experimental filter that attempts to kill any banners if
7620 their URLs seem to point to known or suspected click trackers. It is currently
7621 not of much value and is not recommended for use by default.
7627 <term><emphasis>webbugs</emphasis></term>
7630 Webbugs are small, invisible images (technically 1X1 GIF images), that
7631 are used to track users across websites, and collect information on them.
7632 As an HTML page is loaded by the browser, an embedded image tag causes the
7633 browser to contact a third-party site, disclosing the tracking information
7634 through the requested URL and/or cookies for that third-party domain, without
7635 the user ever becoming aware of the interaction with the third-party site.
7636 HTML-ized spam also uses a similar technique to verify email addresses.
7639 This filter removes the HTML code that loads such <quote>webbugs</quote>.
7645 <term><emphasis>tiny-textforms</emphasis></term>
7648 A rather special-purpose filter that can be used to enlarge textareas (those
7649 multi-line text boxes in web forms) and turn off hard word wrap in them.
7650 It was written for the sourceforge.net tracker system where such boxes are
7651 a nuisance, but it can be handy on other sites, too.
7654 It is not recommended to use this filter as a default.
7660 <term><emphasis>jumping-windows</emphasis></term>
7663 Many consider windows that move, or resize themselves to be abusive. This filter
7664 neutralizes the related JavaScript code. Note that some sites might not display
7665 or behave as intended when using this filter. Use with caution.
7671 <term><emphasis>frameset-borders</emphasis></term>
7674 Some web designers seem to assume that everyone in the world will view their
7675 web sites using the same browser brand and version, screen resolution etc,
7676 because only that assumption could explain why they'd use static frame sizes,
7677 yet prevent their frames from being resized by the user, should they be too
7678 small to show their whole content.
7681 This filter removes the related HTML code. It should only be applied to sites
7688 <term><emphasis>demoronizer</emphasis></term>
7691 Many Microsoft products that generate HTML use non-standard extensions (read:
7692 violations) of the ISO 8859-1 aka Latin-1 character set. This can cause those
7693 HTML documents to display with errors on standard-compliant platforms.
7696 This filter translates the MS-only characters into Latin-1 equivalents.
7697 It is not necessary when using MS products, and will cause corruption of
7698 all documents that use 8-bit character sets other than Latin-1. It's mostly
7699 worthwhile for Europeans on non-MS platforms, if weird garbage characters
7700 sometimes appear on some pages, or user agents that don't correct for this on
7703 My version of Mozilla (ancient) shows little square boxes for quote
7704 characters, and apostrophes on moronized pages. So many pages have this, I
7705 can read them fine now. HB 08/27/06
7712 <term><emphasis>shockwave-flash</emphasis></term>
7715 A filter for shockwave haters. As the name suggests, this filter strips code
7716 out of web pages that is used to embed shockwave flash objects.
7724 <term><emphasis>quicktime-kioskmode</emphasis></term>
7727 Change HTML code that embeds Quicktime objects so that kioskmode, which
7728 prevents saving, is disabled.
7734 <term><emphasis>fun</emphasis></term>
7737 Text replacements for subversive browsing fun. Make fun of your favorite
7738 Monopolist or play buzzword bingo.
7744 <term><emphasis>crude-parental</emphasis></term>
7747 A demonstration-only filter that shows how <application>Privoxy</application>
7748 can be used to delete web content on a keyword basis.
7754 <term><emphasis>ie-exploits</emphasis></term>
7757 An experimental collection of text replacements to disable malicious HTML and JavaScript
7758 code that exploits known security holes in Internet Explorer.
7761 Presently, it only protects against Nimda and a cross-site scripting bug, and
7762 would need active maintenance to provide more substantial protection.
7768 <term><emphasis>site-specifics</emphasis></term>
7771 Some web sites have very specific problems, the cure for which doesn't apply
7772 anywhere else, or could even cause damage on other sites.
7775 This is a collection of such site-specific cures which should only be applied
7776 to the sites they were intended for, which is what the supplied
7777 <filename>default.action</filename> file does. Users shouldn't need to change
7778 anything regarding this filter.
7784 <term><emphasis>google</emphasis></term>
7787 A CSS based block for Google text ads. Also removes a width limitation
7788 and the toolbar advertisement.
7794 <term><emphasis>yahoo</emphasis></term>
7797 Another CSS based block, this time for Yahoo text ads. And removes
7798 a width limitation as well.
7804 <term><emphasis>msn</emphasis></term>
7807 Another CSS based block, this time for MSN text ads. And removes
7808 tracking URLs, as well as a width limitation.
7814 <term><emphasis>blogspot</emphasis></term>
7817 Cleans up some Blogspot blogs. Read the fine print before using this one!
7820 This filter also intentionally removes some navigation stuff and sets the
7821 page width to 100%. As a result, some rounded <quote>corners</quote> would
7822 appear to early or not at all and as fixing this would require a browser
7823 that understands background-size (CSS3), they are removed instead.
7829 <term><emphasis>xml-to-html</emphasis></term>
7832 Server-header filter to change the Content-Type from xml to html.
7838 <term><emphasis>html-to-xml</emphasis></term>
7841 Server-header filter to change the Content-Type from html to xml.
7847 <term><emphasis>no-ping</emphasis></term>
7850 Removes the non-standard <literal>ping</literal> attribute from
7851 anchor and area HTML tags.
7857 <term><emphasis>hide-tor-exit-notation</emphasis></term>
7860 Client-header filter to remove the <command>Tor</command> exit node notation
7861 found in Host and Referer headers.
7864 If &my-app; and <command>Tor</command> are chained and &my-app;
7865 is configured to use socks4a, one can use <quote>http://www.example.org.foobar.exit/</quote>
7866 to access the host <quote>www.example.org</quote> through the
7867 <command>Tor</command> exit node <quote>foobar</quote>.
7870 As the HTTP client isn't aware of this notation, it treats the
7871 whole string <quote>www.example.org.foobar.exit</quote> as host and uses it
7872 for the <quote>Host</quote> and <quote>Referer</quote> headers. From the
7873 server's point of view the resulting headers are invalid and can cause problems.
7876 An invalid <quote>Referer</quote> header can trigger <quote>hot-linking</quote>
7877 protections, an invalid <quote>Host</quote> header will make it impossible for
7878 the server to find the right vhost (several domains hosted on the same IP address).
7881 This client-header filter removes the <quote>foo.exit</quote> part in those headers
7882 to prevent the mentioned problems. Note that it only modifies
7883 the HTTP headers, it doesn't make it impossible for the server
7884 to detect your <command>Tor</command> exit node based on the IP address
7885 the request is coming from.
7892 <term><emphasis> </emphasis></term>
7905 <!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
7906 <sect2 id="external-filter-syntax"><title>External filter syntax</title>
7908 External filters are scripts or programs that can modify the content in
7909 case common <literal><link linkend="filter">filters</link></literal>
7910 aren't powerful enough.
7913 External filters can be written in any language the platform &my-app; runs
7917 They are controlled with the
7918 <literal><link linkend="external-filter">external-filter</link></literal> action
7919 and have to be defined in the <literal><link linkend="filterfile">filterfile</link></literal>
7923 The header looks like any other filter, but instead of pcrs jobs, external
7924 filters contain a single job which can be a program or a shell script (which
7925 may call other scripts or programs).
7928 External filters read the content from STDIN and write the rewritten
7930 The environment variables PRIVOXY_URL, PRIVOXY_PATH, PRIVOXY_HOST,
7931 PRIVOXY_ORIGIN, PRIVOXY_LISTEN_ADDRESS can be used to get some details
7932 about the client request.
7935 &my-app; will temporary store the content to filter in the
7936 <literal><link linkend="temporary-directory">temporary-directory</link></literal>.
7940 EXTERNAL-FILTER: cat Pointless example filter that doesn't actually modify the content
7943 # Incorrect reimplementation of the filter above in POSIX shell.
7945 # Note that it's a single job that spans multiple lines, the line
7946 # breaks are not passed to the shell, thus the semicolons are required.
7948 # If the script isn't trivial, it is recommended to put it into an external file.
7950 # In general, writing external filters entirely in POSIX shell is not
7951 # considered a good idea.
7952 EXTERNAL-FILTER: cat2 Pointless example filter that despite its name may actually modify the content
7958 EXTERNAL-FILTER: rotate-image Rotate an image by 180 degree. Test filter with limited value.
7959 /usr/local/bin/convert - -rotate 180 -
7961 EXTERNAL-FILTER: citation-needed Adds a "[citation needed]" tag to an image. The coordinates may need adjustment.
7962 /usr/local/bin/convert - -pointsize 16 -fill white -annotate +17+418 "[citation needed]" -
7967 Currently external filters are executed with &my-app;'s privileges!
7968 Only use external filters you understand and trust.
7972 External filters are experimental and the syntax may change in the future.
7978 <!-- ~ End section ~ -->
7982 <!-- ~~~~~ New section ~~~~~ -->
7984 <sect1 id="templates">
7985 <title>Privoxy's Template Files</title>
7987 All <application>Privoxy</application> built-in pages, i.e. error pages such as the
7988 <ulink url="http://show-the-404-error.page"><quote>404 - No Such Domain</quote>
7989 error page</ulink>, the <ulink
7990 url="http://ads.bannerserver.example.com/nasty-ads/sponsor.html"><quote>BLOCKED</quote>
7992 and all pages of its <ulink url="http://config.privoxy.org/">web-based
7993 user interface</ulink>, are generated from <emphasis>templates</emphasis>.
7994 (<application>Privoxy</application> must be running for the above links to work as
7999 These templates are stored in a subdirectory of the <link linkend="confdir">configuration
8000 directory</link> called <filename>templates</filename>. On Unixish platforms,
8002 <ulink url="file:///etc/privoxy/templates/"><filename>/etc/privoxy/templates/</filename></ulink>.
8006 The templates are basically normal HTML files, but with place-holders (called symbols
8007 or exports), which <application>Privoxy</application> fills at run time. It
8008 is possible to edit the templates with a normal text editor, should you want
8009 to customize them. (<emphasis>Not recommended for the casual
8010 user</emphasis>). Should you create your own custom templates, you should use
8011 the <filename>config</filename> setting <link linkend="templdir">templdir</link>
8012 to specify an alternate location, so your templates do not get overwritten
8016 Note that just like in configuration files, lines starting
8017 with <literal>#</literal> are ignored when the templates are filled in.
8021 The place-holders are of the form <literal>@name@</literal>, and you will
8022 find a list of available symbols, which vary from template to template,
8023 in the comments at the start of each file. Note that these comments are not
8024 always accurate, and that it's probably best to look at the existing HTML
8025 code to find out which symbols are supported and what they are filled in with.
8029 A special application of this substitution mechanism is to make whole
8030 blocks of HTML code disappear when a specific symbol is set. We use this
8031 for many purposes, one of them being to include the beta warning in all
8032 our user interface (CGI) pages when <application>Privoxy</application>
8033 is in an alpha or beta development stage:
8037 <!-- @if-unstable-start -->
8039 ... beta warning HTML code goes here ...
8041 <!-- if-unstable-end@ --></screen>
8044 If the "unstable" symbol is set, everything in between and including
8045 <literal>@if-unstable-start</literal> and <literal>if-unstable-end@</literal>
8046 will disappear, leaving nothing but an empty comment:
8049 <screen><!-- --></screen>
8052 There's also an if-then-else construct and an <literal>#include</literal>
8053 mechanism, but you'll sure find out if you are inclined to edit the
8058 All templates refer to a style located at
8059 <ulink url="http://config.privoxy.org/send-stylesheet"><literal>http://config.privoxy.org/send-stylesheet</literal></ulink>.
8060 This is, of course, locally served by <application>Privoxy</application>
8061 and the source for it can be found and edited in the
8062 <filename>cgi-style.css</filename> template.
8067 <!-- ~ End section ~ -->
8071 <!-- ~~~~~ New section ~~~~~ -->
8073 <sect1 id="contact"><title>Contacting the Developers, Bug Reporting and Feature
8076 <!-- Include contacting.sgml boilerplate: -->
8078 <!-- end boilerplate -->
8082 <!-- ~ End section ~ -->
8085 <!-- ~~~~~ New section ~~~~~ -->
8086 <sect1 id="copyright"><title>Privoxy Copyright, License and History</title>
8088 <!-- Include copyright.sgml: -->
8090 <!-- end copyright -->
8093 <application>Privoxy</application> is free software; you can
8094 redistribute and/or modify its source code under the terms
8095 of the <citetitle>GNU General Public License</citetitle>
8096 as published by the Free Software Foundation, either version 2
8097 of the license, or (at your option) any later version.
8101 The same is true for <application>Privoxy</application> binaries
8102 unless they are linked with a
8103 <ulink url="https://tls.mbed.org/">mbed TLS</ulink> version
8104 that is licensed under the Apache 2.0 license in which
8105 case you can redistribute and/or modify the <application>Privoxy</application>
8106 binaries under the terms of the <citetitle>GNU General Public License</citetitle>
8107 as published by the Free Software Foundation, either version 3
8108 of the license, or (at your option) any later version.
8112 Both licenses are included in the next section.
8115 <!-- ~~~~~ New section ~~~~~ -->
8116 <sect2 id="license"><title>License</title>
8118 <sect3 id="gplv2"><title>GNU General Public License version 2</title>
8119 <literallayout class="Monospaced"><![ RCDATA [ &GPLv2; ]]></literallayout>
8122 <sect3 id="gplv3"><title>GNU General Public License version 3</title>
8123 <literallayout class="Monospaced"><![ RCDATA [ &GPLv3; ]]></literallayout>
8126 <sect3 id="third-party-licenses"><title>Third-party licenses and copyrights</title>
8128 Privoxy depends on a couple of third-party libraries which have seperate licenses.
8129 Please refer to the third-party websites for up-to-date license and copyright
8133 Privoxy depends on <ulink url="https://pcre.org/">pcre</ulink>.
8136 When compiled with FEATURE_BROTLI (optional), Privoxy depends on
8137 <ulink url="https://www.brotli.org/">brotli</ulink>.
8140 When compiled with FEATURE_HTTPS_INSPECTION (optional),
8141 Privoxy depends on a TLS library. The supported libraries are
8142 <ulink url="https://www.openssl.org/">LibreSSL</ulink>,
8143 <ulink url="https://tls.mbed.org/">mbed TLS</ulink> and
8144 <ulink url="https://www.openssl.org/">OpenSSL</ulink>.
8147 When compiled with FEATURE_ZLIB (optional),
8148 Privoxy depends on <ulink url="https://zlib.net/">zlib</ulink>.
8153 <!-- ~ End section ~ -->
8156 <!-- ~~~~~ New section ~~~~~ -->
8158 <sect2 id="history"><title>History</title>
8159 <!-- Include history.sgml: -->
8161 <!-- end history -->
8164 <sect2 id="authors"><title>Authors</title>
8165 <!-- Include p-authors.sgml: -->
8167 <!-- end authors -->
8172 <!-- ~ End section ~ -->
8175 <!-- ~~~~~ New section ~~~~~ -->
8176 <sect1 id="seealso"><title>See Also</title>
8177 <!-- Include seealso.sgml: -->
8179 <!-- end seealso -->
8184 <!-- ~~~~~ New section ~~~~~ -->
8185 <sect1 id="appendix"><title>Appendix</title>
8188 <!-- ~~~~~ New section ~~~~~ -->
8190 <title>Regular Expressions</title>
8192 <application>Privoxy</application> uses Perl-style <quote>regular
8193 expressions</quote> in its <link linkend="actions-file">actions
8194 files</link> and <link linkend="filter-file">filter file</link>,
8195 through the <ulink url="http://www.pcre.org/">PCRE</ulink> and
8198 <ulink url="http://www.oesterhelt.org/pcrs/">PCRS</ulink> libraries.
8200 <application>PCRS</application> libraries.
8204 If you are reading this, you probably don't understand what <quote>regular
8205 expressions</quote> are, or what they can do. So this will be a very brief
8206 introduction only. A full explanation would require a <ulink
8207 url="http://www.oreilly.com/catalog/regex/">book</ulink> ;-)
8211 Regular expressions provide a language to describe patterns that can be
8212 run against strings of characters (letter, numbers, etc), to see if they
8213 match the string or not. The patterns are themselves (sometimes complex)
8214 strings of literal characters, combined with wild-cards, and other special
8215 characters, called meta-characters. The <quote>meta-characters</quote> have
8216 special meanings and are used to build complex patterns to be matched against.
8217 Perl Compatible Regular Expressions are an especially convenient
8218 <quote>dialect</quote> of the regular expression language.
8222 To make a simple analogy, we do something similar when we use wild-card
8223 characters when listing files with the <command>dir</command> command in DOS.
8224 <literal>*.*</literal> matches all filenames. The <quote>special</quote>
8225 character here is the asterisk which matches any and all characters. We can be
8226 more specific and use <literal>?</literal> to match just individual
8227 characters. So <quote>dir file?.text</quote> would match
8228 <quote>file1.txt</quote>, <quote>file2.txt</quote>, etc. We are pattern
8229 matching, using a similar technique to <quote>regular expressions</quote>!
8233 Regular expressions do essentially the same thing, but are much, much more
8234 powerful. There are many more <quote>special characters</quote> and ways of
8235 building complex patterns however. Let's look at a few of the common ones,
8236 and then some examples:
8241 <emphasis>.</emphasis> - Matches any single character, e.g. <quote>a</quote>,
8242 <quote>A</quote>, <quote>4</quote>, <quote>:</quote>, or <quote>@</quote>.
8248 <emphasis>?</emphasis> - The preceding character or expression is matched ZERO or ONE
8255 <emphasis>+</emphasis> - The preceding character or expression is matched ONE or MORE
8262 <emphasis>*</emphasis> - The preceding character or expression is matched ZERO or MORE
8269 <emphasis>\</emphasis> - The <quote>escape</quote> character denotes that
8270 the following character should be taken literally. This is used where one of the
8271 special characters (e.g. <quote>.</quote>) needs to be taken literally and
8272 not as a special meta-character. Example: <quote>example\.com</quote>, makes
8273 sure the period is recognized only as a period (and not expanded to its
8274 meta-character meaning of any single character).
8280 <emphasis>[ ]</emphasis> - Characters enclosed in brackets will be matched if
8281 any of the enclosed characters are encountered. For instance, <quote>[0-9]</quote>
8282 matches any numeric digit (zero through nine). As an example, we can combine
8283 this with <quote>+</quote> to match any digit one of more times: <quote>[0-9]+</quote>.
8289 <emphasis>( )</emphasis> - parentheses are used to group a sub-expression,
8290 or multiple sub-expressions.
8296 <emphasis>|</emphasis> - The <quote>bar</quote> character works like an
8297 <quote>or</quote> conditional statement. A match is successful if the
8298 sub-expression on either side of <quote>|</quote> matches. As an example:
8299 <quote>/(this|that) example/</quote> uses grouping and the bar character
8300 and would match either <quote>this example</quote> or <quote>that
8301 example</quote>, and nothing else.
8306 These are just some of the ones you are likely to use when matching URLs with
8307 <application>Privoxy</application>, and is a long way from a definitive
8308 list. This is enough to get us started with a few simple examples which may
8309 be more illuminating:
8313 <emphasis><literal>/.*/banners/.*</literal></emphasis> - A simple example
8314 that uses the common combination of <quote>.</quote> and <quote>*</quote> to
8315 denote any character, zero or more times. In other words, any string at all.
8316 So we start with a literal forward slash, then our regular expression pattern
8317 (<quote>.*</quote>) another literal forward slash, the string
8318 <quote>banners</quote>, another forward slash, and lastly another
8319 <quote>.*</quote>. We are building
8320 a directory path here. This will match any file with the path that has a
8321 directory named <quote>banners</quote> in it. The <quote>.*</quote> matches
8322 any characters, and this could conceivably be more forward slashes, so it
8323 might expand into a much longer looking path. For example, this could match:
8324 <quote>/eye/hate/spammers/banners/annoy_me_please.gif</quote>, or just
8325 <quote>/banners/annoying.html</quote>, or almost an infinite number of other
8326 possible combinations, just so it has <quote>banners</quote> in the path
8331 And now something a little more complex:
8335 <emphasis><literal>/.*/adv((er)?ts?|ertis(ing|ements?))?/</literal></emphasis> -
8336 We have several literal forward slashes again (<quote>/</quote>), so we are
8337 building another expression that is a file path statement. We have another
8338 <quote>.*</quote>, so we are matching against any conceivable sub-path, just so
8339 it matches our expression. The only true literal that <emphasis>must
8340 match</emphasis> our pattern is <application>adv</application>, together with
8341 the forward slashes. What comes after the <quote>adv</quote> string is the
8346 Remember the <quote>?</quote> means the preceding expression (either a
8347 literal character or anything grouped with <quote>(...)</quote> in this case)
8348 can exist or not, since this means either zero or one match. So
8349 <quote>((er)?ts?|ertis(ing|ements?))</quote> is optional, as are the
8350 individual sub-expressions: <quote>(er)</quote>,
8351 <quote>(ing|ements?)</quote>, and the <quote>s</quote>. The <quote>|</quote>
8352 means <quote>or</quote>. We have two of those. For instance,
8353 <quote>(ing|ements?)</quote>, can expand to match either <quote>ing</quote>
8354 <emphasis>OR</emphasis> <quote>ements?</quote>. What is being done here, is an
8355 attempt at matching as many variations of <quote>advertisement</quote>, and
8356 similar, as possible. So this would expand to match just <quote>adv</quote>,
8357 or <quote>advert</quote>, or <quote>adverts</quote>, or
8358 <quote>advertising</quote>, or <quote>advertisement</quote>, or
8359 <quote>advertisements</quote>. You get the idea. But it would not match
8360 <quote>advertizements</quote> (with a <quote>z</quote>). We could fix that by
8361 changing our regular expression to:
8362 <quote>/.*/adv((er)?ts?|erti(s|z)(ing|ements?))?/</quote>, which would then match
8367 <emphasis><literal>/.*/advert[0-9]+\.(gif|jpe?g)</literal></emphasis> - Again
8368 another path statement with forward slashes. Anything in the square brackets
8369 <quote>[ ]</quote> can be matched. This is using <quote>0-9</quote> as a
8370 shorthand expression to mean any digit one through nine. It is the same as
8371 saying <quote>0123456789</quote>. So any digit matches. The <quote>+</quote>
8372 means one or more of the preceding expression must be included. The preceding
8373 expression here is what is in the square brackets -- in this case, any digit
8374 one through nine. Then, at the end, we have a grouping: <quote>(gif|jpe?g)</quote>.
8375 This includes a <quote>|</quote>, so this needs to match the expression on
8376 either side of that bar character also. A simple <quote>gif</quote> on one side, and the other
8377 side will in turn match either <quote>jpeg</quote> or <quote>jpg</quote>,
8378 since the <quote>?</quote> means the letter <quote>e</quote> is optional and
8379 can be matched once or not at all. So we are building an expression here to
8380 match image GIF or JPEG type image file. It must include the literal
8381 string <quote>advert</quote>, then one or more digits, and a <quote>.</quote>
8382 (which is now a literal, and not a special character, since it is escaped
8383 with <quote>\</quote>), and lastly either <quote>gif</quote>, or
8384 <quote>jpeg</quote>, or <quote>jpg</quote>. Some possible matches would
8385 include: <quote>//advert1.jpg</quote>,
8386 <quote>/nasty/ads/advert1234.gif</quote>,
8387 <quote>/banners/from/hell/advert99.jpg</quote>. It would not match
8388 <quote>advert1.gif</quote> (no leading slash), or
8389 <quote>/adverts232.jpg</quote> (the expression does not include an
8390 <quote>s</quote>), or <quote>/advert1.jsp</quote> (<quote>jsp</quote> is not
8391 in the expression anywhere).
8395 We are barely scratching the surface of regular expressions here so that you
8396 can understand the default <application>Privoxy</application>
8397 configuration files, and maybe use this knowledge to customize your own
8398 installation. There is much, much more that can be done with regular
8399 expressions. Now that you know enough to get started, you can learn more on
8404 More reading on Perl Compatible Regular expressions:
8405 <ulink url="http://perldoc.perl.org/perlre.html">http://perldoc.perl.org/perlre.html</ulink>
8409 For information on regular expression based substitutions and their applications
8410 in filters, please see the <link linkend="filter-file">filter file tutorial</link>
8415 <!-- ~ End section ~ -->
8418 <!-- ~~~~~ New section ~~~~~ -->
8419 <sect2 id="internal-pages">
8420 <title>Privoxy's Internal Pages</title>
8423 Since <application>Privoxy</application> proxies each requested
8424 web page, it is easy for <application>Privoxy</application> to
8425 trap certain special URLs. In this way, we can talk directly to
8426 <application>Privoxy</application>, and see how it is
8427 configured, see how our rules are being applied, change these
8428 rules and other configuration options, and even turn
8429 <application>Privoxy's</application> filtering off, all with
8434 The URLs listed below are the special ones that allow direct access
8435 to <application>Privoxy</application>. Of course,
8436 <application>Privoxy</application> must be running to access these. If
8437 not, you will get a friendly error message. Internet access is not
8449 <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
8453 There is a shortcut: <ulink url="http://p.p/">http://p.p/</ulink> (But it
8454 doesn't provide a fall-back to a real page, in case the request is not
8455 sent through <application>Privoxy</application>)
8461 View and toggle client tags:
8465 <ulink url="http://config.privoxy.org/client-tags">http://config.privoxy.org/client-tags</ulink>
8472 Show information about the current configuration, including viewing and
8473 editing of actions files:
8477 <ulink url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
8484 Show the browser's request headers:
8488 <ulink url="http://config.privoxy.org/show-request">http://config.privoxy.org/show-request</ulink>
8495 Show which actions apply to a URL and why:
8499 <ulink url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
8506 Toggle Privoxy on or off. This feature can be turned off/on in the main
8507 <filename>config</filename> file. When toggled <quote>off</quote>, <quote>Privoxy</quote>
8508 continues to run, but only as a pass-through proxy, with no actions taking
8513 <ulink url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>
8517 Short cuts. Turn off, then on:
8521 <ulink url="http://config.privoxy.org/toggle?set=disable">http://config.privoxy.org/toggle?set=disable</ulink>
8526 <ulink url="http://config.privoxy.org/toggle?set=enable">http://config.privoxy.org/toggle?set=enable</ulink>
8536 <!-- ~~~~~ New section ~~~~~ -->
8538 <title>Chain of Events</title>
8540 Let's take a quick look at how some of <application>Privoxy's</application>
8541 core features are triggered, and the ensuing sequence of events when a web
8542 page is requested by your browser:
8548 First, your web browser requests a web page. The browser knows to send
8549 the request to <application>Privoxy</application>, which will in turn,
8550 relay the request to the remote web server after passing the following
8556 <application>Privoxy</application> traps any request for its own internal CGI
8557 pages (e.g <ulink url="http://p.p/">http://p.p/</ulink>) and sends the CGI page back to the browser.
8562 Next, <application>Privoxy</application> checks to see if the URL
8564 linkend="BLOCK"><quote>+block</quote></link> patterns. If
8565 so, the URL is then blocked, and the remote web server will not be contacted.
8566 <link linkend="HANDLE-AS-IMAGE"><quote>+handle-as-image</quote></link>
8568 <link linkend="HANDLE-AS-EMPTY-DOCUMENT"><quote>+handle-as-empty-document</quote></link>
8569 are then checked, and if there is no match, an
8570 HTML <quote>BLOCKED</quote> page is sent back to the browser. Otherwise, if
8571 it does match, an image is returned for the former, and an empty text
8572 document for the latter. The type of image would depend on the setting of
8573 <link linkend="SET-IMAGE-BLOCKER"><quote>+set-image-blocker</quote></link>
8574 (blank, checkerboard pattern, or an HTTP redirect to an image elsewhere).
8579 Untrusted URLs are blocked. If URLs are being added to the
8580 <filename>trust</filename> file, then that is done.
8585 If the URL pattern matches the <link
8586 linkend="FAST-REDIRECTS"><quote>+fast-redirects</quote></link> action,
8587 it is then processed. Unwanted parts of the requested URL are stripped.
8592 Now the rest of the client browser's request headers are processed. If any
8593 of these match any of the relevant actions (e.g. <link
8594 linkend="HIDE-USER-AGENT"><quote>+hide-user-agent</quote></link>,
8595 etc.), headers are suppressed or forged as determined by these actions and
8601 Now the web server starts sending its response back (i.e. typically a web
8607 First, the server headers are read and processed to determine, among other
8608 things, the MIME type (document type) and encoding. The headers are then
8609 filtered as determined by the
8610 <link linkend="CRUNCH-INCOMING-COOKIES"><quote>+crunch-incoming-cookies</quote></link>,
8611 <link linkend="SESSION-COOKIES-ONLY"><quote>+session-cookies-only</quote></link>,
8612 and <link linkend="DOWNGRADE-HTTP-VERSION"><quote>+downgrade-http-version</quote></link>
8618 If any <link linkend="FILTER"><quote>+filter</quote></link> action
8620 linkend="DEANIMATE-GIFS"><quote>+deanimate-gifs</quote></link>
8621 action applies (and the document type fits the action), the rest of the page is
8622 read into memory (up to a configurable limit). Then the filter rules (from
8623 <filename>default.filter</filename> and any other filter files) are
8624 processed against the buffered content. Filters are applied in the order
8625 they are specified in one of the filter files. Animated GIFs, if present,
8626 are reduced to either the first or last frame, depending on the action
8627 setting.The entire page, which is now filtered, is then sent by
8628 <application>Privoxy</application> back to your browser.
8631 If neither a <link linkend="FILTER"><quote>+filter</quote></link> action
8633 linkend="DEANIMATE-GIFS"><quote>+deanimate-gifs</quote></link>
8634 matches, then <application>Privoxy</application> passes the raw data through
8635 to the client browser as it becomes available.
8640 As the browser receives the now (possibly filtered) page content, it
8641 reads and then requests any URLs that may be embedded within the page
8642 source, e.g. ad images, stylesheets, JavaScript, other HTML documents (e.g.
8643 frames), sounds, etc. For each of these objects, the browser issues a
8644 separate request (this is easily viewable in <application>Privoxy's</application>
8645 logs). And each such request is in turn processed just as above. Note that a
8646 complex web page will have many, many such embedded URLs. If these
8647 secondary requests are to a different server, then quite possibly a very
8648 differing set of actions is triggered.
8655 NOTE: This is somewhat of a simplistic overview of what happens with each URL
8656 request. For the sake of brevity and simplicity, we have focused on
8657 <application>Privoxy's</application> core features only.
8663 <!-- ~~~~~ New section ~~~~~ -->
8664 <sect2 id="actionsanat">
8665 <title>Troubleshooting: Anatomy of an Action</title>
8668 The way <application>Privoxy</application> applies
8669 <link linkend="ACTIONS">actions</link> and <link linkend="FILTER">filters</link>
8670 to any given URL can be complex, and not always so
8671 easy to understand what is happening. And sometimes we need to be able to
8672 <emphasis>see</emphasis> just what <application>Privoxy</application> is
8673 doing. Especially, if something <application>Privoxy</application> is doing
8674 is causing us a problem inadvertently. It can be a little daunting to look at
8675 the actions and filters files themselves, since they tend to be filled with
8676 <link linkend="regex">regular expressions</link> whose consequences are not
8681 One quick test to see if <application>Privoxy</application> is causing a problem
8682 or not, is to disable it temporarily. This should be the first troubleshooting
8683 step (be sure to flush caches afterward!). Looking at the
8684 logs is a good idea too. (Note that both the toggle feature and logging are
8685 enabled via <filename>config</filename> file settings, and may need to be
8686 turned <quote>on</quote>.)
8689 Another easy troubleshooting step to try is if you have done any
8690 customization of your installation, revert back to the installed
8691 defaults and see if that helps. There are times the developers get complaints
8692 about one thing or another, and the problem is more related to a customized
8693 configuration issue.
8697 <application>Privoxy</application> also provides the
8698 <ulink url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
8699 page that can show us very specifically how <application>actions</application>
8700 are being applied to any given URL. This is a big help for troubleshooting.
8704 First, enter one URL (or partial URL) at the prompt, and then
8705 <application>Privoxy</application> will tell us
8706 how the current configuration will handle it. This will not
8707 help with filtering effects (i.e. the <link
8708 linkend="FILTER"><quote>+filter</quote></link> action) from
8709 one of the filter files since this is handled very
8710 differently and not so easy to trap! It also will not tell you about any other
8711 URLs that may be embedded within the URL you are testing. For instance, images
8712 such as ads are expressed as URLs within the raw page source of HTML pages. So
8713 you will only get info for the actual URL that is pasted into the prompt area
8714 -- not any sub-URLs. If you want to know about embedded URLs like ads, you
8715 will have to dig those out of the HTML source. Use your browser's <quote>View
8716 Page Source</quote> option for this. Or right click on the ad, and grab the
8721 Let's try an example, <ulink url="http://google.com">google.com</ulink>,
8722 and look at it one section at a time in a sample configuration (your real
8723 configuration may vary):
8727 Matches for http://www.google.com:
8729 In file: default.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
8731 {+change-x-forwarded-for{block}
8732 +deanimate-gifs {last}
8733 +fast-redirects {check-decoded-url}
8734 +filter {refresh-tags}
8735 +filter {img-reorder}
8736 +filter {banners-by-size}
8738 +filter {jumping-windows}
8739 +filter {ie-exploits}
8740 +hide-from-header {block}
8741 +hide-referrer {forge}
8742 +session-cookies-only
8743 +set-image-blocker {pattern}
8746 { -session-cookies-only }
8752 In file: user.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
8753 (no matches in this file)
8757 This is telling us how we have defined our
8758 <link linkend="ACTIONS"><quote>actions</quote></link>, and
8759 which ones match for our test case, <quote>google.com</quote>.
8760 Displayed is all the actions that are available to us. Remember,
8761 the <literal>+</literal> sign denotes <quote>on</quote>. <literal>-</literal>
8762 denotes <quote>off</quote>. So some are <quote>on</quote> here, but many
8763 are <quote>off</quote>. Each example we try may provide a slightly different
8764 end result, depending on our configuration directives.
8768 is for our <filename>default.action</filename> file. The large, multi-line
8769 listing, is how the actions are set to match for all URLs, i.e. our default
8770 settings. If you look at your <quote>actions</quote> file, this would be the
8771 section just below the <quote>aliases</quote> section near the top. This
8772 will apply to all URLs as signified by the single forward slash at the end
8773 of the listing -- <quote> / </quote>.
8777 But we have defined additional actions that would be exceptions to these general
8778 rules, and then we list specific URLs (or patterns) that these exceptions
8779 would apply to. Last match wins. Just below this then are two explicit
8780 matches for <quote>.google.com</quote>. The first is negating our previous
8781 cookie setting, which was for <link
8782 linkend="SESSION-COOKIES-ONLY"><quote>+session-cookies-only</quote></link>
8783 (i.e. not persistent). So we will allow persistent cookies for google, at
8784 least that is how it is in this example. The second turns
8785 <emphasis>off</emphasis> any <link
8786 linkend="FAST-REDIRECTS"><quote>+fast-redirects</quote></link>
8787 action, allowing this to take place unmolested. Note that there is a leading
8788 dot here -- <quote>.google.com</quote>. This will match any hosts and
8789 sub-domains, in the google.com domain also, such as
8790 <quote>www.google.com</quote> or <quote>mail.google.com</quote>. But it would not
8791 match <quote>www.google.de</quote>! So, apparently, we have these two actions
8792 defined as exceptions to the general rules at the top somewhere in the lower
8793 part of our <filename>default.action</filename> file, and
8794 <quote>google.com</quote> is referenced somewhere in these latter sections.
8798 Then, for our <filename>user.action</filename> file, we again have no hits.
8799 So there is nothing google-specific that we might have added to our own, local
8800 configuration. If there was, those actions would over-rule any actions from
8801 previously processed files, such as <filename>default.action</filename>.
8802 <filename>user.action</filename> typically has the last word. This is the
8803 best place to put hard and fast exceptions,
8807 And finally we pull it all together in the bottom section and summarize how
8808 <application>Privoxy</application> is applying all its <quote>actions</quote>
8809 to <quote>google.com</quote>:
8817 +change-x-forwarded-for{block}
8818 -client-header-filter{hide-tor-exit-notation}
8819 -content-type-overwrite
8820 -crunch-client-header
8821 -crunch-if-none-match
8822 -crunch-incoming-cookies
8823 -crunch-outgoing-cookies
8824 -crunch-server-header
8825 +deanimate-gifs {last}
8826 -downgrade-http-version
8829 -filter {content-cookies}
8830 -filter {all-popups}
8831 -filter {banners-by-link}
8832 -filter {tiny-textforms}
8833 -filter {frameset-borders}
8834 -filter {demoronizer}
8835 -filter {shockwave-flash}
8836 -filter {quicktime-kioskmode}
8838 -filter {crude-parental}
8839 -filter {site-specifics}
8840 -filter {js-annoyances}
8841 -filter {html-annoyances}
8842 +filter {refresh-tags}
8843 -filter {unsolicited-popups}
8844 +filter {img-reorder}
8845 +filter {banners-by-size}
8847 +filter {jumping-windows}
8848 +filter {ie-exploits}
8855 -handle-as-empty-document
8857 -hide-accept-language
8858 -hide-content-disposition
8859 +hide-from-header {block}
8860 -hide-if-modified-since
8861 +hide-referrer {forge}
8864 -overwrite-last-modified
8865 -prevent-compression
8867 -server-header-filter{xml-to-html}
8868 -server-header-filter{html-to-xml}
8869 -session-cookies-only
8870 +set-image-blocker {pattern}
8874 Notice the only difference here to the previous listing, is to
8875 <quote>fast-redirects</quote> and <quote>session-cookies-only</quote>,
8876 which are activated specifically for this site in our configuration,
8877 and thus show in the <quote>Final Results</quote>.
8881 Now another example, <quote>ad.doubleclick.net</quote>:
8885 { +block{Domains starts with "ad"} }
8888 { +block{Domain contains "ad"} }
8891 { +block{Doubleclick banner server} +handle-as-image }
8892 .[a-vx-z]*.doubleclick.net
8896 We'll just show the interesting part here - the explicit matches. It is
8897 matched three different times. Two <quote>+block{}</quote> sections,
8898 and a <quote>+block{} +handle-as-image</quote>,
8899 which is the expanded form of one of our aliases that had been defined as:
8900 <quote>+block-as-image</quote>. (<link
8901 linkend="ALIASES"><quote>Aliases</quote></link> are defined in
8902 the first section of the actions file and typically used to combine more
8907 Any one of these would have done the trick and blocked this as an unwanted
8908 image. This is unnecessarily redundant since the last case effectively
8909 would also cover the first. No point in taking chances with these guys
8910 though ;-) Note that if you want an ad or obnoxious
8911 URL to be invisible, it should be defined as <quote>ad.doubleclick.net</quote>
8912 is done here -- as both a <link
8913 linkend="BLOCK"><quote>+block{}</quote></link>
8914 <emphasis>and</emphasis> an
8915 <link linkend="HANDLE-AS-IMAGE"><quote>+handle-as-image</quote></link>.
8916 The custom alias <quote><literal>+block-as-image</literal></quote> just
8917 simplifies the process and make it more readable.
8921 One last example. Let's try <quote>http://www.example.net/adsl/HOWTO/</quote>.
8922 This one is giving us problems. We are getting a blank page. Hmmm ...
8926 Matches for http://www.example.net/adsl/HOWTO/:
8928 In file: default.action <guibutton>[ View ]</guibutton> <guibutton>[ Edit ]</guibutton>
8932 +change-x-forwarded-for{block}
8933 -client-header-filter{hide-tor-exit-notation}
8934 -content-type-overwrite
8935 -crunch-client-header
8936 -crunch-if-none-match
8937 -crunch-incoming-cookies
8938 -crunch-outgoing-cookies
8939 -crunch-server-header
8941 -downgrade-http-version
8942 +fast-redirects {check-decoded-url}
8944 -filter {content-cookies}
8945 -filter {all-popups}
8946 -filter {banners-by-link}
8947 -filter {tiny-textforms}
8948 -filter {frameset-borders}
8949 -filter {demoronizer}
8950 -filter {shockwave-flash}
8951 -filter {quicktime-kioskmode}
8953 -filter {crude-parental}
8954 -filter {site-specifics}
8955 -filter {js-annoyances}
8956 -filter {html-annoyances}
8957 +filter {refresh-tags}
8958 -filter {unsolicited-popups}
8959 +filter {img-reorder}
8960 +filter {banners-by-size}
8962 +filter {jumping-windows}
8963 +filter {ie-exploits}
8970 -handle-as-empty-document
8972 -hide-accept-language
8973 -hide-content-disposition
8974 +hide-from-header{block}
8975 +hide-referer{forge}
8977 -overwrite-last-modified
8978 +prevent-compression
8980 -server-header-filter{xml-to-html}
8981 -server-header-filter{html-to-xml}
8982 +session-cookies-only
8983 +set-image-blocker{blank} }
8986 { +block{Path contains "ads".} +handle-as-image }
8991 Ooops, the <quote>/adsl/</quote> is matching <quote>/ads</quote> in our
8992 configuration! But we did not want this at all! Now we see why we get the
8993 blank page. It is actually triggering two different actions here, and
8994 the effects are aggregated so that the URL is blocked, and &my-app; is told
8995 to treat the block as if it were an image. But this is, of course, all wrong.
8996 We could now add a new action below this (or better in our own
8997 <filename>user.action</filename> file) that explicitly
8998 <emphasis>un</emphasis> blocks (
8999 <link linkend="BLOCK"><quote>{-block}</quote></link>) paths with
9000 <quote>adsl</quote> in them (remember, last match in the configuration
9001 wins). There are various ways to handle such exceptions. Example:
9010 Now the page displays ;-)
9011 Remember to flush your browser's caches when making these kinds of changes to
9012 your configuration to insure that you get a freshly delivered page! Or, try
9013 using <literal>Shift+Reload</literal>.
9017 But now what about a situation where we get no explicit matches like
9022 { +block{Path starts with "ads".} +handle-as-image }
9027 That actually was very helpful and pointed us quickly to where the problem
9028 was. If you don't get this kind of match, then it means one of the default
9029 rules in the first section of <filename>default.action</filename> is causing
9030 the problem. This would require some guesswork, and maybe a little trial and
9031 error to isolate the offending rule. One likely cause would be one of the
9032 <link linkend="FILTER"><quote>+filter</quote></link> actions.
9033 These tend to be harder to troubleshoot.
9034 Try adding the URL for the site to one of aliases that turn off
9035 <link linkend="FILTER"><quote>+filter</quote></link>:
9041 .worldpay.com # for quietpc.com
9048 <quote><literal>{ shop }</literal></quote> is an <quote>alias</quote> that expands to
9049 <quote><literal>{ -filter -session-cookies-only }</literal></quote>.
9050 Or you could do your own exception to negate filtering:
9055 # Disable ALL filter actions for sites in this section
9062 This would turn off all filtering for these sites. This is best
9063 put in <filename>user.action</filename>, for local site
9064 exceptions. Note that when a simple domain pattern is used by itself (without
9065 the subsequent path portion), all sub-pages within that domain are included
9066 automatically in the scope of the action.
9070 Images that are inexplicably being blocked, may well be hitting the
9071 <link linkend="FILTER-BANNERS-BY-SIZE"><quote>+filter{banners-by-size}</quote></link>
9073 that images of certain sizes are ad banners (works well
9074 <emphasis>most of the time</emphasis> since these tend to be standardized).
9078 <quote><literal>{ fragile }</literal></quote> is an alias that disables most
9079 actions that are the most likely to cause trouble. This can be used as a
9080 last resort for problem sites.
9085 # Handle with care: easy to break
9087 mybank.example.com</screen>
9091 <emphasis>Remember to flush caches!</emphasis> Note that the
9092 <literal>mail.google</literal> reference lacks the TLD portion (e.g.
9093 <quote>.com</quote>). This will effectively match any TLD with
9094 <literal>google</literal> in it, such as <literal>mail.google.de.</literal>,
9098 If this still does not work, you will have to go through the remaining
9099 actions one by one to find which one(s) is causing the problem.
9108 This program is free software; you can redistribute it
9109 and/or modify it under the terms of the GNU General
9110 Public License as published by the Free Software
9111 Foundation; either version 2 of the License, or (at
9112 your option) any later version.
9114 This program is distributed in the hope that it will
9115 be useful, but WITHOUT ANY WARRANTY; without even the
9116 implied warranty of MERCHANTABILITY or FITNESS FOR A
9117 PARTICULAR PURPOSE. See the GNU General Public
9118 License for more details.
9120 The GNU General Public License should be included with
9121 this file. If not, you can view it at
9122 http://www.gnu.org/copyleft/gpl.html
9123 or write to the Free Software Foundation, Inc.,
9124 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,