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41 <h1 class="SECT1"><a name="CONFIG" id="CONFIG">7. The Main Configuration
44 <p>By default, the main configuration file is named <tt class=
45 "FILENAME">config</tt>, with the exception of Windows, where it is named
46 <tt class="FILENAME">config.txt</tt>. Configuration lines consist of an
47 initial keyword followed by a list of values, all separated by whitespace
48 (any number of spaces or tabs). For example:</p>
50 <p class="LITERALLAYOUT"><tt class="LITERAL"> <span class=
51 "emphasis"><i class="EMPHASIS">confdir /etc/privoxy</i></span></tt></p>
53 <p>Assigns the value <tt class="LITERAL">/etc/privoxy</tt> to the option
54 <tt class="LITERAL">confdir</tt> and thus indicates that the
55 configuration directory is named <span class=
56 "QUOTE">"/etc/privoxy/"</span>.</p>
58 <p>All options in the config file except for <tt class=
59 "LITERAL">confdir</tt> and <tt class="LITERAL">logdir</tt> are optional.
60 Watch out in the below description for what happens if you leave them
63 <p>The main config file controls all aspects of <span class=
64 "APPLICATION">Privoxy</span>'s operation that are not location dependent
65 (i.e. they apply universally, no matter where you may be surfing). Like
66 the filter and action files, the config file is a plain text file and can
67 be modified with a text editor like emacs, vim or notepad.exe.</p>
70 <h2 class="SECT2"><a name="LOCAL-SET-UP" id="LOCAL-SET-UP">7.1. Local
71 Set-up Documentation</a></h2>
73 <p>If you intend to operate <span class="APPLICATION">Privoxy</span>
74 for more users than just yourself, it might be a good idea to let them
75 know how to reach you, what you block and why you do that, your
79 <h4 class="SECT3"><a name="USER-MANUAL" id="USER-MANUAL">7.1.1.
82 <div class="VARIABLELIST">
87 <p>Location of the <span class="APPLICATION">Privoxy</span>
91 <dt>Type of value:</dt>
94 <p>A fully qualified URI</p>
97 <dt>Default value:</dt>
100 <p><span class="emphasis"><i class=
101 "EMPHASIS">Unset</i></span></p>
104 <dt>Effect if unset:</dt>
107 <p><a href="https://www.privoxy.org/user-manual/" target=
108 "_top">https://www.privoxy.org/<tt class=
109 "REPLACEABLE"><i>version</i></tt>/user-manual/</a> will be
110 used, where <tt class="REPLACEABLE"><i>version</i></tt> is the
111 <span class="APPLICATION">Privoxy</span> version.</p>
117 <p>The User Manual URI is the single best source of information
118 on <span class="APPLICATION">Privoxy</span>, and is used for
119 help links from some of the internal CGI pages. The manual
120 itself is normally packaged with the binary distributions, so
121 you probably want to set this to a locally installed copy.</p>
125 <p>The best all purpose solution is simply to put the full
126 local <tt class="LITERAL">PATH</tt> to where the <i class=
127 "CITETITLE">User Manual</i> is located:</p>
129 <table border="0" bgcolor="#E0E0E0" width="90%">
133 user-manual /usr/share/doc/privoxy/user-manual
139 <p>The User Manual is then available to anyone with access to
140 <span class="APPLICATION">Privoxy</span>, by following the
141 built-in URL: <tt class=
142 "LITERAL">http://config.privoxy.org/user-manual/</tt> (or the
144 "LITERAL">http://p.p/user-manual/</tt>).</p>
146 <p>If the documentation is not on the local system, it can be
147 accessed from a remote server, as:</p>
149 <table border="0" bgcolor="#E0E0E0" width="90%">
153 user-manual http://example.com/privoxy/user-manual/
159 <div class="WARNING">
160 <table class="WARNING" border="1" width="90%">
162 <td align="center"><b>Warning</b></td>
167 <p>If set, this option should be <span class=
168 "emphasis"><i class="EMPHASIS">the first option in the
169 config file</i></span>, because it is used while the
170 config file is being read on start-up.</p>
181 <h4 class="SECT3"><a name="TRUST-INFO-URL" id="TRUST-INFO-URL">7.1.2.
182 trust-info-url</a></h4>
184 <div class="VARIABLELIST">
189 <p>A URL to be displayed in the error page that users will see
190 if access to an untrusted page is denied.</p>
193 <dt>Type of value:</dt>
199 <dt>Default value:</dt>
202 <p><span class="emphasis"><i class=
203 "EMPHASIS">Unset</i></span></p>
206 <dt>Effect if unset:</dt>
209 <p>No links are displayed on the "untrusted" error page.</p>
215 <p>The value of this option only matters if the experimental
216 trust mechanism has been activated. (See <a href=
217 "config.html#TRUSTFILE"><span class="emphasis"><i class=
218 "EMPHASIS">trustfile</i></span></a> below.)</p>
220 <p>If you use the trust mechanism, it is a good idea to write
221 up some on-line documentation about your trust policy and to
222 specify the URL(s) here. Use multiple times for multiple
225 <p>The URL(s) should be added to the trustfile as well, so
226 users don't end up locked out from the information on why they
227 were locked out in the first place!</p>
234 <h4 class="SECT3"><a name="ADMIN-ADDRESS" id="ADMIN-ADDRESS">7.1.3.
235 admin-address</a></h4>
237 <div class="VARIABLELIST">
242 <p>An email address to reach the <span class=
243 "APPLICATION">Privoxy</span> administrator.</p>
246 <dt>Type of value:</dt>
252 <dt>Default value:</dt>
255 <p><span class="emphasis"><i class=
256 "EMPHASIS">Unset</i></span></p>
259 <dt>Effect if unset:</dt>
262 <p>No email address is displayed on error pages and the CGI
269 <p>If both <tt class="LITERAL">admin-address</tt> and
270 <tt class="LITERAL">proxy-info-url</tt> are unset, the whole
271 "Local Privoxy Support" box on all generated pages will not be
279 <h4 class="SECT3"><a name="PROXY-INFO-URL" id="PROXY-INFO-URL">7.1.4.
280 proxy-info-url</a></h4>
282 <div class="VARIABLELIST">
287 <p>A URL to documentation about the local <span class=
288 "APPLICATION">Privoxy</span> setup, configuration or
292 <dt>Type of value:</dt>
298 <dt>Default value:</dt>
301 <p><span class="emphasis"><i class=
302 "EMPHASIS">Unset</i></span></p>
305 <dt>Effect if unset:</dt>
308 <p>No link to local documentation is displayed on error pages
309 and the CGI user interface.</p>
315 <p>If both <tt class="LITERAL">admin-address</tt> and
316 <tt class="LITERAL">proxy-info-url</tt> are unset, the whole
317 "Local Privoxy Support" box on all generated pages will not be
320 <p>This URL shouldn't be blocked ;-)</p>
328 <h2 class="SECT2"><a name="CONF-LOG-LOC" id="CONF-LOG-LOC">7.2.
329 Configuration and Log File Locations</a></h2>
331 <p><span class="APPLICATION">Privoxy</span> can (and normally does) use
332 a number of other files for additional configuration, help and logging.
333 This section of the configuration file tells <span class=
334 "APPLICATION">Privoxy</span> where to find those other files.</p>
336 <p>The user running <span class="APPLICATION">Privoxy</span>, must have
337 read permission for all configuration files, and write permission to
338 any files that would be modified, such as log files and actions
342 <h4 class="SECT3"><a name="CONFDIR" id="CONFDIR">7.2.1.
345 <div class="VARIABLELIST">
350 <p>The directory where the other configuration files are
354 <dt>Type of value:</dt>
360 <dt>Default value:</dt>
363 <p>/etc/privoxy (Unix) <span class="emphasis"><i class=
364 "EMPHASIS">or</i></span> <span class=
365 "APPLICATION">Privoxy</span> installation dir (Windows)</p>
368 <dt>Effect if unset:</dt>
371 <p><span class="emphasis"><i class=
372 "EMPHASIS">Mandatory</i></span></p>
378 <p>No trailing <span class="QUOTE">"<tt class=
379 "LITERAL">/</tt>"</span>, please.</p>
386 <h4 class="SECT3"><a name="TEMPLDIR" id="TEMPLDIR">7.2.2.
389 <div class="VARIABLELIST">
394 <p>An alternative directory where the templates are loaded
398 <dt>Type of value:</dt>
404 <dt>Default value:</dt>
410 <dt>Effect if unset:</dt>
413 <p>The templates are assumed to be located in
414 confdir/template.</p>
420 <p><span class="APPLICATION">Privoxy's</span> original
421 templates are usually overwritten with each update. Use this
422 option to relocate customized templates that should be kept. As
423 template variables might change between updates, you shouldn't
424 expect templates to work with <span class=
425 "APPLICATION">Privoxy</span> releases other than the one they
426 were part of, though.</p>
433 <h4 class="SECT3"><a name="TEMPORARY-DIRECTORY" id=
434 "TEMPORARY-DIRECTORY">7.2.3. temporary-directory</a></h4>
436 <div class="VARIABLELIST">
441 <p>A directory where Privoxy can create temporary files.</p>
444 <dt>Type of value:</dt>
450 <dt>Default value:</dt>
456 <dt>Effect if unset:</dt>
459 <p>No temporary files are created, external filters don't
466 <p>To execute <tt class="LITERAL"><a href=
467 "actions-file.html#EXTERNAL-FILTER" target="_top">external
468 filters</a></tt>, <span class="APPLICATION">Privoxy</span> has
469 to create temporary files. This directive specifies the
470 directory the temporary files should be written to.</p>
472 <p>It should be a directory only <span class=
473 "APPLICATION">Privoxy</span> (and trusted users) can
481 <h4 class="SECT3"><a name="LOGDIR" id="LOGDIR">7.2.4. logdir</a></h4>
483 <div class="VARIABLELIST">
488 <p>The directory where all logging takes place (i.e. where the
489 <tt class="FILENAME">logfile</tt> is located).</p>
492 <dt>Type of value:</dt>
498 <dt>Default value:</dt>
501 <p>/var/log/privoxy (Unix) <span class="emphasis"><i class=
502 "EMPHASIS">or</i></span> <span class=
503 "APPLICATION">Privoxy</span> installation dir (Windows)</p>
506 <dt>Effect if unset:</dt>
509 <p><span class="emphasis"><i class=
510 "EMPHASIS">Mandatory</i></span></p>
516 <p>No trailing <span class="QUOTE">"<tt class=
517 "LITERAL">/</tt>"</span>, please.</p>
524 <h4 class="SECT3"><a name="ACTIONSFILE" id="ACTIONSFILE">7.2.5.
525 actionsfile</a></h4><a name="DEFAULT.ACTION" id=
526 "DEFAULT.ACTION"></a><a name="STANDARD.ACTION" id=
527 "STANDARD.ACTION"></a><a name="USER.ACTION" id="USER.ACTION"></a>
529 <div class="VARIABLELIST">
534 <p>The <a href="actions-file.html">actions file(s)</a> to
538 <dt>Type of value:</dt>
541 <p>Complete file name, relative to <tt class=
542 "LITERAL">confdir</tt></p>
545 <dt>Default values:</dt>
552 <p class="LITERALLAYOUT">
553 match-all.action # Actions that are applied to all sites and maybe overruled later on.</p>
559 <p class="LITERALLAYOUT">
560 default.action # Main actions file</p>
566 <p class="LITERALLAYOUT">
567 user.action # User customizations</p>
574 <dt>Effect if unset:</dt>
577 <p>No actions are taken at all. More or less neutral
584 <p>Multiple <tt class="LITERAL">actionsfile</tt> lines are
585 permitted, and are in fact recommended!</p>
587 <p>The default values are <tt class=
588 "FILENAME">default.action</tt>, which is the <span class=
589 "QUOTE">"main"</span> actions file maintained by the
590 developers, and <tt class="FILENAME">user.action</tt>, where
591 you can make your personal additions.</p>
593 <p>Actions files contain all the per site and per URL
594 configuration for ad blocking, cookie management, privacy
595 considerations, etc.</p>
602 <h4 class="SECT3"><a name="FILTERFILE" id="FILTERFILE">7.2.6.
603 filterfile</a></h4><a name="DEFAULT.FILTER" id="DEFAULT.FILTER"></a>
605 <div class="VARIABLELIST">
610 <p>The <a href="filter-file.html">filter file(s)</a> to use</p>
613 <dt>Type of value:</dt>
616 <p>File name, relative to <tt class="LITERAL">confdir</tt></p>
619 <dt>Default value:</dt>
622 <p>default.filter (Unix) <span class="emphasis"><i class=
623 "EMPHASIS">or</i></span> default.filter.txt (Windows)</p>
626 <dt>Effect if unset:</dt>
629 <p>No textual content filtering takes place, i.e. all
630 <tt class="LITERAL">+<a href=
631 "actions-file.html#FILTER">filter</a>{<tt class=
632 "REPLACEABLE"><i>name</i></tt>}</tt> actions in the actions
633 files are turned neutral.</p>
639 <p>Multiple <tt class="LITERAL">filterfile</tt> lines are
642 <p>The <a href="filter-file.html">filter files</a> contain
643 content modification rules that use <a href=
644 "appendix.html#REGEX">regular expressions</a>. These rules
645 permit powerful changes on the content of Web pages, and
646 optionally the headers as well, e.g., you could try to disable
647 your favorite JavaScript annoyances, re-write the actual
648 displayed text, or just have some fun playing buzzword bingo
651 <p>The <tt class="LITERAL">+<a href=
652 "actions-file.html#FILTER">filter</a>{<tt class=
653 "REPLACEABLE"><i>name</i></tt>}</tt> actions rely on the
654 relevant filter (<tt class="REPLACEABLE"><i>name</i></tt>) to
655 be defined in a filter file!</p>
657 <p>A pre-defined filter file called <tt class=
658 "FILENAME">default.filter</tt> that contains a number of useful
659 filters for common problems is included in the distribution.
660 See the section on the <tt class="LITERAL"><a href=
661 "actions-file.html#FILTER">filter</a></tt> action for a
664 <p>It is recommended to place any locally adapted filters into
665 a separate file, such as <tt class=
666 "FILENAME">user.filter</tt>.</p>
673 <h4 class="SECT3"><a name="LOGFILE" id="LOGFILE">7.2.7.
676 <div class="VARIABLELIST">
681 <p>The log file to use</p>
684 <dt>Type of value:</dt>
687 <p>File name, relative to <tt class="LITERAL">logdir</tt></p>
690 <dt>Default value:</dt>
693 <p><span class="emphasis"><i class="EMPHASIS">Unset (commented
694 out)</i></span>. When activated: logfile (Unix) <span class=
695 "emphasis"><i class="EMPHASIS">or</i></span> privoxy.log
699 <dt>Effect if unset:</dt>
702 <p>No logfile is written.</p>
708 <p>The logfile is where all logging and error messages are
709 written. The level of detail and number of messages are set
710 with the <tt class="LITERAL">debug</tt> option (see below). The
711 logfile can be useful for tracking down a problem with
712 <span class="APPLICATION">Privoxy</span> (e.g., it's not
713 blocking an ad you think it should block) and it can help you
714 to monitor what your browser is doing.</p>
716 <p>Depending on the debug options below, the logfile may be a
717 privacy risk if third parties can get access to it. As most
718 users will never look at it, <span class=
719 "APPLICATION">Privoxy</span> only logs fatal errors by
722 <p>For most troubleshooting purposes, you will have to change
723 that, please refer to the debugging section for details.</p>
725 <p>Any log files must be writable by whatever user <span class=
726 "APPLICATION">Privoxy</span> is being run as (on Unix, default
727 user id is <span class="QUOTE">"privoxy"</span>).</p>
729 <p>To prevent the logfile from growing indefinitely, it is
730 recommended to periodically rotate or shorten it. Many
731 operating systems support log rotation out of the box, some
732 require additional software to do it. For details, please refer
733 to the documentation for your operating system.</p>
740 <h4 class="SECT3"><a name="TRUSTFILE" id="TRUSTFILE">7.2.8.
743 <div class="VARIABLELIST">
748 <p>The name of the trust file to use</p>
751 <dt>Type of value:</dt>
754 <p>File name, relative to <tt class="LITERAL">confdir</tt></p>
757 <dt>Default value:</dt>
760 <p><span class="emphasis"><i class="EMPHASIS">Unset (commented
761 out)</i></span>. When activated: trust (Unix) <span class=
762 "emphasis"><i class="EMPHASIS">or</i></span> trust.txt
766 <dt>Effect if unset:</dt>
769 <p>The entire trust mechanism is disabled.</p>
775 <p>The trust mechanism is an experimental feature for building
776 white-lists and should be used with care. It is <span class=
777 "emphasis"><i class="EMPHASIS">NOT</i></span> recommended for
780 <p>If you specify a trust file, <span class=
781 "APPLICATION">Privoxy</span> will only allow access to sites
782 that are specified in the trustfile. Sites can be listed in one
785 <p>Prepending a <tt class="LITERAL">~</tt> character limits
786 access to this site only (and any sub-paths within this site),
787 e.g. <tt class="LITERAL">~www.example.com</tt> allows access to
788 <tt class="LITERAL">~www.example.com/features/news.html</tt>,
791 <p>Or, you can designate sites as <span class=
792 "emphasis"><i class="EMPHASIS">trusted referrers</i></span>, by
793 prepending the name with a <tt class="LITERAL">+</tt>
794 character. The effect is that access to untrusted sites will be
795 granted -- but only if a link from this trusted referrer was
796 used to get there. The link target will then be added to the
797 <span class="QUOTE">"trustfile"</span> so that future, direct
798 accesses will be granted. Sites added via this mechanism do not
799 become trusted referrers themselves (i.e. they are added with a
800 <tt class="LITERAL">~</tt> designation). There is a limit of
801 512 such entries, after which new entries will not be made.</p>
803 <p>If you use the <tt class="LITERAL">+</tt> operator in the
804 trust file, it may grow considerably over time.</p>
806 <p>It is recommended that <span class=
807 "APPLICATION">Privoxy</span> be compiled with the <tt class=
808 "LITERAL">--disable-force</tt>, <tt class=
809 "LITERAL">--disable-toggle</tt> and <tt class=
810 "LITERAL">--disable-editor</tt> options, if this feature is to
813 <p>Possible applications include limiting Internet access for
822 <h2 class="SECT2"><a name="DEBUGGING" id="DEBUGGING">7.3.
825 <p>These options are mainly useful when tracing a problem. Note that
826 you might also want to invoke <span class="APPLICATION">Privoxy</span>
827 with the <tt class="LITERAL">--no-daemon</tt> command line option when
831 <h4 class="SECT3"><a name="DEBUG" id="DEBUG">7.3.1. debug</a></h4>
833 <div class="VARIABLELIST">
838 <p>Key values that determine what information gets logged.</p>
841 <dt>Type of value:</dt>
844 <p>Integer values</p>
847 <dt>Default value:</dt>
850 <p>0 (i.e.: only fatal errors (that cause Privoxy to exit) are
854 <dt>Effect if unset:</dt>
857 <p>Default value is used (see above).</p>
863 <p>The available debug levels are:</p>
865 <table border="0" bgcolor="#E0E0E0" width="90%">
868 <pre class="PROGRAMLISTING">
869 debug 1 # Log the destination for each request <span class=
870 "APPLICATION">Privoxy</span> let through. See also debug 1024.
871 debug 2 # show each connection status
872 debug 4 # show I/O status
873 debug 8 # show header parsing
874 debug 16 # log all data written to the network
875 debug 32 # debug force feature
876 debug 64 # debug regular expression filters
877 debug 128 # debug redirects
878 debug 256 # debug GIF de-animation
879 debug 512 # Common Log Format
880 debug 1024 # Log the destination for requests <span class=
881 "APPLICATION">Privoxy</span> didn't let through, and the reason why.
882 debug 2048 # CGI user interface
883 debug 4096 # Startup banner and warnings.
884 debug 8192 # Non-fatal errors
885 debug 32768 # log all data read from the network
886 debug 65536 # Log the applying actions
892 <p>To select multiple debug levels, you can either add them or
893 use multiple <tt class="LITERAL">debug</tt> lines.</p>
895 <p>A debug level of 1 is informative because it will show you
896 each request as it happens. <span class="emphasis"><i class=
897 "EMPHASIS">1, 1024, 4096 and 8192 are recommended</i></span> so
898 that you will notice when things go wrong. The other levels are
899 probably only of interest if you are hunting down a specific
900 problem. They can produce a hell of an output (especially
903 <p>If you are used to the more verbose settings, simply enable
904 the debug lines below again.</p>
906 <p>If you want to use pure CLF (Common Log Format), you should
907 set <span class="QUOTE">"debug 512"</span> <span class=
908 "emphasis"><i class="EMPHASIS">ONLY</i></span> and not enable
911 <p><span class="APPLICATION">Privoxy</span> has a hard-coded
912 limit for the length of log messages. If it's reached, messages
913 are logged truncated and marked with <span class="QUOTE">"...
914 [too long, truncated]"</span>.</p>
916 <p>Please don't file any support requests without trying to
917 reproduce the problem with increased debug level first. Once
918 you read the log messages, you may even be able to solve the
919 problem on your own.</p>
926 <h4 class="SECT3"><a name="SINGLE-THREADED" id=
927 "SINGLE-THREADED">7.3.2. single-threaded</a></h4>
929 <div class="VARIABLELIST">
934 <p>Whether to run only one server thread.</p>
937 <dt>Type of value:</dt>
940 <p><span class="emphasis"><i class="EMPHASIS">1 or
944 <dt>Default value:</dt>
947 <p><span class="emphasis"><i class="EMPHASIS">0</i></span></p>
950 <dt>Effect if unset:</dt>
953 <p>Multi-threaded (or, where unavailable: forked) operation,
954 i.e. the ability to serve multiple requests simultaneously.</p>
960 <p>This option is only there for debugging purposes.
961 <span class="emphasis"><i class="EMPHASIS">It will drastically
962 reduce performance.</i></span></p>
969 <h4 class="SECT3"><a name="HOSTNAME" id="HOSTNAME">7.3.3.
972 <div class="VARIABLELIST">
977 <p>The hostname shown on the CGI pages.</p>
980 <dt>Type of value:</dt>
986 <dt>Default value:</dt>
989 <p><span class="emphasis"><i class=
990 "EMPHASIS">Unset</i></span></p>
993 <dt>Effect if unset:</dt>
996 <p>The hostname provided by the operating system is used.</p>
1002 <p>On some misconfigured systems resolving the hostname fails
1003 or takes too much time and slows Privoxy down. Setting a fixed
1004 hostname works around the problem.</p>
1006 <p>In other circumstances it might be desirable to show a
1007 hostname other than the one returned by the operating system.
1008 For example if the system has several different hostnames and
1009 you don't want to use the first one.</p>
1011 <p>Note that Privoxy does not validate the specified hostname
1020 <h2 class="SECT2"><a name="ACCESS-CONTROL" id="ACCESS-CONTROL">7.4.
1021 Access Control and Security</a></h2>
1023 <p>This section of the config file controls the security-relevant
1024 aspects of <span class="APPLICATION">Privoxy</span>'s
1028 <h4 class="SECT3"><a name="LISTEN-ADDRESS" id="LISTEN-ADDRESS">7.4.1.
1029 listen-address</a></h4>
1031 <div class="VARIABLELIST">
1036 <p>The address and TCP port on which <span class=
1037 "APPLICATION">Privoxy</span> will listen for client
1041 <dt>Type of value:</dt>
1044 <p>[<tt class="REPLACEABLE"><i>IP-Address</i></tt>]:<tt class=
1045 "REPLACEABLE"><i>Port</i></tt></p>
1047 <p>[<tt class="REPLACEABLE"><i>Hostname</i></tt>]:<tt class=
1048 "REPLACEABLE"><i>Port</i></tt></p>
1051 <dt>Default value:</dt>
1054 <p>127.0.0.1:8118</p>
1057 <dt>Effect if unset:</dt>
1060 <p>Bind to 127.0.0.1 (IPv4 localhost), port 8118. This is
1061 suitable and recommended for home users who run <span class=
1062 "APPLICATION">Privoxy</span> on the same machine as their
1069 <p>You will need to configure your browser(s) to this proxy
1070 address and port.</p>
1072 <p>If you already have another service running on port 8118, or
1073 if you want to serve requests from other machines (e.g. on your
1074 local network) as well, you will need to override the
1077 <p>You can use this statement multiple times to make
1078 <span class="APPLICATION">Privoxy</span> listen on more ports
1079 or more <abbr class="ABBREV">IP</abbr> addresses. Suitable if
1080 your operating system does not support sharing <abbr class=
1081 "ABBREV">IPv6</abbr> and <abbr class="ABBREV">IPv4</abbr>
1082 protocols on the same socket.</p>
1084 <p>If a hostname is used instead of an IP address, <span class=
1085 "APPLICATION">Privoxy</span> will try to resolve it to an IP
1086 address and if there are multiple, use the first one
1089 <p>If the address for the hostname isn't already known on the
1090 system (for example because it's in /etc/hostname), this may
1091 result in DNS traffic.</p>
1093 <p>If the specified address isn't available on the system, or
1094 if the hostname can't be resolved, <span class=
1095 "APPLICATION">Privoxy</span> will fail to start.</p>
1097 <p>IPv6 addresses containing colons have to be quoted by
1098 brackets. They can only be used if <span class=
1099 "APPLICATION">Privoxy</span> has been compiled with IPv6
1100 support. If you aren't sure if your version supports it, have a
1102 "LITERAL">http://config.privoxy.org/show-status</tt>.</p>
1104 <p>Some operating systems will prefer IPv6 to IPv4 addresses
1105 even if the system has no IPv6 connectivity which is usually
1106 not expected by the user. Some even rely on DNS to resolve
1107 localhost which mean the "localhost" address used may not
1108 actually be local.</p>
1110 <p>It is therefore recommended to explicitly configure the
1111 intended IP address instead of relying on the operating system,
1112 unless there's a strong reason not to.</p>
1114 <p>If you leave out the address, <span class=
1115 "APPLICATION">Privoxy</span> will bind to all IPv4 interfaces
1116 (addresses) on your machine and may become reachable from the
1117 Internet and/or the local network. Be aware that some GNU/Linux
1118 distributions modify that behaviour without updating the
1119 documentation. Check for non-standard patches if your
1120 <span class="APPLICATION">Privoxy</span> version behaves
1123 <p>If you configure <span class="APPLICATION">Privoxy</span> to
1124 be reachable from the network, consider using <a href=
1125 "config.html#ACLS">access control lists</a> (ACL's, see below),
1126 and/or a firewall.</p>
1128 <p>If you open <span class="APPLICATION">Privoxy</span> to
1129 untrusted users, you will also want to make sure that the
1130 following actions are disabled: <tt class="LITERAL"><a href=
1131 "config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</a></tt>
1132 and <tt class="LITERAL"><a href=
1133 "config.html#ENABLE-REMOTE-TOGGLE">enable-remote-toggle</a></tt></p>
1139 <p>Suppose you are running <span class=
1140 "APPLICATION">Privoxy</span> on a machine which has the address
1141 192.168.0.1 on your local private network (192.168.0.0) and has
1142 another outside connection with a different address. You want
1143 it to serve requests from inside only:</p>
1145 <table border="0" bgcolor="#E0E0E0" width="90%">
1148 <pre class="PROGRAMLISTING">
1149 listen-address 192.168.0.1:8118
1155 <p>Suppose you are running <span class=
1156 "APPLICATION">Privoxy</span> on an IPv6-capable machine and you
1157 want it to listen on the IPv6 address of the loopback
1160 <table border="0" bgcolor="#E0E0E0" width="90%">
1163 <pre class="PROGRAMLISTING">
1164 listen-address [::1]:8118
1175 <h4 class="SECT3"><a name="TOGGLE" id="TOGGLE">7.4.2. toggle</a></h4>
1177 <div class="VARIABLELIST">
1182 <p>Initial state of "toggle" status</p>
1185 <dt>Type of value:</dt>
1191 <dt>Default value:</dt>
1197 <dt>Effect if unset:</dt>
1200 <p>Act as if toggled on</p>
1206 <p>If set to 0, <span class="APPLICATION">Privoxy</span> will
1207 start in <span class="QUOTE">"toggled off"</span> mode, i.e.
1208 mostly behave like a normal, content-neutral proxy with both ad
1209 blocking and content filtering disabled. See <tt class=
1210 "LITERAL">enable-remote-toggle</tt> below.</p>
1217 <h4 class="SECT3"><a name="ENABLE-REMOTE-TOGGLE" id=
1218 "ENABLE-REMOTE-TOGGLE">7.4.3. enable-remote-toggle</a></h4>
1220 <div class="VARIABLELIST">
1225 <p>Whether or not the <a href=
1226 "http://config.privoxy.org/toggle" target="_top">web-based
1227 toggle feature</a> may be used</p>
1230 <dt>Type of value:</dt>
1236 <dt>Default value:</dt>
1242 <dt>Effect if unset:</dt>
1245 <p>The web-based toggle feature is disabled.</p>
1251 <p>When toggled off, <span class="APPLICATION">Privoxy</span>
1252 mostly acts like a normal, content-neutral proxy, i.e. doesn't
1253 block ads or filter content.</p>
1255 <p>Access to the toggle feature can <span class=
1256 "emphasis"><i class="EMPHASIS">not</i></span> be controlled
1257 separately by <span class="QUOTE">"ACLs"</span> or HTTP
1258 authentication, so that everybody who can access <span class=
1259 "APPLICATION">Privoxy</span> (see <span class=
1260 "QUOTE">"ACLs"</span> and <tt class=
1261 "LITERAL">listen-address</tt> above) can toggle it for all
1262 users. So this option is <span class="emphasis"><i class=
1263 "EMPHASIS">not recommended</i></span> for multi-user
1264 environments with untrusted users.</p>
1266 <p>Note that malicious client side code (e.g Java) is also
1267 capable of using this option.</p>
1269 <p>As a lot of <span class="APPLICATION">Privoxy</span> users
1270 don't read documentation, this feature is disabled by
1273 <p>Note that you must have compiled <span class=
1274 "APPLICATION">Privoxy</span> with support for this feature,
1275 otherwise this option has no effect.</p>
1282 <h4 class="SECT3"><a name="ENABLE-REMOTE-HTTP-TOGGLE" id=
1283 "ENABLE-REMOTE-HTTP-TOGGLE">7.4.4. enable-remote-http-toggle</a></h4>
1285 <div class="VARIABLELIST">
1290 <p>Whether or not Privoxy recognizes special HTTP headers to
1291 change its behaviour.</p>
1294 <dt>Type of value:</dt>
1300 <dt>Default value:</dt>
1306 <dt>Effect if unset:</dt>
1309 <p>Privoxy ignores special HTTP headers.</p>
1315 <p>When toggled on, the client can change <span class=
1316 "APPLICATION">Privoxy's</span> behaviour by setting special
1317 HTTP headers. Currently the only supported special header is
1318 <span class="QUOTE">"X-Filter: No"</span>, to disable filtering
1319 for the ongoing request, even if it is enabled in one of the
1322 <p>This feature is disabled by default. If you are using
1323 <span class="APPLICATION">Privoxy</span> in a environment with
1324 trusted clients, you may enable this feature at your
1325 discretion. Note that malicious client side code (e.g Java) is
1326 also capable of using this feature.</p>
1328 <p>This option will be removed in future releases as it has
1329 been obsoleted by the more general header taggers.</p>
1336 <h4 class="SECT3"><a name="ENABLE-EDIT-ACTIONS" id=
1337 "ENABLE-EDIT-ACTIONS">7.4.5. enable-edit-actions</a></h4>
1339 <div class="VARIABLELIST">
1344 <p>Whether or not the <a href=
1345 "http://config.privoxy.org/show-status" target="_top">web-based
1346 actions file editor</a> may be used</p>
1349 <dt>Type of value:</dt>
1355 <dt>Default value:</dt>
1361 <dt>Effect if unset:</dt>
1364 <p>The web-based actions file editor is disabled.</p>
1370 <p>Access to the editor can <span class="emphasis"><i class=
1371 "EMPHASIS">not</i></span> be controlled separately by
1372 <span class="QUOTE">"ACLs"</span> or HTTP authentication, so
1373 that everybody who can access <span class=
1374 "APPLICATION">Privoxy</span> (see <span class=
1375 "QUOTE">"ACLs"</span> and <tt class=
1376 "LITERAL">listen-address</tt> above) can modify its
1377 configuration for all users.</p>
1379 <p>This option is <span class="emphasis"><i class=
1380 "EMPHASIS">not recommended</i></span> for environments with
1381 untrusted users and as a lot of <span class=
1382 "APPLICATION">Privoxy</span> users don't read documentation,
1383 this feature is disabled by default.</p>
1385 <p>Note that malicious client side code (e.g Java) is also
1386 capable of using the actions editor and you shouldn't enable
1387 this options unless you understand the consequences and are
1388 sure your browser is configured correctly.</p>
1390 <p>Note that you must have compiled <span class=
1391 "APPLICATION">Privoxy</span> with support for this feature,
1392 otherwise this option has no effect.</p>
1399 <h4 class="SECT3"><a name="ENFORCE-BLOCKS" id="ENFORCE-BLOCKS">7.4.6.
1400 enforce-blocks</a></h4>
1402 <div class="VARIABLELIST">
1407 <p>Whether the user is allowed to ignore blocks and can
1408 <span class="QUOTE">"go there anyway"</span>.</p>
1411 <dt>Type of value:</dt>
1414 <p><tt class="REPLACEABLE"><i>0 or 1</i></tt></p>
1417 <dt>Default value:</dt>
1420 <p><span class="emphasis"><i class="EMPHASIS">0</i></span></p>
1423 <dt>Effect if unset:</dt>
1426 <p>Blocks are not enforced.</p>
1432 <p><span class="APPLICATION">Privoxy</span> is mainly used to
1433 block and filter requests as a service to the user, for example
1434 to block ads and other junk that clogs the pipes. <span class=
1435 "APPLICATION">Privoxy's</span> configuration isn't perfect and
1436 sometimes innocent pages are blocked. In this situation it
1437 makes sense to allow the user to enforce the request and have
1438 <span class="APPLICATION">Privoxy</span> ignore the block.</p>
1440 <p>In the default configuration <span class=
1441 "APPLICATION">Privoxy's</span> <span class=
1442 "QUOTE">"Blocked"</span> page contains a <span class=
1443 "QUOTE">"go there anyway"</span> link to adds a special string
1444 (the force prefix) to the request URL. If that link is used,
1445 <span class="APPLICATION">Privoxy</span> will detect the force
1446 prefix, remove it again and let the request pass.</p>
1448 <p>Of course <span class="APPLICATION">Privoxy</span> can also
1449 be used to enforce a network policy. In that case the user
1450 obviously should not be able to bypass any blocks, and that's
1451 what the <span class="QUOTE">"enforce-blocks"</span> option is
1452 for. If it's enabled, <span class="APPLICATION">Privoxy</span>
1453 hides the <span class="QUOTE">"go there anyway"</span> link. If
1454 the user adds the force prefix by hand, it will not be accepted
1455 and the circumvention attempt is logged.</p>
1461 <p>enforce-blocks 1</p>
1468 <h4 class="SECT3"><a name="ACLS" id="ACLS">7.4.7. ACLs: permit-access
1469 and deny-access</a></h4><a name="PERMIT-ACCESS" id=
1470 "PERMIT-ACCESS"></a><a name="DENY-ACCESS" id="DENY-ACCESS"></a>
1472 <div class="VARIABLELIST">
1477 <p>Who can access what.</p>
1480 <dt>Type of value:</dt>
1483 <p><tt class="REPLACEABLE"><i>src_addr</i></tt>[:<tt class=
1484 "REPLACEABLE"><i>port</i></tt>][/<tt class=
1485 "REPLACEABLE"><i>src_masklen</i></tt>] [<tt class=
1486 "REPLACEABLE"><i>dst_addr</i></tt>[:<tt class=
1487 "REPLACEABLE"><i>port</i></tt>][/<tt class=
1488 "REPLACEABLE"><i>dst_masklen</i></tt>]]</p>
1490 <p>Where <tt class="REPLACEABLE"><i>src_addr</i></tt> and
1491 <tt class="REPLACEABLE"><i>dst_addr</i></tt> are IPv4 addresses
1492 in dotted decimal notation or valid DNS names, <tt class=
1493 "REPLACEABLE"><i>port</i></tt> is a port number, and <tt class=
1494 "REPLACEABLE"><i>src_masklen</i></tt> and <tt class=
1495 "REPLACEABLE"><i>dst_masklen</i></tt> are subnet masks in CIDR
1496 notation, i.e. integer values from 2 to 30 representing the
1497 length (in bits) of the network address. The masks and the
1498 whole destination part are optional.</p>
1500 <p>If your system implements <a href=
1501 "http://tools.ietf.org/html/rfc3493" target="_top">RFC
1502 3493</a>, then <tt class="REPLACEABLE"><i>src_addr</i></tt> and
1503 <tt class="REPLACEABLE"><i>dst_addr</i></tt> can be IPv6
1504 addresses delimeted by brackets, <tt class=
1505 "REPLACEABLE"><i>port</i></tt> can be a number or a service
1506 name, and <tt class="REPLACEABLE"><i>src_masklen</i></tt> and
1507 <tt class="REPLACEABLE"><i>dst_masklen</i></tt> can be a number
1511 <dt>Default value:</dt>
1514 <p><span class="emphasis"><i class=
1515 "EMPHASIS">Unset</i></span></p>
1517 <p>If no <tt class="REPLACEABLE"><i>port</i></tt> is specified,
1518 any port will match. If no <tt class=
1519 "REPLACEABLE"><i>src_masklen</i></tt> or <tt class=
1520 "REPLACEABLE"><i>src_masklen</i></tt> is given, the complete IP
1521 address has to match (i.e. 32 bits for IPv4 and 128 bits for
1525 <dt>Effect if unset:</dt>
1528 <p>Don't restrict access further than implied by <tt class=
1529 "LITERAL">listen-address</tt></p>
1535 <p>Access controls are included at the request of ISPs and
1536 systems administrators, and <span class="emphasis"><i class=
1537 "EMPHASIS">are not usually needed by individual
1538 users</i></span>. For a typical home user, it will normally
1539 suffice to ensure that <span class="APPLICATION">Privoxy</span>
1540 only listens on the localhost (127.0.0.1) or internal (home)
1541 network address by means of the <a href=
1542 "config.html#LISTEN-ADDRESS"><span class="emphasis"><i class=
1543 "EMPHASIS">listen-address</i></span></a> option.</p>
1545 <p>Please see the warnings in the FAQ that <span class=
1546 "APPLICATION">Privoxy</span> is not intended to be a substitute
1547 for a firewall or to encourage anyone to defer addressing basic
1548 security weaknesses.</p>
1550 <p>Multiple ACL lines are OK. If any ACLs are specified,
1551 <span class="APPLICATION">Privoxy</span> only talks to IP
1552 addresses that match at least one <tt class=
1553 "LITERAL">permit-access</tt> line and don't match any
1554 subsequent <tt class="LITERAL">deny-access</tt> line. In other
1555 words, the last match wins, with the default being <tt class=
1556 "LITERAL">deny-access</tt>.</p>
1558 <p>If <span class="APPLICATION">Privoxy</span> is using a
1559 forwarder (see <tt class="LITERAL">forward</tt> below) for a
1560 particular destination URL, the <tt class=
1561 "REPLACEABLE"><i>dst_addr</i></tt> that is examined is the
1562 address of the forwarder and <span class="emphasis"><i class=
1563 "EMPHASIS">NOT</i></span> the address of the ultimate target.
1564 This is necessary because it may be impossible for the local
1565 <span class="APPLICATION">Privoxy</span> to determine the IP
1566 address of the ultimate target (that's often what gateways are
1569 <p>You should prefer using IP addresses over DNS names, because
1570 the address lookups take time. All DNS names must resolve! You
1571 can <span class="emphasis"><i class="EMPHASIS">not</i></span>
1572 use domain patterns like <span class="QUOTE">"*.org"</span> or
1573 partial domain names. If a DNS name resolves to multiple IP
1574 addresses, only the first one is used.</p>
1576 <p>Some systems allow IPv4 clients to connect to IPv6 server
1577 sockets. Then the client's IPv4 address will be translated by
1578 the system into IPv6 address space with special prefix
1579 ::ffff:0:0/96 (so called IPv4 mapped IPv6 address).
1580 <span class="APPLICATION">Privoxy</span> can handle it and maps
1581 such ACL addresses automatically.</p>
1583 <p>Denying access to particular sites by ACL may have undesired
1584 side effects if the site in question is hosted on a machine
1585 which also hosts other sites (most sites are).</p>
1591 <p>Explicitly define the default behavior if no ACL and
1592 <tt class="LITERAL">listen-address</tt> are set: <span class=
1593 "QUOTE">"localhost"</span> is OK. The absence of a <tt class=
1594 "REPLACEABLE"><i>dst_addr</i></tt> implies that <span class=
1595 "emphasis"><i class="EMPHASIS">all</i></span> destination
1596 addresses are OK:</p>
1598 <table border="0" bgcolor="#E0E0E0" width="90%">
1601 <pre class="SCREEN">
1602 permit-access localhost
1608 <p>Allow any host on the same class C subnet as www.privoxy.org
1609 access to nothing but www.example.com (or other domains hosted
1610 on the same system):</p>
1612 <table border="0" bgcolor="#E0E0E0" width="90%">
1615 <pre class="SCREEN">
1616 permit-access www.privoxy.org/24 www.example.com/32
1622 <p>Allow access from any host on the 26-bit subnet
1623 192.168.45.64 to anywhere, with the exception that
1624 192.168.45.73 may not access the IP address behind
1625 www.dirty-stuff.example.com:</p>
1627 <table border="0" bgcolor="#E0E0E0" width="90%">
1630 <pre class="SCREEN">
1631 permit-access 192.168.45.64/26
1632 deny-access 192.168.45.73 www.dirty-stuff.example.com
1638 <p>Allow access from the IPv4 network 192.0.2.0/24 even if
1639 listening on an IPv6 wild card address (not supported on all
1642 <table border="0" bgcolor="#E0E0E0" width="90%">
1645 <pre class="PROGRAMLISTING">
1646 permit-access 192.0.2.0/24
1652 <p>This is equivalent to the following line even if listening
1653 on an IPv4 address (not supported on all platforms):</p>
1655 <table border="0" bgcolor="#E0E0E0" width="90%">
1658 <pre class="PROGRAMLISTING">
1659 permit-access [::ffff:192.0.2.0]/120
1670 <h4 class="SECT3"><a name="BUFFER-LIMIT" id="BUFFER-LIMIT">7.4.8.
1671 buffer-limit</a></h4>
1673 <div class="VARIABLELIST">
1678 <p>Maximum size of the buffer for content filtering.</p>
1681 <dt>Type of value:</dt>
1684 <p>Size in Kbytes</p>
1687 <dt>Default value:</dt>
1693 <dt>Effect if unset:</dt>
1696 <p>Use a 4MB (4096 KB) limit.</p>
1702 <p>For content filtering, i.e. the <tt class=
1703 "LITERAL">+filter</tt> and <tt class=
1704 "LITERAL">+deanimate-gif</tt> actions, it is necessary that
1705 <span class="APPLICATION">Privoxy</span> buffers the entire
1706 document body. This can be potentially dangerous, since a
1707 server could just keep sending data indefinitely and wait for
1708 your RAM to exhaust -- with nasty consequences. Hence this
1711 <p>When a document buffer size reaches the <tt class=
1712 "LITERAL">buffer-limit</tt>, it is flushed to the client
1713 unfiltered and no further attempt to filter the rest of the
1714 document is made. Remember that there may be multiple threads
1715 running, which might require up to <tt class=
1716 "LITERAL">buffer-limit</tt> Kbytes <span class=
1717 "emphasis"><i class="EMPHASIS">each</i></span>, unless you have
1718 enabled <span class="QUOTE">"single-threaded"</span> above.</p>
1725 <h4 class="SECT3"><a name="ENABLE-PROXY-AUTHENTICATION-FORWARDING"
1726 id="ENABLE-PROXY-AUTHENTICATION-FORWARDING">7.4.9.
1727 enable-proxy-authentication-forwarding</a></h4>
1729 <div class="VARIABLELIST">
1734 <p>Whether or not proxy authentication through <span class=
1735 "APPLICATION">Privoxy</span> should work.</p>
1738 <dt>Type of value:</dt>
1744 <dt>Default value:</dt>
1750 <dt>Effect if unset:</dt>
1753 <p>Proxy authentication headers are removed.</p>
1759 <p>Privoxy itself does not support proxy authentication, but
1760 can allow clients to authenticate against Privoxy's parent
1763 <p>By default Privoxy (3.0.21 and later) don't do that and
1764 remove Proxy-Authorization headers in requests and
1765 Proxy-Authenticate headers in responses to make it harder for
1766 malicious sites to trick inexperienced users into providing
1767 login information.</p>
1769 <p>If this option is enabled the headers are forwarded.</p>
1771 <p>Enabling this option is <span class="emphasis"><i class=
1772 "EMPHASIS">not recommended</i></span> if there is no parent
1773 proxy that requires authentication or if the local network
1774 between Privoxy and the parent proxy isn't trustworthy. If
1775 proxy authentication is only required for some requests, it is
1776 recommended to use a client header filter to remove the
1777 authentication headers for requests where they aren't
1786 <h2 class="SECT2"><a name="FORWARDING" id="FORWARDING">7.5.
1789 <p>This feature allows routing of HTTP requests through a chain of
1790 multiple proxies.</p>
1792 <p>Forwarding can be used to chain Privoxy with a caching proxy to
1793 speed up browsing. Using a parent proxy may also be necessary if the
1794 machine that <span class="APPLICATION">Privoxy</span> runs on has no
1795 direct Internet access.</p>
1797 <p>Note that parent proxies can severely decrease your privacy level.
1798 For example a parent proxy could add your IP address to the request
1799 headers and if it's a caching proxy it may add the <span class=
1800 "QUOTE">"Etag"</span> header to revalidation requests again, even
1801 though you configured Privoxy to remove it. It may also ignore
1802 Privoxy's header time randomization and use the original values which
1803 could be used by the server as cookie replacement to track your steps
1806 <p>Also specified here are SOCKS proxies. <span class=
1807 "APPLICATION">Privoxy</span> supports the SOCKS 4 and SOCKS 4A
1811 <h4 class="SECT3"><a name="FORWARD" id="FORWARD">7.5.1.
1814 <div class="VARIABLELIST">
1819 <p>To which parent HTTP proxy specific requests should be
1823 <dt>Type of value:</dt>
1826 <p><tt class="REPLACEABLE"><i>target_pattern</i></tt>
1827 <tt class="REPLACEABLE"><i>http_parent</i></tt>[:<tt class=
1828 "REPLACEABLE"><i>port</i></tt>]</p>
1830 <p>where <tt class="REPLACEABLE"><i>target_pattern</i></tt> is
1831 a <a href="actions-file.html#AF-PATTERNS">URL pattern</a> that
1832 specifies to which requests (i.e. URLs) this forward rule shall
1833 apply. Use <tt class="LITERAL">/</tt> to denote <span class=
1834 "QUOTE">"all URLs"</span>. <tt class=
1835 "REPLACEABLE"><i>http_parent</i></tt>[:<tt class=
1836 "REPLACEABLE"><i>port</i></tt>] is the DNS name or IP address
1837 of the parent HTTP proxy through which the requests should be
1838 forwarded, optionally followed by its listening port (default:
1839 8000). Use a single dot (<tt class="LITERAL">.</tt>) to denote
1840 <span class="QUOTE">"no forwarding"</span>.</p>
1843 <dt>Default value:</dt>
1846 <p><span class="emphasis"><i class=
1847 "EMPHASIS">Unset</i></span></p>
1850 <dt>Effect if unset:</dt>
1853 <p>Don't use parent HTTP proxies.</p>
1859 <p>If <tt class="REPLACEABLE"><i>http_parent</i></tt> is
1860 <span class="QUOTE">"."</span>, then requests are not forwarded
1861 to another HTTP proxy but are made directly to the web
1864 <p><tt class="REPLACEABLE"><i>http_parent</i></tt> can be a
1865 numerical IPv6 address (if <a href=
1866 "http://tools.ietf.org/html/rfc3493" target="_top">RFC 3493</a>
1867 is implemented). To prevent clashes with the port delimiter,
1868 the whole IP address has to be put into brackets. On the other
1869 hand a <tt class="REPLACEABLE"><i>target_pattern</i></tt>
1870 containing an IPv6 address has to be put into angle brackets
1871 (normal brackets are reserved for regular expressions
1874 <p>Multiple lines are OK, they are checked in sequence, and the
1875 last match wins.</p>
1881 <p>Everything goes to an example parent proxy, except SSL on
1882 port 443 (which it doesn't handle):</p>
1884 <table border="0" bgcolor="#E0E0E0" width="90%">
1887 <pre class="SCREEN">
1888 forward / parent-proxy.example.org:8080
1895 <p>Everything goes to our example ISP's caching proxy, except
1896 for requests to that ISP's sites:</p>
1898 <table border="0" bgcolor="#E0E0E0" width="90%">
1901 <pre class="SCREEN">
1902 forward / caching-proxy.isp.example.net:8000
1903 forward .isp.example.net .
1909 <p>Parent proxy specified by an IPv6 address:</p>
1911 <table border="0" bgcolor="#E0E0E0" width="90%">
1914 <pre class="PROGRAMLISTING">
1915 forward / [2001:DB8::1]:8000
1921 <p>Suppose your parent proxy doesn't support IPv6:</p>
1923 <table border="0" bgcolor="#E0E0E0" width="90%">
1926 <pre class="PROGRAMLISTING">
1927 forward / parent-proxy.example.org:8000
1928 forward ipv6-server.example.org .
1929 forward <[2-3][0-9a-f][0-9a-f][0-9a-f]:*> .
1940 <h4 class="SECT3"><a name="SOCKS" id="SOCKS">7.5.2. forward-socks4,
1941 forward-socks4a, forward-socks5 and forward-socks5t</a></h4><a name=
1942 "FORWARD-SOCKS4" id="FORWARD-SOCKS4"></a><a name="FORWARD-SOCKS4A"
1943 id="FORWARD-SOCKS4A"></a>
1945 <div class="VARIABLELIST">
1950 <p>Through which SOCKS proxy (and optionally to which parent
1951 HTTP proxy) specific requests should be routed.</p>
1954 <dt>Type of value:</dt>
1957 <p><tt class="REPLACEABLE"><i>target_pattern</i></tt>
1958 <tt class="REPLACEABLE"><i>socks_proxy</i></tt>[:<tt class=
1959 "REPLACEABLE"><i>port</i></tt>] <tt class=
1960 "REPLACEABLE"><i>http_parent</i></tt>[:<tt class=
1961 "REPLACEABLE"><i>port</i></tt>]</p>
1963 <p>where <tt class="REPLACEABLE"><i>target_pattern</i></tt> is
1964 a <a href="actions-file.html#AF-PATTERNS">URL pattern</a> that
1965 specifies to which requests (i.e. URLs) this forward rule shall
1966 apply. Use <tt class="LITERAL">/</tt> to denote <span class=
1967 "QUOTE">"all URLs"</span>. <tt class=
1968 "REPLACEABLE"><i>http_parent</i></tt> and <tt class=
1969 "REPLACEABLE"><i>socks_proxy</i></tt> are IP addresses in
1970 dotted decimal notation or valid DNS names (<tt class=
1971 "REPLACEABLE"><i>http_parent</i></tt> may be <span class=
1972 "QUOTE">"."</span> to denote <span class="QUOTE">"no HTTP
1973 forwarding"</span>), and the optional <tt class=
1974 "REPLACEABLE"><i>port</i></tt> parameters are TCP ports, i.e.
1975 integer values from 1 to 65535</p>
1978 <dt>Default value:</dt>
1981 <p><span class="emphasis"><i class=
1982 "EMPHASIS">Unset</i></span></p>
1985 <dt>Effect if unset:</dt>
1988 <p>Don't use SOCKS proxies.</p>
1994 <p>Multiple lines are OK, they are checked in sequence, and the
1995 last match wins.</p>
1997 <p>The difference between <tt class=
1998 "LITERAL">forward-socks4</tt> and <tt class=
1999 "LITERAL">forward-socks4a</tt> is that in the SOCKS 4A
2000 protocol, the DNS resolution of the target hostname happens on
2001 the SOCKS server, while in SOCKS 4 it happens locally.</p>
2003 <p>With <tt class="LITERAL">forward-socks5</tt> the DNS
2004 resolution will happen on the remote server as well.</p>
2006 <p><tt class="LITERAL">forward-socks5t</tt> works like vanilla
2007 <tt class="LITERAL">forward-socks5</tt> but lets <span class=
2008 "APPLICATION">Privoxy</span> additionally use Tor-specific
2009 SOCKS extensions. Currently the only supported SOCKS extension
2010 is optimistic data which can reduce the latency for the first
2011 request made on a newly created connection.</p>
2013 <p><tt class="REPLACEABLE"><i>socks_proxy</i></tt> and
2014 <tt class="REPLACEABLE"><i>http_parent</i></tt> can be a
2015 numerical IPv6 address (if <a href=
2016 "http://tools.ietf.org/html/rfc3493" target="_top">RFC 3493</a>
2017 is implemented). To prevent clashes with the port delimiter,
2018 the whole IP address has to be put into brackets. On the other
2019 hand a <tt class="REPLACEABLE"><i>target_pattern</i></tt>
2020 containing an IPv6 address has to be put into angle brackets
2021 (normal brackets are reserved for regular expressions
2024 <p>If <tt class="REPLACEABLE"><i>http_parent</i></tt> is
2025 <span class="QUOTE">"."</span>, then requests are not forwarded
2026 to another HTTP proxy but are made (HTTP-wise) directly to the
2027 web servers, albeit through a SOCKS proxy.</p>
2033 <p>From the company example.com, direct connections are made to
2034 all <span class="QUOTE">"internal"</span> domains, but
2035 everything outbound goes through their ISP's proxy by way of
2036 example.com's corporate SOCKS 4A gateway to the Internet.</p>
2038 <table border="0" bgcolor="#E0E0E0" width="90%">
2041 <pre class="SCREEN">
2042 forward-socks4a / socks-gw.example.com:1080 www-cache.isp.example.net:8080
2043 forward .example.com .
2049 <p>A rule that uses a SOCKS 4 gateway for all destinations but
2050 no HTTP parent looks like this:</p>
2052 <table border="0" bgcolor="#E0E0E0" width="90%">
2055 <pre class="SCREEN">
2056 forward-socks4 / socks-gw.example.com:1080 .
2062 <p>To chain Privoxy and Tor, both running on the same system,
2063 you would use something like:</p>
2065 <table border="0" bgcolor="#E0E0E0" width="90%">
2068 <pre class="SCREEN">
2069 forward-socks5t / 127.0.0.1:9050 .
2075 <p>Note that if you got Tor through one of the bundles, you may
2076 have to change the port from 9050 to 9150 (or even another
2077 one). For details, please check the documentation on the
2078 <a href="https://torproject.org/" target="_top">Tor
2081 <p>The public <span class="APPLICATION">Tor</span> network
2082 can't be used to reach your local network, if you need to
2083 access local servers you therefore might want to make some
2086 <table border="0" bgcolor="#E0E0E0" width="90%">
2089 <pre class="SCREEN">
2090 forward 192.168.*.*/ .
2092 forward 127.*.*.*/ .
2098 <p>Unencrypted connections to systems in these address ranges
2099 will be as (un)secure as the local network is, but the
2100 alternative is that you can't reach the local network through
2101 <span class="APPLICATION">Privoxy</span> at all. Of course this
2102 may actually be desired and there is no reason to make these
2103 exceptions if you aren't sure you need them.</p>
2105 <p>If you also want to be able to reach servers in your local
2106 network by using their names, you will need additional
2107 exceptions that look like this:</p>
2109 <table border="0" bgcolor="#E0E0E0" width="90%">
2112 <pre class="SCREEN">
2113 forward localhost/ .
2124 <h4 class="SECT3"><a name="ADVANCED-FORWARDING-EXAMPLES" id=
2125 "ADVANCED-FORWARDING-EXAMPLES">7.5.3. Advanced Forwarding
2128 <p>If you have links to multiple ISPs that provide various special
2129 content only to their subscribers, you can configure multiple
2130 <span class="APPLICATION">Privoxies</span> which have connections to
2131 the respective ISPs to act as forwarders to each other, so that
2132 <span class="emphasis"><i class="EMPHASIS">your</i></span> users can
2133 see the internal content of all ISPs.</p>
2135 <p>Assume that host-a has a PPP connection to isp-a.example.net. And
2136 host-b has a PPP connection to isp-b.example.org. Both run
2137 <span class="APPLICATION">Privoxy</span>. Their forwarding
2138 configuration can look like this:</p>
2142 <table border="0" bgcolor="#E0E0E0" width="100%">
2145 <pre class="SCREEN">
2147 forward .isp-b.example.net host-b:8118
2155 <table border="0" bgcolor="#E0E0E0" width="100%">
2158 <pre class="SCREEN">
2160 forward .isp-a.example.org host-a:8118
2166 <p>Now, your users can set their browser's proxy to use either host-a
2167 or host-b and be able to browse the internal content of both isp-a
2170 <p>If you intend to chain <span class="APPLICATION">Privoxy</span>
2171 and <span class="APPLICATION">squid</span> locally, then chaining as
2172 <tt class="LITERAL">browser -> squid -> privoxy</tt> is the
2173 recommended way.</p>
2175 <p>Assuming that <span class="APPLICATION">Privoxy</span> and
2176 <span class="APPLICATION">squid</span> run on the same box, your
2177 <span class="APPLICATION">squid</span> configuration could then look
2180 <table border="0" bgcolor="#E0E0E0" width="100%">
2183 <pre class="SCREEN">
2184 # Define Privoxy as parent proxy (without ICP)
2185 cache_peer 127.0.0.1 parent 8118 7 no-query
2187 # Define ACL for protocol FTP
2190 # Do not forward FTP requests to Privoxy
2191 always_direct allow ftp
2193 # Forward all the rest to Privoxy
2194 never_direct allow all
2200 <p>You would then need to change your browser's proxy settings to
2201 <span class="APPLICATION">squid</span>'s address and port. Squid
2202 normally uses port 3128. If unsure consult <tt class=
2203 "LITERAL">http_port</tt> in <tt class="FILENAME">squid.conf</tt>.</p>
2205 <p>You could just as well decide to only forward requests you suspect
2206 of leading to Windows executables through a virus-scanning parent
2207 proxy, say, on <tt class="LITERAL">antivir.example.com</tt>, port
2210 <table border="0" bgcolor="#E0E0E0" width="100%">
2213 <pre class="SCREEN">
2215 forward /.*\.(exe|com|dll|zip)$ antivir.example.com:8010
2223 <h4 class="SECT3"><a name="FORWARDED-CONNECT-RETRIES" id=
2224 "FORWARDED-CONNECT-RETRIES">7.5.4. forwarded-connect-retries</a></h4>
2226 <div class="VARIABLELIST">
2231 <p>How often Privoxy retries if a forwarded connection request
2235 <dt>Type of value:</dt>
2238 <p><tt class="REPLACEABLE"><i>Number of retries.</i></tt></p>
2241 <dt>Default value:</dt>
2244 <p><span class="emphasis"><i class="EMPHASIS">0</i></span></p>
2247 <dt>Effect if unset:</dt>
2250 <p>Connections forwarded through other proxies are treated like
2251 direct connections and no retry attempts are made.</p>
2258 "REPLACEABLE"><i>forwarded-connect-retries</i></tt> is mainly
2259 interesting for socks4a connections, where <span class=
2260 "APPLICATION">Privoxy</span> can't detect why the connections
2261 failed. The connection might have failed because of a DNS
2262 timeout in which case a retry makes sense, but it might also
2263 have failed because the server doesn't exist or isn't
2264 reachable. In this case the retry will just delay the
2265 appearance of Privoxy's error message.</p>
2267 <p>Note that in the context of this option, <span class=
2268 "QUOTE">"forwarded connections"</span> includes all connections
2269 that Privoxy forwards through other proxies. This option is not
2270 limited to the HTTP CONNECT method.</p>
2272 <p>Only use this option, if you are getting lots of
2273 forwarding-related error messages that go away when you try
2274 again manually. Start with a small value and check Privoxy's
2275 logfile from time to time, to see how many retries are usually
2282 <p>forwarded-connect-retries 1</p>
2290 <h2 class="SECT2"><a name="MISC" id="MISC">7.6. Miscellaneous</a></h2>
2293 <h4 class="SECT3"><a name="ACCEPT-INTERCEPTED-REQUESTS" id=
2294 "ACCEPT-INTERCEPTED-REQUESTS">7.6.1.
2295 accept-intercepted-requests</a></h4>
2297 <div class="VARIABLELIST">
2302 <p>Whether intercepted requests should be treated as valid.</p>
2305 <dt>Type of value:</dt>
2308 <p><tt class="REPLACEABLE"><i>0 or 1</i></tt></p>
2311 <dt>Default value:</dt>
2314 <p><span class="emphasis"><i class="EMPHASIS">0</i></span></p>
2317 <dt>Effect if unset:</dt>
2320 <p>Only proxy requests are accepted, intercepted requests are
2321 treated as invalid.</p>
2327 <p>If you don't trust your clients and want to force them to
2328 use <span class="APPLICATION">Privoxy</span>, enable this
2329 option and configure your packet filter to redirect outgoing
2330 HTTP connections into <span class=
2331 "APPLICATION">Privoxy</span>.</p>
2333 <p>Note that intercepting encrypted connections (HTTPS) isn't
2336 <p>Make sure that <span class="APPLICATION">Privoxy's</span>
2337 own requests aren't redirected as well. Additionally take care
2338 that <span class="APPLICATION">Privoxy</span> can't
2339 intentionally connect to itself, otherwise you could run into
2340 redirection loops if <span class="APPLICATION">Privoxy's</span>
2341 listening port is reachable by the outside or an attacker has
2342 access to the pages you visit.</p>
2344 <p>If you are running Privoxy as intercepting proxy without
2345 being able to intercept all client requests you may want to
2346 adjust the CGI templates to make sure they don't reference
2347 content from config.privoxy.org.</p>
2353 <p>accept-intercepted-requests 1</p>
2360 <h4 class="SECT3"><a name="ALLOW-CGI-REQUEST-CRUNCHING" id=
2361 "ALLOW-CGI-REQUEST-CRUNCHING">7.6.2.
2362 allow-cgi-request-crunching</a></h4>
2364 <div class="VARIABLELIST">
2369 <p>Whether requests to <span class=
2370 "APPLICATION">Privoxy's</span> CGI pages can be blocked or
2374 <dt>Type of value:</dt>
2377 <p><tt class="REPLACEABLE"><i>0 or 1</i></tt></p>
2380 <dt>Default value:</dt>
2383 <p><span class="emphasis"><i class="EMPHASIS">0</i></span></p>
2386 <dt>Effect if unset:</dt>
2389 <p><span class="APPLICATION">Privoxy</span> ignores block and
2390 redirect actions for its CGI pages.</p>
2396 <p>By default <span class="APPLICATION">Privoxy</span> ignores
2397 block or redirect actions for its CGI pages. Intercepting these
2398 requests can be useful in multi-user setups to implement
2399 fine-grained access control, but it can also render the
2400 complete web interface useless and make debugging problems
2401 painful if done without care.</p>
2403 <p>Don't enable this option unless you're sure that you really
2410 <p>allow-cgi-request-crunching 1</p>
2417 <h4 class="SECT3"><a name="SPLIT-LARGE-FORMS" id=
2418 "SPLIT-LARGE-FORMS">7.6.3. split-large-forms</a></h4>
2420 <div class="VARIABLELIST">
2425 <p>Whether the CGI interface should stay compatible with broken
2429 <dt>Type of value:</dt>
2432 <p><tt class="REPLACEABLE"><i>0 or 1</i></tt></p>
2435 <dt>Default value:</dt>
2438 <p><span class="emphasis"><i class="EMPHASIS">0</i></span></p>
2441 <dt>Effect if unset:</dt>
2444 <p>The CGI form generate long GET URLs.</p>
2450 <p><span class="APPLICATION">Privoxy's</span> CGI forms can
2451 lead to rather long URLs. This isn't a problem as far as the
2452 HTTP standard is concerned, but it can confuse clients with
2453 arbitrary URL length limitations.</p>
2455 <p>Enabling split-large-forms causes <span class=
2456 "APPLICATION">Privoxy</span> to divide big forms into smaller
2457 ones to keep the URL length down. It makes editing a lot less
2458 convenient and you can no longer submit all changes at once,
2459 but at least it works around this browser bug.</p>
2461 <p>If you don't notice any editing problems, there is no reason
2462 to enable this option, but if one of the submit buttons appears
2463 to be broken, you should give it a try.</p>
2469 <p>split-large-forms 1</p>
2476 <h4 class="SECT3"><a name="KEEP-ALIVE-TIMEOUT" id=
2477 "KEEP-ALIVE-TIMEOUT">7.6.4. keep-alive-timeout</a></h4>
2479 <div class="VARIABLELIST">
2484 <p>Number of seconds after which an open connection will no
2485 longer be reused.</p>
2488 <dt>Type of value:</dt>
2491 <p><tt class="REPLACEABLE"><i>Time in seconds.</i></tt></p>
2494 <dt>Default value:</dt>
2500 <dt>Effect if unset:</dt>
2503 <p>Connections are not kept alive.</p>
2509 <p>This option allows clients to keep the connection to
2510 <span class="APPLICATION">Privoxy</span> alive. If the server
2511 supports it, <span class="APPLICATION">Privoxy</span> will keep
2512 the connection to the server alive as well. Under certain
2513 circumstances this may result in speed-ups.</p>
2515 <p>By default, <span class="APPLICATION">Privoxy</span> will
2516 close the connection to the server if the client connection
2517 gets closed, or if the specified timeout has been reached
2518 without a new request coming in. This behaviour can be changed
2519 with the <a href="#CONNECTION-SHARING" target=
2520 "_top">connection-sharing</a> option.</p>
2522 <p>This option has no effect if <span class=
2523 "APPLICATION">Privoxy</span> has been compiled without
2524 keep-alive support.</p>
2526 <p>Note that a timeout of five seconds as used in the default
2527 configuration file significantly decreases the number of
2528 connections that will be reused. The value is used because some
2529 browsers limit the number of connections they open to a single
2530 host and apply the same limit to proxies. This can result in a
2531 single website <span class="QUOTE">"grabbing"</span> all the
2532 connections the browser allows, which means connections to
2533 other websites can't be opened until the connections currently
2534 in use time out.</p>
2536 <p>Several users have reported this as a Privoxy bug, so the
2537 default value has been reduced. Consider increasing it to 300
2538 seconds or even more if you think your browser can handle it.
2539 If your browser appears to be hanging, it probably can't.</p>
2545 <p>keep-alive-timeout 300</p>
2552 <h4 class="SECT3"><a name="TOLERATE-PIPELINING" id=
2553 "TOLERATE-PIPELINING">7.6.5. tolerate-pipelining</a></h4>
2555 <div class="VARIABLELIST">
2560 <p>Whether or not pipelined requests should be served.</p>
2563 <dt>Type of value:</dt>
2566 <p><tt class="REPLACEABLE"><i>0 or 1.</i></tt></p>
2569 <dt>Default value:</dt>
2575 <dt>Effect if unset:</dt>
2578 <p>If Privoxy receives more than one request at once, it
2579 terminates the client connection after serving the first
2586 <p><span class="APPLICATION">Privoxy</span> currently doesn't
2587 pipeline outgoing requests, thus allowing pipelining on the
2588 client connection is not guaranteed to improve the
2591 <p>By default <span class="APPLICATION">Privoxy</span> tries to
2592 discourage clients from pipelining by discarding aggressively
2593 pipelined requests, which forces the client to resend them
2594 through a new connection.</p>
2596 <p>This option lets <span class="APPLICATION">Privoxy</span>
2597 tolerate pipelining. Whether or not that improves performance
2598 mainly depends on the client configuration.</p>
2600 <p>If you are seeing problems with pages not properly loading,
2601 disabling this option could work around the problem.</p>
2607 <p>tolerate-pipelining 1</p>
2614 <h4 class="SECT3"><a name="DEFAULT-SERVER-TIMEOUT" id=
2615 "DEFAULT-SERVER-TIMEOUT">7.6.6. default-server-timeout</a></h4>
2617 <div class="VARIABLELIST">
2622 <p>Assumed server-side keep-alive timeout if not specified by
2626 <dt>Type of value:</dt>
2629 <p><tt class="REPLACEABLE"><i>Time in seconds.</i></tt></p>
2632 <dt>Default value:</dt>
2638 <dt>Effect if unset:</dt>
2641 <p>Connections for which the server didn't specify the
2642 keep-alive timeout are not reused.</p>
2648 <p>Enabling this option significantly increases the number of
2649 connections that are reused, provided the <a href=
2650 "#KEEP-ALIVE-TIMEOUT" target="_top">keep-alive-timeout</a>
2651 option is also enabled.</p>
2653 <p>While it also increases the number of connections problems
2654 when <span class="APPLICATION">Privoxy</span> tries to reuse a
2655 connection that already has been closed on the server side, or
2656 is closed while <span class="APPLICATION">Privoxy</span> is
2657 trying to reuse it, this should only be a problem if it happens
2658 for the first request sent by the client. If it happens for
2659 requests on reused client connections, <span class=
2660 "APPLICATION">Privoxy</span> will simply close the connection
2661 and the client is supposed to retry the request without
2662 bothering the user.</p>
2664 <p>Enabling this option is therefore only recommended if the
2665 <a href="#CONNECTION-SHARING" target=
2666 "_top">connection-sharing</a> option is disabled.</p>
2668 <p>It is an error to specify a value larger than the <a href=
2669 "#KEEP-ALIVE-TIMEOUT" target="_top">keep-alive-timeout</a>
2672 <p>This option has no effect if <span class=
2673 "APPLICATION">Privoxy</span> has been compiled without
2674 keep-alive support.</p>
2680 <p>default-server-timeout 60</p>
2687 <h4 class="SECT3"><a name="CONNECTION-SHARING" id=
2688 "CONNECTION-SHARING">7.6.7. connection-sharing</a></h4>
2690 <div class="VARIABLELIST">
2695 <p>Whether or not outgoing connections that have been kept
2696 alive should be shared between different incoming
2700 <dt>Type of value:</dt>
2703 <p><tt class="REPLACEABLE"><i>0 or 1</i></tt></p>
2706 <dt>Default value:</dt>
2712 <dt>Effect if unset:</dt>
2715 <p>Connections are not shared.</p>
2721 <p>This option has no effect if <span class=
2722 "APPLICATION">Privoxy</span> has been compiled without
2723 keep-alive support, or if it's disabled.</p>
2729 <p>Note that reusing connections doesn't necessary cause
2730 speedups. There are also a few privacy implications you should
2733 <p>If this option is effective, outgoing connections are shared
2734 between clients (if there are more than one) and closing the
2735 browser that initiated the outgoing connection does no longer
2736 affect the connection between <span class=
2737 "APPLICATION">Privoxy</span> and the server unless the client's
2738 request hasn't been completed yet.</p>
2740 <p>If the outgoing connection is idle, it will not be closed
2741 until either <span class="APPLICATION">Privoxy's</span> or the
2742 server's timeout is reached. While it's open, the server knows
2743 that the system running <span class=
2744 "APPLICATION">Privoxy</span> is still there.</p>
2746 <p>If there are more than one client (maybe even belonging to
2747 multiple users), they will be able to reuse each others
2748 connections. This is potentially dangerous in case of
2749 authentication schemes like NTLM where only the connection is
2750 authenticated, instead of requiring authentication for each
2753 <p>If there is only a single client, and if said client can
2754 keep connections alive on its own, enabling this option has
2755 next to no effect. If the client doesn't support connection
2756 keep-alive, enabling this option may make sense as it allows
2757 <span class="APPLICATION">Privoxy</span> to keep outgoing
2758 connections alive even if the client itself doesn't support
2761 <p>You should also be aware that enabling this option increases
2762 the likelihood of getting the "No server or forwarder data"
2763 error message, especially if you are using a slow connection to
2766 <p>This option should only be used by experienced users who
2767 understand the risks and can weight them against the
2774 <p>connection-sharing 1</p>
2781 <h4 class="SECT3"><a name="SOCKET-TIMEOUT" id="SOCKET-TIMEOUT">7.6.8.
2782 socket-timeout</a></h4>
2784 <div class="VARIABLELIST">
2789 <p>Number of seconds after which a socket times out if no data
2793 <dt>Type of value:</dt>
2796 <p><tt class="REPLACEABLE"><i>Time in seconds.</i></tt></p>
2799 <dt>Default value:</dt>
2805 <dt>Effect if unset:</dt>
2808 <p>A default value of 300 seconds is used.</p>
2814 <p>The default is quite high and you probably want to reduce
2815 it. If you aren't using an occasionally slow proxy like Tor,
2816 reducing it to a few seconds should be fine.</p>
2822 <p>socket-timeout 300</p>
2829 <h4 class="SECT3"><a name="MAX-CLIENT-CONNECTIONS" id=
2830 "MAX-CLIENT-CONNECTIONS">7.6.9. max-client-connections</a></h4>
2832 <div class="VARIABLELIST">
2837 <p>Maximum number of client connections that will be
2841 <dt>Type of value:</dt>
2844 <p><tt class="REPLACEABLE"><i>Positive number.</i></tt></p>
2847 <dt>Default value:</dt>
2853 <dt>Effect if unset:</dt>
2856 <p>Connections are served until a resource limit is
2863 <p><span class="APPLICATION">Privoxy</span> creates one thread
2864 (or process) for every incoming client connection that isn't
2865 rejected based on the access control settings.</p>
2867 <p>If the system is powerful enough, <span class=
2868 "APPLICATION">Privoxy</span> can theoretically deal with
2869 several hundred (or thousand) connections at the same time, but
2870 some operating systems enforce resource limits by shutting down
2871 offending processes and their default limits may be below the
2872 ones <span class="APPLICATION">Privoxy</span> would require
2873 under heavy load.</p>
2875 <p>Configuring <span class="APPLICATION">Privoxy</span> to
2876 enforce a connection limit below the thread or process limit
2877 used by the operating system makes sure this doesn't happen.
2878 Simply increasing the operating system's limit would work too,
2879 but if <span class="APPLICATION">Privoxy</span> isn't the only
2880 application running on the system, you may actually want to
2881 limit the resources used by <span class=
2882 "APPLICATION">Privoxy</span>.</p>
2884 <p>If <span class="APPLICATION">Privoxy</span> is only used by
2885 a single trusted user, limiting the number of client
2886 connections is probably unnecessary. If there are multiple
2887 possibly untrusted users you probably still want to
2888 additionally use a packet filter to limit the maximal number of
2889 incoming connections per client. Otherwise a malicious user
2890 could intentionally create a high number of connections to
2891 prevent other users from using <span class=
2892 "APPLICATION">Privoxy</span>.</p>
2894 <p>Obviously using this option only makes sense if you choose a
2895 limit below the one enforced by the operating system.</p>
2897 <p>One most POSIX-compliant systems <span class=
2898 "APPLICATION">Privoxy</span> can't properly deal with more than
2899 FD_SETSIZE file descriptors at the same time and has to reject
2900 connections if the limit is reached. This will likely change in
2901 a future version, but currently this limit can't be increased
2902 without recompiling <span class="APPLICATION">Privoxy</span>
2903 with a different FD_SETSIZE limit.</p>
2909 <p>max-client-connections 256</p>
2916 <h4 class="SECT3"><a name="HANDLE-AS-EMPTY-DOC-RETURNS-OK" id=
2917 "HANDLE-AS-EMPTY-DOC-RETURNS-OK">7.6.10.
2918 handle-as-empty-doc-returns-ok</a></h4>
2920 <div class="VARIABLELIST">
2925 <p>The status code Privoxy returns for pages blocked with
2926 <tt class="LITERAL"><a href=
2927 "actions-file.html#HANDLE-AS-EMPTY-DOCUMENT" target=
2928 "_top">+handle-as-empty-document</a></tt>.</p>
2931 <dt>Type of value:</dt>
2934 <p><tt class="REPLACEABLE"><i>0 or 1</i></tt></p>
2937 <dt>Default value:</dt>
2943 <dt>Effect if unset:</dt>
2946 <p>Privoxy returns a status 403(forbidden) for all blocked
2950 <dt>Effect if set:</dt>
2953 <p>Privoxy returns a status 200(OK) for pages blocked with
2954 +handle-as-empty-document and a status 403(Forbidden) for all
2955 other blocked pages.</p>
2961 <p>This directive was added as a work-around for Firefox bug
2962 492459: <span class="QUOTE">"Websites are no longer rendered if
2963 SSL requests for JavaScripts are blocked by a proxy."</span>
2964 (<a href="https://bugzilla.mozilla.org/show_bug.cgi?id=492459"
2966 "_top">https://bugzilla.mozilla.org/show_bug.cgi?id=492459</a>),
2967 the bug has been fixed for quite some time, but this directive
2968 is also useful to make it harder for websites to detect whether
2969 or not resources are being blocked.</p>
2976 <h4 class="SECT3"><a name="ENABLE-COMPRESSION" id=
2977 "ENABLE-COMPRESSION">7.6.11. enable-compression</a></h4>
2979 <div class="VARIABLELIST">
2984 <p>Whether or not buffered content is compressed before
2988 <dt>Type of value:</dt>
2991 <p><tt class="REPLACEABLE"><i>0 or 1</i></tt></p>
2994 <dt>Default value:</dt>
3000 <dt>Effect if unset:</dt>
3003 <p>Privoxy does not compress buffered content.</p>
3006 <dt>Effect if set:</dt>
3009 <p>Privoxy compresses buffered content before delivering it to
3010 the client, provided the client supports it.</p>
3016 <p>This directive is only supported if Privoxy has been
3017 compiled with FEATURE_COMPRESSION, which should not to be
3018 confused with FEATURE_ZLIB.</p>
3020 <p>Compressing buffered content is mainly useful if Privoxy and
3021 the client are running on different systems. If they are
3022 running on the same system, enabling compression is likely to
3023 slow things down. If you didn't measure otherwise, you should
3024 assume that it does and keep this option disabled.</p>
3026 <p>Privoxy will not compress buffered content below a certain
3034 <h4 class="SECT3"><a name="COMPRESSION-LEVEL" id=
3035 "COMPRESSION-LEVEL">7.6.12. compression-level</a></h4>
3037 <div class="VARIABLELIST">
3042 <p>The compression level that is passed to the zlib library
3043 when compressing buffered content.</p>
3046 <dt>Type of value:</dt>
3049 <p><tt class="REPLACEABLE"><i>Positive number ranging from 0 to
3053 <dt>Default value:</dt>
3062 <p>Compressing the data more takes usually longer than
3063 compressing it less or not compressing it at all. Which level
3064 is best depends on the connection between Privoxy and the
3065 client. If you can't be bothered to benchmark it for yourself,
3066 you should stick with the default and keep compression
3069 <p>If compression is disabled, the compression level is
3076 <table border="0" bgcolor="#E0E0E0" width="90%">
3079 <pre class="SCREEN">
3080 # Best speed (compared to the other levels)
3084 # No compression. Only useful for testing as the added header
3085 # slightly increases the amount of data that has to be sent.
3086 # If your benchmark shows that using this compression level
3087 # is superior to using no compression at all, the benchmark
3088 # is likely to be flawed.
3101 <h4 class="SECT3"><a name="CLIENT-HEADER-ORDER" id=
3102 "CLIENT-HEADER-ORDER">7.6.13. client-header-order</a></h4>
3104 <div class="VARIABLELIST">
3109 <p>The order in which client headers are sorted before
3110 forwarding them.</p>
3113 <dt>Type of value:</dt>
3116 <p><tt class="REPLACEABLE"><i>Client header names delimited by
3117 spaces or tabs</i></tt></p>
3120 <dt>Default value:</dt>
3129 <p>By default <span class="APPLICATION">Privoxy</span> leaves
3130 the client headers in the order they were sent by the client.
3131 Headers are modified in-place, new headers are added at the end
3132 of the already existing headers.</p>
3134 <p>The header order can be used to fingerprint client requests
3135 independently of other headers like the User-Agent.</p>
3137 <p>This directive allows to sort the headers differently to
3138 better mimic a different User-Agent. Client headers will be
3139 emitted in the order given, headers whose name isn't explicitly
3140 specified are added at the end.</p>
3142 <p>Note that sorting headers in an uncommon way will make
3143 fingerprinting actually easier. Encrypted headers are not
3144 affected by this directive.</p>
3151 <h4 class="SECT3"><a name="CLIENT-SPECIFIC-TAG" id=
3152 "CLIENT-SPECIFIC-TAG">7.6.14. client-specific-tag</a></h4>
3154 <div class="VARIABLELIST">
3159 <p>The name of a tag that will always be set for clients that
3160 requested it through the webinterface.</p>
3163 <dt>Type of value:</dt>
3166 <p><tt class="REPLACEABLE"><i>Tag name followed by a
3167 description that will be shown in the webinterface</i></tt></p>
3170 <dt>Default value:</dt>
3179 <div class="WARNING">
3180 <table class="WARNING" border="1" width="90%">
3182 <td align="center"><b>Warning</b></td>
3187 <p>This is an experimental feature. The syntax is
3188 likely to change in future versions.</p>
3194 <p>Client-specific tags allow Privoxy admins to create
3195 different profiles and let the users chose which one they want
3196 without impacting other users.</p>
3198 <p>One use case is allowing users to circumvent certain blocks
3199 without having to allow them to circumvent all blocks. This is
3200 not possible with the <a href=
3201 "config.html#ENABLE-REMOTE-TOGGLE">enable-remote-toggle
3202 feature</a> because it would bluntly disable all blocks for all
3203 users and also affect other actions like filters. It also is
3204 set globally which renders it useless in most multi-user
3207 <p>After a client-specific tag has been defined with the
3208 client-specific-tag directive, action sections can be activated
3209 based on the tag by using a <a href=
3210 "actions-file.html#CLIENT-TAG-PATTERN" target=
3211 "_top">CLIENT-TAG</a> pattern. The CLIENT-TAG pattern is
3212 evaluated at the same priority as URL patterns, as a result the
3213 last matching pattern wins. Tags that are created based on
3214 client or server headers are evaluated later on and can
3215 overrule CLIENT-TAG and URL patterns!</p>
3217 <p>The tag is set for all requests that come from clients that
3218 requested it to be set. Note that "clients" are differentiated
3219 by IP address, if the IP address changes the tag has to be
3220 requested again.</p>
3222 <p>Clients can request tags to be set by using the CGI
3223 interface <a href="http://config.privoxy.org/client-tags"
3224 target="_top">http://config.privoxy.org/client-tags</a>. The
3225 specific tag description is only used on the web page and
3226 should be phrased in away that the user understand the effect
3233 <table border="0" bgcolor="#E0E0E0" width="90%">
3236 <pre class="SCREEN">
3237 # Define a couple of tags, the described effect requires action sections
3238 # that are enabled based on CLIENT-TAG patterns.
3239 client-specific-tag circumvent-blocks Overrule blocks but do not affect other actions
3240 disable-content-filters Disable content-filters but do not affect other actions
3252 <h4 class="SECT3"><a name="CLIENT-TAG-LIFETIME" id=
3253 "CLIENT-TAG-LIFETIME">7.6.15. client-tag-lifetime</a></h4>
3255 <div class="VARIABLELIST">
3260 <p>How long a temporarily enabled tag remains enabled.</p>
3263 <dt>Type of value:</dt>
3266 <p><tt class="REPLACEABLE"><i>Time in seconds.</i></tt></p>
3269 <dt>Default value:</dt>
3278 <div class="WARNING">
3279 <table class="WARNING" border="1" width="90%">
3281 <td align="center"><b>Warning</b></td>
3286 <p>This is an experimental feature. The syntax is
3287 likely to change in future versions.</p>
3293 <p>In case of some tags users may not want to enable them
3294 permanently, but only for a short amount of time, for example
3295 to circumvent a block that is the result of an overly-broad URL
3298 <p>The CGI interface <a href=
3299 "http://config.privoxy.org/client-tags" target=
3300 "_top">http://config.privoxy.org/client-tags</a> therefore
3301 provides a "enable this tag temporarily" option. If it is used,
3302 the tag will be set until the client-tag-lifetime is over.</p>
3308 <table border="0" bgcolor="#E0E0E0" width="90%">
3311 <pre class="SCREEN">
3312 # Increase the time to life for temporarily enabled tags to 3 minutes
3313 client-tag-lifetime 180
3325 <h4 class="SECT3"><a name="TRUST-X-FORWARDED-FOR" id=
3326 "TRUST-X-FORWARDED-FOR">7.6.16. trust-x-forwarded-for</a></h4>
3328 <div class="VARIABLELIST">
3333 <p>Whether or not Privoxy should use IP addresses specified
3334 with the X-Forwarded-For header</p>
3337 <dt>Type of value:</dt>
3340 <p><tt class="REPLACEABLE"><i>0 or one</i></tt></p>
3343 <dt>Default value:</dt>
3352 <div class="WARNING">
3353 <table class="WARNING" border="1" width="90%">
3355 <td align="center"><b>Warning</b></td>
3360 <p>This is an experimental feature. The syntax is
3361 likely to change in future versions.</p>
3367 <p>If clients reach Privoxy through another proxy, for example
3368 a load balancer, Privoxy can't tell the client's IP address
3369 from the connection. If multiple clients use the same proxy,
3370 they will share the same client tag settings which is usually
3373 <p>This option lets Privoxy use the X-Forwarded-For header
3374 value as client IP address. If the proxy sets the header,
3375 multiple clients using the same proxy do not share the same
3376 client tag settings.</p>
3378 <p>This option should only be enabled if Privoxy can only be
3379 reached through a proxy and if the proxy can be trusted to set
3380 the header correctly. It is recommended that ACL are used to
3381 make sure only trusted systems can reach Privoxy.</p>
3383 <p>If access to Privoxy isn't limited to trusted systems, this
3384 option would allow malicious clients to change the client tags
3385 for other clients or increase Privoxy's memory requirements by
3386 registering lots of client tag settings for clients that don't
3393 <table border="0" bgcolor="#E0E0E0" width="90%">
3396 <pre class="SCREEN">
3397 # Allow systems that can reach Privoxy to provide the client
3398 # IP address with a X-Forwarded-For header.
3399 trust-x-forwarded-for 1
3412 <h2 class="SECT2"><a name="WINDOWS-GUI" id="WINDOWS-GUI">7.7. Windows
3413 GUI Options</a></h2>
3415 <p><span class="APPLICATION">Privoxy</span> has a number of options
3416 specific to the Windows GUI interface:</p><a name="ACTIVITY-ANIMATION"
3417 id="ACTIVITY-ANIMATION"></a>
3419 <p>If <span class="QUOTE">"activity-animation"</span> is set to 1, the
3420 <span class="APPLICATION">Privoxy</span> icon will animate when
3421 <span class="QUOTE">"Privoxy"</span> is active. To turn off, set to
3424 <p class="LITERALLAYOUT"><tt class="LITERAL"> <span class=
3425 "emphasis"><i class="EMPHASIS">activity-animation 1</i></span><br>
3426 </tt></p><a name="LOG-MESSAGES" id=
3429 <p>If <span class="QUOTE">"log-messages"</span> is set to 1,
3430 <span class="APPLICATION">Privoxy</span> copies log messages to the
3431 console window. The log detail depends on the <a href=
3432 "config.html#DEBUG">debug</a> directive.</p>
3434 <p class="LITERALLAYOUT"><tt class="LITERAL"> <span class=
3435 "emphasis"><i class="EMPHASIS">log-messages 1</i></span><br>
3436 </tt></p><a name="LOG-BUFFER-SIZE" id=
3437 "LOG-BUFFER-SIZE"></a>
3439 <p>If <span class="QUOTE">"log-buffer-size"</span> is set to 1, the
3440 size of the log buffer, i.e. the amount of memory used for the log
3441 messages displayed in the console window, will be limited to
3442 <span class="QUOTE">"log-max-lines"</span> (see below).</p>
3444 <p>Warning: Setting this to 0 will result in the buffer to grow
3445 infinitely and eat up all your memory!</p>
3447 <p class="LITERALLAYOUT"><tt class="LITERAL"> <span class=
3448 "emphasis"><i class="EMPHASIS">log-buffer-size 1</i></span><br>
3449 </tt></p><a name="LOG-MAX-LINES" id=
3450 "LOG-MAX-LINES"></a>
3452 <p><span class="APPLICATION">log-max-lines</span> is the maximum number
3453 of lines held in the log buffer. See above.</p>
3455 <p class="LITERALLAYOUT"><tt class="LITERAL"> <span class=
3456 "emphasis"><i class="EMPHASIS">log-max-lines 200</i></span><br>
3457 </tt></p><a name="LOG-HIGHLIGHT-MESSAGES" id=
3458 "LOG-HIGHLIGHT-MESSAGES"></a>
3460 <p>If <span class="QUOTE">"log-highlight-messages"</span> is set to 1,
3461 <span class="APPLICATION">Privoxy</span> will highlight portions of the
3462 log messages with a bold-faced font:</p>
3464 <p class="LITERALLAYOUT"><tt class="LITERAL"> <span class=
3465 "emphasis"><i class="EMPHASIS">log-highlight-messages 1</i></span><br>
3466 </tt></p><a name="LOG-FONT-NAME" id=
3467 "LOG-FONT-NAME"></a>
3469 <p>The font used in the console window:</p>
3471 <p class="LITERALLAYOUT"><tt class="LITERAL"> <span class=
3472 "emphasis"><i class="EMPHASIS">log-font-name Comic Sans
3474 </tt></p><a name="LOG-FONT-SIZE" id=
3475 "LOG-FONT-SIZE"></a>
3477 <p>Font size used in the console window:</p>
3479 <p class="LITERALLAYOUT"><tt class="LITERAL"> <span class=
3480 "emphasis"><i class="EMPHASIS">log-font-size 8</i></span><br>
3481 </tt></p><a name="SHOW-ON-TASK-BAR" id=
3482 "SHOW-ON-TASK-BAR"></a>
3484 <p><span class="QUOTE">"show-on-task-bar"</span> controls whether or
3485 not <span class="APPLICATION">Privoxy</span> will appear as a button on
3486 the Task bar when minimized:</p>
3488 <p class="LITERALLAYOUT"><tt class="LITERAL"> <span class=
3489 "emphasis"><i class="EMPHASIS">show-on-task-bar 0</i></span><br>
3490 </tt></p><a name="CLOSE-BUTTON-MINIMIZES" id=
3491 "CLOSE-BUTTON-MINIMIZES"></a>
3493 <p>If <span class="QUOTE">"close-button-minimizes"</span> is set to 1,
3494 the Windows close button will minimize <span class=
3495 "APPLICATION">Privoxy</span> instead of closing the program (close with
3496 the exit option on the File menu).</p>
3498 <p class="LITERALLAYOUT"><tt class="LITERAL"> <span class=
3499 "emphasis"><i class="EMPHASIS">close-button-minimizes 1</i></span><br>
3500 </tt></p><a name="HIDE-CONSOLE" id=
3503 <p>The <span class="QUOTE">"hide-console"</span> option is specific to
3504 the MS-Win console version of <span class="APPLICATION">Privoxy</span>.
3505 If this option is used, <span class="APPLICATION">Privoxy</span> will
3506 disconnect from and hide the command console.</p>
3508 <p class="LITERALLAYOUT"><tt class="LITERAL"> #<span class=
3509 "emphasis"><i class="EMPHASIS">hide-console</i></span><br>
3510 </tt></p>
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