5 $Id: user-manual.sgml,v 1.95 2002/04/26 17:23:29 swa Exp $
7 The user manual gives users information on how to install, configure and use
10 Privoxy is a web proxy with advanced filtering capabilities for protecting
11 privacy, filtering web page content, managing cookies, controlling access, and
12 removing ads, banners, pop-ups and other obnoxious Internet junk. Privoxy has a
13 very flexible configuration and can be customized to suit individual needs and
14 tastes. Privoxy has application for both stand-alone systems and multi-user
17 Privoxy is based on Internet Junkbuster (tm).
19 You can find the latest version of the user manual at http://www.privoxy.org/
20 user-manual/. Please see the Contact section on how to contact the developers.
22 -------------------------------------------------------------------------------
32 3.1. Red Hat and SuSE RPMs
35 3.4. Solaris, NetBSD, FreeBSD, HP-UX
41 5. Quickstart to Using Privoxy
44 6.1. Command Line Options
46 7. Privoxy Configuration
48 7.1. Controlling Privoxy with Your Web Browser
49 7.2. Configuration Files Overview
50 7.3. The Main Configuration File
52 7.3.1. Configuration and Log File Locations
53 7.3.2. Local Set-up Documentation
55 7.3.4. Access Control and Security
57 7.3.6. Windows GUI Options
61 7.4.1. Finding the Right Mix
63 7.4.3. How Actions are Applied to URLs
71 8. Contacting the Developers, Bug Reporting and Feature Requests
75 8.3. Request new features
76 8.4. Report ads or other filter problems
79 9. Copyright and History
87 11.1. Regular Expressions
88 11.2. Privoxy's Internal Pages
93 11.4. Anatomy of an Action
95 -------------------------------------------------------------------------------
99 This documentation is included with the current beta version of Privoxy,
100 v.2.9.14, and is mostly complete at this point. The most up to date reference
101 for the time being is still the comments in the source files and in the
102 individual configuration files. Development of version 3.0 is currently nearing
103 completion, and includes many significant changes and enhancements over earlier
104 versions. The target release date for stable v3.0 is "soon" ;-).
106 Since this is a beta version, not all new features are well tested. This
107 documentation may be slightly out of sync as a result (especially with CVS
108 sources). And there may be bugs, though hopefully not many!
110 -------------------------------------------------------------------------------
114 In addition to Internet Junkbuster's traditional features of ad and banner
115 blocking and cookie management, Privoxy provides new features, some of them
116 currently under development:
118 * FIXME: complete the list of features. change the order: most important
119 features to the top of the list. prefix new features with "NEW".
121 * Integrated browser based configuration and control utility at http://
122 config.privoxy.org/ (shortcut: http://p.p/). Browser-based tracing of rule
123 and filter effects. Remote toggling.
125 * Blocking of annoying pop-up browser windows.
127 * HTTP/1.1 compliant (but not all optional 1.1 features are supported).
129 * Support for Perl Compatible Regular Expressions in the configuration files,
130 and generally a more sophisticated and flexible configuration syntax over
135 * Web page content filtering (removes banners based on size, invisible
136 "web-bugs", JavaScript and HTML annoyances, pop-ups, etc.)
138 * Bypass many click-tracking scripts (avoids script redirection).
140 * Multi-threaded (POSIX and native threads).
142 * Auto-detection and re-reading of config file changes.
144 * User-customizable HTML templates (e.g. 404 error page).
146 * Improved cookie management features (e.g. session based cookies).
148 * Improved signal handling, and a true daemon mode (Unix).
150 * Every feature now controllable on a per-site or per-location basis,
151 configuration more powerful and versatile over-all.
153 * Many smaller new features added, limitations and bugs removed, and security
156 -------------------------------------------------------------------------------
160 Privoxy is available both in convenient pre-compiled packages for a wide range
161 of operating systems, and as raw source code. For most users, we recommend
162 using the packages, which can be downloaded from our Privoxy Project Page. For
163 installing and compiling the source code, please look into our Developer
166 If you like to live on the bleeding edge and are not afraid of using possibly
167 unstable development versions, you can check out the up-to-the-minute version
168 directly from the CVS repository or simply download the nightly CVS tarball.
169 Again, we refer you to the Developer Manual.
171 At present, Privoxy is known to run on Windows(95, 98, ME, 2000, XP), Linux
172 (RedHat, Suse, Debian), Mac OSX, OS/2, AmigaOS, FreeBSD, NetBSD, BeOS, and many
173 more flavors of Unix.
175 Note: If you have a previous Junkbuster or Privoxy installation on your system,
176 you will need to remove it. Some platforms do this for you as part of their
177 installation procedure. (See below for your platform).
179 In any case be sure to backup your old configuration if it is valuable to you.
180 See the note to upgraders section below.
182 -------------------------------------------------------------------------------
184 3.1. Red Hat and SuSE RPMs
186 RPMs can be installed with rpm -Uvh privoxy-2.9.14-1.rpm, and will use /etc/
187 privoxy for the location of configuration files.
189 Note that on Red Hat, Privoxy will not be automatically started on system boot.
190 You will need to enable that using chkconfig, ntsysv, or similar methods. Note
191 that SuSE will automatically start Privoxy in the boot process.
193 If you have problems with failed dependencies, try rebuilding the SRC RPM: rpm
194 --rebuild privoxy-2.9.14-1.src.rpm;. This will use your locally installed
195 libraries and RPM version.
197 Also note that if you have a Junkbuster RPM installed on your system, you need
198 to remove it first, because the packages conflict. Otherwise, RPM will try to
199 remove Junkbuster automatically, before installing Privoxy.
201 -------------------------------------------------------------------------------
207 -------------------------------------------------------------------------------
211 Just double-click the installer, which will guide you through the installation
212 process. You will find the configuration files in the same directory as you
213 installed Privoxy in. We do not use the registry of Windows.
215 -------------------------------------------------------------------------------
217 3.4. Solaris, NetBSD, FreeBSD, HP-UX
219 Create a new directory, cd to it, then unzip and untar the archive. For the
220 most part, you'll have to figure out where things go. FIXME.
222 -------------------------------------------------------------------------------
226 First, make sure that no previous installations of Junkbuster and / or Privoxy
227 are left on your system. You can do this by
229 Then, just double-click the WarpIN self-installing archive, which will guide
230 you through the installation process. A shadow of the Privoxy executable will
231 be placed in your startup folder so it will start automatically whenever OS/2
234 The directory you choose to install Privoxy into will contain all of the
237 -------------------------------------------------------------------------------
241 Unzip the downloaded package (you can either double-click on the file in the
242 finder, or on the desktop if you downloaded it there). Then, double-click on
243 the package installer icon and follow the installation process. Privoxy will be
244 installed in the subdirectory /Applications/Privoxy.app. Privoxy will set
245 itself up to start automatically on system bring-up via /System/Library/
246 StartupItems/Privoxy.
248 -------------------------------------------------------------------------------
252 Copy and then unpack the lha archive to a suitable location. All necessary
253 files will be installed into Privoxy directory, including all configuration and
254 log files. To uninstall, just remove this directory.
256 Start Privoxy (with RUN <>NIL:) in your startnet script (AmiTCP), in s:
257 user-startup (RoadShow), as startup program in your startup script (Genesis),
258 or as startup action (Miami and MiamiDx). Privoxy will automatically quit when
259 you quit your TCP/IP stack (just ignore the harmless warning your TCP/IP stack
260 may display that Privoxy is still running).
262 -------------------------------------------------------------------------------
266 There are very significant changes from older versions of Junkbuster to the
267 current Privoxy. Configuration is substantially changed. Junkbuster 2.0.x and
268 earlier configuration files will not migrate. The functionality of the old
269 blockfile, cookiefile and imagelist, are now combined into the "actions files".
270 default.action, is the main actions file. Local exceptions should best be put
273 A "filter file" (typically default.filter) is new as of Privoxy 2.9.x, and
274 provides some of the new sophistication (explained below). config is much the
277 If upgrading from a 2.0.x version, you will have to use the new config files,
278 and possibly adapt any personal rules from your older files. When porting
279 personal rules over from the old blockfile to the new actions files, please
280 note that even the pattern syntax has changed. If upgrading from 2.9.x
281 development versions, it is still recommended to use the new configuration
284 A quick list of things to be aware of before upgrading:
286 * The default listening port is now 8118 due to a conflict with another
289 * Some installers may remove earlier versions completely. Save any important
292 * Privoxy is controllable with a web browser at the special URL: http://
293 config.privoxy.org/ (Shortcut: http://p.p/). Many aspects of configuration
294 can be done here, including temporarily disabling Privoxy.
296 * The primary configuration file for cookie management, ad and banner
297 blocking, and many other aspects of Privoxy configuration is in the
298 "actions" files. It is strongly recommended to become familiar with the new
299 actions concept below, before modifying these files. Locally defined rules
300 should go into user.action.
302 * Some installers may not automatically start Privoxy after installation.
304 -------------------------------------------------------------------------------
306 5. Quickstart to Using Privoxy
308 * Install Privoxy. See the section Installing.
310 * Start Privoxy. See the section Starting Privoxy.
312 * Change your browser's configuration to use the proxy localhost on port
313 8118. See the section Starting Privoxy.
315 * Enjoy surfing with enhanced comfort and privacy. Please see the section
316 Contacting the Developers on how to report bugs or problems with websites
317 or to get help. You may want to change the file user.action to further
318 tweak your new browsing experience.
320 -------------------------------------------------------------------------------
324 Before launching Privoxy for the first time, you will want to configure your
325 browser(s) to use Privoxy as a HTTP and HTTPS proxy. The default is localhost
326 for the proxy address, and port 8118 (earlier versions used port 8000). This is
327 the one configuration step that must be done!
329 With Netscape (and Mozilla), this can be set under Edit -> Preferences ->
330 Advanced -> Proxies -> HTTP Proxy. For Internet Explorer: Tools -> Internet
331 Properties -> Connections -> LAN Setting. Then, check "Use Proxy" and fill in
332 the appropriate info (Address: localhost, Port: 8118). Include if HTTPS proxy
335 After doing this, flush your browser's disk and memory caches to force a
336 re-reading of all pages and to get rid of any ads that may be cached. You are
337 now ready to start enjoying the benefits of using Privoxy!
339 Privoxy is typically started by specifying the main configuration file to be
340 used on the command line. Example Unix startup command:
343 # /usr/sbin/privoxy /etc/privoxy/config
345 See below for other command line options.
347 An init script is provided for SuSE and Red Hat.
349 For for SuSE: rcprivoxy start
351 For Red Hat and Debian: /etc/rc.d/init.d/privoxy start
353 If no configuration file is specified on the command line, Privoxy will look
354 for a file named config in the current directory. Except on Win32 where it will
355 try config.txt. If no file is specified on the command line and no default
356 configuration file can be found, Privoxy will fail to start.
358 The included default configuration files should give a reasonable starting
359 point. Most of the per site configuration is done in the "actions" files. These
360 are where various cookie actions are defined, ad and banner blocking, and other
361 aspects of Privoxy configuration. There are several such files included, with
362 varying levels of aggressiveness.
364 You will probably want to keep an eye out for sites for which you may prefer
365 persistent cookies, and add these to your actions configuration as needed. By
366 default, most of these will be accepted only during the current browser session
367 (aka "session cookies"), unless you add them to the configuration. If you want
368 the browser to handle this instead, you will need to edit user.action (or
369 through the web based interface) and disable this feature. If you use more than
370 one browser, it would make more sense to let Privoxy handle this. In which
371 case, the browser(s) should be set to accept all cookies.
373 Another feature where you will probably want to define exceptions for trusted
374 sites is the popup-killing (through the +popup and +filter{popups} actions),
375 because your favorite shopping, banking, or leisure site may need popups
378 Privoxy is HTTP/1.1 compliant, but not all of the optional 1.1 features are as
379 yet supported. In the unlikely event that you experience inexplicable problems
380 with browsers that use HTTP/1.1 per default (like Mozilla or recent versions of
381 I.E.), you might try to force HTTP/1.0 compatibility. For Mozilla, look under
382 Edit -> Preferences -> Debug -> Networking. Alternatively, set the
383 "+downgrade-http-version" config option in default.action which will downgrade
384 your browser's HTTP requests from HTTP/1.1 to HTTP/1.0 before processing them.
386 After running Privoxy for a while, you can start to fine tune the configuration
387 to suit your personal, or site, preferences and requirements. There are many,
388 many aspects that can be customized. "Actions" can be adjusted by pointing your
389 browser to http://config.privoxy.org/ (shortcut: http://p.p/), and then follow
390 the link to "View & Change the Current Configuration". (This is an internal
391 page and does not require Internet access.)
393 In fact, various aspects of Privoxy configuration can be viewed from this page,
394 including current configuration parameters, source code version numbers, the
395 browser's request headers, and "actions" that apply to a given URL. In addition
396 to the actions file editor mentioned above, Privoxy can also be turned "on" and
397 "off" (toggled) from this page.
399 If you encounter problems, try loading the page without Privoxy. If that helps,
400 enter the URL where you have the problems into the browser based rule tracing
401 utility. See which rules apply and why, and then try turning them off for that
402 site one after the other, until the problem is gone. When you have found the
403 culprit, you might want to turn the rest on again.
405 If the above paragraph sounds gibberish to you, you might want to read more
406 about the actions concept or even dive deep into the Appendix on actions.
408 If you can't get rid of the problem at all, think you've found a bug in
409 Privoxy, want to propose a new feature or smarter rules, please see the section
410 "Contacting the Developers" below.
412 -------------------------------------------------------------------------------
414 6.1. Command Line Options
416 Privoxy may be invoked with the following command-line options:
420 Print version info and exit. Unix only.
424 Print short usage info and exit. Unix only.
428 Don't become a daemon, i.e. don't fork and become process group leader, and
429 don't detach from controlling tty. Unix only.
433 On startup, write the process ID to FILE. Delete the FILE on exit. Failure
434 to create or delete the FILE is non-fatal. If no FILE option is given, no
435 PID file will be used. Unix only.
437 * --user USER[.GROUP]
439 After (optionally) writing the PID file, assume the user ID of USER, and if
440 included the GID of GROUP. Exit if the privileges are not sufficient to do
445 If no configfile is included on the command line, Privoxy will look for a
446 file named "config" in the current directory (except on Win32 where it will
447 look for "config.txt" instead). Specify full path to avoid confusion. If no
448 config file is found, Privoxy will fail to start.
450 -------------------------------------------------------------------------------
452 7. Privoxy Configuration
454 All Privoxy configuration is stored in text files. These files can be edited
455 with a text editor. Many important aspects of Privoxy can also be controlled
456 easily with a web browser.
458 -------------------------------------------------------------------------------
460 7.1. Controlling Privoxy with Your Web Browser
462 Privoxy's user interface can be reached through the special URL http://
463 config.privoxy.org/ (shortcut: http://p.p/), which is a built-in page and works
464 without Internet access. You will see the following section:
467 ?? View & change the current configuration
468 ?? View the source code version numbers
469 ?? View the request headers.
470 ?? Look up which actions apply to a URL and why
471 ?? Toggle Privoxy on or off
474 This should be self-explanatory. Note the first item leads to an editor for the
475 "actions list", which is where the ad, banner, cookie, and URL blocking magic
476 is configured as well as other advanced features of Privoxy. This is an easy
477 way to adjust various aspects of Privoxy configuration. The actions file, and
478 other configuration files, are explained in detail below.
480 "Toggle Privoxy On or Off" is handy for sites that might have problems with
481 your current actions and filters. You can in fact use it as a test to see
482 whether it is Privoxy causing the problem or not. Privoxy continues to run as a
483 proxy in this case, but all filtering is disabled. There is even a toggle
484 Bookmarklet offered, so that you can toggle Privoxy with one click from your
487 -------------------------------------------------------------------------------
489 7.2. Configuration Files Overview
491 For Unix, *BSD and Linux, all configuration files are located in /etc/privoxy/
492 by default. For MS Windows, OS/2, and AmigaOS these are all in the same
493 directory as the Privoxy executable. The name and number of configuration files
494 has changed from previous versions, and is subject to change as development
497 The installed defaults provide a reasonable starting point, though some
498 settings may be aggressive by some standards. For the time being, the principle
499 configuration files are:
501 * The main configuration file is named config on Linux, Unix, BSD, OS/2, and
502 AmigaOS and config.txt on Windows. This is a required file.
504 * default.action (the main actions file) is used to define the default
505 settings for various "actions" relating to images, banners, pop-ups, access
506 restrictions, banners and cookies.
508 Multiple actions files may be defined in config. These are processed in the
509 order they are defined. Local customizations and locally preferred
510 exceptions to the default policies as defined in default.action are
511 probably best applied in user.action, which should be preserved across
512 upgrades. standard.action is also included. This is mostly for Privoxy's
515 There is also a web based editor that can be accessed from http://
516 config.privoxy.org/show-status/ (Shortcut: http://p.p/show-status/) for the
517 various actions files.
519 * default.filter (the filter file) can be used to re-write the raw page
520 content, including viewable text as well as embedded HTML and JavaScript,
521 and whatever else lurks on any given web page. The filtering jobs are only
522 pre-defined here; whether to apply them or not is up to the actions files.
524 All files use the "#" character to denote a comment (the rest of the line will
525 be ignored) angd understand line continuation through placing a backslash ("\")
526 as the very last character in a line. If the # is preceded by a backslash, it
527 looses its special function. Placing a # in front of an otherwise valid
528 configuration line to prevent it from being interpreted is called "commenting
531 The actions files and default.filter can use Perl style regular expressions for
534 After making any changes, there is no need to restart Privoxy in order for the
535 changes to take effect. Privoxy detects such changes automatically. Note,
536 however, that it may take one or two additional requests for the change to take
537 effect. When changing the listening address of Privoxy, these "wake up"
538 requests must obviously be sent to the old listening address.
540 While under development, the configuration content is subject to change. The
541 below documentation may not be accurate by the time you read this. Also, what
542 constitutes a "default" setting, may change, so please check all your
543 configuration files on important issues.
545 -------------------------------------------------------------------------------
547 7.3. The Main Configuration File
549 Again, the main configuration file is named config on Linux/Unix/BSD and OS/2,
550 and config.txt on Windows. Configuration lines consist of an initial keyword
551 followed by a list of values, all separated by whitespace (any number of spaces
552 or tabs). For example:
557 Assigns the value /etc/privoxy to the option confdir and thus indicates that
558 the configuration directory is named "/etc/privoxy/".
560 All options in the config file except for confdir and logdir are optional.
561 Watch out in the below description for what happens if you leave them unset.
563 The main config file controls all aspects of Privoxy's operation that are not
564 location dependent (i.e. they apply universally, no matter where you may be
567 -------------------------------------------------------------------------------
569 7.3.1. Configuration and Log File Locations
571 Privoxy can (and normally does) use a number of other files for additional
572 configuration and logging. This section of the configuration file tells Privoxy
573 where to find those other files.
575 -------------------------------------------------------------------------------
581 The directory where the other configuration files are located
589 /etc/privoxy (Unix) or Privoxy installation dir (Windows)
597 No trailing "/", please
599 When development goes modular and multi-user, the blocker, filter, and
600 per-user config will be stored in subdirectories of "confdir". For now, the
601 configuration directory structure is flat, except for confdir/templates,
602 where the HTML templates for CGI output reside (e.g. Privoxy's 404 error
605 -------------------------------------------------------------------------------
611 The directory where all logging takes place (i.e. where logfile and jarfile
620 /var/log/privoxy (Unix) or Privoxy installation dir (Windows)
628 No trailing "/", please
630 -------------------------------------------------------------------------------
636 The actions file(s) to use
640 File name, relative to confdir
644 standard # Internal purposes, recommended not editing
646 default # Main actions file
648 user # User customizations
652 No actions are taken at all. Simple neutral proxying.
656 Multiple actionsfile lines are OK and are in fact recommended!
658 The default values include standard.action, which is used for internal
659 purposes and should be loaded, default.action, which is the "main" actions
660 file maintained by the developers, and user.action, where you can make your
663 There is no point in using Privoxy without an actions file.
665 -------------------------------------------------------------------------------
671 The filter file to use
675 File name, relative to confdir
679 default.filter (Unix) or default.filter.txt (Windows)
683 No textual content filtering takes place, i.e. all +filter{name} actions in
684 the actions files are turned off
688 The "default.filter" file contains content modification rules that use
689 "regular expressions". These rules permit powerful changes on the content
690 of Web pages, e.g., you could disable your favorite JavaScript annoyances,
691 re-write the actual displayed text, or just have some fun replacing
692 "Microsoft" with "MicroSuck" wherever it appears on a Web page.
694 -------------------------------------------------------------------------------
704 File name, relative to logdir
708 logfile (Unix) or privoxy.log (Windows)
712 No log file is used, all log messages go to the console (stderr).
716 The windows version will additionally log to the console.
718 The logfile is where all logging and error messages are written. The level
719 of detail and number of messages are set with the debug option (see below).
720 The logfile can be useful for tracking down a problem with Privoxy (e.g.,
721 it's not blocking an ad you think it should block) but in most cases you
722 probably will never look at it.
724 Your logfile will grow indefinitely, and you will probably want to
725 periodically remove it. On Unix systems, you can do this with a cron job
726 (see "man cron"). For Red Hat, a logrotate script has been included.
728 On SuSE Linux systems, you can place a line like "/var/log/privoxy.* +1024k
729 644 nobody.nogroup" in /etc/logfiles, with the effect that cron.daily will
730 automatically archive, gzip, and empty the log, when it exceeds 1M size.
732 -------------------------------------------------------------------------------
738 The file to store intercepted cookies in
742 File name, relative to logdir
746 jarfile (Unix) or privoxy.jar (Windows)
750 Intercepted cookies are not stored at all.
754 The jarfile may grow to ridiculous sizes over time.
756 -------------------------------------------------------------------------------
762 The trust file to use
766 File name, relative to confdir
770 Unset (commented out). When activated: trust (Unix) or trust.txt (Windows)
774 The whole trust mechanism is turned off.
778 The trust mechanism is an experimental feature for building white-lists and
779 should be used with care. It is NOT recommended for the casual user.
781 If you specify a trust file, Privoxy will only allow access to sites that
782 are named in the trustfile. You can also mark sites as trusted referrers
783 (with +), with the effect that access to untrusted sites will be granted,
784 if a link from a trusted referrer was used. The link target will then be
785 added to the "trustfile". Possible applications include limiting Internet
788 If you use + operator in the trust file, it may grow considerably over
791 -------------------------------------------------------------------------------
793 7.3.2. Local Set-up Documentation
795 If you intend to operate Privoxy for more users that just yourself, it might be
796 a good idea to let them know how to reach you, what you block and why you do
797 that, your policies etc.
799 -------------------------------------------------------------------------------
801 7.3.2.1. trust-info-url
805 A URL to be displayed in the error page that users will see if access to an
806 untrusted page is denied.
814 Two example URL are provided
818 No links are displayed on the "untrusted" error page.
822 The value of this option only matters if the experimental trust mechanism
823 has been activated. (See trustfile above.)
825 If you use the trust mechanism, it is a good idea to write up some on-line
826 documentation about your trust policy and to specify the URL(s) here. Use
827 multiple times for multiple URLs.
829 The URL(s) should be added to the trustfile as well, so users don't end up
830 locked out from the information on why they were locked out in the first
833 -------------------------------------------------------------------------------
835 7.3.2.2. admin-address
839 An email address to reach the proxy administrator.
851 No email address is displayed on error pages and the CGI user interface.
855 If both admin-address and proxy-info-url are unset, the whole "Local
856 Privoxy Support" box on all generated pages will not be shown.
858 -------------------------------------------------------------------------------
860 7.3.2.3. proxy-info-url
864 A URL to documentation about the local Privoxy setup, configuration or
877 No link to local documentation is displayed on error pages and the CGI user
882 If both admin-address and proxy-info-url are unset, the whole "Local
883 Privoxy Support" box on all generated pages will not be shown.
885 This URL shouldn't be blocked ;-)
887 -------------------------------------------------------------------------------
891 These options are mainly useful when tracing a problem. Note that you might
892 also want to invoke Privoxy with the --no-daemon command line option when
895 -------------------------------------------------------------------------------
901 Key values that determine what information gets logged.
909 12289 (i.e.: URLs plus informational and warning messages)
917 The available debug levels are:
919 debug 1 # show each GET/POST/CONNECT request
920 debug 2 # show each connection status
921 debug 4 # show I/O status
922 debug 8 # show header parsing
923 debug 16 # log all data into the logfile
924 debug 32 # debug force feature
925 debug 64 # debug regular expression filter
926 debug 128 # debug fast redirects
927 debug 256 # debug GIF de-animation
928 debug 512 # Common Log Format
929 debug 1024 # debug kill pop-ups
930 debug 4096 # Startup banner and warnings.
931 debug 8192 # Non-fatal errors
933 To select multiple debug levels, you can either add them or use multiple
936 A debug level of 1 is informative because it will show you each request as
937 it happens. 1, 4096 and 8192 are highly recommended so that you will notice
938 when things go wrong. The other levels are probably only of interest if you
939 are hunting down a specific problem. They can produce a hell of an output
942 The reporting of fatal errors (i.e. ones which crash Privoxy) is always on
943 and cannot be disabled.
945 If you want to use CLF (Common Log Format), you should set "debug 512" ONLY
946 and not enable anything else.
948 -------------------------------------------------------------------------------
950 7.3.3.2. single-threaded
954 Whether to run only one server thread
966 Multi-threaded (or, where unavailable: forked) operation, i.e. the ability
967 to serve multiple requests simultaneously.
971 This option is only there for debug purposes and you should never need to
972 use it. It will drastically reduce performance.
974 -------------------------------------------------------------------------------
976 7.3.4. Access Control and Security
978 This section of the config file controls the security-relevant aspects of
979 Privoxy's configuration.
981 -------------------------------------------------------------------------------
983 7.3.4.1. listen-address
987 The IP address and TCP port on which Privoxy will listen for client
1000 Bind to localhost (127.0.0.1), port 8118. This is suitable and recommended
1001 for home users who run Privoxy on the same machine as their browser.
1005 You will need to configure your browser(s) to this proxy address and port.
1007 If you already have another service running on port 8118, or if you want to
1008 serve requests from other machines (e.g. on your local network) as well,
1009 you will need to override the default.
1011 If you leave out the IP address, Privoxy will bind to all interfaces
1012 (addresses) on your machine and may become reachable from the Internet. In
1013 that case, consider using access control lists (ACL's) (see "ACLs" below),
1018 Suppose you are running Privoxy on a machine which has the address
1019 192.168.0.1 on your local private network (192.168.0.0) and has another
1020 outside connection with a different address. You want it to serve requests
1023 listen-address 192.168.0.1:8118
1025 -------------------------------------------------------------------------------
1031 Initial state of "toggle" status
1043 Act as if toggled on
1047 If set to 0, Privoxy will start in "toggled off" mode, i.e. behave like a
1048 normal, content-neutral proxy. See enable-remote-toggle below. This is not
1049 really useful anymore, since toggling is much easier via the web interface
1050 then via editing the conf file.
1052 The windows version will only display the toggle icon in the system tray if
1053 this option is present.
1055 -------------------------------------------------------------------------------
1057 7.3.4.3. enable-remote-toggle
1061 Whether or not the web-based toggle feature may be used
1073 The web-based toggle feature is disabled.
1077 When toggled off, Privoxy acts like a normal, content-neutral proxy, i.e.
1078 it acts as if none of the actions applied to any URL.
1080 For the time being, access to the toggle feature can not be controlled
1081 separately by "ACLs" or HTTP authentication, so that everybody who can
1082 access Privoxy (see "ACLs" and listen-address above) can toggle it for all
1083 users. So this option is not recommended for multi-user environments with
1086 Note that you must have compiled Privoxy with support for this feature,
1087 otherwise this option has no effect.
1089 -------------------------------------------------------------------------------
1091 7.3.4.4. enable-edit-actions
1095 Whether or not the web-based actions file editor may be used
1107 The web-based actions file editor is disabled.
1111 For the time being, access to the editor can not be controlled separately
1112 by "ACLs" or HTTP authentication, so that everybody who can access Privoxy
1113 (see "ACLs" and listen-address above) can modify its configuration for all
1114 users. So this option is not recommended for multi-user environments with
1117 Note that you must have compiled Privoxy with support for this feature,
1118 otherwise this option has no effect.
1120 -------------------------------------------------------------------------------
1122 7.3.4.5. ACLs: permit-access and deny-access
1126 Who can access what.
1130 src_addr[/src_masklen] [dst_addr[/dst_masklen]]
1132 Where src_addr and dst_addr are IP addresses in dotted decimal notation or
1133 valid DNS names, and src_masklen and dst_masklen are subnet masks in CIDR
1134 notation, i.e. integer values from 2 to 30 representing the length (in
1135 bits) of the network address. The masks and the whole destination part are
1144 Don't restrict access further than implied by listen-address
1148 Access controls are included at the request of ISPs and systems
1149 administrators, and are not usually needed by individual users. For a
1150 typical home user, it will normally suffice to ensure that Privoxy only
1151 listens on the localhost or internal (home) network address by means of the
1152 listen-address option.
1154 Please see the warnings in the FAQ that this proxy is not intended to be a
1155 substitute for a firewall or to encourage anyone to defer addressing basic
1156 security weaknesses.
1158 Multiple ACL lines are OK. If any ACLs are specified, then the Privoxy
1159 talks only to IP addresses that match at least one permit-access line and
1160 don't match any subsequent deny-access line. In other words, the last match
1161 wins, with the default being deny-access.
1163 If Privoxy is using a forwarder (see forward below) for a particular
1164 destination URL, the dst_addr that is examined is the address of the
1165 forwarder and NOT the address of the ultimate target. This is necessary
1166 because it may be impossible for the local Privoxy to determine the IP
1167 address of the ultimate target (that's often what gateways are used for).
1169 You should prefer using IP addresses over DNS names, because the address
1170 lookups take time. All DNS names must resolve! You can not use domain
1171 patterns like "*.org" or partial domain names. If a DNS name resolves to
1172 multiple IP addresses, only the first one is used.
1174 Denying access to particular sites by ACL may have undesired side effects
1175 if the site in question is hosted on a machine which also hosts other
1180 Explicitly define the default behavior if no ACL and listen-address are
1181 set: "localhost" is OK. The absence of a dst_addr implies that all
1182 destination addresses are OK:
1184 permit-access localhost
1186 Allow any host on the same class C subnet as www.privoxy.org access to
1187 nothing but www.example.com:
1189 permit-access www.privoxy.org/24 www.example.com/32
1191 Allow access from any host on the 26-bit subnet 192.168.45.64 to anywhere,
1192 with the exception that 192.168.45.73 may not access
1193 www.dirty-stuff.example.com:
1195 permit-access 192.168.45.64/26
1196 deny-access 192.168.45.73 www.dirty-stuff.example.com
1198 -------------------------------------------------------------------------------
1200 7.3.4.6. buffer-limit
1204 Maximum size of the buffer for content filtering.
1216 Use a 4MB (4096 KB) limit.
1220 For content filtering, i.e. the +filter and +deanimate-gif actions, it is
1221 necessary that Privoxy buffers the entire document body. This can be
1222 potentially dangerous, since a server could just keep sending data
1223 indefinitely and wait for your RAM to exhaust -- with nasty consequences.
1226 When a document buffer size reaches the buffer-limit, it is flushed to the
1227 client unfiltered and no further attempt to filter the rest of the document
1228 is made. Remember that there may be multiple threads running, which might
1229 require up to buffer-limit Kbytes each, unless you have enabled
1230 "single-threaded" above.
1232 -------------------------------------------------------------------------------
1236 This feature allows routing of HTTP requests through a chain of multiple
1237 proxies. It can be used to better protect privacy and confidentiality when
1238 accessing specific domains by routing requests to those domains through an
1239 anonymous public proxy (see e.g. http://www.multiproxy.org/anon_list.htm) Or to
1240 use a caching proxy to speed up browsing. Or chaining to a parent proxy may be
1241 necessary because the machine that Privoxy runs on has no direct Internet
1244 Also specified here are SOCKS proxies. Privoxy supports the SOCKS 4 and SOCKS
1247 -------------------------------------------------------------------------------
1253 To which parent HTTP proxy specific requests should be routed.
1257 target_domain[:port] http_parent[/port]
1259 Where target_domain is a domain name pattern (see the chapter on domain
1260 matching in the default.action file), http_parent is the address of the
1261 parent HTTP proxy as an IP addresses in dotted decimal notation or as a
1262 valid DNS name (or "." to denote "no forwarding", and the optional port
1263 parameters are TCP ports, i.e. integer values from 1 to 64535
1271 Don't use parent HTTP proxies.
1275 If http_parent is ".", then requests are not forwarded to another HTTP
1276 proxy but are made directly to the web servers.
1278 Multiple lines are OK, they are checked in sequence, and the last match
1283 Everything goes to an example anonymizing proxy, except SSL on port 443
1284 (which it doesn't handle):
1286 forward .* anon-proxy.example.org:8080
1289 Everything goes to our example ISP's caching proxy, except for requests to
1292 forward .*. caching-proxy.example-isp.net:8000
1293 forward .example-isp.net .
1295 -------------------------------------------------------------------------------
1297 7.3.5.2. forward-socks4 and forward-socks4a
1301 Through which SOCKS proxy (and to which parent HTTP proxy) specific
1302 requests should be routed.
1306 target_domain[:port] socks_proxy[/port] http_parent[/port]
1308 Where target_domain is a domain name pattern (see the chapter on domain
1309 matching in the default.action file), http_parent and socks_proxy are IP
1310 addresses in dotted decimal notation or valid DNS names (http_parent may be
1311 "." to denote "no HTTP forwarding"), and the optional port parameters are
1312 TCP ports, i.e. integer values from 1 to 64535
1320 Don't use SOCKS proxies.
1324 Multiple lines are OK, they are checked in sequence, and the last match
1327 The difference between forward-socks4 and forward-socks4a is that in the
1328 SOCKS 4A protocol, the DNS resolution of the target hostname happens on the
1329 SOCKS server, while in SOCKS 4 it happens locally.
1331 If http_parent is ".", then requests are not forwarded to another HTTP
1332 proxy but are made (HTTP-wise) directly to the web servers, albeit through
1337 From the company example.com, direct connections are made to all "internal"
1338 domains, but everything outbound goes through their ISP's proxy by way of
1339 example.com's corporate SOCKS 4A gateway to the Internet.
1341 forward-socks4a .*. socks-gw.example.com:1080 www-cache.example-isp.net:8080
1342 forward .example.com .
1344 A rule that uses a SOCKS 4 gateway for all destinations but no HTTP parent
1347 forward-socks4 .*. socks-gw.example.com:1080 .
1349 -------------------------------------------------------------------------------
1351 7.3.5.3. Advanced Forwarding Examples
1353 If you have links to multiple ISPs that provide various special content only to
1354 their subscribers, you can configure multiple Privoxies which have connections
1355 to the respective ISPs to act as forwarders to each other, so that your users
1356 can see the internal content of all ISPs.
1358 Assume that host-a has a PPP connection to isp-a.net. And host-b has a PPP
1359 connection to isp-b.net. Both run Privoxy. Their forwarding configuration can
1365 forward .isp-b.net host-b:8118
1370 forward .isp-a.net host-a:8118
1372 Now, your users can set their browser's proxy to use either host-a or host-b
1373 and be able to browse the internal content of both isp-a and isp-b.
1375 If you intend to chain Privoxy and squid locally, then chain as browser ->
1376 squid -> privoxy is the recommended way.
1378 Assuming that Privoxy and squid run on the same box, your squid configuration
1379 could then look like this:
1381 # Define Privoxy as parent proxy (without ICP)
1382 cache_peer 127.0.0.1 parent 8118 7 no-query
1384 # Define ACL for protocol FTP
1387 # Do not forward FTP requests to Privoxy
1388 always_direct allow ftp
1390 # Forward all the rest to Privoxy
1391 never_direct allow all
1393 You would then need to change your browser's proxy settings to squid's address
1394 and port. Squid normally uses port 3128. If unsure consult http_port in
1397 -------------------------------------------------------------------------------
1399 7.3.6. Windows GUI Options
1401 Privoxy has a number of options specific to the Windows GUI interface:
1403 If "activity-animation" is set to 1, the Privoxy icon will animate when
1404 "Privoxy" is active. To turn off, set to 0.
1406 activity-animation 1
1409 If "log-messages" is set to 1, Privoxy will log messages to the console window:
1414 If "log-buffer-size" is set to 1, the size of the log buffer, i.e. the amount
1415 of memory used for the log messages displayed in the console window, will be
1416 limited to "log-max-lines" (see below).
1418 Warning: Setting this to 0 will result in the buffer to grow infinitely and eat
1424 log-max-lines is the maximum number of lines held in the log buffer. See above.
1429 If "log-highlight-messages" is set to 1, Privoxy will highlight portions of the
1430 log messages with a bold-faced font:
1432 log-highlight-messages 1
1435 The font used in the console window:
1437 log-font-name Comic Sans MS
1440 Font size used in the console window:
1445 "show-on-task-bar" controls whether or not Privoxy will appear as a button on
1446 the Task bar when minimized:
1451 If "close-button-minimizes" is set to 1, the Windows close button will minimize
1452 Privoxy instead of closing the program (close with the exit option on the File
1455 close-button-minimizes 1
1458 The "hide-console" option is specific to the MS-Win console version of Privoxy.
1459 If this option is used, Privoxy will disconnect from and hide the command
1465 -------------------------------------------------------------------------------
1469 The actions files are used to define what actions Privoxy takes for which URLs,
1470 and thus determines how ad images, cookies and various other aspects of HTTP
1471 content and transactions are handled, and on which sites (or even parts
1472 thereof). There are three such files included with Privoxy, with slightly
1473 different purposes. default.action sets the default policies. standard.action
1474 is used by Privoxy and the web based editor to set pre-defined values (and
1475 normally should not be edited). Local exceptions are best done in user.action.
1476 The content of these can all be viewed and edited from http://
1477 config.privoxy.org/show-status.
1479 Anything you want can blocked, including ads, banners, or just some obnoxious
1480 URL that you would rather not see is done here. Cookies can be accepted or
1481 rejected, or accepted only during the current browser session (i.e. not written
1482 to disk), content can be modified, JavaScripts tamed, user-tracking fooled, and
1483 much more. See below for a complete list of available actions.
1485 An actions file typically has sections. Near the top, "aliases" are optionally
1486 defined (discussed below), then the default set of rules which will apply
1487 universally to all sites and pages. And then below that, exceptions to the
1488 defined universal policies.
1490 -------------------------------------------------------------------------------
1492 7.4.1. Finding the Right Mix
1494 Note that some actions like cookie suppression or script disabling may render
1495 some sites unusable, which rely on these techniques to work properly. Finding
1496 the right mix of actions is not easy and certainly a matter of personal taste.
1497 In general, it can be said that the more "aggressive" your default settings (in
1498 the top section of the actions file) are, the more exceptions for "trusted"
1499 sites you will have to make later. If, for example, you want to kill popup
1500 windows per default, you'll have to make exceptions from that rule for sites
1501 that you regularly use and that require popups for actually useful content,
1502 like maybe your bank, favorite shop, or newspaper.
1504 We have tried to provide you with reasonable rules to start from in the
1505 distribution actions files. But there is no general rule of thumb on these
1506 things. There just are too many variables, and sites are constantly changing.
1507 Sooner or later you will want to change the rules (and read this chapter again
1510 -------------------------------------------------------------------------------
1514 The easiest way to edit the "actions" files is with a browser by using our
1515 browser-based editor, which can be reached from http://config.privoxy.org/
1518 If you prefer plain text editing to GUIs, you can of course also directly edit
1519 the the actions files.
1521 -------------------------------------------------------------------------------
1523 7.4.3. How Actions are Applied to URLs
1525 Actions files are divided into sections. There are special sections, like the "
1526 alias" sections which will be discussed later. For now let's concentrate on
1527 regular sections: They have a heading line (often split up to multiple lines
1528 for readability) which consist of a list of actions, separated by whitespace
1529 and enclosed in curly braces. Below that, there is a list of URL patterns, each
1532 To determine which actions apply to a request, the URL of the request is
1533 compared to all patterns in this file. Every time it matches, the list of
1534 applicable actions for the URL is incrementally updated, using the heading of
1535 the section in which the pattern is located. If multiple matches for the same
1536 URL set the same action differently, the last match wins. If not, the effects
1537 are aggregated (e.g. a URL might match both the "+handle-as-image" and "+block"
1540 You can trace this process by visiting http://config.privoxy.org/show-url-info.
1542 More detail on this is provided in the Appendix, Anatomy of an Action.
1544 -------------------------------------------------------------------------------
1548 Generally, a pattern has the form <domain>/<path>, where both the <domain> and
1549 <path> are optional. (This is why the pattern / matches all URLs).
1553 is a domain-only pattern and will match any request to www.example.com,
1554 regardless of which document on that server is requested.
1558 means exactly the same. For domain-only patterns, the trailing / may be
1561 www.example.com/index.html
1563 matches only the single document /index.html on www.example.com.
1567 matches the document /index.html, regardless of the domain, i.e. on any web
1572 matches nothing, since it would be interpreted as a domain name and there
1573 is no top-level domain called .html.
1575 -------------------------------------------------------------------------------
1577 7.4.4.1. The Domain Pattern
1579 The matching of the domain part offers some flexible options: if the domain
1580 starts or ends with a dot, it becomes unanchored at that end. For example:
1584 matches any domain that ENDS in .example.com
1588 matches any domain that STARTS with www.
1592 matches any domain that CONTAINS .example. (Correctly speaking: It matches
1593 any FQDN that contains example as a domain.)
1595 Additionally, there are wild-cards that you can use in the domain names
1596 themselves. They work pretty similar to shell wild-cards: "*" stands for zero
1597 or more arbitrary characters, "?" stands for any single character, you can
1598 define character classes in square brackets and all of that can be freely
1603 matches "adserver.example.com", "ads.example.com", etc but not
1608 matches all of the above, and then some.
1612 matches www.ipix.com, pictures.epix.com, a.b.c.d.e.upix.com etc.
1614 www[1-9a-ez].example.c*
1616 matches www1.example.com, www4.example.cc, wwwd.example.cy,
1617 wwwz.example.com etc., but not wwww.example.com.
1619 -------------------------------------------------------------------------------
1621 7.4.4.2. The Path Pattern
1623 Privoxy uses Perl compatible regular expressions (through the PCRE library) for
1626 There is an Appendix with a brief quick-start into regular expressions, and
1627 full (very technical) documentation on PCRE regex syntax is available on-line
1628 at http://www.pcre.org/man.txt. You might also find the Perl man page on
1629 regular expressions (man perlre) useful, which is available on-line at http://
1630 www.perldoc.com/perl5.6/pod/perlre.html.
1632 Note that the path pattern is automatically left-anchored at the "/", i.e. it
1633 matches as if it would start with a "^" (regular expression speak for the
1634 beginning of a line).
1636 Please also note that matching in the path is case INSENSITIVE by default, but
1637 you can switch to case sensitive at any point in the pattern by using the "(?
1638 -i)" switch: www.example.com/(?-i)PaTtErN.* will match only documents whose
1639 path starts with PaTtErN in exactly this capitalization.
1641 -------------------------------------------------------------------------------
1645 All actions are disabled by default, until they are explicitly enabled
1646 somewhere in an actions file. Actions are turned on if preceded with a "+", and
1647 turned off if preceded with a "-". So a "+action" means "do that action", e.g.
1648 "+block" means please "block the following URL patterns".
1650 Actions are invoked by enclosing the action name in curly braces (e.g.
1651 {+some_action}), followed by a list of URLs (or patterns that match URLs) to
1652 which the action applies. There are three classes of actions:
1654 * Boolean, i.e the action can only be "on" or "off". Examples:
1656 {+name} # enable this action
1657 {-name} # disable this action
1660 * Parameterized, e.g. "+/-hide-user-agent{ Mozilla 1.0 }", where some value
1661 is required in order to enable this type of action. Examples:
1663 {+name{param}} # enable action and set parameter to "param"
1664 {-name} # disable action ("parameter") can be omitted
1667 * Multi-value, e.g. "{+/-add-header{Name: value}}" or "{+/-send-wafer{name=
1668 value}}"), where some value needs to be defined in addition to simply
1669 enabling the action. Examples:
1671 {+name{param=value}} # enable action and set "param" to "value"
1672 {-name{param=value}} # remove the parameter "param" completely
1673 {-name} # disable this action totally and remove param too
1676 If nothing is specified in any actions file, no "actions" are taken. So in this
1677 case Privoxy would just be a normal, non-blocking, non-anonymizing proxy. You
1678 must specifically enable the privacy and blocking features you need (although
1679 the provided default actions files will give a good starting point).
1681 Later defined actions always over-ride earlier ones. So exceptions to any rules
1682 you make, should come in the latter part of the file. For multi-valued actions,
1683 the actions are applied in the order they are specified. Actions files are
1684 processed in the order they are defined in config (the default installation has
1685 three actions files). It also quite possible for any given URL pattern to match
1686 more than one action!
1688 The list of valid Privoxy "actions" are:
1690 -------------------------------------------------------------------------------
1692 7.4.5.1. +add-header{Name: value}
1700 Send a user defined HTTP header to the web server.
1704 Any value is possible. Validity of the defined HTTP headers is not checked.
1708 {+add-header{X-User-Tracking: sucks}}
1714 This action may be specified multiple times, in order to define multiple
1715 headers. This is rarely needed for the typical user. If you don't know what
1716 "HTTP headers" are, you definitely don't need to worry about this one.
1718 -------------------------------------------------------------------------------
1728 Used to block a URL from reaching your browser. The URL may be anything,
1729 but is typically used to block ads or other obnoxious content.
1738 .banners.example.com
1744 If a URL matches one of the blocked patterns, Privoxy will intercept the
1745 URL and display its special "BLOCKED" page instead. If there is sufficient
1746 space, a large red banner will appear with a friendly message about why the
1747 page was blocked, and a way to go there anyway. If there is insufficient
1748 space a smaller blocked page will appear without the red banner. Click here
1749 to view the default blocked HTML page (Privoxy must be running for this to
1752 A very important exception is if the URL matches both "+block" and
1753 "+handle-as-image", then it will be handled by "+set-image-blocker" (see
1754 below). It is important to understand this process, in order to understand
1755 how Privoxy is able to deal with ads and other objectionable content.
1757 The "+filter" action can also perform some of the same functionality as
1758 "+block", but by virtue of very different programming techniques, and is
1759 most often used for different reasons.
1761 -------------------------------------------------------------------------------
1763 7.4.5.3. +deanimate-gifs
1771 To stop those annoying, distracting animated GIF images.
1779 {+deanimate-gifs{last}}
1785 De-animate all animated GIF images, i.e. reduce them to their last frame.
1786 This will also shrink the images considerably (in bytes, not pixels!). If
1787 the option "first" is given, the first frame of the animation is used as
1788 the replacement. If "last" is given, the last frame of the animation is
1789 used instead, which probably makes more sense for most banner animations,
1790 but also has the risk of not showing the entire last frame (if it is only a
1791 delta to an earlier frame).
1793 -------------------------------------------------------------------------------
1795 7.4.5.4. +downgrade-http-version
1803 "+downgrade-http-version" will downgrade HTTP/1.1 client requests to HTTP/
1804 1.0 and downgrade the responses as well.
1812 {+downgrade-http-version}
1818 Use this action for servers that use HTTP/1.1 protocol features that
1819 Privoxy doesn't handle well yet. HTTP/1.1 is only partially implemented.
1820 Default is not to downgrade requests. This is an infrequently needed
1821 action, and is used to help with rare problem sites only.
1823 -------------------------------------------------------------------------------
1825 7.4.5.5. +fast-redirects
1833 The "+fast-redirects" action enables interception of "redirect" requests
1834 from one server to another, which are used to track users.Privoxy can cut
1835 off all but the last valid URL in a redirect request and send a local
1836 redirect back to your browser without contacting the intermediate site(s).
1850 Many sites, like yahoo.com, don't just link to other sites. Instead, they
1851 will link to some script on their own server, giving the destination as a
1852 parameter, which will then redirect you to the final target. URLs resulting
1853 from this scheme typically look like: http://some.place/some_script?http://
1856 Sometimes, there are even multiple consecutive redirects encoded in the
1857 URL. These redirections via scripts make your web browsing more traceable,
1858 since the server from which you follow such a link can see where you go to.
1859 Apart from that, valuable bandwidth and time is wasted, while your browser
1860 ask the server for one redirect after the other. Plus, it feeds the
1863 This is a normally "on" feature, and often requires exceptions for sites
1864 that are sensitive to defeating this mechanism.
1866 -------------------------------------------------------------------------------
1876 Apply page filtering as defined by named sections of the default.filter
1877 file to the specified site(s). "Filtering" can be any modification of the
1878 raw page content, including re-writing or deletion of content.
1882 "+filter" must include the name of one of the section identifiers from
1883 default.filter (or whatever filterfile is specified in config).
1885 Example usage (from the current default.filter):
1887 +filter{html-annoyances}: Get rid of particularly annoying HTML abuse.
1889 +filter{js-annoyances}: Get rid of particularly annoying JavaScript abuse
1891 +filter{content-cookies}: Kill cookies that come in the HTML or JS content
1893 +filter{popups}: Kill all popups in JS and HTML
1895 +filter{frameset-borders}: Give frames a border and make them resizable
1897 +filter{webbugs}: Squish WebBugs (1x1 invisible GIFs used for user
1900 +filter{refresh-tags}: Kill automatic refresh tags (for dial-on-demand
1903 +filter{fun}: Text replacements for subversive browsing fun!
1905 +filter{nimda}: Remove Nimda (virus) code.
1907 +filter{banners-by-size}: Kill banners by size (very efficient!)
1909 +filter{shockwave-flash}: Kill embedded Shockwave Flash objects
1911 +filter{crude-parental}: Kill all web pages that contain the words "sex" or
1916 This is potentially a very powerful feature! And requires a knowledge of
1917 regular expressions if you want to "roll your own". Filtering operates on a
1918 line by line basis throughout the entire page.
1920 Filtering requires buffering the page content, which may appear to slow
1921 down page rendering since nothing is displayed until all content has passed
1922 the filters. (It does not really take longer, but seems that way since the
1923 page is not incrementally displayed.) This effect will be more noticeable
1924 on slower connections.
1926 Filtering can achieve some of the effects as the "+block" action, i.e. it
1927 can be used to block ads and banners. In the overall scheme of things,
1928 filtering is one of the first things "Privoxy" does with a web page. So
1929 other most other actions are applied to the already "filtered" page.
1931 -------------------------------------------------------------------------------
1933 7.4.5.7. +hide-forwarded-for-headers
1941 Block any existing X-Forwarded-for HTTP header, and do not add a new one.
1949 {+hide-forwarded-for-headers}
1955 It is fairly safe to leave this on. It does not seem to break many sites.
1957 -------------------------------------------------------------------------------
1959 7.4.5.8. +hide-from-header
1967 To block the browser from sending your email address in a "From:" header.
1971 Keyword: "block", or any user defined value.
1975 {+hide-from-header{block}}
1981 The keyword "block" will completely remove the header (not to be confused
1982 with the "+block" action). Alternately, you can specify any value you
1983 prefer to send to the web server.
1985 -------------------------------------------------------------------------------
1987 7.4.5.9. +hide-referer
1995 Don't send the "Referer:" (sic) HTTP header to the web site. Or,
1996 alternately send a forged header instead.
2000 Prevent the header from being sent with the keyword, "block". Or, "forge" a
2001 URL to one from the same server as the request. Or, set to user defined
2002 value of your choice.
2006 {+hide-referer{forge}}
2012 "forge" is the preferred option here, since some servers will not send
2013 images back otherwise.
2015 "+hide-referrer" is an alternate spelling of "+hide-referer". It has the
2016 exact same parameters, and can be freely mixed with, "+hide-referer".
2017 ("referrer" is the correct English spelling, however the HTTP specification
2018 has a bug - it requires it to be spelled as "referer".)
2020 -------------------------------------------------------------------------------
2022 7.4.5.10. +hide-user-agent
2030 To change the "User-Agent:" header so web servers can't tell your browser
2031 type. Who's business is it anyway?
2035 Any user defined string.
2039 {+hide-user-agent{Netscape 6.1 (X11; I; Linux 2.4.18 i686)}}
2045 Warning! This breaks many web sites that depend on this in order to
2046 determine how the target browser will respond to various requests. Use with
2049 -------------------------------------------------------------------------------
2051 7.4.5.11. +handle-as-image
2059 To define what Privoxy should treat automatically as an image, and is an
2060 important ingredient of how ads are handled.
2069 /.*\.(gif|jpg|jpeg|png|bmp|ico)
2074 This only has meaning if the URL (or pattern) also is "+block"ed, in which
2075 case a user definable image can be sent rather than a HTML page. This is
2076 integral to the whole concept of ad blocking: the URL must match both a
2077 "+block" rule, and "+handle-as-image". (See "+set-image-blocker" below for
2078 control over what will actually be displayed by the browser.)
2080 There is little reason to change the default definition for this action.
2082 -------------------------------------------------------------------------------
2084 7.4.5.12. +set-image-blocker
2092 Decide what to do with URLs that end up tagged with both "+block" and
2093 "+handle-as-image", e.g an advertisement.
2097 There are four available options: "-set-image-blocker" will send a HTML
2098 "blocked" page, usually resulting in a "broken image" icon.
2099 "+set-image-blocker{blank}" will send a 1x1 transparent GIF image.
2100 "+set-image-blocker{pattern}" will send a checkerboard type pattern (the
2101 default). And finally, "+set-image-blocker{http://xyz.com}" will send a
2102 HTTP temporary redirect to the specified image. This has the advantage of
2103 the icon being being cached by the browser, which will speed up the
2108 {+set-image-blocker{blank}}
2114 If you want invisible ads, they need to meet criteria as matching both
2115 images and blocked actions. And then, "image-blocker" should be set to
2116 "blank" for invisibility. Note you cannot treat HTML pages as images in
2117 most cases. For instance, frames require an HTML page to display. So a
2118 frame that is an ad, typically cannot be treated as an image. Forcing an
2119 "image" in this situation just will not work reliably.
2121 -------------------------------------------------------------------------------
2123 7.4.5.13. +limit-connect
2131 By default, Privoxy only allows HTTP CONNECT requests to port 443 (the
2132 standard, secure HTTPS port). Use "+limit-connect" to disable this
2133 altogether, or to allow more ports.
2137 Any valid port number, or port number range.
2141 +limit-connect{443} #
2142 This is the default and need not be specified.
2143 +limit-connect{80,443} # Ports 80 and 443 are OK.
2144 +limit-connect{-3, 7, 20-100, 500-} #
2145 Port less than 3, 7, 20 to 100 and above 500 are OK.
2150 The CONNECT methods exists in HTTP to allow access to secure websites
2151 (https:// URLs) through proxies. It works very simply: the proxy connects
2152 to the server on the specified port, and then short-circuits its
2153 connections to the client and to the remote proxy. This can be a big
2154 security hole, since CONNECT-enabled proxies can be abused as TCP relays
2157 If you want to allow CONNECT for more ports than this, or want to forbid
2158 CONNECT altogether, you can specify a comma separated list of ports and
2159 port ranges (the latter using dashes, with the minimum defaulting to 0 and
2162 If you don't know what any of this means, there probably is no reason to
2165 -------------------------------------------------------------------------------
2167 7.4.5.14. +prevent-compression
2175 Prevent the specified websites from compressing HTTP data.
2183 {+prevent-compression}
2189 Some websites do this, which can be a problem for Privoxy, since "+filter",
2190 "+kill-popups" and "+gif-deanimate" will not work on compressed data. This
2191 will slow down connections to those websites, though. Default typically is
2192 to turn "prevent-compression" on.
2194 -------------------------------------------------------------------------------
2196 7.4.5.15. +session-cookies-only
2204 Allow cookies for the current browser session only.
2210 Example usage (disabling):
2212 {-session-cookies-only}
2218 If websites set cookies, "+session-cookies-only" will make sure they are
2219 erased when you exit and restart your web browser. This makes profiling
2220 cookies useless, but won't break sites which require cookies so that you
2221 can log in for transactions. This is generally turned on for all sites, and
2222 is the recommended setting.
2224 "+prevent-*-cookies" actions should be turned off as well (see below), for
2225 "+session-cookies-only" to work. Or, else no cookies will get through at
2226 all. For, "persistent" cookies that survive across browser sessions, see
2229 -------------------------------------------------------------------------------
2231 7.4.5.16. +prevent-reading-cookies
2239 Explicitly prevent the web server from reading any cookies on your system.
2247 {+prevent-reading-cookies}
2253 Often used in conjunction with "+prevent-setting-cookies" to disable
2254 cookies completely. Note that "+session-cookies-only" requires these to
2255 both be disabled (or else it never gets any cookies to cache).
2257 For "persistent" cookies to work (i.e. they survive across browser sessions
2258 and reboots), all three cookie settings should be "off" for the specified
2261 -------------------------------------------------------------------------------
2263 7.4.5.17. +prevent-setting-cookies
2271 Explicitly block the web server from storing cookies on your system.
2279 {+prevent-setting-cookies}
2285 Often used in conjunction with "+prevent-reading-cookies" to disable
2286 cookies completely (see above).
2288 -------------------------------------------------------------------------------
2290 7.4.5.18. +kill-popups
2298 Stop those annoying JavaScript pop-up windows!
2312 "+kill-popups" uses a built in filter to disable pop-ups that use the
2313 window.open() function, etc. This is one of the first actions processed by
2314 Privoxy as it contacts the remote web server. This action is not always
2315 100% reliable, and is supplemented by "+filter{popups}".
2317 -------------------------------------------------------------------------------
2319 7.4.5.19. +send-vanilla-wafer
2327 Sends a cookie for every site stating that you do not accept any copyright
2328 on cookies sent to you, and asking them not to track you.
2336 {+send-vanilla-wafer}
2342 This action only applies if you are using a jarfile for saving cookies. Of
2343 course, this is a (relatively) unique header and could conceivably be used
2346 -------------------------------------------------------------------------------
2348 7.4.5.20. +send-wafer
2356 This allows you to send an arbitrary, user definable cookie.
2360 User specified cookie name and corresponding value.
2364 {+send-wafer{name=value}}
2370 This can be specified multiple times in order to add as many cookies as you
2373 -------------------------------------------------------------------------------
2375 7.4.5.21. Actions Examples
2377 Note that the meaning of any of the above examples is reversed by preceding the
2378 action with a "-", in place of the "+". Also, that some actions are turned on
2379 in the default section of the actions file, and require little to no additional
2380 configuration. These are just "on". But, other actions that are turned on the
2381 default section do typically require exceptions to be listed in the lower
2382 sections of actions file. E.g. by default no URLs are "blocked" (i.e. in the
2383 default definitions of default.action). We need exceptions to this in order to
2388 Turn off cookies by default, then allow a few through for specified sites
2389 (showing an excerpt from the "default" section of an actions file ONLY):
2392 # Allow cookies to and from the server, but
2393 # for this browser session ONLY
2395 # other actions normally listed here...
2396 -prevent-setting-cookies \
2397 -prevent-reading-cookies \
2398 +session-cookies-only \
2402 # Exceptions to the above, sites that benefit from persistent cookies
2403 # that are saved from one browser session to the next.
2404 { -session-cookies-only }
2413 Now turn off "fast redirects", and then we allow two exceptions:
2415 # Turn them off (excerpt only)!
2417 # other actions normally listed here...
2422 # Reverse it for these two sites, which don't work right without it.
2424 www.ukc.ac.uk/cgi-bin/wac\.cgi\?
2428 Turn on page filtering according to rules in the defined sections of
2429 default.filter, and make one exception for Sourceforge:
2431 # Run everything through the filter file, using only certain
2432 # specified sections:
2434 # other actions normally listed here...
2435 +filter{html-annoyances} +filter{js-annoyances} +filter{kill-popups}\
2436 +filter{webbugs} +filter{nimda} +filter{banners-by-size}
2440 # Then disable filtering of code from all sourceforge domains!
2445 Now some URLs that we want "blocked" (normally generates the "blocked" banner).
2446 Typically, the "block" action is off by default in the upper section of an
2447 actions file, then enabled against certain URLs and patterns in the lower part
2448 of the file. Many of these use regular expressions that will expand to match
2457 /.*count(er)?\.(pl|cgi|exe|dll|asp|php[34]?)
2458 /(?:.*/)?(publicite|werbung|rekla(ma|me|am)|annonse|maino(kset|nta|s)?)/
2460 /.*/(ng)?adclient\.cgi
2461 /.*/(plain|live|rotate)[-_.]?ads?/
2466 Note that many of these actions have the potential to cause a page to
2467 misbehave, possibly even not to display at all. There are many ways a site
2468 designer may choose to design his site, and what HTTP header content, and other
2469 criteria, he may depend on. There is no way to have hard and fast rules for all
2470 sites. See the Appendix for a brief example on troubleshooting actions.
2472 -------------------------------------------------------------------------------
2476 Custom "actions", known to Privoxy as "aliases", can be defined by combining
2477 other "actions". These can in turn be invoked just like the built-in "actions".
2478 Currently, an alias can contain any character except space, tab, "=", "{" or "}
2479 ". But please use only "a"- "z", "0"-"9", "+", and "-". Alias names are not
2480 case sensitive, and must be defined before other actions in the actions file!
2481 And there can only be one set of "aliases" defined per file. Each actions file
2482 may have its own aliases, but they are only visible within that file.
2484 Now let's define a few aliases:
2486 # Useful custom aliases we can use later. These must come first!
2488 +prevent-cookies = +prevent-setting-cookies +prevent-reading-cookies
2489 -prevent-cookies = -prevent-setting-cookies -prevent-reading-cookies
2491 -block -prevent-cookies -filter -fast-redirects -hide-referer -kill-popups
2492 shop = -prevent-cookies -filter -fast-redirects
2493 +imageblock = +block +handle-as-image
2495 # Aliases defined from other aliases, for people who don't like to type
2497 c0 = +prevent-cookies
2498 c1 = -prevent-cookies
2499 #... etc. Customize to your heart's content.
2502 Some examples using our "shop" and "fragile" aliases from above. These would
2503 appear in the lower sections of an actions file as exceptions to the default
2504 actions (as defined in the upper section):
2506 # These sites are very complex and require
2507 # minimal interference.
2509 .office.microsoft.com
2510 .windowsupdate.microsoft.com
2513 # Shopping sites - but we still want to block ads.
2516 .worldpay.com # for quietpc.com
2519 # These shops require pop-ups also
2525 The "shop" and "fragile" aliases are often used for "problem" sites that
2526 require most actions to be disabled in order to function properly.
2528 -------------------------------------------------------------------------------
2530 7.5. The Filter File
2532 Any web page can be dynamically modified with the filter file. This
2533 modification can be removal, or re-writing, of any web page content, including
2534 tags and non-visible content. The default filter file is default.filter,
2535 located in the config directory.
2537 This is potentially a very powerful feature, and requires knowledge of both
2538 "regular expression" and HTML in order create custom filters. But, there are a
2539 number of useful filters included with Privoxy for many common situations.
2541 The included example file is divided into sections. Each section begins with
2542 the FILTER keyword, followed by the identifier for that section, e.g. "FILTER:
2543 webbugs". Each section performs a similar type of filtering, such as
2546 This file uses regular expressions to alter or remove any string in the target
2547 page. The expressions can only operate on one line at a time. Some examples
2548 from the included default default.filter:
2550 Stop web pages from displaying annoying messages in the status bar by deleting
2553 FILTER: html-annoyances
2555 # New browser windows should be resizeable and have a location and status
2558 s/resizable="?(no|0)"?/resizable=1/ig s/noresize/yesresize/ig
2559 s/location="?(no|0)"?/location=1/ig s/status="?(no|0)"?/status=1/ig
2560 s/scrolling="?(no|0|Auto)"?/scrolling=1/ig
2561 s/menubar="?(no|0)"?/menubar=1/ig
2563 # The <BLINK> tag was a crime!
2565 s*<blink>|</blink>**ig
2569 #s/framespacing="?(no|0)"?//ig
2570 #s/margin(height|width)=[0-9]*//gi
2573 Just for kicks, replace any occurrence of "Microsoft" with "MicroSuck", and
2574 have a little fun with topical buzzwords:
2578 s/microsoft(?!.com)/MicroSuck/ig
2582 s/industry-leading|cutting-edge|award-winning/<font color=red><b>BINGO!</b></
2586 Kill those pesky little web-bugs:
2588 # webbugs: Squish WebBugs (1x1 invisible GIFs used for user tracking)
2591 s/<img\s+[^>]*?(width|height)\s*=\s*['"]?1\D[^>]*?(width|height)\s*=\s*['"]?1
2592 (\D[^>]*?)?>/<!-- Squished WebBug -->/sig
2595 -------------------------------------------------------------------------------
2599 When Privoxy displays one of its internal pages, such as a 404 Not Found error
2600 page, it uses the appropriate template. On Linux, BSD, and Unix, these are
2601 located in /etc/privoxy/templates by default. These may be customized, if
2602 desired. cgi-style.css is used to control the HTML attributes (fonts, etc).
2604 The default "Blocked" banner page with the bright red top banner, is called
2605 just "blocked". This may be customized or replaced with something else if
2608 -------------------------------------------------------------------------------
2610 8. Contacting the Developers, Bug Reporting and Feature Requests
2612 We value your feedback. However, to provide you with the best support, please
2613 note the following sections.
2615 -------------------------------------------------------------------------------
2619 To get support, use the Sourceforge Support Forum:
2621 http://sourceforge.net/tracker/?group_id=11118&atid=211118
2624 -------------------------------------------------------------------------------
2628 To submit bugs, use the Sourceforge Bug Forum:
2630 http://sourceforge.net/tracker/?group_id=11118&atid=111118.
2633 Make sure that the bug has not already been submitted. Please try to verify
2634 that it is a Privoxy bug, and not a browser or site bug first. If you are using
2635 your own custom configuration, please try the stock configs to see if the
2636 problem is a configuration related bug. And if not using the latest development
2637 snapshot, please try the latest one. Or even better, CVS sources. Please be
2638 sure to include the Privoxy version, platform, browser, any pertinent log data,
2639 any other relevant details (please be specific) and, if possible, some way to
2642 -------------------------------------------------------------------------------
2644 8.3. Request new features
2646 To submit ideas on new features, use the Sourceforge feature request forum:
2648 http://sourceforge.net/tracker/?atid=361118&group_id=11118&func=browse.
2651 -------------------------------------------------------------------------------
2653 8.4. Report ads or other filter problems
2655 You can also send feedback on websites that Privoxy has problems with. Please
2656 bookmark the following link: "Privoxy - Submit Filter Feedback". Once you surf
2657 to a page with problems, use the bookmark to send us feedback. We will look
2658 into the issue as soon as possible.
2660 New, improved default.action files will occasionally be made available based on
2661 your feedback. These will be announced on the ijbswa-announce list.
2663 -------------------------------------------------------------------------------
2667 For any other issues, feel free to use the mailing lists:
2669 http://sourceforge.net/mail/?group_id=11118.
2672 Anyone interested in actively participating in development and related
2673 discussions can also join the appropriate mailing list. Archives are available,
2674 too. See the page on Sourceforge.
2676 -------------------------------------------------------------------------------
2678 9. Copyright and History
2682 Privoxy is free software; you can redistribute it and/or modify it under the
2683 terms of the GNU General Public License as published by the Free Software
2684 Foundation; either version 2 of the License, or (at your option) any later
2687 This program is distributed in the hope that it will be useful, but WITHOUT ANY
2688 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
2689 PARTICULAR PURPOSE. See the GNU General Public License for more details, which
2690 is available from the Free Software Foundation, Inc, 59 Temple Place - Suite
2691 330, Boston, MA 02111-1307, USA.
2693 You should have received a copy of the GNU General Public License along with
2694 this program; if not, write to the Free Software Foundation, Inc., 59 Temple
2695 Place, Suite 330, Boston, MA 02111-1307 USA.
2697 -------------------------------------------------------------------------------
2701 Privoxy is evolved, and derived from, the Internet Junkbuster, with many
2702 improvments and enhancements over the original.
2704 Junkbuster was originally written by Anonymous Coders and Junkbusters
2705 Corporation, and was released as free open-source software under the GNU GPL.
2706 Stefan Waldherr made many improvements, and started the SourceForge project
2707 Privoxy to rekindle development. There are now several active developers
2708 contributing. The last stable release of Junkbuster was v2.0.2, which has now
2711 -------------------------------------------------------------------------------
2715 Other references and sites of interest to Privoxy users:
2717 http://www.privoxy.org/, The Privoxy Home page.
2719 http://sourceforge.net/projects/ijbswa, the Project Page for Privoxy on
2722 http://p.p/, access Privoxy from your browser. Alternately, http://
2723 config.privoxy.org may work in some situations where the first does not.
2725 http://p.p/, and select "actions file feedback system" to submit "misses" to
2728 http://www.junkbusters.com/ht/en/cookies.html
2730 http://www.waldherr.org/junkbuster/
2732 http://privacy.net/analyze/
2734 http://www.squid-cache.org/
2738 -------------------------------------------------------------------------------
2742 11.1. Regular Expressions
2744 Privoxy can use "regular expressions" in various config files. Assuming support
2745 for "pcre" (Perl Compatible Regular Expressions) is compiled in, which is the
2746 default. Such configuration directives do not require regular expressions, but
2747 they can be used to increase flexibility by matching a pattern with wild-cards
2750 If you are reading this, you probably don't understand what "regular
2751 expressions" are, or what they can do. So this will be a very brief
2752 introduction only. A full explanation would require a book ;-)
2754 "Regular expressions" is a way of matching one character expression against
2755 another to see if it matches or not. One of the "expressions" is a literal
2756 string of readable characters (letter, numbers, etc), and the other is a
2757 complex string of literal characters combined with wild-cards, and other
2758 special characters, called meta-characters. The "meta-characters" have special
2759 meanings and are used to build the complex pattern to be matched against. Perl
2760 Compatible Regular Expressions is an enhanced form of the regular expression
2761 language with backward compatibility.
2763 To make a simple analogy, we do something similar when we use wild-card
2764 characters when listing files with the dir command in DOS. *.* matches all
2765 filenames. The "special" character here is the asterisk which matches any and
2766 all characters. We can be more specific and use ? to match just individual
2767 characters. So "dir file?.text" would match "file1.txt", "file2.txt", etc. We
2768 are pattern matching, using a similar technique to "regular expressions"!
2770 Regular expressions do essentially the same thing, but are much, much more
2771 powerful. There are many more "special characters" and ways of building complex
2772 patterns however. Let's look at a few of the common ones, and then some
2775 . - Matches any single character, e.g. "a", "A", "4", ":", or "@".
2777 ? - The preceding character or expression is matched ZERO or ONE times. Either/
2780 + - The preceding character or expression is matched ONE or MORE times.
2782 * - The preceding character or expression is matched ZERO or MORE times.
2784 \ - The "escape" character denotes that the following character should be taken
2785 literally. This is used where one of the special characters (e.g. ".") needs to
2786 be taken literally and not as a special meta-character. Example: "example
2787 \.com", makes sure the period is recognized only as a period (and not expanded
2788 to its meta-character meaning of any single character).
2790 [] - Characters enclosed in brackets will be matched if any of the enclosed
2791 characters are encountered. For instance, "[0-9]" matches any numeric digit
2792 (zero through nine). As an example, we can combine this with "+" to match any
2793 digit one of more times: "[0-9]+".
2795 () - parentheses are used to group a sub-expression, or multiple
2798 | - The "bar" character works like an "or" conditional statement. A match is
2799 successful if the sub-expression on either side of "|" matches. As an example:
2800 "/(this|that) example/" uses grouping and the bar character and would match
2801 either "this example" or "that example", and nothing else.
2803 s/string1/string2/g - This is used to rewrite strings of text. "string1" is
2804 replaced by "string2" in this example. There must of course be a match on
2807 These are just some of the ones you are likely to use when matching URLs with
2808 Privoxy, and is a long way from a definitive list. This is enough to get us
2809 started with a few simple examples which may be more illuminating:
2811 /.*/banners/.* - A simple example that uses the common combination of "." and "
2812 *" to denote any character, zero or more times. In other words, any string at
2813 all. So we start with a literal forward slash, then our regular expression
2814 pattern (".*") another literal forward slash, the string "banners", another
2815 forward slash, and lastly another ".*". We are building a directory path here.
2816 This will match any file with the path that has a directory named "banners" in
2817 it. The ".*" matches any characters, and this could conceivably be more forward
2818 slashes, so it might expand into a much longer looking path. For example, this
2819 could match: "/eye/hate/spammers/banners/annoy_me_please.gif", or just "/
2820 banners/annoying.html", or almost an infinite number of other possible
2821 combinations, just so it has "banners" in the path somewhere.
2823 A now something a little more complex:
2825 /.*/adv((er)?ts?|ertis(ing|ements?))?/ - We have several literal forward
2826 slashes again ("/"), so we are building another expression that is a file path
2827 statement. We have another ".*", so we are matching against any conceivable
2828 sub-path, just so it matches our expression. The only true literal that must
2829 match our pattern is adv, together with the forward slashes. What comes after
2830 the "adv" string is the interesting part.
2832 Remember the "?" means the preceding expression (either a literal character or
2833 anything grouped with "(...)" in this case) can exist or not, since this means
2834 either zero or one match. So "((er)?ts?|ertis(ing|ements?))" is optional, as
2835 are the individual sub-expressions: "(er)", "(ing|ements?)", and the "s". The "
2836 |" means "or". We have two of those. For instance, "(ing|ements?)", can expand
2837 to match either "ing" OR "ements?". What is being done here, is an attempt at
2838 matching as many variations of "advertisement", and similar, as possible. So
2839 this would expand to match just "adv", or "advert", or "adverts", or
2840 "advertising", or "advertisement", or "advertisements". You get the idea. But
2841 it would not match "advertizements" (with a "z"). We could fix that by changing
2842 our regular expression to: "/.*/adv((er)?ts?|erti(s|z)(ing|ements?))?/", which
2843 would then match either spelling.
2845 /.*/advert[0-9]+\.(gif|jpe?g) - Again another path statement with forward
2846 slashes. Anything in the square brackets "[]" can be matched. This is using
2847 "0-9" as a shorthand expression to mean any digit one through nine. It is the
2848 same as saying "0123456789". So any digit matches. The "+" means one or more of
2849 the preceding expression must be included. The preceding expression here is
2850 what is in the square brackets -- in this case, any digit one through nine.
2851 Then, at the end, we have a grouping: "(gif|jpe?g)". This includes a "|", so
2852 this needs to match the expression on either side of that bar character also. A
2853 simple "gif" on one side, and the other side will in turn match either "jpeg"
2854 or "jpg", since the "?" means the letter "e" is optional and can be matched
2855 once or not at all. So we are building an expression here to match image GIF or
2856 JPEG type image file. It must include the literal string "advert", then one or
2857 more digits, and a "." (which is now a literal, and not a special character,
2858 since it is escaped with "\"), and lastly either "gif", or "jpeg", or "jpg".
2859 Some possible matches would include: "//advert1.jpg", "/nasty/ads/
2860 advert1234.gif", "/banners/from/hell/advert99.jpg". It would not match
2861 "advert1.gif" (no leading slash), or "/adverts232.jpg" (the expression does not
2862 include an "s"), or "/advert1.jsp" ("jsp" is not in the expression anywhere).
2864 s/microsoft(?!.com)/MicroSuck/i - This is a substitution. "MicroSuck" will
2865 replace any occurrence of "microsoft". The "i" at the end of the expression
2866 means ignore case. The "(?!.com)" means the match should fail if "microsoft" is
2867 followed by ".com". In other words, this acts like a "NOT" modifier. In case
2868 this is a hyperlink, we don't want to break it ;-).
2870 We are barely scratching the surface of regular expressions here so that you
2871 can understand the default Privoxy configuration files, and maybe use this
2872 knowledge to customize your own installation. There is much, much more that can
2873 be done with regular expressions. Now that you know enough to get started, you
2874 can learn more on your own :/
2876 More reading on Perl Compatible Regular expressions: http://www.perldoc.com/
2877 perl5.6/pod/perlre.html
2879 -------------------------------------------------------------------------------
2881 11.2. Privoxy's Internal Pages
2883 Since Privoxy proxies each requested web page, it is easy for Privoxy to trap
2884 certain special URLs. In this way, we can talk directly to Privoxy, and see how
2885 it is configured, see how our rules are being applied, change these rules and
2886 other configuration options, and even turn Privoxy's filtering off, all with a
2889 The URLs listed below are the special ones that allow direct access to Privoxy.
2890 Of course, Privoxy must be running to access these. If not, you will get a
2891 friendly error message. Internet access is not necessary either.
2893 * Privoxy main page:
2895 http://config.privoxy.org/
2897 Alternately, this may be reached at http://p.p/, but this variation may not
2898 work as reliably as the above in some configurations.
2900 * Show information about the current configuration, including viewing and
2901 editing of actions files:
2903 http://config.privoxy.org/show-status
2905 * Show the source code version numbers:
2907 http://config.privoxy.org/show-version
2909 * Show the browser's request headers:
2911 http://config.privoxy.org/show-request
2913 * Show which actions apply to a URL and why:
2915 http://config.privoxy.org/show-url-info
2917 * Toggle Privoxy on or off. In this case, "Privoxy" continues to run, but
2918 only as a pass-through proxy, with no actions taking place:
2920 http://config.privoxy.org/toggle
2922 Short cuts. Turn off, then on:
2924 http://config.privoxy.org/toggle?set=disable
2926 http://config.privoxy.org/toggle?set=enable
2928 These may be bookmarked for quick reference. See next.
2930 -------------------------------------------------------------------------------
2932 11.2.1. Bookmarklets
2934 Below are some "bookmarklets" to allow you to easily access a "mini" version of
2935 some of Privoxy's special pages. They are designed for MS Internet Explorer,
2936 but should work equally well in Netscape, Mozilla, and other browsers which
2937 support JavaScript. They are designed to run directly from your bookmarks - not
2938 by clicking the links below (although that should work for testing).
2940 To save them, right-click the link and choose "Add to Favorites" (IE) or "Add
2941 Bookmark" (Netscape). You will get a warning that the bookmark "may not be
2942 safe" - just click OK. Then you can run the Bookmarklet directly from your
2943 favorites/bookmarks. For even faster access, you can put them on the "Links"
2944 bar (IE) or the "Personal Toolbar" (Netscape), and run them with a single
2951 * Privoxy - Toggle Privoxy (Toggles between enabled and disabled)
2953 * Privoxy- View Status
2955 * Privoxy - Submit Filter Feedback
2957 Credit: The site which gave me the general idea for these bookmarklets is
2958 www.bookmarklets.com. They have more information about bookmarklets.
2960 -------------------------------------------------------------------------------
2962 11.3. Chain of Events
2964 Let's take a quick look at the basic sequence of events when a web page is
2965 requested by your browser and Privoxy is on duty:
2967 * First, your web browser requests a web page. The browser knows to send the
2968 request to Privoxy, which will in turn, relay the request to the remote web
2969 server after passing the following tests:
2971 * Privoxy traps any request for its own internal CGI pages (e.g http://p.p/)
2972 and sends the CGI page back to the browser.
2974 * Next, Privoxy checks to see if the URL matches any "+block" patterns. If
2975 so, the URL is then blocked, and the remote web server will not be
2976 contacted. "+handle-as-image" is then checked and if it does not match, an
2977 HTML "BLOCKED" page is sent back. Otherwise, if it does match, an image is
2978 returned. The type of image depends on the setting of "+set-image-blocker"
2979 (blank, checkerboard pattern, or an HTTP redirect to an image elsewhere).
2981 * Untrusted URLs are blocked. If URLs are being added to the trust file, then
2984 * If the URL pattern matches the "+fast-redirects" action, it is then
2985 processed. Unwanted parts of the requested URL are stripped.
2987 * Now the rest of the client browser's request headers are processed. If any
2988 of these match any of the relevant actions (e.g. "+hide-user-agent", etc.),
2989 headers are suppressed or forged as determined by these actions and their
2992 * Now the web server starts sending its response back (i.e. typically a web
2993 page and related data).
2995 * First, the server headers are read and processed to determine, among other
2996 things, the MIME type (document type) and encoding. The headers are then
2997 filtered as deterimed by the "+prevent-setting-cookies",
2998 "+session-cookies-only", and "+downgrade-http-version" actions.
3000 * If the "+kill-popups" action applies, and it is an HTML or JavaScript
3001 document, the popup-code in the response is filtered on-the-fly as it is
3004 * If a "+filter" or "+deanimate-gifs" action applies (and the document type
3005 fits the action), the rest of the page is read into memory (up to a
3006 configurable limit). Then the filter rules (from default.filter) are
3007 processed against the buffered content. Filters are applied in the order
3008 they are specified in the default.filter file. Animated GIFs, if present,
3009 are reduced to either the first or last frame, depending on the action
3010 setting.The entire page, which is now filtered, is then sent by Privoxy
3011 back to your browser.
3013 If neither "+filter" or "+deanimate-gifs" matches, then Privoxy passes the
3014 raw data through to the client browser as it becomes available.
3016 * As the browser receives the now (probably filtered) page content, it reads
3017 and then requests any URLs that may be embedded within the page source,
3018 e.g. ad images, stylesheets, JavaScript, other HTML documents (e.g.
3019 frames), sounds, etc. For each of these objects, the browser issues a new
3020 request. And each such request is in turn processed as above. Note that a
3021 complex web page may have many such embedded URLs.
3023 -------------------------------------------------------------------------------
3025 11.4. Anatomy of an Action
3027 The way Privoxy applies "actions" and "filters" to any given URL can be
3028 complex, and not always so easy to understand what is happening. And sometimes
3029 we need to be able to see just what Privoxy is doing. Especially, if something
3030 Privoxy is doing is causing us a problem inadvertently. It can be a little
3031 daunting to look at the actions and filters files themselves, since they tend
3032 to be filled with "regular expressions" whose consequences are not always so
3035 One quick test to see if Privoxy is causing a problem or not, is to disable it
3036 temporarily. This should be the first troubleshooting step. See the
3037 Bookmarklets section on a quick and easy way to do this (be sure to flush
3040 Privoxy also provides the http://config.privoxy.org/show-url-info page that can
3041 show us very specifically how actions are being applied to any given URL. This
3042 is a big help for troubleshooting.
3044 First, enter one URL (or partial URL) at the prompt, and then Privoxy will tell
3045 us how the current configuration will handle it. This will not help with
3046 filtering effects (i.e. the "+filter" action) from the default.filter file
3047 since this is handled very differently and not so easy to trap! It also will
3048 not tell you about any other URLs that may be embedded within the URL you are
3049 testing. For instance, images such as ads are expressed as URLs within the raw
3050 page source of HTML pages. So you will only get info for the actual URL that is
3051 pasted into the prompt area -- not any sub-URLs. If you want to know about
3052 embedded URLs like ads, you will have to dig those out of the HTML source. Use
3053 your browser's "View Page Source" option for this. Or right click on the ad,
3056 Let's try an example, google.com, and look at it one section at a time:
3058 Matches for http://google.com:
3060 --- File standard ---
3061 (no matches in this file)
3063 --- File default ---
3065 { -add-header -block +deanimate-gifs{last} -downgrade-http-version +fast-redirects
3066 -filter{popups} -filter{fun} -filter{shockwave-flash} -filter{crude-parental}
3067 +filter{html-annoyances} +filter{js-annoyances} +filter{content-cookies}
3068 +filter{webbugs} +filter{refresh-tags} +filter{nimda} +filter{banners-by-size}
3069 +hide-forwarded-for-headers +hide-from-header{block} +hide-referer{forge}
3070 -hide-user-agent -handle-as-image +set-image-blocker{pattern} -limit-connect
3071 +prevent-compression +session-cookies-only -prevent-reading-cookies
3072 -prevent-setting-cookies -kill-popups -send-vanilla-wafer -send-wafer }
3075 { -session-cookies-only }
3082 (no matches in this file)
3084 This tells us how we have defined our "actions", and which ones match for our
3085 example, "google.com". The first listing is any matches for the standard.action
3086 file. No hits at all here on "standard". Then next is "default", or our
3087 default.action file. The large, multi-line listing, is how the actions are set
3088 to match for all URLs, i.e. our default settings. If you look at your "actions"
3089 file, this would be the section just below the "aliases" section near the top.
3090 This will apply to all URLs as signified by the single forward slash at the end
3091 of the listing -- "/".
3093 But we can define additional actions that would be exceptions to these general
3094 rules, and then list specific URLs (or patterns) that these exceptions would
3095 apply to. Last match wins. Just below this then are two explicit matches for
3096 ".google.com". The first is negating our previous cookie setting, which was for
3097 "+session-cookies-only" (i.e. not persistent). So we will allow persistent
3098 cookies for google. The second turns off any "+fast-redirects" action, allowing
3099 this to take place unmolested. Note that there is a leading dot here --
3100 ".google.com". This will match any hosts and sub-domains, in the google.com
3101 domain also, such as "www.google.com". So, apparently, we have these two
3102 actions defined somewhere in the lower part of our default.action file, and
3103 "google.com" is referenced somewhere in these latter sections.
3105 Then, for our user.action file, we again have no hits.
3107 And finally we pull it all together in the bottom section and summarize how
3108 Privoxy is applying all its "actions" to "google.com":
3111 -add-header -block +deanimate-gifs{last} -downgrade-http-version -fast-redirects
3112 -filter{popups} -filter{fun} -filter{shockwave-flash} -filter{crude-parental}
3113 +filter{html-annoyances} +filter{js-annoyances} +filter{content-cookies}
3114 +filter{webbugs} +filter{refresh-tags} +filter{nimda} +filter{banners-by-size}
3115 +hide-forwarded-for-headers +hide-from-header{block} +hide-referer{forge}
3116 -hide-user-agent -handle-as-image +set-image-blocker{pattern} -limit-connect
3117 +prevent-compression -session-cookies-only -prevent-reading-cookies
3118 -prevent-setting-cookies -kill-popups -send-vanilla-wafer -send-wafer
3120 Notice the only difference here to the previous listing, is to "fast-redirects"
3121 and "session-cookies-only".
3123 Now another example, "ad.doubleclick.net":
3125 { +block +handle-as-image }
3128 { +block +handle-as-image }
3131 { +block +handle-as-image }
3134 We'll just show the interesting part here, the explicit matches. It is matched
3135 three different times. Each as an "+block +handle-as-image", which is the
3136 expanded form of one of our aliases that had been defined as: "+imageblock". (
3137 "Aliases" are defined in the first section of the actions file and typically
3138 used to combine more than one action.)
3140 Any one of these would have done the trick and blocked this as an unwanted
3141 image. This is unnecessarily redundant since the last case effectively would
3142 also cover the first. No point in taking chances with these guys though ;-)
3143 Note that if you want an ad or obnoxious URL to be invisible, it should be
3144 defined as "ad.doubleclick.net" is done here -- as both a "+block" and an
3145 "+handle-as-image". The custom alias "+imageblock" just simplifies the process
3146 and make it more readable.
3148 One last example. Let's try "http://www.rhapsodyk.net/adsl/HOWTO/". This one is
3149 giving us problems. We are getting a blank page. Hmmm...
3151 Matches for http://www.rhapsodyk.net/adsl/HOWTO/:
3153 { -add-header -block +deanimate-gifs -downgrade-http-version +fast-redirects
3154 +filter{html-annoyances} +filter{js-annoyances} +filter{kill-popups}
3155 +filter{webbugs} +filter{nimda} +filter{banners-by-size} +filter{hal}
3156 +filter{fun} +hide-forwarded-for-headers +hide-from-header{block}
3157 +hide-referer{forge} -hide-user-agent -handle-as-image +set-image-blocker{blank}
3158 +prevent-compression +session-cookies-only -prevent-setting-cookies
3159 -prevent-reading-cookies +kill-popups -send-vanilla-wafer -send-wafer }
3162 { +block +handle-as-image }
3165 Ooops, the "/adsl/" is matching "/ads"! But we did not want this at all! Now we
3166 see why we get the blank page. We could now add a new action below this that
3167 explicitly does not block ("{-block}") paths with "adsl". There are various
3168 ways to handle such exceptions. Example:
3173 Now the page displays ;-) Be sure to flush your browser's caches when making
3174 such changes. Or, try using Shift+Reload.
3176 But now what about a situation where we get no explicit matches like we did
3179 { +block +handle-as-image }
3182 That actually was very telling and pointed us quickly to where the problem was.
3183 If you don't get this kind of match, then it means one of the default rules in
3184 the first section is causing the problem. This would require some guesswork,
3185 and maybe a little trial and error to isolate the offending rule. One likely
3186 cause would be one of the "{+filter}" actions. Try adding the URL for the site
3187 to one of aliases that turn off "+filter":
3191 .worldpay.com # for quietpc.com
3196 "{shop}" is an "alias" that expands to "{ -filter -session-cookies-only }". Or
3197 you could do your own exception to negate filtering:
3202 This would probably be most appropriately put in user.action, for local site
3205 "{fragile}" is an alias that disables most actions. This can be used as a last
3206 resort for problem sites. Remember to flush caches! If this still does not
3207 work, you will have to go through the remaining actions one by one to find
3208 which one(s) is causing the problem.
projects / privoxy.git / blob