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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="http://www.privoxy.org/user-manual/" target=
108 "_top">http://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. There is no point in using <span class=
596 "APPLICATION">Privoxy</span> without at least one actions
599 <p>Note that since Privoxy 3.0.7, the complete filename,
600 including the <span class="QUOTE">".action"</span> extension
601 has to be specified. The syntax change was necessary to be
602 consistent with the other file options and to allow previously
603 forbidden characters.</p>
610 <h4 class="SECT3"><a name="FILTERFILE" id="FILTERFILE">7.2.6.
611 filterfile</a></h4><a name="DEFAULT.FILTER" id="DEFAULT.FILTER"></a>
613 <div class="VARIABLELIST">
618 <p>The <a href="filter-file.html">filter file(s)</a> to use</p>
621 <dt>Type of value:</dt>
624 <p>File name, relative to <tt class="LITERAL">confdir</tt></p>
627 <dt>Default value:</dt>
630 <p>default.filter (Unix) <span class="emphasis"><i class=
631 "EMPHASIS">or</i></span> default.filter.txt (Windows)</p>
634 <dt>Effect if unset:</dt>
637 <p>No textual content filtering takes place, i.e. all
638 <tt class="LITERAL">+<a href=
639 "actions-file.html#FILTER">filter</a>{<tt class=
640 "REPLACEABLE"><i>name</i></tt>}</tt> actions in the actions
641 files are turned neutral.</p>
647 <p>Multiple <tt class="LITERAL">filterfile</tt> lines are
650 <p>The <a href="filter-file.html">filter files</a> contain
651 content modification rules that use <a href=
652 "appendix.html#REGEX">regular expressions</a>. These rules
653 permit powerful changes on the content of Web pages, and
654 optionally the headers as well, e.g., you could try to disable
655 your favorite JavaScript annoyances, re-write the actual
656 displayed text, or just have some fun playing buzzword bingo
659 <p>The <tt class="LITERAL">+<a href=
660 "actions-file.html#FILTER">filter</a>{<tt class=
661 "REPLACEABLE"><i>name</i></tt>}</tt> actions rely on the
662 relevant filter (<tt class="REPLACEABLE"><i>name</i></tt>) to
663 be defined in a filter file!</p>
665 <p>A pre-defined filter file called <tt class=
666 "FILENAME">default.filter</tt> that contains a number of useful
667 filters for common problems is included in the distribution.
668 See the section on the <tt class="LITERAL"><a href=
669 "actions-file.html#FILTER">filter</a></tt> action for a
672 <p>It is recommended to place any locally adapted filters into
673 a separate file, such as <tt class=
674 "FILENAME">user.filter</tt>.</p>
681 <h4 class="SECT3"><a name="LOGFILE" id="LOGFILE">7.2.7.
684 <div class="VARIABLELIST">
689 <p>The log file to use</p>
692 <dt>Type of value:</dt>
695 <p>File name, relative to <tt class="LITERAL">logdir</tt></p>
698 <dt>Default value:</dt>
701 <p><span class="emphasis"><i class="EMPHASIS">Unset (commented
702 out)</i></span>. When activated: logfile (Unix) <span class=
703 "emphasis"><i class="EMPHASIS">or</i></span> privoxy.log
707 <dt>Effect if unset:</dt>
710 <p>No logfile is written.</p>
716 <p>The logfile is where all logging and error messages are
717 written. The level of detail and number of messages are set
718 with the <tt class="LITERAL">debug</tt> option (see below). The
719 logfile can be useful for tracking down a problem with
720 <span class="APPLICATION">Privoxy</span> (e.g., it's not
721 blocking an ad you think it should block) and it can help you
722 to monitor what your browser is doing.</p>
724 <p>Depending on the debug options below, the logfile may be a
725 privacy risk if third parties can get access to it. As most
726 users will never look at it, <span class=
727 "APPLICATION">Privoxy</span> 3.0.7 and later only log fatal
728 errors by default.</p>
730 <p>For most troubleshooting purposes, you will have to change
731 that, please refer to the debugging section for details.</p>
733 <p>Your logfile will grow indefinitely, and you will probably
734 want to periodically remove it. On Unix systems, you can do
735 this with a cron job (see <span class="QUOTE">"man
738 <p>Any log files must be writable by whatever user <span class=
739 "APPLICATION">Privoxy</span> is being run as (on Unix, default
740 user id is <span class="QUOTE">"privoxy"</span>).</p>
747 <h4 class="SECT3"><a name="TRUSTFILE" id="TRUSTFILE">7.2.8.
750 <div class="VARIABLELIST">
755 <p>The name of the trust file to use</p>
758 <dt>Type of value:</dt>
761 <p>File name, relative to <tt class="LITERAL">confdir</tt></p>
764 <dt>Default value:</dt>
767 <p><span class="emphasis"><i class="EMPHASIS">Unset (commented
768 out)</i></span>. When activated: trust (Unix) <span class=
769 "emphasis"><i class="EMPHASIS">or</i></span> trust.txt
773 <dt>Effect if unset:</dt>
776 <p>The entire trust mechanism is disabled.</p>
782 <p>The trust mechanism is an experimental feature for building
783 white-lists and should be used with care. It is <span class=
784 "emphasis"><i class="EMPHASIS">NOT</i></span> recommended for
787 <p>If you specify a trust file, <span class=
788 "APPLICATION">Privoxy</span> will only allow access to sites
789 that are specified in the trustfile. Sites can be listed in one
792 <p>Prepending a <tt class="LITERAL">~</tt> character limits
793 access to this site only (and any sub-paths within this site),
794 e.g. <tt class="LITERAL">~www.example.com</tt> allows access to
795 <tt class="LITERAL">~www.example.com/features/news.html</tt>,
798 <p>Or, you can designate sites as <span class=
799 "emphasis"><i class="EMPHASIS">trusted referrers</i></span>, by
800 prepending the name with a <tt class="LITERAL">+</tt>
801 character. The effect is that access to untrusted sites will be
802 granted -- but only if a link from this trusted referrer was
803 used to get there. The link target will then be added to the
804 <span class="QUOTE">"trustfile"</span> so that future, direct
805 accesses will be granted. Sites added via this mechanism do not
806 become trusted referrers themselves (i.e. they are added with a
807 <tt class="LITERAL">~</tt> designation). There is a limit of
808 512 such entries, after which new entries will not be made.</p>
810 <p>If you use the <tt class="LITERAL">+</tt> operator in the
811 trust file, it may grow considerably over time.</p>
813 <p>It is recommended that <span class=
814 "APPLICATION">Privoxy</span> be compiled with the <tt class=
815 "LITERAL">--disable-force</tt>, <tt class=
816 "LITERAL">--disable-toggle</tt> and <tt class=
817 "LITERAL">--disable-editor</tt> options, if this feature is to
820 <p>Possible applications include limiting Internet access for
829 <h2 class="SECT2"><a name="DEBUGGING" id="DEBUGGING">7.3.
832 <p>These options are mainly useful when tracing a problem. Note that
833 you might also want to invoke <span class="APPLICATION">Privoxy</span>
834 with the <tt class="LITERAL">--no-daemon</tt> command line option when
838 <h4 class="SECT3"><a name="DEBUG" id="DEBUG">7.3.1. debug</a></h4>
840 <div class="VARIABLELIST">
845 <p>Key values that determine what information gets logged.</p>
848 <dt>Type of value:</dt>
851 <p>Integer values</p>
854 <dt>Default value:</dt>
857 <p>0 (i.e.: only fatal errors (that cause Privoxy to exit) are
861 <dt>Effect if unset:</dt>
864 <p>Default value is used (see above).</p>
870 <p>The available debug levels are:</p>
872 <table border="0" bgcolor="#E0E0E0" width="90%">
875 <pre class="PROGRAMLISTING">
876 debug 1 # Log the destination for each request <span class=
877 "APPLICATION">Privoxy</span> let through. See also debug 1024.
878 debug 2 # show each connection status
879 debug 4 # show I/O status
880 debug 8 # show header parsing
881 debug 16 # log all data written to the network
882 debug 32 # debug force feature
883 debug 64 # debug regular expression filters
884 debug 128 # debug redirects
885 debug 256 # debug GIF de-animation
886 debug 512 # Common Log Format
887 debug 1024 # Log the destination for requests <span class=
888 "APPLICATION">Privoxy</span> didn't let through, and the reason why.
889 debug 2048 # CGI user interface
890 debug 4096 # Startup banner and warnings.
891 debug 8192 # Non-fatal errors
892 debug 32768 # log all data read from the network
893 debug 65536 # Log the applying actions
899 <p>To select multiple debug levels, you can either add them or
900 use multiple <tt class="LITERAL">debug</tt> lines.</p>
902 <p>A debug level of 1 is informative because it will show you
903 each request as it happens. <span class="emphasis"><i class=
904 "EMPHASIS">1, 1024, 4096 and 8192 are recommended</i></span> so
905 that you will notice when things go wrong. The other levels are
906 probably only of interest if you are hunting down a specific
907 problem. They can produce a hell of an output (especially
910 <p><span class="APPLICATION">Privoxy</span> used to ship with
911 the debug levels recommended above enabled by default, but due
912 to privacy concerns 3.0.7 and later are configured to only log
915 <p>If you are used to the more verbose settings, simply enable
916 the debug lines below again.</p>
918 <p>If you want to use pure CLF (Common Log Format), you should
919 set <span class="QUOTE">"debug 512"</span> <span class=
920 "emphasis"><i class="EMPHASIS">ONLY</i></span> and not enable
923 <p><span class="APPLICATION">Privoxy</span> has a hard-coded
924 limit for the length of log messages. If it's reached, messages
925 are logged truncated and marked with <span class="QUOTE">"...
926 [too long, truncated]"</span>.</p>
928 <p>Please don't file any support requests without trying to
929 reproduce the problem with increased debug level first. Once
930 you read the log messages, you may even be able to solve the
931 problem on your own.</p>
938 <h4 class="SECT3"><a name="SINGLE-THREADED" id=
939 "SINGLE-THREADED">7.3.2. single-threaded</a></h4>
941 <div class="VARIABLELIST">
946 <p>Whether to run only one server thread.</p>
949 <dt>Type of value:</dt>
952 <p><span class="emphasis"><i class="EMPHASIS">1 or
956 <dt>Default value:</dt>
959 <p><span class="emphasis"><i class="EMPHASIS">0</i></span></p>
962 <dt>Effect if unset:</dt>
965 <p>Multi-threaded (or, where unavailable: forked) operation,
966 i.e. the ability to serve multiple requests simultaneously.</p>
972 <p>This option is only there for debugging purposes.
973 <span class="emphasis"><i class="EMPHASIS">It will drastically
974 reduce performance.</i></span></p>
981 <h4 class="SECT3"><a name="HOSTNAME" id="HOSTNAME">7.3.3.
984 <div class="VARIABLELIST">
989 <p>The hostname shown on the CGI pages.</p>
992 <dt>Type of value:</dt>
998 <dt>Default value:</dt>
1001 <p><span class="emphasis"><i class=
1002 "EMPHASIS">Unset</i></span></p>
1005 <dt>Effect if unset:</dt>
1008 <p>The hostname provided by the operating system is used.</p>
1014 <p>On some misconfigured systems resolving the hostname fails
1015 or takes too much time and slows Privoxy down. Setting a fixed
1016 hostname works around the problem.</p>
1018 <p>In other circumstances it might be desirable to show a
1019 hostname other than the one returned by the operating system.
1020 For example if the system has several different hostnames and
1021 you don't want to use the first one.</p>
1023 <p>Note that Privoxy does not validate the specified hostname
1032 <h2 class="SECT2"><a name="ACCESS-CONTROL" id="ACCESS-CONTROL">7.4.
1033 Access Control and Security</a></h2>
1035 <p>This section of the config file controls the security-relevant
1036 aspects of <span class="APPLICATION">Privoxy</span>'s
1040 <h4 class="SECT3"><a name="LISTEN-ADDRESS" id="LISTEN-ADDRESS">7.4.1.
1041 listen-address</a></h4>
1043 <div class="VARIABLELIST">
1048 <p>The address and TCP port on which <span class=
1049 "APPLICATION">Privoxy</span> will listen for client
1053 <dt>Type of value:</dt>
1056 <p>[<tt class="REPLACEABLE"><i>IP-Address</i></tt>]:<tt class=
1057 "REPLACEABLE"><i>Port</i></tt></p>
1059 <p>[<tt class="REPLACEABLE"><i>Hostname</i></tt>]:<tt class=
1060 "REPLACEABLE"><i>Port</i></tt></p>
1063 <dt>Default value:</dt>
1066 <p>127.0.0.1:8118</p>
1069 <dt>Effect if unset:</dt>
1072 <p>Bind to 127.0.0.1 (IPv4 localhost), port 8118. This is
1073 suitable and recommended for home users who run <span class=
1074 "APPLICATION">Privoxy</span> on the same machine as their
1081 <p>You will need to configure your browser(s) to this proxy
1082 address and port.</p>
1084 <p>If you already have another service running on port 8118, or
1085 if you want to serve requests from other machines (e.g. on your
1086 local network) as well, you will need to override the
1089 <p>You can use this statement multiple times to make
1090 <span class="APPLICATION">Privoxy</span> listen on more ports
1091 or more <abbr class="ABBREV">IP</abbr> addresses. Suitable if
1092 your operating system does not support sharing <abbr class=
1093 "ABBREV">IPv6</abbr> and <abbr class="ABBREV">IPv4</abbr>
1094 protocols on the same socket.</p>
1096 <p>If a hostname is used instead of an IP address, <span class=
1097 "APPLICATION">Privoxy</span> will try to resolve it to an IP
1098 address and if there are multiple, use the first one
1101 <p>If the address for the hostname isn't already known on the
1102 system (for example because it's in /etc/hostname), this may
1103 result in DNS traffic.</p>
1105 <p>If the specified address isn't available on the system, or
1106 if the hostname can't be resolved, <span class=
1107 "APPLICATION">Privoxy</span> will fail to start.</p>
1109 <p>IPv6 addresses containing colons have to be quoted by
1110 brackets. They can only be used if <span class=
1111 "APPLICATION">Privoxy</span> has been compiled with IPv6
1112 support. If you aren't sure if your version supports it, have a
1114 "LITERAL">http://config.privoxy.org/show-status</tt>.</p>
1116 <p>Some operating systems will prefer IPv6 to IPv4 addresses
1117 even if the system has no IPv6 connectivity which is usually
1118 not expected by the user. Some even rely on DNS to resolve
1119 localhost which mean the "localhost" address used may not
1120 actually be local.</p>
1122 <p>It is therefore recommended to explicitly configure the
1123 intended IP address instead of relying on the operating system,
1124 unless there's a strong reason not to.</p>
1126 <p>If you leave out the address, <span class=
1127 "APPLICATION">Privoxy</span> will bind to all IPv4 interfaces
1128 (addresses) on your machine and may become reachable from the
1129 Internet and/or the local network. Be aware that some GNU/Linux
1130 distributions modify that behaviour without updating the
1131 documentation. Check for non-standard patches if your
1132 <span class="APPLICATION">Privoxy</span> version behaves
1135 <p>If you configure <span class="APPLICATION">Privoxy</span> to
1136 be reachable from the network, consider using <a href=
1137 "config.html#ACLS">access control lists</a> (ACL's, see below),
1138 and/or a firewall.</p>
1140 <p>If you open <span class="APPLICATION">Privoxy</span> to
1141 untrusted users, you will also want to make sure that the
1142 following actions are disabled: <tt class="LITERAL"><a href=
1143 "config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions</a></tt>
1144 and <tt class="LITERAL"><a href=
1145 "config.html#ENABLE-REMOTE-TOGGLE">enable-remote-toggle</a></tt></p>
1151 <p>Suppose you are running <span class=
1152 "APPLICATION">Privoxy</span> on a machine which has the address
1153 192.168.0.1 on your local private network (192.168.0.0) and has
1154 another outside connection with a different address. You want
1155 it to serve requests from inside only:</p>
1157 <table border="0" bgcolor="#E0E0E0" width="90%">
1160 <pre class="PROGRAMLISTING">
1161 listen-address 192.168.0.1:8118
1167 <p>Suppose you are running <span class=
1168 "APPLICATION">Privoxy</span> on an IPv6-capable machine and you
1169 want it to listen on the IPv6 address of the loopback
1172 <table border="0" bgcolor="#E0E0E0" width="90%">
1175 <pre class="PROGRAMLISTING">
1176 listen-address [::1]:8118
1187 <h4 class="SECT3"><a name="TOGGLE" id="TOGGLE">7.4.2. toggle</a></h4>
1189 <div class="VARIABLELIST">
1194 <p>Initial state of "toggle" status</p>
1197 <dt>Type of value:</dt>
1203 <dt>Default value:</dt>
1209 <dt>Effect if unset:</dt>
1212 <p>Act as if toggled on</p>
1218 <p>If set to 0, <span class="APPLICATION">Privoxy</span> will
1219 start in <span class="QUOTE">"toggled off"</span> mode, i.e.
1220 mostly behave like a normal, content-neutral proxy with both ad
1221 blocking and content filtering disabled. See <tt class=
1222 "LITERAL">enable-remote-toggle</tt> below.</p>
1229 <h4 class="SECT3"><a name="ENABLE-REMOTE-TOGGLE" id=
1230 "ENABLE-REMOTE-TOGGLE">7.4.3. enable-remote-toggle</a></h4>
1232 <div class="VARIABLELIST">
1237 <p>Whether or not the <a href=
1238 "http://config.privoxy.org/toggle" target="_top">web-based
1239 toggle feature</a> may be used</p>
1242 <dt>Type of value:</dt>
1248 <dt>Default value:</dt>
1254 <dt>Effect if unset:</dt>
1257 <p>The web-based toggle feature is disabled.</p>
1263 <p>When toggled off, <span class="APPLICATION">Privoxy</span>
1264 mostly acts like a normal, content-neutral proxy, i.e. doesn't
1265 block ads or filter content.</p>
1267 <p>Access to the toggle feature can <span class=
1268 "emphasis"><i class="EMPHASIS">not</i></span> be controlled
1269 separately by <span class="QUOTE">"ACLs"</span> or HTTP
1270 authentication, so that everybody who can access <span class=
1271 "APPLICATION">Privoxy</span> (see <span class=
1272 "QUOTE">"ACLs"</span> and <tt class=
1273 "LITERAL">listen-address</tt> above) can toggle it for all
1274 users. So this option is <span class="emphasis"><i class=
1275 "EMPHASIS">not recommended</i></span> for multi-user
1276 environments with untrusted users.</p>
1278 <p>Note that malicious client side code (e.g Java) is also
1279 capable of using this option.</p>
1281 <p>As a lot of <span class="APPLICATION">Privoxy</span> users
1282 don't read documentation, this feature is disabled by
1285 <p>Note that you must have compiled <span class=
1286 "APPLICATION">Privoxy</span> with support for this feature,
1287 otherwise this option has no effect.</p>
1294 <h4 class="SECT3"><a name="ENABLE-REMOTE-HTTP-TOGGLE" id=
1295 "ENABLE-REMOTE-HTTP-TOGGLE">7.4.4. enable-remote-http-toggle</a></h4>
1297 <div class="VARIABLELIST">
1302 <p>Whether or not Privoxy recognizes special HTTP headers to
1303 change its behaviour.</p>
1306 <dt>Type of value:</dt>
1312 <dt>Default value:</dt>
1318 <dt>Effect if unset:</dt>
1321 <p>Privoxy ignores special HTTP headers.</p>
1327 <p>When toggled on, the client can change <span class=
1328 "APPLICATION">Privoxy's</span> behaviour by setting special
1329 HTTP headers. Currently the only supported special header is
1330 <span class="QUOTE">"X-Filter: No"</span>, to disable filtering
1331 for the ongoing request, even if it is enabled in one of the
1334 <p>This feature is disabled by default. If you are using
1335 <span class="APPLICATION">Privoxy</span> in a environment with
1336 trusted clients, you may enable this feature at your
1337 discretion. Note that malicious client side code (e.g Java) is
1338 also capable of using this feature.</p>
1340 <p>This option will be removed in future releases as it has
1341 been obsoleted by the more general header taggers.</p>
1348 <h4 class="SECT3"><a name="ENABLE-EDIT-ACTIONS" id=
1349 "ENABLE-EDIT-ACTIONS">7.4.5. enable-edit-actions</a></h4>
1351 <div class="VARIABLELIST">
1356 <p>Whether or not the <a href=
1357 "http://config.privoxy.org/show-status" target="_top">web-based
1358 actions file editor</a> may be used</p>
1361 <dt>Type of value:</dt>
1367 <dt>Default value:</dt>
1373 <dt>Effect if unset:</dt>
1376 <p>The web-based actions file editor is disabled.</p>
1382 <p>Access to the editor can <span class="emphasis"><i class=
1383 "EMPHASIS">not</i></span> be controlled separately by
1384 <span class="QUOTE">"ACLs"</span> or HTTP authentication, so
1385 that everybody who can access <span class=
1386 "APPLICATION">Privoxy</span> (see <span class=
1387 "QUOTE">"ACLs"</span> and <tt class=
1388 "LITERAL">listen-address</tt> above) can modify its
1389 configuration for all users.</p>
1391 <p>This option is <span class="emphasis"><i class=
1392 "EMPHASIS">not recommended</i></span> for environments with
1393 untrusted users and as a lot of <span class=
1394 "APPLICATION">Privoxy</span> users don't read documentation,
1395 this feature is disabled by default.</p>
1397 <p>Note that malicious client side code (e.g Java) is also
1398 capable of using the actions editor and you shouldn't enable
1399 this options unless you understand the consequences and are
1400 sure your browser is configured correctly.</p>
1402 <p>Note that you must have compiled <span class=
1403 "APPLICATION">Privoxy</span> with support for this feature,
1404 otherwise this option has no effect.</p>
1411 <h4 class="SECT3"><a name="ENFORCE-BLOCKS" id="ENFORCE-BLOCKS">7.4.6.
1412 enforce-blocks</a></h4>
1414 <div class="VARIABLELIST">
1419 <p>Whether the user is allowed to ignore blocks and can
1420 <span class="QUOTE">"go there anyway"</span>.</p>
1423 <dt>Type of value:</dt>
1426 <p><tt class="REPLACEABLE"><i>0 or 1</i></tt></p>
1429 <dt>Default value:</dt>
1432 <p><span class="emphasis"><i class="EMPHASIS">0</i></span></p>
1435 <dt>Effect if unset:</dt>
1438 <p>Blocks are not enforced.</p>
1444 <p><span class="APPLICATION">Privoxy</span> is mainly used to
1445 block and filter requests as a service to the user, for example
1446 to block ads and other junk that clogs the pipes. <span class=
1447 "APPLICATION">Privoxy's</span> configuration isn't perfect and
1448 sometimes innocent pages are blocked. In this situation it
1449 makes sense to allow the user to enforce the request and have
1450 <span class="APPLICATION">Privoxy</span> ignore the block.</p>
1452 <p>In the default configuration <span class=
1453 "APPLICATION">Privoxy's</span> <span class=
1454 "QUOTE">"Blocked"</span> page contains a <span class=
1455 "QUOTE">"go there anyway"</span> link to adds a special string
1456 (the force prefix) to the request URL. If that link is used,
1457 <span class="APPLICATION">Privoxy</span> will detect the force
1458 prefix, remove it again and let the request pass.</p>
1460 <p>Of course <span class="APPLICATION">Privoxy</span> can also
1461 be used to enforce a network policy. In that case the user
1462 obviously should not be able to bypass any blocks, and that's
1463 what the <span class="QUOTE">"enforce-blocks"</span> option is
1464 for. If it's enabled, <span class="APPLICATION">Privoxy</span>
1465 hides the <span class="QUOTE">"go there anyway"</span> link. If
1466 the user adds the force prefix by hand, it will not be accepted
1467 and the circumvention attempt is logged.</p>
1473 <p>enforce-blocks 1</p>
1480 <h4 class="SECT3"><a name="ACLS" id="ACLS">7.4.7. ACLs: permit-access
1481 and deny-access</a></h4><a name="PERMIT-ACCESS" id=
1482 "PERMIT-ACCESS"></a><a name="DENY-ACCESS" id="DENY-ACCESS"></a>
1484 <div class="VARIABLELIST">
1489 <p>Who can access what.</p>
1492 <dt>Type of value:</dt>
1495 <p><tt class="REPLACEABLE"><i>src_addr</i></tt>[:<tt class=
1496 "REPLACEABLE"><i>port</i></tt>][/<tt class=
1497 "REPLACEABLE"><i>src_masklen</i></tt>] [<tt class=
1498 "REPLACEABLE"><i>dst_addr</i></tt>[:<tt class=
1499 "REPLACEABLE"><i>port</i></tt>][/<tt class=
1500 "REPLACEABLE"><i>dst_masklen</i></tt>]]</p>
1502 <p>Where <tt class="REPLACEABLE"><i>src_addr</i></tt> and
1503 <tt class="REPLACEABLE"><i>dst_addr</i></tt> are IPv4 addresses
1504 in dotted decimal notation or valid DNS names, <tt class=
1505 "REPLACEABLE"><i>port</i></tt> is a port number, and <tt class=
1506 "REPLACEABLE"><i>src_masklen</i></tt> and <tt class=
1507 "REPLACEABLE"><i>dst_masklen</i></tt> are subnet masks in CIDR
1508 notation, i.e. integer values from 2 to 30 representing the
1509 length (in bits) of the network address. The masks and the
1510 whole destination part are optional.</p>
1512 <p>If your system implements <a href=
1513 "http://tools.ietf.org/html/rfc3493" target="_top">RFC
1514 3493</a>, then <tt class="REPLACEABLE"><i>src_addr</i></tt> and
1515 <tt class="REPLACEABLE"><i>dst_addr</i></tt> can be IPv6
1516 addresses delimeted by brackets, <tt class=
1517 "REPLACEABLE"><i>port</i></tt> can be a number or a service
1518 name, and <tt class="REPLACEABLE"><i>src_masklen</i></tt> and
1519 <tt class="REPLACEABLE"><i>dst_masklen</i></tt> can be a number
1523 <dt>Default value:</dt>
1526 <p><span class="emphasis"><i class=
1527 "EMPHASIS">Unset</i></span></p>
1529 <p>If no <tt class="REPLACEABLE"><i>port</i></tt> is specified,
1530 any port will match. If no <tt class=
1531 "REPLACEABLE"><i>src_masklen</i></tt> or <tt class=
1532 "REPLACEABLE"><i>src_masklen</i></tt> is given, the complete IP
1533 address has to match (i.e. 32 bits for IPv4 and 128 bits for
1537 <dt>Effect if unset:</dt>
1540 <p>Don't restrict access further than implied by <tt class=
1541 "LITERAL">listen-address</tt></p>
1547 <p>Access controls are included at the request of ISPs and
1548 systems administrators, and <span class="emphasis"><i class=
1549 "EMPHASIS">are not usually needed by individual
1550 users</i></span>. For a typical home user, it will normally
1551 suffice to ensure that <span class="APPLICATION">Privoxy</span>
1552 only listens on the localhost (127.0.0.1) or internal (home)
1553 network address by means of the <a href=
1554 "config.html#LISTEN-ADDRESS"><span class="emphasis"><i class=
1555 "EMPHASIS">listen-address</i></span></a> option.</p>
1557 <p>Please see the warnings in the FAQ that <span class=
1558 "APPLICATION">Privoxy</span> is not intended to be a substitute
1559 for a firewall or to encourage anyone to defer addressing basic
1560 security weaknesses.</p>
1562 <p>Multiple ACL lines are OK. If any ACLs are specified,
1563 <span class="APPLICATION">Privoxy</span> only talks to IP
1564 addresses that match at least one <tt class=
1565 "LITERAL">permit-access</tt> line and don't match any
1566 subsequent <tt class="LITERAL">deny-access</tt> line. In other
1567 words, the last match wins, with the default being <tt class=
1568 "LITERAL">deny-access</tt>.</p>
1570 <p>If <span class="APPLICATION">Privoxy</span> is using a
1571 forwarder (see <tt class="LITERAL">forward</tt> below) for a
1572 particular destination URL, the <tt class=
1573 "REPLACEABLE"><i>dst_addr</i></tt> that is examined is the
1574 address of the forwarder and <span class="emphasis"><i class=
1575 "EMPHASIS">NOT</i></span> the address of the ultimate target.
1576 This is necessary because it may be impossible for the local
1577 <span class="APPLICATION">Privoxy</span> to determine the IP
1578 address of the ultimate target (that's often what gateways are
1581 <p>You should prefer using IP addresses over DNS names, because
1582 the address lookups take time. All DNS names must resolve! You
1583 can <span class="emphasis"><i class="EMPHASIS">not</i></span>
1584 use domain patterns like <span class="QUOTE">"*.org"</span> or
1585 partial domain names. If a DNS name resolves to multiple IP
1586 addresses, only the first one is used.</p>
1588 <p>Some systems allow IPv4 clients to connect to IPv6 server
1589 sockets. Then the client's IPv4 address will be translated by
1590 the system into IPv6 address space with special prefix
1591 ::ffff:0:0/96 (so called IPv4 mapped IPv6 address).
1592 <span class="APPLICATION">Privoxy</span> can handle it and maps
1593 such ACL addresses automatically.</p>
1595 <p>Denying access to particular sites by ACL may have undesired
1596 side effects if the site in question is hosted on a machine
1597 which also hosts other sites (most sites are).</p>
1603 <p>Explicitly define the default behavior if no ACL and
1604 <tt class="LITERAL">listen-address</tt> are set: <span class=
1605 "QUOTE">"localhost"</span> is OK. The absence of a <tt class=
1606 "REPLACEABLE"><i>dst_addr</i></tt> implies that <span class=
1607 "emphasis"><i class="EMPHASIS">all</i></span> destination
1608 addresses are OK:</p>
1610 <table border="0" bgcolor="#E0E0E0" width="90%">
1613 <pre class="SCREEN">
1614 permit-access localhost
1620 <p>Allow any host on the same class C subnet as www.privoxy.org
1621 access to nothing but www.example.com (or other domains hosted
1622 on the same system):</p>
1624 <table border="0" bgcolor="#E0E0E0" width="90%">
1627 <pre class="SCREEN">
1628 permit-access www.privoxy.org/24 www.example.com/32
1634 <p>Allow access from any host on the 26-bit subnet
1635 192.168.45.64 to anywhere, with the exception that
1636 192.168.45.73 may not access the IP address behind
1637 www.dirty-stuff.example.com:</p>
1639 <table border="0" bgcolor="#E0E0E0" width="90%">
1642 <pre class="SCREEN">
1643 permit-access 192.168.45.64/26
1644 deny-access 192.168.45.73 www.dirty-stuff.example.com
1650 <p>Allow access from the IPv4 network 192.0.2.0/24 even if
1651 listening on an IPv6 wild card address (not supported on all
1654 <table border="0" bgcolor="#E0E0E0" width="90%">
1657 <pre class="PROGRAMLISTING">
1658 permit-access 192.0.2.0/24
1664 <p>This is equivalent to the following line even if listening
1665 on an IPv4 address (not supported on all platforms):</p>
1667 <table border="0" bgcolor="#E0E0E0" width="90%">
1670 <pre class="PROGRAMLISTING">
1671 permit-access [::ffff:192.0.2.0]/120
1682 <h4 class="SECT3"><a name="BUFFER-LIMIT" id="BUFFER-LIMIT">7.4.8.
1683 buffer-limit</a></h4>
1685 <div class="VARIABLELIST">
1690 <p>Maximum size of the buffer for content filtering.</p>
1693 <dt>Type of value:</dt>
1696 <p>Size in Kbytes</p>
1699 <dt>Default value:</dt>
1705 <dt>Effect if unset:</dt>
1708 <p>Use a 4MB (4096 KB) limit.</p>
1714 <p>For content filtering, i.e. the <tt class=
1715 "LITERAL">+filter</tt> and <tt class=
1716 "LITERAL">+deanimate-gif</tt> actions, it is necessary that
1717 <span class="APPLICATION">Privoxy</span> buffers the entire
1718 document body. This can be potentially dangerous, since a
1719 server could just keep sending data indefinitely and wait for
1720 your RAM to exhaust -- with nasty consequences. Hence this
1723 <p>When a document buffer size reaches the <tt class=
1724 "LITERAL">buffer-limit</tt>, it is flushed to the client
1725 unfiltered and no further attempt to filter the rest of the
1726 document is made. Remember that there may be multiple threads
1727 running, which might require up to <tt class=
1728 "LITERAL">buffer-limit</tt> Kbytes <span class=
1729 "emphasis"><i class="EMPHASIS">each</i></span>, unless you have
1730 enabled <span class="QUOTE">"single-threaded"</span> above.</p>
1737 <h4 class="SECT3"><a name="ENABLE-PROXY-AUTHENTICATION-FORWARDING"
1738 id="ENABLE-PROXY-AUTHENTICATION-FORWARDING">7.4.9.
1739 enable-proxy-authentication-forwarding</a></h4>
1741 <div class="VARIABLELIST">
1746 <p>Whether or not proxy authentication through <span class=
1747 "APPLICATION">Privoxy</span> should work.</p>
1750 <dt>Type of value:</dt>
1756 <dt>Default value:</dt>
1762 <dt>Effect if unset:</dt>
1765 <p>Proxy authentication headers are removed.</p>
1771 <p>Privoxy itself does not support proxy authentication, but
1772 can allow clients to authenticate against Privoxy's parent
1775 <p>By default Privoxy (3.0.21 and later) don't do that and
1776 remove Proxy-Authorization headers in requests and
1777 Proxy-Authenticate headers in responses to make it harder for
1778 malicious sites to trick inexperienced users into providing
1779 login information.</p>
1781 <p>If this option is enabled the headers are forwarded.</p>
1783 <p>Enabling this option is <span class="emphasis"><i class=
1784 "EMPHASIS">not recommended</i></span> if there is no parent
1785 proxy that requires authentication or if the local network
1786 between Privoxy and the parent proxy isn't trustworthy. If
1787 proxy authentication is only required for some requests, it is
1788 recommended to use a client header filter to remove the
1789 authentication headers for requests where they aren't
1798 <h2 class="SECT2"><a name="FORWARDING" id="FORWARDING">7.5.
1801 <p>This feature allows routing of HTTP requests through a chain of
1802 multiple proxies.</p>
1804 <p>Forwarding can be used to chain Privoxy with a caching proxy to
1805 speed up browsing. Using a parent proxy may also be necessary if the
1806 machine that <span class="APPLICATION">Privoxy</span> runs on has no
1807 direct Internet access.</p>
1809 <p>Note that parent proxies can severely decrease your privacy level.
1810 For example a parent proxy could add your IP address to the request
1811 headers and if it's a caching proxy it may add the <span class=
1812 "QUOTE">"Etag"</span> header to revalidation requests again, even
1813 though you configured Privoxy to remove it. It may also ignore
1814 Privoxy's header time randomization and use the original values which
1815 could be used by the server as cookie replacement to track your steps
1818 <p>Also specified here are SOCKS proxies. <span class=
1819 "APPLICATION">Privoxy</span> supports the SOCKS 4 and SOCKS 4A
1823 <h4 class="SECT3"><a name="FORWARD" id="FORWARD">7.5.1.
1826 <div class="VARIABLELIST">
1831 <p>To which parent HTTP proxy specific requests should be
1835 <dt>Type of value:</dt>
1838 <p><tt class="REPLACEABLE"><i>target_pattern</i></tt>
1839 <tt class="REPLACEABLE"><i>http_parent</i></tt>[:<tt class=
1840 "REPLACEABLE"><i>port</i></tt>]</p>
1842 <p>where <tt class="REPLACEABLE"><i>target_pattern</i></tt> is
1843 a <a href="actions-file.html#AF-PATTERNS">URL pattern</a> that
1844 specifies to which requests (i.e. URLs) this forward rule shall
1845 apply. Use <tt class="LITERAL">/</tt> to denote <span class=
1846 "QUOTE">"all URLs"</span>. <tt class=
1847 "REPLACEABLE"><i>http_parent</i></tt>[:<tt class=
1848 "REPLACEABLE"><i>port</i></tt>] is the DNS name or IP address
1849 of the parent HTTP proxy through which the requests should be
1850 forwarded, optionally followed by its listening port (default:
1851 8000). Use a single dot (<tt class="LITERAL">.</tt>) to denote
1852 <span class="QUOTE">"no forwarding"</span>.</p>
1855 <dt>Default value:</dt>
1858 <p><span class="emphasis"><i class=
1859 "EMPHASIS">Unset</i></span></p>
1862 <dt>Effect if unset:</dt>
1865 <p>Don't use parent HTTP proxies.</p>
1871 <p>If <tt class="REPLACEABLE"><i>http_parent</i></tt> is
1872 <span class="QUOTE">"."</span>, then requests are not forwarded
1873 to another HTTP proxy but are made directly to the web
1876 <p><tt class="REPLACEABLE"><i>http_parent</i></tt> can be a
1877 numerical IPv6 address (if <a href=
1878 "http://tools.ietf.org/html/rfc3493" target="_top">RFC 3493</a>
1879 is implemented). To prevent clashes with the port delimiter,
1880 the whole IP address has to be put into brackets. On the other
1881 hand a <tt class="REPLACEABLE"><i>target_pattern</i></tt>
1882 containing an IPv6 address has to be put into angle brackets
1883 (normal brackets are reserved for regular expressions
1886 <p>Multiple lines are OK, they are checked in sequence, and the
1887 last match wins.</p>
1893 <p>Everything goes to an example parent proxy, except SSL on
1894 port 443 (which it doesn't handle):</p>
1896 <table border="0" bgcolor="#E0E0E0" width="90%">
1899 <pre class="SCREEN">
1900 forward / parent-proxy.example.org:8080
1907 <p>Everything goes to our example ISP's caching proxy, except
1908 for requests to that ISP's sites:</p>
1910 <table border="0" bgcolor="#E0E0E0" width="90%">
1913 <pre class="SCREEN">
1914 forward / caching-proxy.isp.example.net:8000
1915 forward .isp.example.net .
1921 <p>Parent proxy specified by an IPv6 address:</p>
1923 <table border="0" bgcolor="#E0E0E0" width="90%">
1926 <pre class="PROGRAMLISTING">
1927 forward / [2001:DB8::1]:8000
1933 <p>Suppose your parent proxy doesn't support IPv6:</p>
1935 <table border="0" bgcolor="#E0E0E0" width="90%">
1938 <pre class="PROGRAMLISTING">
1939 forward / parent-proxy.example.org:8000
1940 forward ipv6-server.example.org .
1941 forward <[2-3][0-9a-f][0-9a-f][0-9a-f]:*> .
1952 <h4 class="SECT3"><a name="SOCKS" id="SOCKS">7.5.2. forward-socks4,
1953 forward-socks4a, forward-socks5 and forward-socks5t</a></h4><a name=
1954 "FORWARD-SOCKS4" id="FORWARD-SOCKS4"></a><a name="FORWARD-SOCKS4A"
1955 id="FORWARD-SOCKS4A"></a>
1957 <div class="VARIABLELIST">
1962 <p>Through which SOCKS proxy (and optionally to which parent
1963 HTTP proxy) specific requests should be routed.</p>
1966 <dt>Type of value:</dt>
1969 <p><tt class="REPLACEABLE"><i>target_pattern</i></tt>
1970 <tt class="REPLACEABLE"><i>socks_proxy</i></tt>[:<tt class=
1971 "REPLACEABLE"><i>port</i></tt>] <tt class=
1972 "REPLACEABLE"><i>http_parent</i></tt>[:<tt class=
1973 "REPLACEABLE"><i>port</i></tt>]</p>
1975 <p>where <tt class="REPLACEABLE"><i>target_pattern</i></tt> is
1976 a <a href="actions-file.html#AF-PATTERNS">URL pattern</a> that
1977 specifies to which requests (i.e. URLs) this forward rule shall
1978 apply. Use <tt class="LITERAL">/</tt> to denote <span class=
1979 "QUOTE">"all URLs"</span>. <tt class=
1980 "REPLACEABLE"><i>http_parent</i></tt> and <tt class=
1981 "REPLACEABLE"><i>socks_proxy</i></tt> are IP addresses in
1982 dotted decimal notation or valid DNS names (<tt class=
1983 "REPLACEABLE"><i>http_parent</i></tt> may be <span class=
1984 "QUOTE">"."</span> to denote <span class="QUOTE">"no HTTP
1985 forwarding"</span>), and the optional <tt class=
1986 "REPLACEABLE"><i>port</i></tt> parameters are TCP ports, i.e.
1987 integer values from 1 to 65535</p>
1990 <dt>Default value:</dt>
1993 <p><span class="emphasis"><i class=
1994 "EMPHASIS">Unset</i></span></p>
1997 <dt>Effect if unset:</dt>
2000 <p>Don't use SOCKS proxies.</p>
2006 <p>Multiple lines are OK, they are checked in sequence, and the
2007 last match wins.</p>
2009 <p>The difference between <tt class=
2010 "LITERAL">forward-socks4</tt> and <tt class=
2011 "LITERAL">forward-socks4a</tt> is that in the SOCKS 4A
2012 protocol, the DNS resolution of the target hostname happens on
2013 the SOCKS server, while in SOCKS 4 it happens locally.</p>
2015 <p>With <tt class="LITERAL">forward-socks5</tt> the DNS
2016 resolution will happen on the remote server as well.</p>
2018 <p><tt class="LITERAL">forward-socks5t</tt> works like vanilla
2019 <tt class="LITERAL">forward-socks5</tt> but lets <span class=
2020 "APPLICATION">Privoxy</span> additionally use Tor-specific
2021 SOCKS extensions. Currently the only supported SOCKS extension
2022 is optimistic data which can reduce the latency for the first
2023 request made on a newly created connection.</p>
2025 <p><tt class="REPLACEABLE"><i>socks_proxy</i></tt> and
2026 <tt class="REPLACEABLE"><i>http_parent</i></tt> can be a
2027 numerical IPv6 address (if <a href=
2028 "http://tools.ietf.org/html/rfc3493" target="_top">RFC 3493</a>
2029 is implemented). To prevent clashes with the port delimiter,
2030 the whole IP address has to be put into brackets. On the other
2031 hand a <tt class="REPLACEABLE"><i>target_pattern</i></tt>
2032 containing an IPv6 address has to be put into angle brackets
2033 (normal brackets are reserved for regular expressions
2036 <p>If <tt class="REPLACEABLE"><i>http_parent</i></tt> is
2037 <span class="QUOTE">"."</span>, then requests are not forwarded
2038 to another HTTP proxy but are made (HTTP-wise) directly to the
2039 web servers, albeit through a SOCKS proxy.</p>
2045 <p>From the company example.com, direct connections are made to
2046 all <span class="QUOTE">"internal"</span> domains, but
2047 everything outbound goes through their ISP's proxy by way of
2048 example.com's corporate SOCKS 4A gateway to the Internet.</p>
2050 <table border="0" bgcolor="#E0E0E0" width="90%">
2053 <pre class="SCREEN">
2054 forward-socks4a / socks-gw.example.com:1080 www-cache.isp.example.net:8080
2055 forward .example.com .
2061 <p>A rule that uses a SOCKS 4 gateway for all destinations but
2062 no HTTP parent looks like this:</p>
2064 <table border="0" bgcolor="#E0E0E0" width="90%">
2067 <pre class="SCREEN">
2068 forward-socks4 / socks-gw.example.com:1080 .
2074 <p>To chain Privoxy and Tor, both running on the same system,
2075 you would use something like:</p>
2077 <table border="0" bgcolor="#E0E0E0" width="90%">
2080 <pre class="SCREEN">
2081 forward-socks5t / 127.0.0.1:9050 .
2087 <p>The public <span class="APPLICATION">Tor</span> network
2088 can't be used to reach your local network, if you need to
2089 access local servers you therefore might want to make some
2092 <table border="0" bgcolor="#E0E0E0" width="90%">
2095 <pre class="SCREEN">
2096 forward 192.168.*.*/ .
2098 forward 127.*.*.*/ .
2104 <p>Unencrypted connections to systems in these address ranges
2105 will be as (un)secure as the local network is, but the
2106 alternative is that you can't reach the local network through
2107 <span class="APPLICATION">Privoxy</span> at all. Of course this
2108 may actually be desired and there is no reason to make these
2109 exceptions if you aren't sure you need them.</p>
2111 <p>If you also want to be able to reach servers in your local
2112 network by using their names, you will need additional
2113 exceptions that look like this:</p>
2115 <table border="0" bgcolor="#E0E0E0" width="90%">
2118 <pre class="SCREEN">
2119 forward localhost/ .
2130 <h4 class="SECT3"><a name="ADVANCED-FORWARDING-EXAMPLES" id=
2131 "ADVANCED-FORWARDING-EXAMPLES">7.5.3. Advanced Forwarding
2134 <p>If you have links to multiple ISPs that provide various special
2135 content only to their subscribers, you can configure multiple
2136 <span class="APPLICATION">Privoxies</span> which have connections to
2137 the respective ISPs to act as forwarders to each other, so that
2138 <span class="emphasis"><i class="EMPHASIS">your</i></span> users can
2139 see the internal content of all ISPs.</p>
2141 <p>Assume that host-a has a PPP connection to isp-a.example.net. And
2142 host-b has a PPP connection to isp-b.example.org. Both run
2143 <span class="APPLICATION">Privoxy</span>. Their forwarding
2144 configuration can look like this:</p>
2148 <table border="0" bgcolor="#E0E0E0" width="100%">
2151 <pre class="SCREEN">
2153 forward .isp-b.example.net host-b:8118
2161 <table border="0" bgcolor="#E0E0E0" width="100%">
2164 <pre class="SCREEN">
2166 forward .isp-a.example.org host-a:8118
2172 <p>Now, your users can set their browser's proxy to use either host-a
2173 or host-b and be able to browse the internal content of both isp-a
2176 <p>If you intend to chain <span class="APPLICATION">Privoxy</span>
2177 and <span class="APPLICATION">squid</span> locally, then chaining as
2178 <tt class="LITERAL">browser -> squid -> privoxy</tt> is the
2179 recommended way.</p>
2181 <p>Assuming that <span class="APPLICATION">Privoxy</span> and
2182 <span class="APPLICATION">squid</span> run on the same box, your
2183 <span class="APPLICATION">squid</span> configuration could then look
2186 <table border="0" bgcolor="#E0E0E0" width="100%">
2189 <pre class="SCREEN">
2190 # Define Privoxy as parent proxy (without ICP)
2191 cache_peer 127.0.0.1 parent 8118 7 no-query
2193 # Define ACL for protocol FTP
2196 # Do not forward FTP requests to Privoxy
2197 always_direct allow ftp
2199 # Forward all the rest to Privoxy
2200 never_direct allow all
2206 <p>You would then need to change your browser's proxy settings to
2207 <span class="APPLICATION">squid</span>'s address and port. Squid
2208 normally uses port 3128. If unsure consult <tt class=
2209 "LITERAL">http_port</tt> in <tt class="FILENAME">squid.conf</tt>.</p>
2211 <p>You could just as well decide to only forward requests you suspect
2212 of leading to Windows executables through a virus-scanning parent
2213 proxy, say, on <tt class="LITERAL">antivir.example.com</tt>, port
2216 <table border="0" bgcolor="#E0E0E0" width="100%">
2219 <pre class="SCREEN">
2221 forward /.*\.(exe|com|dll|zip)$ antivir.example.com:8010
2229 <h4 class="SECT3"><a name="FORWARDED-CONNECT-RETRIES" id=
2230 "FORWARDED-CONNECT-RETRIES">7.5.4. forwarded-connect-retries</a></h4>
2232 <div class="VARIABLELIST">
2237 <p>How often Privoxy retries if a forwarded connection request
2241 <dt>Type of value:</dt>
2244 <p><tt class="REPLACEABLE"><i>Number of retries.</i></tt></p>
2247 <dt>Default value:</dt>
2250 <p><span class="emphasis"><i class="EMPHASIS">0</i></span></p>
2253 <dt>Effect if unset:</dt>
2256 <p>Connections forwarded through other proxies are treated like
2257 direct connections and no retry attempts are made.</p>
2264 "REPLACEABLE"><i>forwarded-connect-retries</i></tt> is mainly
2265 interesting for socks4a connections, where <span class=
2266 "APPLICATION">Privoxy</span> can't detect why the connections
2267 failed. The connection might have failed because of a DNS
2268 timeout in which case a retry makes sense, but it might also
2269 have failed because the server doesn't exist or isn't
2270 reachable. In this case the retry will just delay the
2271 appearance of Privoxy's error message.</p>
2273 <p>Note that in the context of this option, <span class=
2274 "QUOTE">"forwarded connections"</span> includes all connections
2275 that Privoxy forwards through other proxies. This option is not
2276 limited to the HTTP CONNECT method.</p>
2278 <p>Only use this option, if you are getting lots of
2279 forwarding-related error messages that go away when you try
2280 again manually. Start with a small value and check Privoxy's
2281 logfile from time to time, to see how many retries are usually
2288 <p>forwarded-connect-retries 1</p>
2296 <h2 class="SECT2"><a name="MISC" id="MISC">7.6. Miscellaneous</a></h2>
2299 <h4 class="SECT3"><a name="ACCEPT-INTERCEPTED-REQUESTS" id=
2300 "ACCEPT-INTERCEPTED-REQUESTS">7.6.1.
2301 accept-intercepted-requests</a></h4>
2303 <div class="VARIABLELIST">
2308 <p>Whether intercepted requests should be treated as valid.</p>
2311 <dt>Type of value:</dt>
2314 <p><tt class="REPLACEABLE"><i>0 or 1</i></tt></p>
2317 <dt>Default value:</dt>
2320 <p><span class="emphasis"><i class="EMPHASIS">0</i></span></p>
2323 <dt>Effect if unset:</dt>
2326 <p>Only proxy requests are accepted, intercepted requests are
2327 treated as invalid.</p>
2333 <p>If you don't trust your clients and want to force them to
2334 use <span class="APPLICATION">Privoxy</span>, enable this
2335 option and configure your packet filter to redirect outgoing
2336 HTTP connections into <span class=
2337 "APPLICATION">Privoxy</span>.</p>
2339 <p>Note that intercepting encrypted connections (HTTPS) isn't
2342 <p>Make sure that <span class="APPLICATION">Privoxy's</span>
2343 own requests aren't redirected as well. Additionally take care
2344 that <span class="APPLICATION">Privoxy</span> can't
2345 intentionally connect to itself, otherwise you could run into
2346 redirection loops if <span class="APPLICATION">Privoxy's</span>
2347 listening port is reachable by the outside or an attacker has
2348 access to the pages you visit.</p>
2354 <p>accept-intercepted-requests 1</p>
2361 <h4 class="SECT3"><a name="ALLOW-CGI-REQUEST-CRUNCHING" id=
2362 "ALLOW-CGI-REQUEST-CRUNCHING">7.6.2.
2363 allow-cgi-request-crunching</a></h4>
2365 <div class="VARIABLELIST">
2370 <p>Whether requests to <span class=
2371 "APPLICATION">Privoxy's</span> CGI pages can be blocked or
2375 <dt>Type of value:</dt>
2378 <p><tt class="REPLACEABLE"><i>0 or 1</i></tt></p>
2381 <dt>Default value:</dt>
2384 <p><span class="emphasis"><i class="EMPHASIS">0</i></span></p>
2387 <dt>Effect if unset:</dt>
2390 <p><span class="APPLICATION">Privoxy</span> ignores block and
2391 redirect actions for its CGI pages.</p>
2397 <p>By default <span class="APPLICATION">Privoxy</span> ignores
2398 block or redirect actions for its CGI pages. Intercepting these
2399 requests can be useful in multi-user setups to implement
2400 fine-grained access control, but it can also render the
2401 complete web interface useless and make debugging problems
2402 painful if done without care.</p>
2404 <p>Don't enable this option unless you're sure that you really
2411 <p>allow-cgi-request-crunching 1</p>
2418 <h4 class="SECT3"><a name="SPLIT-LARGE-FORMS" id=
2419 "SPLIT-LARGE-FORMS">7.6.3. split-large-forms</a></h4>
2421 <div class="VARIABLELIST">
2426 <p>Whether the CGI interface should stay compatible with broken
2430 <dt>Type of value:</dt>
2433 <p><tt class="REPLACEABLE"><i>0 or 1</i></tt></p>
2436 <dt>Default value:</dt>
2439 <p><span class="emphasis"><i class="EMPHASIS">0</i></span></p>
2442 <dt>Effect if unset:</dt>
2445 <p>The CGI form generate long GET URLs.</p>
2451 <p><span class="APPLICATION">Privoxy's</span> CGI forms can
2452 lead to rather long URLs. This isn't a problem as far as the
2453 HTTP standard is concerned, but it can confuse clients with
2454 arbitrary URL length limitations.</p>
2456 <p>Enabling split-large-forms causes <span class=
2457 "APPLICATION">Privoxy</span> to divide big forms into smaller
2458 ones to keep the URL length down. It makes editing a lot less
2459 convenient and you can no longer submit all changes at once,
2460 but at least it works around this browser bug.</p>
2462 <p>If you don't notice any editing problems, there is no reason
2463 to enable this option, but if one of the submit buttons appears
2464 to be broken, you should give it a try.</p>
2470 <p>split-large-forms 1</p>
2477 <h4 class="SECT3"><a name="KEEP-ALIVE-TIMEOUT" id=
2478 "KEEP-ALIVE-TIMEOUT">7.6.4. keep-alive-timeout</a></h4>
2480 <div class="VARIABLELIST">
2485 <p>Number of seconds after which an open connection will no
2486 longer be reused.</p>
2489 <dt>Type of value:</dt>
2492 <p><tt class="REPLACEABLE"><i>Time in seconds.</i></tt></p>
2495 <dt>Default value:</dt>
2501 <dt>Effect if unset:</dt>
2504 <p>Connections are not kept alive.</p>
2510 <p>This option allows clients to keep the connection to
2511 <span class="APPLICATION">Privoxy</span> alive. If the server
2512 supports it, <span class="APPLICATION">Privoxy</span> will keep
2513 the connection to the server alive as well. Under certain
2514 circumstances this may result in speed-ups.</p>
2516 <p>By default, <span class="APPLICATION">Privoxy</span> will
2517 close the connection to the server if the client connection
2518 gets closed, or if the specified timeout has been reached
2519 without a new request coming in. This behaviour can be changed
2520 with the <a href="#CONNECTION-SHARING" target=
2521 "_top">connection-sharing</a> option.</p>
2523 <p>This option has no effect if <span class=
2524 "APPLICATION">Privoxy</span> has been compiled without
2525 keep-alive support.</p>
2527 <p>Note that a timeout of five seconds as used in the default
2528 configuration file significantly decreases the number of
2529 connections that will be reused. The value is used because some
2530 browsers limit the number of connections they open to a single
2531 host and apply the same limit to proxies. This can result in a
2532 single website <span class="QUOTE">"grabbing"</span> all the
2533 connections the browser allows, which means connections to
2534 other websites can't be opened until the connections currently
2535 in use time out.</p>
2537 <p>Several users have reported this as a Privoxy bug, so the
2538 default value has been reduced. Consider increasing it to 300
2539 seconds or even more if you think your browser can handle it.
2540 If your browser appears to be hanging, it probably can't.</p>
2546 <p>keep-alive-timeout 300</p>
2553 <h4 class="SECT3"><a name="TOLERATE-PIPELINING" id=
2554 "TOLERATE-PIPELINING">7.6.5. tolerate-pipelining</a></h4>
2556 <div class="VARIABLELIST">
2561 <p>Whether or not pipelined requests should be served.</p>
2564 <dt>Type of value:</dt>
2567 <p><tt class="REPLACEABLE"><i>0 or 1.</i></tt></p>
2570 <dt>Default value:</dt>
2576 <dt>Effect if unset:</dt>
2579 <p>If Privoxy receives more than one request at once, it
2580 terminates the client connection after serving the first
2587 <p><span class="APPLICATION">Privoxy</span> currently doesn't
2588 pipeline outgoing requests, thus allowing pipelining on the
2589 client connection is not guaranteed to improve the
2592 <p>By default <span class="APPLICATION">Privoxy</span> tries to
2593 discourage clients from pipelining by discarding aggressively
2594 pipelined requests, which forces the client to resend them
2595 through a new connection.</p>
2597 <p>This option lets <span class="APPLICATION">Privoxy</span>
2598 tolerate pipelining. Whether or not that improves performance
2599 mainly depends on the client configuration.</p>
2601 <p>If you are seeing problems with pages not properly loading,
2602 disabling this option could work around the problem.</p>
2608 <p>tolerate-pipelining 1</p>
2615 <h4 class="SECT3"><a name="DEFAULT-SERVER-TIMEOUT" id=
2616 "DEFAULT-SERVER-TIMEOUT">7.6.6. default-server-timeout</a></h4>
2618 <div class="VARIABLELIST">
2623 <p>Assumed server-side keep-alive timeout if not specified by
2627 <dt>Type of value:</dt>
2630 <p><tt class="REPLACEABLE"><i>Time in seconds.</i></tt></p>
2633 <dt>Default value:</dt>
2639 <dt>Effect if unset:</dt>
2642 <p>Connections for which the server didn't specify the
2643 keep-alive timeout are not reused.</p>
2649 <p>Enabling this option significantly increases the number of
2650 connections that are reused, provided the <a href=
2651 "#KEEP-ALIVE-TIMEOUT" target="_top">keep-alive-timeout</a>
2652 option is also enabled.</p>
2654 <p>While it also increases the number of connections problems
2655 when <span class="APPLICATION">Privoxy</span> tries to reuse a
2656 connection that already has been closed on the server side, or
2657 is closed while <span class="APPLICATION">Privoxy</span> is
2658 trying to reuse it, this should only be a problem if it happens
2659 for the first request sent by the client. If it happens for
2660 requests on reused client connections, <span class=
2661 "APPLICATION">Privoxy</span> will simply close the connection
2662 and the client is supposed to retry the request without
2663 bothering the user.</p>
2665 <p>Enabling this option is therefore only recommended if the
2666 <a href="#CONNECTION-SHARING" target=
2667 "_top">connection-sharing</a> option is disabled.</p>
2669 <p>It is an error to specify a value larger than the <a href=
2670 "#KEEP-ALIVE-TIMEOUT" target="_top">keep-alive-timeout</a>
2673 <p>This option has no effect if <span class=
2674 "APPLICATION">Privoxy</span> has been compiled without
2675 keep-alive support.</p>
2681 <p>default-server-timeout 60</p>
2688 <h4 class="SECT3"><a name="CONNECTION-SHARING" id=
2689 "CONNECTION-SHARING">7.6.7. connection-sharing</a></h4>
2691 <div class="VARIABLELIST">
2696 <p>Whether or not outgoing connections that have been kept
2697 alive should be shared between different incoming
2701 <dt>Type of value:</dt>
2704 <p><tt class="REPLACEABLE"><i>0 or 1</i></tt></p>
2707 <dt>Default value:</dt>
2713 <dt>Effect if unset:</dt>
2716 <p>Connections are not shared.</p>
2722 <p>This option has no effect if <span class=
2723 "APPLICATION">Privoxy</span> has been compiled without
2724 keep-alive support, or if it's disabled.</p>
2730 <p>Note that reusing connections doesn't necessary cause
2731 speedups. There are also a few privacy implications you should
2734 <p>If this option is effective, outgoing connections are shared
2735 between clients (if there are more than one) and closing the
2736 browser that initiated the outgoing connection does no longer
2737 affect the connection between <span class=
2738 "APPLICATION">Privoxy</span> and the server unless the client's
2739 request hasn't been completed yet.</p>
2741 <p>If the outgoing connection is idle, it will not be closed
2742 until either <span class="APPLICATION">Privoxy's</span> or the
2743 server's timeout is reached. While it's open, the server knows
2744 that the system running <span class=
2745 "APPLICATION">Privoxy</span> is still there.</p>
2747 <p>If there are more than one client (maybe even belonging to
2748 multiple users), they will be able to reuse each others
2749 connections. This is potentially dangerous in case of
2750 authentication schemes like NTLM where only the connection is
2751 authenticated, instead of requiring authentication for each
2754 <p>If there is only a single client, and if said client can
2755 keep connections alive on its own, enabling this option has
2756 next to no effect. If the client doesn't support connection
2757 keep-alive, enabling this option may make sense as it allows
2758 <span class="APPLICATION">Privoxy</span> to keep outgoing
2759 connections alive even if the client itself doesn't support
2762 <p>You should also be aware that enabling this option increases
2763 the likelihood of getting the "No server or forwarder data"
2764 error message, especially if you are using a slow connection to
2767 <p>This option should only be used by experienced users who
2768 understand the risks and can weight them against the
2775 <p>connection-sharing 1</p>
2782 <h4 class="SECT3"><a name="SOCKET-TIMEOUT" id="SOCKET-TIMEOUT">7.6.8.
2783 socket-timeout</a></h4>
2785 <div class="VARIABLELIST">
2790 <p>Number of seconds after which a socket times out if no data
2794 <dt>Type of value:</dt>
2797 <p><tt class="REPLACEABLE"><i>Time in seconds.</i></tt></p>
2800 <dt>Default value:</dt>
2806 <dt>Effect if unset:</dt>
2809 <p>A default value of 300 seconds is used.</p>
2815 <p>The default is quite high and you probably want to reduce
2816 it. If you aren't using an occasionally slow proxy like Tor,
2817 reducing it to a few seconds should be fine.</p>
2823 <p>socket-timeout 300</p>
2830 <h4 class="SECT3"><a name="MAX-CLIENT-CONNECTIONS" id=
2831 "MAX-CLIENT-CONNECTIONS">7.6.9. max-client-connections</a></h4>
2833 <div class="VARIABLELIST">
2838 <p>Maximum number of client connections that will be
2842 <dt>Type of value:</dt>
2845 <p><tt class="REPLACEABLE"><i>Positive number.</i></tt></p>
2848 <dt>Default value:</dt>
2854 <dt>Effect if unset:</dt>
2857 <p>Connections are served until a resource limit is
2864 <p><span class="APPLICATION">Privoxy</span> creates one thread
2865 (or process) for every incoming client connection that isn't
2866 rejected based on the access control settings.</p>
2868 <p>If the system is powerful enough, <span class=
2869 "APPLICATION">Privoxy</span> can theoretically deal with
2870 several hundred (or thousand) connections at the same time, but
2871 some operating systems enforce resource limits by shutting down
2872 offending processes and their default limits may be below the
2873 ones <span class="APPLICATION">Privoxy</span> would require
2874 under heavy load.</p>
2876 <p>Configuring <span class="APPLICATION">Privoxy</span> to
2877 enforce a connection limit below the thread or process limit
2878 used by the operating system makes sure this doesn't happen.
2879 Simply increasing the operating system's limit would work too,
2880 but if <span class="APPLICATION">Privoxy</span> isn't the only
2881 application running on the system, you may actually want to
2882 limit the resources used by <span class=
2883 "APPLICATION">Privoxy</span>.</p>
2885 <p>If <span class="APPLICATION">Privoxy</span> is only used by
2886 a single trusted user, limiting the number of client
2887 connections is probably unnecessary. If there are multiple
2888 possibly untrusted users you probably still want to
2889 additionally use a packet filter to limit the maximal number of
2890 incoming connections per client. Otherwise a malicious user
2891 could intentionally create a high number of connections to
2892 prevent other users from using <span class=
2893 "APPLICATION">Privoxy</span>.</p>
2895 <p>Obviously using this option only makes sense if you choose a
2896 limit below the one enforced by the operating system.</p>
2898 <p>One most POSIX-compliant systems <span class=
2899 "APPLICATION">Privoxy</span> can't properly deal with more than
2900 FD_SETSIZE file descriptors at the same time and has to reject
2901 connections if the limit is reached. This will likely change in
2902 a future version, but currently this limit can't be increased
2903 without recompiling <span class="APPLICATION">Privoxy</span>
2904 with a different FD_SETSIZE limit.</p>
2910 <p>max-client-connections 256</p>
2917 <h4 class="SECT3"><a name="HANDLE-AS-EMPTY-DOC-RETURNS-OK" id=
2918 "HANDLE-AS-EMPTY-DOC-RETURNS-OK">7.6.10.
2919 handle-as-empty-doc-returns-ok</a></h4>
2921 <div class="VARIABLELIST">
2926 <p>The status code Privoxy returns for pages blocked with
2927 <tt class="LITERAL"><a href=
2928 "actions-file.html#HANDLE-AS-EMPTY-DOCUMENT" target=
2929 "_top">+handle-as-empty-document</a></tt>.</p>
2932 <dt>Type of value:</dt>
2935 <p><tt class="REPLACEABLE"><i>0 or 1</i></tt></p>
2938 <dt>Default value:</dt>
2944 <dt>Effect if unset:</dt>
2947 <p>Privoxy returns a status 403(forbidden) for all blocked
2951 <dt>Effect if set:</dt>
2954 <p>Privoxy returns a status 200(OK) for pages blocked with
2955 +handle-as-empty-document and a status 403(Forbidden) for all
2956 other blocked pages.</p>
2962 <p>This is a work-around for Firefox bug 492459: <span class=
2963 "QUOTE">" Websites are no longer rendered if SSL requests for
2964 JavaScripts are blocked by a proxy. "</span> (<a href=
2965 "https://bugzilla.mozilla.org/show_bug.cgi?id=492459" target=
2966 "_top">https://bugzilla.mozilla.org/show_bug.cgi?id=492459</a>)
2967 As the bug has been fixed for quite some time this option
2968 should no longer be needed and will be removed in a future
2969 release. Please speak up if you have a reason why the option
2970 should be kept around.</p>
2977 <h4 class="SECT3"><a name="ENABLE-COMPRESSION" id=
2978 "ENABLE-COMPRESSION">7.6.11. enable-compression</a></h4>
2980 <div class="VARIABLELIST">
2985 <p>Whether or not buffered content is compressed before
2989 <dt>Type of value:</dt>
2992 <p><tt class="REPLACEABLE"><i>0 or 1</i></tt></p>
2995 <dt>Default value:</dt>
3001 <dt>Effect if unset:</dt>
3004 <p>Privoxy does not compress buffered content.</p>
3007 <dt>Effect if set:</dt>
3010 <p>Privoxy compresses buffered content before delivering it to
3011 the client, provided the client supports it.</p>
3017 <p>This directive is only supported if Privoxy has been
3018 compiled with FEATURE_COMPRESSION, which should not to be
3019 confused with FEATURE_ZLIB.</p>
3021 <p>Compressing buffered content is mainly useful if Privoxy and
3022 the client are running on different systems. If they are
3023 running on the same system, enabling compression is likely to
3024 slow things down. If you didn't measure otherwise, you should
3025 assume that it does and keep this option disabled.</p>
3027 <p>Privoxy will not compress buffered content below a certain
3035 <h4 class="SECT3"><a name="COMPRESSION-LEVEL" id=
3036 "COMPRESSION-LEVEL">7.6.12. compression-level</a></h4>
3038 <div class="VARIABLELIST">
3043 <p>The compression level that is passed to the zlib library
3044 when compressing buffered content.</p>
3047 <dt>Type of value:</dt>
3050 <p><tt class="REPLACEABLE"><i>Positive number ranging from 0 to
3054 <dt>Default value:</dt>
3063 <p>Compressing the data more takes usually longer than
3064 compressing it less or not compressing it at all. Which level
3065 is best depends on the connection between Privoxy and the
3066 client. If you can't be bothered to benchmark it for yourself,
3067 you should stick with the default and keep compression
3070 <p>If compression is disabled, the compression level is
3077 <table border="0" bgcolor="#E0E0E0" width="90%">
3080 <pre class="SCREEN">
3081 # Best speed (compared to the other levels)
3085 # No compression. Only useful for testing as the added header
3086 # slightly increases the amount of data that has to be sent.
3087 # If your benchmark shows that using this compression level
3088 # is superior to using no compression at all, the benchmark
3089 # is likely to be flawed.
3102 <h4 class="SECT3"><a name="CLIENT-HEADER-ORDER" id=
3103 "CLIENT-HEADER-ORDER">7.6.13. client-header-order</a></h4>
3105 <div class="VARIABLELIST">
3110 <p>The order in which client headers are sorted before
3111 forwarding them.</p>
3114 <dt>Type of value:</dt>
3117 <p><tt class="REPLACEABLE"><i>Client header names delimited by
3118 spaces or tabs</i></tt></p>
3121 <dt>Default value:</dt>
3130 <p>By default <span class="APPLICATION">Privoxy</span> leaves
3131 the client headers in the order they were sent by the client.
3132 Headers are modified in-place, new headers are added at the end
3133 of the already existing headers.</p>
3135 <p>The header order can be used to fingerprint client requests
3136 independently of other headers like the User-Agent.</p>
3138 <p>This directive allows to sort the headers differently to
3139 better mimic a different User-Agent. Client headers will be
3140 emitted in the order given, headers whose name isn't explicitly
3141 specified are added at the end.</p>
3143 <p>Note that sorting headers in an uncommon way will make
3144 fingerprinting actually easier. Encrypted headers are not
3145 affected by this directive.</p>
3153 <h2 class="SECT2"><a name="WINDOWS-GUI" id="WINDOWS-GUI">7.7. Windows
3154 GUI Options</a></h2>
3156 <p><span class="APPLICATION">Privoxy</span> has a number of options
3157 specific to the Windows GUI interface:</p><a name="ACTIVITY-ANIMATION"
3158 id="ACTIVITY-ANIMATION"></a>
3160 <p>If <span class="QUOTE">"activity-animation"</span> is set to 1, the
3161 <span class="APPLICATION">Privoxy</span> icon will animate when
3162 <span class="QUOTE">"Privoxy"</span> is active. To turn off, set to
3165 <p class="LITERALLAYOUT"><tt class="LITERAL"> <span class=
3166 "emphasis"><i class="EMPHASIS">activity-animation 1</i></span><br>
3167 </tt></p><a name="LOG-MESSAGES" id=
3170 <p>If <span class="QUOTE">"log-messages"</span> is set to 1,
3171 <span class="APPLICATION">Privoxy</span> copies log messages to the
3172 console window. The log detail depends on the <a href=
3173 "config.html#DEBUG">debug</a> directive.</p>
3175 <p class="LITERALLAYOUT"><tt class="LITERAL"> <span class=
3176 "emphasis"><i class="EMPHASIS">log-messages 1</i></span><br>
3177 </tt></p><a name="LOG-BUFFER-SIZE" id=
3178 "LOG-BUFFER-SIZE"></a>
3180 <p>If <span class="QUOTE">"log-buffer-size"</span> is set to 1, the
3181 size of the log buffer, i.e. the amount of memory used for the log
3182 messages displayed in the console window, will be limited to
3183 <span class="QUOTE">"log-max-lines"</span> (see below).</p>
3185 <p>Warning: Setting this to 0 will result in the buffer to grow
3186 infinitely and eat up all your memory!</p>
3188 <p class="LITERALLAYOUT"><tt class="LITERAL"> <span class=
3189 "emphasis"><i class="EMPHASIS">log-buffer-size 1</i></span><br>
3190 </tt></p><a name="LOG-MAX-LINES" id=
3191 "LOG-MAX-LINES"></a>
3193 <p><span class="APPLICATION">log-max-lines</span> is the maximum number
3194 of lines held in the log buffer. See above.</p>
3196 <p class="LITERALLAYOUT"><tt class="LITERAL"> <span class=
3197 "emphasis"><i class="EMPHASIS">log-max-lines 200</i></span><br>
3198 </tt></p><a name="LOG-HIGHLIGHT-MESSAGES" id=
3199 "LOG-HIGHLIGHT-MESSAGES"></a>
3201 <p>If <span class="QUOTE">"log-highlight-messages"</span> is set to 1,
3202 <span class="APPLICATION">Privoxy</span> will highlight portions of the
3203 log messages with a bold-faced font:</p>
3205 <p class="LITERALLAYOUT"><tt class="LITERAL"> <span class=
3206 "emphasis"><i class="EMPHASIS">log-highlight-messages 1</i></span><br>
3207 </tt></p><a name="LOG-FONT-NAME" id=
3208 "LOG-FONT-NAME"></a>
3210 <p>The font used in the console window:</p>
3212 <p class="LITERALLAYOUT"><tt class="LITERAL"> <span class=
3213 "emphasis"><i class="EMPHASIS">log-font-name Comic Sans
3215 </tt></p><a name="LOG-FONT-SIZE" id=
3216 "LOG-FONT-SIZE"></a>
3218 <p>Font size used in the console window:</p>
3220 <p class="LITERALLAYOUT"><tt class="LITERAL"> <span class=
3221 "emphasis"><i class="EMPHASIS">log-font-size 8</i></span><br>
3222 </tt></p><a name="SHOW-ON-TASK-BAR" id=
3223 "SHOW-ON-TASK-BAR"></a>
3225 <p><span class="QUOTE">"show-on-task-bar"</span> controls whether or
3226 not <span class="APPLICATION">Privoxy</span> will appear as a button on
3227 the Task bar when minimized:</p>
3229 <p class="LITERALLAYOUT"><tt class="LITERAL"> <span class=
3230 "emphasis"><i class="EMPHASIS">show-on-task-bar 0</i></span><br>
3231 </tt></p><a name="CLOSE-BUTTON-MINIMIZES" id=
3232 "CLOSE-BUTTON-MINIMIZES"></a>
3234 <p>If <span class="QUOTE">"close-button-minimizes"</span> is set to 1,
3235 the Windows close button will minimize <span class=
3236 "APPLICATION">Privoxy</span> instead of closing the program (close with
3237 the exit option on the File menu).</p>
3239 <p class="LITERALLAYOUT"><tt class="LITERAL"> <span class=
3240 "emphasis"><i class="EMPHASIS">close-button-minimizes 1</i></span><br>
3241 </tt></p><a name="HIDE-CONSOLE" id=
3244 <p>The <span class="QUOTE">"hide-console"</span> option is specific to
3245 the MS-Win console version of <span class="APPLICATION">Privoxy</span>.
3246 If this option is used, <span class="APPLICATION">Privoxy</span> will
3247 disconnect from and hide the command console.</p>
3249 <p class="LITERALLAYOUT"><tt class="LITERAL"> #<span class=
3250 "emphasis"><i class="EMPHASIS">hide-console</i></span><br>
3251 </tt></p>
3255 <div class="NAVFOOTER">
3256 <hr align="left" width="100%">
3258 <table summary="Footer navigation table" width="100%" border="0"
3259 cellpadding="0" cellspacing="0">
3261 <td width="33%" align="left" valign="top"><a href=
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3265 accesskey="H">Home</a></td>
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