+ <para>
+ If this option is enabled the headers are forwarded.
+ </para>
+ <para>
+ Enabling this option is <emphasis>not recommended</emphasis> if there is
+ no parent proxy that requires authentication or if the local network between
+ Privoxy and the parent proxy isn't trustworthy. If proxy authentication is
+ only required for some requests, it is recommended to use a client header filter
+ to remove the authentication headers for requests where they aren't needed.
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+
+<![%config-file;[<literallayout>@@enable-proxy-authentication-forwarding 0</literallayout>]]>
+</sect3>
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="trusted-cgi-referer"><title>trusted-cgi-referer</title>
+<variablelist>
+ <varlistentry>
+ <term>Specifies:</term>
+ <listitem>
+ <para>
+ A trusted website or webpage whose links can be followed to reach sensitive CGI pages
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Type of value:</term>
+ <listitem>
+ <para>URL or URL prefix</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Default value:</term>
+ <listitem>
+ <para>Unset</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effect if unset:</term>
+ <listitem>
+ <para>
+ No external pages are considered trusted referers.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ Before &my-app; accepts configuration changes through CGI pages like
+ <link linkend="client-specific-tag">client-tags</link> or the
+ <link linkend="enable-remote-toggle">remote toggle</link>, it checks
+ the Referer header to see if the request comes from a trusted source.
+ </para>
+ <para>
+ By default only the webinterface domains
+ <ulink url="http://config.privoxy.org/">config.privoxy.org</ulink>
+ and
+ <ulink url="http://p.p/">p.p</ulink>
+ are considered trustworthy.
+ Requests originating from other domains are rejected to prevent
+ third-parties from modifiying Privoxy's state by e.g. embedding
+ images that result in CGI requests.
+ </para>
+ <para>
+ In some environments it may be desirable to embed links to CGI pages
+ on external pages, for example on an Intranet homepage the Privoxy admin
+ controls.
+ </para>
+ <para>
+ The <quote>trusted-cgi-referer</quote> option can be used to add that page,
+ or the whole domain, as trusted source so the resulting requests aren't
+ rejected.
+ Requests are accepted if the specified trusted-cgi-refer is the prefix
+ of the Referer.
+ </para>
+ <para>
+ If the trusted source is supposed to access the CGI pages via
+ JavaScript the <link linkend="cors-allowed-origin">cors-allowed-origin</link>
+ option can be used.
+ </para>
+ <warning>
+ <para>
+ Declaring pages the admin doesn't control trustworthy may allow
+ malicious third parties to modify Privoxy's internal state against
+ the user's wishes and without the user's knowledge.
+ </para>
+ </warning>
+ </listitem>
+ </varlistentry>
+</variablelist>
+
+<![%config-file;[<literallayout>@@#trusted-cgi-referer http://www.example.org/local-privoxy-control-page</literallayout>]]>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="cors-allowed-origin"><title>cors-allowed-origin</title>
+<variablelist>
+ <varlistentry>
+ <term>Specifies:</term>
+ <listitem>
+ <para>
+ A trusted website which can access &my-app;'s CGI pages through JavaScript.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Type of value:</term>
+ <listitem>
+ <para>URL</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Default value:</term>
+ <listitem>
+ <para>Unset</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effect if unset:</term>
+ <listitem>
+ <para>
+ No external sites get access via cross-origin resource sharing.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ Modern browsers by default prevent cross-origin requests made
+ via JavaScript to &my-app;'s CGI interface even if &my-app;
+ would trust the referer because it's white listed via the
+ <link linkend="trusted-cgi-referer">trusted-cgi-referer</link>
+ directive.
+ </para>
+ <para>
+ <ulink url="https://en.wikipedia.org/wiki/Cross-origin_resource_sharing"
+ >Cross-origin resource sharing (CORS)</ulink> is a mechanism to allow
+ cross-origin requests.
+ </para>
+ <para>
+ The <quote>cors-allowed-origin</quote> option can be used to specify
+ a domain that is allowed to make requests to Privoxy CGI interface
+ via JavaScript. It is used in combination with the
+ <link linkend="trusted-cgi-referer">trusted-cgi-referer</link>
+ directive.
+ </para>
+ <warning>
+ <para>
+ Declaring domains the admin doesn't control trustworthy may allow
+ malicious third parties to modify Privoxy's internal state against
+ the user's wishes and without the user's knowledge.
+ </para>
+ </warning>
+ </listitem>
+ </varlistentry>
+</variablelist>
+
+<![%config-file;[<literallayout>@@#cors-allowed-origin http://www.example.org/</literallayout>]]>
+</sect3>
+
+</sect2>
+
+<!-- ~ End section ~ -->
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+
+<sect2 id="forwarding">
+<title>Forwarding</title>
+
+<para>
+ This feature allows routing of HTTP requests through a chain of
+ multiple proxies.
+</para>
+<para>
+ Forwarding can be used to chain Privoxy with a caching proxy to speed
+ up browsing. Using a parent proxy may also be necessary if the machine
+ that <application>Privoxy</application> runs on has no direct Internet access.
+</para>
+<para>
+ Note that parent proxies can severely decrease your privacy level.
+ For example a parent proxy could add your IP address to the request
+ headers and if it's a caching proxy it may add the <quote>Etag</quote>
+ header to revalidation requests again, even though you configured Privoxy
+ to remove it. It may also ignore Privoxy's header time randomization and use the
+ original values which could be used by the server as cookie replacement
+ to track your steps between visits.
+</para>
+
+<para>
+ Also specified here are SOCKS proxies. <application>Privoxy</application>
+ supports the SOCKS 4 and SOCKS 4A protocols.
+</para>
+
+<sect3 renderas="sect4" id="forward"><title>forward</title>
+<variablelist>
+ <varlistentry>
+ <term>Specifies:</term>
+ <listitem>
+ <para>
+ To which parent HTTP proxy specific requests should be routed.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Type of value:</term>
+ <listitem>
+ <para>
+ <replaceable class="parameter">target_pattern</replaceable>
+ <replaceable class="parameter">http_parent</replaceable>[:<replaceable class="parameter">port</replaceable>]
+ </para>
+ <para>
+ where <replaceable class="parameter">target_pattern</replaceable> is a <link linkend="af-patterns">URL pattern</link>
+ that specifies to which requests (i.e. URLs) this forward rule shall apply. Use <literal>/</literal> to
+ denote <quote>all URLs</quote>.
+ <replaceable class="parameter">http_parent</replaceable>[:<replaceable class="parameter">port</replaceable>]
+ is the DNS name or IP address of the parent HTTP proxy through which the requests should be forwarded,
+ optionally followed by its listening port (default: 8000).
+ Use a single dot (<literal>.</literal>) to denote <quote>no forwarding</quote>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Default value:</term>
+ <listitem>
+ <para><emphasis>Unset</emphasis></para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effect if unset:</term>
+ <listitem>
+ <para>
+ Don't use parent HTTP proxies.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ If <replaceable class="parameter">http_parent</replaceable> is <quote>.</quote>, then requests are not
+ forwarded to another HTTP proxy but are made directly to the web servers.
+ </para>
+ <para>
+ <replaceable class="parameter">http_parent</replaceable> can be a
+ numerical IPv6 address (if
+ <ulink url="http://tools.ietf.org/html/rfc3493">RFC 3493</ulink> is
+ implemented). To prevent clashes with the port delimiter, the whole IP
+ address has to be put into brackets. On the other hand a <replaceable
+ class="parameter">target_pattern</replaceable> containing an IPv6 address
+ has to be put into angle brackets (normal brackets are reserved for
+ regular expressions already).
+ </para>
+ <para>
+ Multiple lines are OK, they are checked in sequence, and the last match wins.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Examples:</term>
+ <listitem>
+ <para>
+ Everything goes to an example parent proxy, except SSL on port 443 (which it doesn't handle):
+ </para>
+ <screen>
+ forward / parent-proxy.example.org:8080
+ forward :443 .
+</screen>
+ <para>
+ Everything goes to our example ISP's caching proxy, except for requests
+ to that ISP's sites:
+ </para>
+ <screen>
+ forward / caching-proxy.isp.example.net:8000
+ forward .isp.example.net .
+</screen>
+ <para>
+ Parent proxy specified by an IPv6 address:
+ </para>
+ <programlisting>
+ forward / [2001:DB8::1]:8000
+</programlisting>
+ <para>
+ Suppose your parent proxy doesn't support IPv6:
+ </para>
+ <programlisting>
+ forward / parent-proxy.example.org:8000
+ forward ipv6-server.example.org .
+ forward <[2-3][0-9a-f][0-9a-f][0-9a-f]:*> .
+</programlisting>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="socks"><title>
+forward-socks4, forward-socks4a, forward-socks5 and forward-socks5t</title>
+<anchor id="forward-socks4">
+<anchor id="forward-socks4a">
+
+<variablelist>
+ <varlistentry>
+ <term>Specifies:</term>
+ <listitem>
+ <para>
+ Through which SOCKS proxy (and optionally to which parent HTTP proxy) specific requests should be routed.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Type of value:</term>
+ <listitem>
+ <para>
+ <replaceable class="parameter">target_pattern</replaceable>
+ [<replaceable class="parameter">user</replaceable>:<replaceable class="parameter">pass</replaceable>@]<replaceable class="parameter">socks_proxy</replaceable>[:<replaceable class="parameter">port</replaceable>]
+ <replaceable class="parameter">http_parent</replaceable>[:<replaceable class="parameter">port</replaceable>]
+ </para>
+ <para>
+ where <replaceable class="parameter">target_pattern</replaceable> is a
+ <link linkend="af-patterns">URL pattern</link> that specifies to which
+ requests (i.e. URLs) this forward rule shall apply. Use <literal>/</literal> to
+ denote <quote>all URLs</quote>. <replaceable class="parameter">http_parent</replaceable>
+ and <replaceable class="parameter">socks_proxy</replaceable>
+ are IP addresses in dotted decimal notation or valid DNS names
+ (<replaceable class="parameter">http_parent</replaceable>
+ may be <quote>.</quote> to denote <quote>no HTTP forwarding</quote>), and the optional
+ <replaceable class="parameter">port</replaceable> parameters are TCP ports,
+ i.e. integer values from 1 to 65535. <replaceable class="parameter">user</replaceable> and
+ <replaceable class="parameter">pass</replaceable> can be used for SOCKS5 authentication if required.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Default value:</term>
+ <listitem>
+ <para><emphasis>Unset</emphasis></para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effect if unset:</term>
+ <listitem>
+ <para>
+ Don't use SOCKS proxies.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ Multiple lines are OK, they are checked in sequence, and the last match wins.
+ </para>
+ <para>
+ The difference between <literal>forward-socks4</literal> and <literal>forward-socks4a</literal>
+ is that in the SOCKS 4A protocol, the DNS resolution of the target hostname happens on the SOCKS
+ server, while in SOCKS 4 it happens locally.
+ </para>
+ <para>
+ With <literal>forward-socks5</literal> the DNS resolution will happen on the remote server as well.
+ </para>
+ <para>
+ <literal>forward-socks5t</literal> works like vanilla <literal>forward-socks5</literal> but
+ lets &my-app; additionally use Tor-specific SOCKS extensions. Currently the only supported
+ SOCKS extension is optimistic data which can reduce the latency for the first request made
+ on a newly created connection.
+ </para>
+ <para>
+ <replaceable class="parameter">socks_proxy</replaceable> and
+ <replaceable class="parameter">http_parent</replaceable> can be a
+ numerical IPv6 address (if
+ <ulink url="http://tools.ietf.org/html/rfc3493">RFC 3493</ulink> is
+ implemented). To prevent clashes with the port delimiter, the whole IP
+ address has to be put into brackets. On the other hand a <replaceable
+ class="parameter">target_pattern</replaceable> containing an IPv6 address
+ has to be put into angle brackets (normal brackets are reserved for
+ regular expressions already).
+ </para>
+ <para>
+ If <replaceable class="parameter">http_parent</replaceable> is <quote>.</quote>, then requests are not
+ forwarded to another HTTP proxy but are made (HTTP-wise) directly to the web servers, albeit through
+ a SOCKS proxy.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Examples:</term>
+ <listitem>
+ <para>
+ From the company example.com, direct connections are made to all
+ <quote>internal</quote> domains, but everything outbound goes through
+ their ISP's proxy by way of example.com's corporate SOCKS 4A gateway to
+ the Internet.
+ </para>
+ <screen>
+ forward-socks4a / socks-gw.example.com:1080 www-cache.isp.example.net:8080
+ forward .example.com .
+</screen>
+ <para>
+ A rule that uses a SOCKS 4 gateway for all destinations but no HTTP parent looks like this:
+ </para>
+ <screen>
+ forward-socks4 / socks-gw.example.com:1080 .
+</screen>
+
+ <para>
+ To connect SOCKS5 proxy which requires username/password authentication:
+ </para>
+ <screen>
+ forward-socks5 / user:pass@socks-gw.example.com:1080 .
+</screen>
+
+ <para>
+ To chain Privoxy and Tor, both running on the same system, you would use
+ something like:
+ </para>
+ <screen>
+ forward-socks5t / 127.0.0.1:9050 .
+</screen>
+ <para>
+ Note that if you got Tor through one of the bundles, you may
+ have to change the port from 9050 to 9150 (or even another one).
+ For details, please check the documentation on the
+ <ulink url="https://torproject.org/">Tor website</ulink>.
+ </para>
+ <para>
+ The public <application>Tor</application> network can't be used to
+ reach your local network, if you need to access local servers you
+ therefore might want to make some exceptions:
+ </para>
+ <screen>
+ forward 192.168.*.*/ .
+ forward 10.*.*.*/ .
+ forward 127.*.*.*/ .
+</screen>
+ <para>
+ Unencrypted connections to systems in these address ranges will
+ be as (un)secure as the local network is, but the alternative is that you
+ can't reach the local network through <application>Privoxy</application>
+ at all. Of course this may actually be desired and there is no reason
+ to make these exceptions if you aren't sure you need them.
+ </para>
+ <para>
+ If you also want to be able to reach servers in your local network by
+ using their names, you will need additional exceptions that look like
+ this:
+ </para>
+ <screen>
+ forward localhost/ .
+</screen>
+
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+<![%user-man;[ <!-- not included in config due to length -->
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="advanced-forwarding-examples"><title>Advanced Forwarding Examples</title>
+
+<para>
+ If you have links to multiple ISPs that provide various special content
+ only to their subscribers, you can configure multiple <application>Privoxies</application>
+ which have connections to the respective ISPs to act as forwarders to each other, so that
+ <emphasis>your</emphasis> users can see the internal content of all ISPs.
+</para>
+
+<para>
+ Assume that host-a has a PPP connection to isp-a.example.net. And host-b has a PPP connection to
+ isp-b.example.org. Both run <application>Privoxy</application>. Their forwarding
+ configuration can look like this:
+</para>
+
+<para>
+ host-a:
+</para>
+
+ <screen>
+ forward / .
+ forward .isp-b.example.net host-b:8118
+</screen>
+
+<para>
+ host-b:
+</para>
+
+ <screen>
+ forward / .
+ forward .isp-a.example.org host-a:8118
+</screen>
+
+<para>
+ Now, your users can set their browser's proxy to use either
+ host-a or host-b and be able to browse the internal content
+ of both isp-a and isp-b.
+</para>
+
+<para>
+ If you intend to chain <application>Privoxy</application> and
+ <application>squid</application> locally, then chaining as
+ <literal>browser -> squid -> privoxy</literal> is the recommended way.
+</para>
+
+<para>
+ Assuming that <application>Privoxy</application> and <application>squid</application>
+ run on the same box, your <application>squid</application> configuration could then look like this:
+</para>
+
+ <screen>
+ # Define Privoxy as parent proxy (without ICP)
+ cache_peer 127.0.0.1 parent 8118 7 no-query
+
+ # Define ACL for protocol FTP
+ acl ftp proto FTP
+
+ # Do not forward FTP requests to Privoxy
+ always_direct allow ftp
+
+ # Forward all the rest to Privoxy
+ never_direct allow all</screen>
+
+<para>
+ You would then need to change your browser's proxy settings to <application>squid</application>'s address and port.
+ Squid normally uses port 3128. If unsure consult <literal>http_port</literal> in <filename>squid.conf</filename>.
+</para>
+
+<para>
+ You could just as well decide to only forward requests you suspect
+ of leading to Windows executables through a virus-scanning parent proxy,
+ say, on <literal>antivir.example.com</literal>, port 8010:
+</para>
+
+ <screen>
+ forward / .
+ forward /.*\.(exe|com|dll|zip)$ antivir.example.com:8010</screen>
+
+</sect3>
+]]>
+
+<sect3 renderas="sect4" id="forwarded-connect-retries"><title>forwarded-connect-retries</title>
+<variablelist>
+ <varlistentry>
+ <term>Specifies:</term>
+ <listitem>
+ <para>
+ How often Privoxy retries if a forwarded connection request fails.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Type of value:</term>
+ <listitem>
+ <para>
+ <replaceable class="parameter">Number of retries.</replaceable>
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Default value:</term>
+ <listitem>
+ <para><emphasis>0</emphasis></para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effect if unset:</term>
+ <listitem>
+ <para>
+ Connections forwarded through other proxies are treated like direct connections and no retry attempts are made.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ <replaceable class="parameter">forwarded-connect-retries</replaceable> is mainly interesting
+ for socks4a connections, where <application>Privoxy</application> can't detect why the connections failed.
+ The connection might have failed because of a DNS timeout in which case a retry makes sense,
+ but it might also have failed because the server doesn't exist or isn't reachable. In this
+ case the retry will just delay the appearance of Privoxy's error message.
+ </para>
+ <para>
+ Note that in the context of this option, <quote>forwarded connections</quote> includes all connections
+ that Privoxy forwards through other proxies. This option is not limited to the HTTP CONNECT method.
+ </para>
+ <para>
+ Only use this option, if you are getting lots of forwarding-related error messages
+ that go away when you try again manually. Start with a small value and check Privoxy's
+ logfile from time to time, to see how many retries are usually needed.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Examples:</term>
+ <listitem>
+ <para>
+ forwarded-connect-retries 1
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+<![%config-file;[<literallayout>@@forwarded-connect-retries 0</literallayout>]]>
+</sect3>
+
+</sect2>
+
+<sect2 id="misc">
+<title>Miscellaneous</title>
+
+<sect3 renderas="sect4" id="accept-intercepted-requests"><title>accept-intercepted-requests</title>
+<variablelist>
+ <varlistentry>
+ <term>Specifies:</term>
+ <listitem>
+ <para>
+ Whether intercepted requests should be treated as valid.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Type of value:</term>
+ <listitem>
+ <para>
+ <replaceable>0 or 1</replaceable>
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Default value:</term>
+ <listitem>
+ <para><emphasis>0</emphasis></para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effect if unset:</term>
+ <listitem>
+ <para>
+ Only proxy requests are accepted, intercepted requests are treated as invalid.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ If you don't trust your clients and want to force them
+ to use <application>Privoxy</application>, enable this
+ option and configure your packet filter to redirect outgoing
+ HTTP connections into <application>Privoxy</application>.
+ </para>
+ <para>
+ Note that intercepting encrypted connections (HTTPS) isn't supported.
+ </para>
+ <para>
+ Make sure that <application>Privoxy's</application> own requests
+ aren't redirected as well. Additionally take care that
+ <application>Privoxy</application> can't intentionally connect
+ to itself, otherwise you could run into redirection loops if
+ <application>Privoxy's</application> listening port is reachable
+ by the outside or an attacker has access to the pages you visit.
+ </para>
+ <para>
+ If you are running Privoxy as intercepting proxy without being
+ able to intercept all client requests you may want to adjust
+ the CGI templates to make sure they don't reference content from
+ config.privoxy.org.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Examples:</term>
+ <listitem>
+ <para>
+ accept-intercepted-requests 1
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+<![%config-file;[<literallayout>@@accept-intercepted-requests 0</literallayout>]]>
+</sect3>
+
+<sect3 renderas="sect4" id="allow-cgi-request-crunching"><title>allow-cgi-request-crunching</title>
+<variablelist>
+ <varlistentry>
+ <term>Specifies:</term>
+ <listitem>
+ <para>
+ Whether requests to <application>Privoxy's</application> CGI pages can be blocked or redirected.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Type of value:</term>
+ <listitem>
+ <para>
+ <replaceable>0 or 1</replaceable>
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Default value:</term>
+ <listitem>
+ <para><emphasis>0</emphasis></para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effect if unset:</term>
+ <listitem>
+ <para>
+ <application>Privoxy</application> ignores block and redirect actions for its CGI pages.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ By default <application>Privoxy</application> ignores block or redirect actions
+ for its CGI pages. Intercepting these requests can be useful in multi-user
+ setups to implement fine-grained access control, but it can also render the complete
+ web interface useless and make debugging problems painful if done without care.
+ </para>
+ <para>
+ Don't enable this option unless you're sure that you really need it.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Examples:</term>
+ <listitem>
+ <para>
+ allow-cgi-request-crunching 1
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+<![%config-file;[<literallayout>@@allow-cgi-request-crunching 0</literallayout>]]>
+</sect3>
+
+<sect3 renderas="sect4" id="split-large-forms"><title>split-large-forms</title>
+<variablelist>
+ <varlistentry>
+ <term>Specifies:</term>
+ <listitem>
+ <para>
+ Whether the CGI interface should stay compatible with broken HTTP clients.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Type of value:</term>
+ <listitem>
+ <para>
+ <replaceable>0 or 1</replaceable>
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Default value:</term>
+ <listitem>
+ <para><emphasis>0</emphasis></para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effect if unset:</term>
+ <listitem>
+ <para>
+ The CGI form generate long GET URLs.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ <application>Privoxy's</application> CGI forms can lead to
+ rather long URLs. This isn't a problem as far as the HTTP
+ standard is concerned, but it can confuse clients with arbitrary
+ URL length limitations.
+ </para>
+ <para>
+ Enabling split-large-forms causes <application>Privoxy</application>
+ to divide big forms into smaller ones to keep the URL length down.
+ It makes editing a lot less convenient and you can no longer
+ submit all changes at once, but at least it works around this
+ browser bug.
+ </para>
+ <para>
+ If you don't notice any editing problems, there is no reason
+ to enable this option, but if one of the submit buttons appears
+ to be broken, you should give it a try.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Examples:</term>
+ <listitem>
+ <para>
+ split-large-forms 1
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+<![%config-file;[<literallayout>@@split-large-forms 0</literallayout>]]>
+</sect3>
+
+<sect3 renderas="sect4" id="keep-alive-timeout"><title>keep-alive-timeout</title>
+<variablelist>
+ <varlistentry>
+ <term>Specifies:</term>
+ <listitem>
+ <para>
+ Number of seconds after which an open connection will no longer be reused.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Type of value:</term>
+ <listitem>
+ <para>
+ <replaceable>Time in seconds.</replaceable>
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Default value:</term>
+ <listitem>
+ <para>None</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effect if unset:</term>
+ <listitem>
+ <para>
+ Connections are not kept alive.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ This option allows clients to keep the connection to &my-app;
+ alive. If the server supports it, &my-app; will keep
+ the connection to the server alive as well. Under certain
+ circumstances this may result in speed-ups.
+ </para>
+ <para>
+ By default, &my-app; will close the connection to the server if
+ the client connection gets closed, or if the specified timeout
+ has been reached without a new request coming in. This behaviour
+ can be changed with the <ulink
+ url="#CONNECTION-SHARING">connection-sharing</ulink> option.
+ </para>
+ <para>
+ This option has no effect if <application>Privoxy</application>
+ has been compiled without keep-alive support.
+ </para>
+ <para>
+ Note that a timeout of five seconds as used in the default
+ configuration file significantly decreases the number of
+ connections that will be reused. The value is used because
+ some browsers limit the number of connections they open to
+ a single host and apply the same limit to proxies. This can
+ result in a single website <quote>grabbing</quote> all the
+ connections the browser allows, which means connections to
+ other websites can't be opened until the connections currently
+ in use time out.
+ </para>
+ <para>
+ Several users have reported this as a Privoxy bug, so the
+ default value has been reduced. Consider increasing it to
+ 300 seconds or even more if you think your browser can handle
+ it. If your browser appears to be hanging, it probably can't.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Examples:</term>
+ <listitem>
+ <para>
+ keep-alive-timeout 300
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+<![%config-file;[<literallayout>@@keep-alive-timeout 5</literallayout>]]>
+</sect3>
+
+
+<sect3 renderas="sect4" id="tolerate-pipelining"><title>tolerate-pipelining</title>
+<variablelist>
+ <varlistentry>
+ <term>Specifies:</term>
+ <listitem>
+ <para>
+ Whether or not pipelined requests should be served.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Type of value:</term>
+ <listitem>
+ <para>
+ <replaceable>0 or 1.</replaceable>
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Default value:</term>
+ <listitem>
+ <para>None</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effect if unset:</term>
+ <listitem>
+ <para>
+ If Privoxy receives more than one request at once, it terminates the
+ client connection after serving the first one.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ &my-app; currently doesn't pipeline outgoing requests,
+ thus allowing pipelining on the client connection is not
+ guaranteed to improve the performance.
+ </para>
+ <para>
+ By default &my-app; tries to discourage clients from pipelining
+ by discarding aggressively pipelined requests, which forces the
+ client to resend them through a new connection.
+ </para>
+ <para>
+ This option lets &my-app; tolerate pipelining. Whether or not
+ that improves performance mainly depends on the client configuration.
+ </para>
+ <para>
+ If you are seeing problems with pages not properly loading,
+ disabling this option could work around the problem.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Examples:</term>
+ <listitem>
+ <para>
+ tolerate-pipelining 1
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+<![%config-file;[<literallayout>@@tolerate-pipelining 1</literallayout>]]>
+</sect3>
+
+
+<sect3 renderas="sect4" id="default-server-timeout"><title>default-server-timeout</title>
+<variablelist>
+ <varlistentry>
+ <term>Specifies:</term>
+ <listitem>
+ <para>
+ Assumed server-side keep-alive timeout if not specified by the server.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Type of value:</term>
+ <listitem>
+ <para>
+ <replaceable>Time in seconds.</replaceable>
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Default value:</term>
+ <listitem>
+ <para>None</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effect if unset:</term>
+ <listitem>
+ <para>
+ Connections for which the server didn't specify the keep-alive
+ timeout are not reused.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ Enabling this option significantly increases the number of connections
+ that are reused, provided the <ulink
+ url="#KEEP-ALIVE-TIMEOUT">keep-alive-timeout</ulink> option
+ is also enabled.
+ </para>
+ <para>
+ While it also increases the number of connections problems
+ when &my-app; tries to reuse a connection that already has
+ been closed on the server side, or is closed while &my-app;
+ is trying to reuse it, this should only be a problem if it
+ happens for the first request sent by the client. If it happens
+ for requests on reused client connections, &my-app; will simply
+ close the connection and the client is supposed to retry the
+ request without bothering the user.
+ </para>
+ <para>
+ Enabling this option is therefore only recommended if the
+ <ulink
+ url="#CONNECTION-SHARING">connection-sharing</ulink> option
+ is disabled.
+ </para>
+ <para>
+ It is an error to specify a value larger than the <ulink
+ url="#KEEP-ALIVE-TIMEOUT">keep-alive-timeout</ulink> value.
+ </para>
+ <para>
+ This option has no effect if <application>Privoxy</application>
+ has been compiled without keep-alive support.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Examples:</term>
+ <listitem>
+ <para>
+ default-server-timeout 60
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+<![%config-file;[<literallayout>@@#default-server-timeout 60</literallayout>]]>
+</sect3>
+
+
+<sect3 renderas="sect4" id="connection-sharing"><title>connection-sharing</title>
+<variablelist>
+ <varlistentry>
+ <term>Specifies:</term>
+ <listitem>
+ <para>
+ Whether or not outgoing connections that have been kept alive
+ should be shared between different incoming connections.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Type of value:</term>
+ <listitem>
+ <para>
+ <replaceable>0 or 1</replaceable>
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Default value:</term>
+ <listitem>
+ <para>None</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effect if unset:</term>
+ <listitem>
+ <para>
+ Connections are not shared.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ This option has no effect if <application>Privoxy</application>
+ has been compiled without keep-alive support, or if it's disabled.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ Note that reusing connections doesn't necessary cause speedups.
+ There are also a few privacy implications you should be aware of.
+ </para>
+ <para>
+ If this option is effective, outgoing connections are shared between
+ clients (if there are more than one) and closing the browser that initiated
+ the outgoing connection does no longer affect the connection between &my-app;
+ and the server unless the client's request hasn't been completed yet.
+ </para>
+ <para>
+ If the outgoing connection is idle, it will not be closed until either
+ <application>Privoxy's</application> or the server's timeout is reached.
+ While it's open, the server knows that the system running &my-app; is still
+ there.
+ </para>
+ <para>
+ If there are more than one client (maybe even belonging to multiple users),
+ they will be able to reuse each others connections. This is potentially
+ dangerous in case of authentication schemes like NTLM where only the
+ connection is authenticated, instead of requiring authentication for
+ each request.
+ </para>
+ <para>
+ If there is only a single client, and if said client can keep connections
+ alive on its own, enabling this option has next to no effect. If the client
+ doesn't support connection keep-alive, enabling this option may make sense
+ as it allows &my-app; to keep outgoing connections alive even if the client
+ itself doesn't support it.
+ </para>
+ <para>
+ You should also be aware that enabling this option increases the likelihood
+ of getting the "No server or forwarder data" error message, especially if you
+ are using a slow connection to the Internet.
+ </para>
+ <para>
+ This option should only be used by experienced users who
+ understand the risks and can weight them against the benefits.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Examples:</term>
+ <listitem>
+ <para>
+ connection-sharing 1
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+<![%config-file;[<literallayout>@@#connection-sharing 1</literallayout>]]>
+</sect3>
+
+
+<sect3 renderas="sect4" id="socket-timeout"><title>socket-timeout</title>
+<variablelist>
+ <varlistentry>
+ <term>Specifies:</term>
+ <listitem>
+ <para>
+ Number of seconds after which a socket times out if
+ no data is received.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Type of value:</term>
+ <listitem>
+ <para>
+ <replaceable>Time in seconds.</replaceable>
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Default value:</term>
+ <listitem>
+ <para>None</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effect if unset:</term>
+ <listitem>
+ <para>
+ A default value of 300 seconds is used.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ The default is quite high and you probably want to reduce it.
+ If you aren't using an occasionally slow proxy like Tor, reducing
+ it to a few seconds should be fine.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Examples:</term>
+ <listitem>
+ <para>
+ socket-timeout 300
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+<![%config-file;[<literallayout>@@socket-timeout 300</literallayout>]]>
+</sect3>
+
+
+<sect3 renderas="sect4" id="max-client-connections"><title>max-client-connections</title>
+<variablelist>
+ <varlistentry>
+ <term>Specifies:</term>
+ <listitem>
+ <para>
+ Maximum number of client connections that will be served.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Type of value:</term>
+ <listitem>
+ <para>
+ <replaceable>Positive number.</replaceable>
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Default value:</term>
+ <listitem>
+ <para>128</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effect if unset:</term>
+ <listitem>
+ <para>
+ Connections are served until a resource limit is reached.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ &my-app; creates one thread (or process) for every incoming client
+ connection that isn't rejected based on the access control settings.
+ </para>
+ <para>
+ If the system is powerful enough, &my-app; can theoretically deal with
+ several hundred (or thousand) connections at the same time, but some
+ operating systems enforce resource limits by shutting down offending
+ processes and their default limits may be below the ones &my-app; would
+ require under heavy load.
+ </para>
+ <para>
+ Configuring &my-app; to enforce a connection limit below the thread
+ or process limit used by the operating system makes sure this doesn't
+ happen. Simply increasing the operating system's limit would work too,
+ but if &my-app; isn't the only application running on the system,
+ you may actually want to limit the resources used by &my-app;.
+ </para>
+ <para>
+ If &my-app; is only used by a single trusted user, limiting the
+ number of client connections is probably unnecessary. If there
+ are multiple possibly untrusted users you probably still want to
+ additionally use a packet filter to limit the maximal number of
+ incoming connections per client. Otherwise a malicious user could
+ intentionally create a high number of connections to prevent other
+ users from using &my-app;.
+ </para>
+ <para>
+ Obviously using this option only makes sense if you choose a limit
+ below the one enforced by the operating system.
+ </para>
+ <para>
+ One most POSIX-compliant systems &my-app; can't properly deal with
+ more than FD_SETSIZE file descriptors at the same time and has to reject
+ connections if the limit is reached. This will likely change in a
+ future version, but currently this limit can't be increased without
+ recompiling &my-app; with a different FD_SETSIZE limit.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Examples:</term>
+ <listitem>
+ <para>
+ max-client-connections 256
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+<![%config-file;[<literallayout>@@#max-client-connections 256</literallayout>]]>
+</sect3>
+
+
+<sect3 renderas="sect4" id="listen-backlog"><title>listen-backlog</title>
+<variablelist>
+ <varlistentry>
+ <term>Specifies:</term>
+ <listitem>
+ <para>
+ Connection queue length requested from the operating system.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Type of value:</term>
+ <listitem>
+ <para>
+ <replaceable>Number.</replaceable>
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Default value:</term>
+ <listitem>
+ <para>128</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effect if unset:</term>
+ <listitem>
+ <para>
+ A connection queue length of 128 is requested from the operating system.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ Under high load incoming connection may queue up before Privoxy
+ gets around to serve them. The queue length is limitted by the
+ operating system. Once the queue is full, additional connections
+ are dropped before Privoxy can accept and serve them.
+ </para>
+ <para>
+ Increasing the queue length allows Privoxy to accept more
+ incomming connections that arrive roughly at the same time.
+ </para>
+ <para>
+ Note that Privoxy can only request a certain queue length,
+ whether or not the requested length is actually used depends
+ on the operating system which may use a different length instead.
+ </para>
+ <para>
+ On many operating systems a limit of -1 can be specified to
+ instruct the operating system to use the maximum queue length
+ allowed. Check the listen man page to see if your platform allows this.
+ </para>
+ <para>
+ On some platforms you can use "netstat -Lan -p tcp" to see the effective
+ queue length.
+ </para>
+ <para>
+ Effectively using a value above 128 usually requires changing
+ the system configuration as well. On FreeBSD-based system the
+ limit is controlled by the kern.ipc.soacceptqueue sysctl.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Examples:</term>
+ <listitem>
+ <para>
+ listen-backlog 4096
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+<![%config-file;[<literallayout>@@#listen-backlog -1</literallayout>]]>
+</sect3>
+
+
+<sect3 renderas="sect4" id="enable-accept-filter"><title>enable-accept-filter</title>
+<variablelist>
+ <varlistentry>
+ <term>Specifies:</term>
+ <listitem>
+ <para>
+ Whether or not Privoxy should use an accept filter
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Type of value:</term>
+ <listitem>
+ <para>
+ <replaceable>0 or 1</replaceable>
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Default value:</term>
+ <listitem>
+ <para>0</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effect if unset:</term>
+ <listitem>
+ <para>
+ No accept filter is enabled.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ Accept filters reduce the number of context switches by not
+ passing sockets for new connections to Privoxy until a complete
+ HTTP request is available.
+ </para>
+ <para>
+ As a result, Privoxy can process the whole request right away
+ without having to wait for additional data first.
+ </para>
+ <para>
+ For this option to work, Privoxy has to be compiled with
+ FEATURE_ACCEPT_FILTER and the operating system has to support
+ it (which may require loading a kernel module).
+ </para>
+ <para>
+ Currently accept filters are only supported on FreeBSD-based
+ systems. Check the
+ <ulink url="https://www.freebsd.org/cgi/man.cgi?query=accf_http">accf_http(9)
+ man page</ulink>
+ to learn how to enable the support in the operating system.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Examples:</term>
+ <listitem>
+ <para>
+ enable-accept-filter 1
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+<![%config-file;[<literallayout>@@#enable-accept-filter 1</literallayout>]]>
+</sect3>
+
+
+<sect3 renderas="sect4" id="handle-as-empty-doc-returns-ok"><title>handle-as-empty-doc-returns-ok</title>
+<variablelist>
+ <varlistentry>
+ <term>Specifies:</term>
+ <listitem>
+ <para>
+ The status code Privoxy returns for pages blocked with
+ <!-- URL will only end up in the user manual so the relative link should work. -->
+ <literal><ulink url="actions-file.html#HANDLE-AS-EMPTY-DOCUMENT">+handle-as-empty-document</ulink></literal>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Type of value:</term>
+ <listitem>
+ <para>
+ <replaceable>0 or 1</replaceable>
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Default value:</term>
+ <listitem>
+ <para>0</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effect if unset:</term>
+ <listitem>
+ <para>
+ Privoxy returns a status 403(forbidden) for all blocked pages.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effect if set:</term>
+ <listitem>
+ <para>
+ Privoxy returns a status 200(OK) for pages blocked with +handle-as-empty-document
+ and a status 403(Forbidden) for all other blocked pages.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ This directive was added as a work-around for Firefox bug 492459:
+ <quote>Websites are no longer rendered if SSL requests for JavaScripts are blocked by a proxy.</quote>
+ (<ulink url="https://bugzilla.mozilla.org/show_bug.cgi?id=492459">
+ https://bugzilla.mozilla.org/show_bug.cgi?id=492459</ulink>),
+ the bug has been fixed for quite some time, but this directive is also useful
+ to make it harder for websites to detect whether or not resources are being
+ blocked.
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+<![%config-file;[<literallayout>@@#handle-as-empty-doc-returns-ok 1</literallayout>]]>
+</sect3>
+
+
+<sect3 renderas="sect4" id="enable-compression"><title>enable-compression</title>
+<variablelist>
+ <varlistentry>
+ <term>Specifies:</term>
+ <listitem>
+ <para>
+ Whether or not buffered content is compressed before delivery.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Type of value:</term>
+ <listitem>
+ <para>
+ <replaceable>0 or 1</replaceable>
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Default value:</term>
+ <listitem>
+ <para>0</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effect if unset:</term>
+ <listitem>
+ <para>
+ Privoxy does not compress buffered content.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effect if set:</term>
+ <listitem>
+ <para>
+ Privoxy compresses buffered content before delivering it to the client,
+ provided the client supports it.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ This directive is only supported if Privoxy has been compiled with
+ FEATURE_COMPRESSION, which should not to be confused with FEATURE_ZLIB.
+ </para>
+ <para>
+ Compressing buffered content is mainly useful if Privoxy and the
+ client are running on different systems. If they are running on the
+ same system, enabling compression is likely to slow things down.
+ If you didn't measure otherwise, you should assume that it does
+ and keep this option disabled.
+ </para>
+ <para>
+ Privoxy will not compress buffered content below a certain length.
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+<![%config-file;[<literallayout>@@#enable-compression 1</literallayout>]]>
+</sect3>
+
+
+<sect3 renderas="sect4" id="compression-level"><title>compression-level</title>
+<variablelist>
+ <varlistentry>
+ <term>Specifies:</term>
+ <listitem>
+ <para>
+ The compression level that is passed to the zlib library when compressing buffered content.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Type of value:</term>
+ <listitem>
+ <para>
+ <replaceable>Positive number ranging from 0 to 9.</replaceable>
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Default value:</term>
+ <listitem>
+ <para>1</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ Compressing the data more takes usually longer than compressing
+ it less or not compressing it at all. Which level is best depends
+ on the connection between Privoxy and the client. If you can't
+ be bothered to benchmark it for yourself, you should stick with
+ the default and keep compression disabled.
+ </para>
+ <para>
+ If compression is disabled, the compression level is irrelevant.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Examples:</term>
+ <listitem>
+ <screen>
+ # Best speed (compared to the other levels)
+ compression-level 1
+
+ # Best compression
+ compression-level 9
+
+ # No compression. Only useful for testing as the added header
+ # slightly increases the amount of data that has to be sent.
+ # If your benchmark shows that using this compression level
+ # is superior to using no compression at all, the benchmark
+ # is likely to be flawed.
+ compression-level 0
+</screen>
+ </listitem>
+ </varlistentry>
+</variablelist>
+<![%config-file;[<literallayout>@@#compression-level 1</literallayout>]]>
+</sect3>
+
+
+<sect3 renderas="sect4" id="client-header-order"><title>client-header-order</title>
+<variablelist>
+ <varlistentry>
+ <term>Specifies:</term>
+ <listitem>
+ <para>
+ The order in which client headers are sorted before forwarding them.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Type of value:</term>
+ <listitem>
+ <para>
+ <replaceable>Client header names delimited by spaces or tabs</replaceable>
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Default value:</term>
+ <listitem>
+ <para>None</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ By default &my-app; leaves the client headers in the order they
+ were sent by the client. Headers are modified in-place, new headers
+ are added at the end of the already existing headers.
+ </para>
+ <para>
+ The header order can be used to fingerprint client requests
+ independently of other headers like the User-Agent.
+ </para>
+ <para>
+ This directive allows to sort the headers differently to better
+ mimic a different User-Agent. Client headers will be emitted
+ in the order given, headers whose name isn't explicitly specified
+ are added at the end.
+ </para>
+ <para>
+ Note that sorting headers in an uncommon way will make fingerprinting
+ actually easier. Encrypted headers are not affected by this directive.
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+<![%config-file;[<literallayout>@@#client-header-order Host \
+ User-Agent \
+ Accept \
+ Accept-Language \
+ Accept-Encoding \
+ Proxy-Connection \
+ Referer \
+ Cookie \
+ DNT \
+ If-Modified-Since \
+ Cache-Control \
+ Content-Length \
+ Content-Type
+</literallayout>]]>
+</sect3>
+
+
+<sect3 renderas="sect4" id="client-specific-tag"><title>client-specific-tag</title>
+<variablelist>
+ <varlistentry>
+ <term>Specifies:</term>
+ <listitem>
+ <para>
+ The name of a tag that will always be set for clients that
+ requested it through the webinterface.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Type of value:</term>
+ <listitem>
+ <para>
+ <replaceable>Tag name followed by a description that will be shown in the webinterface</replaceable>
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Default value:</term>
+ <listitem>
+ <para>None</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <warning>
+ <para>
+ This is an experimental feature. The syntax is likely to change
+ in future versions.
+ </para>
+ </warning>
+ <para>
+ Client-specific tags allow Privoxy admins to create different
+ profiles and let the users chose which one they want without
+ impacting other users.
+ </para>
+ <para>
+ One use case is allowing users to circumvent certain blocks
+ without having to allow them to circumvent all blocks.
+ This is not possible with the
+ <link linkend="enable-remote-toggle">enable-remote-toggle feature</link>
+ because it would bluntly disable all blocks for all users and also affect
+ other actions like filters.
+ It also is set globally which renders it useless in most multi-user setups.
+ </para>
+ <para>
+ After a client-specific tag has been defined with the client-specific-tag
+ directive, action sections can be activated based on the tag by using a
+ <ulink url="actions-file.html#CLIENT-TAG-PATTERN">CLIENT-TAG</ulink> pattern.
+ The CLIENT-TAG pattern is evaluated at the same priority
+ as URL patterns, as a result the last matching pattern wins.
+ Tags that are created based on client or server headers are evaluated
+ later on and can overrule CLIENT-TAG and URL patterns!
+ </para>
+ <para>
+ The tag is set for all requests that come from clients that requested
+ it to be set.
+ Note that "clients" are differentiated by IP address,
+ if the IP address changes the tag has to be requested again.
+ </para>
+ <para>
+ Clients can request tags to be set by using the CGI interface <ulink
+ url="http://config.privoxy.org/client-tags">http://config.privoxy.org/client-tags</ulink>.
+ The specific tag description is only used on the web page and should
+ be phrased in away that the user understand the effect of the tag.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Examples:</term>
+ <listitem>
+ <screen>
+ # Define a couple of tags, the described effect requires action sections
+ # that are enabled based on CLIENT-TAG patterns.
+ client-specific-tag circumvent-blocks Overrule blocks but do not affect other actions
+ disable-content-filters Disable content-filters but do not affect other actions
+</screen>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+<!-- ~ End section ~ -->
+
+<sect3 renderas="sect4" id="client-tag-lifetime"><title>client-tag-lifetime</title>
+<variablelist>
+ <varlistentry>
+ <term>Specifies:</term>
+ <listitem>
+ <para>
+ How long a temporarily enabled tag remains enabled.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Type of value:</term>
+ <listitem>
+ <para>
+ <replaceable>Time in seconds.</replaceable>
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Default value:</term>
+ <listitem>
+ <para>60</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <warning>
+ <para>
+ This is an experimental feature. The syntax is likely to change
+ in future versions.
+ </para>
+ </warning>
+ <para>
+ In case of some tags users may not want to enable them permanently,
+ but only for a short amount of time, for example to circumvent a block
+ that is the result of an overly-broad URL pattern.
+ </para>
+ <para>
+ The CGI interface <ulink
+ url="http://config.privoxy.org/client-tags">http://config.privoxy.org/client-tags</ulink>
+ therefore provides a "enable this tag temporarily" option.
+ If it is used, the tag will be set until the client-tag-lifetime
+ is over.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Examples:</term>
+ <listitem>
+ <screen>
+ # Increase the time to life for temporarily enabled tags to 3 minutes
+ client-tag-lifetime 180
+</screen>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+<!-- ~ End section ~ -->
+
+<sect3 renderas="sect4" id="trust-x-forwarded-for"><title>trust-x-forwarded-for</title>
+<variablelist>
+ <varlistentry>
+ <term>Specifies:</term>
+ <listitem>
+ <para>
+ Whether or not Privoxy should use IP addresses specified with the X-Forwarded-For header
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Type of value:</term>
+ <listitem>
+ <para>
+ <replaceable>0 or one</replaceable>
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Default value:</term>
+ <listitem>
+ <para>0</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <warning>
+ <para>
+ This is an experimental feature. The syntax is likely to change
+ in future versions.
+ </para>
+ </warning>
+ <para>
+ If clients reach Privoxy through another proxy, for example a load
+ balancer, Privoxy can't tell the client's IP address from the connection.
+ If multiple clients use the same proxy, they will share the same
+ client tag settings which is usually not desired.
+ </para>
+ <para>
+ This option lets Privoxy use the X-Forwarded-For header value as
+ client IP address. If the proxy sets the header, multiple clients
+ using the same proxy do not share the same client tag settings.
+ </para>
+ <para>
+ This option should only be enabled if Privoxy can only be reached
+ through a proxy and if the proxy can be trusted to set the header
+ correctly. It is recommended that ACL are used to make sure only
+ trusted systems can reach Privoxy.
+ </para>
+ <para>
+ If access to Privoxy isn't limited to trusted systems, this option
+ would allow malicious clients to change the client tags for other
+ clients or increase Privoxy's memory requirements by registering
+ lots of client tag settings for clients that don't exist.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Examples:</term>
+ <listitem>
+ <screen>
+ # Allow systems that can reach Privoxy to provide the client
+ # IP address with a X-Forwarded-For header.
+ trust-x-forwarded-for 1
+</screen>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+<!-- ~ End section ~ -->
+
+<!-- ~~~~~ New section ~~~~~ -->
+
+<sect3 renderas="sect4" id="receive-buffer-size"><title>receive-buffer-size</title>
+<variablelist>
+ <varlistentry>
+ <term>Specifies:</term>
+ <listitem>
+ <para>
+ The size of the buffer Privoxy uses to receive data from the server.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Type of value:</term>
+ <listitem>
+ <para>
+ <replaceable>Size in bytes</replaceable>
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Default value:</term>
+ <listitem>
+ <para>5000</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ Increasing the receive-buffer-size increases Privoxy's memory usage but
+ can lower the number of context switches and thereby reduce the
+ cpu usage and potentially increase the throughput.
+ </para>
+ <para>
+ This is mostly relevant for fast network connections and
+ large downloads that don't require filtering.
+ </para>
+ <para>
+ Reducing the buffer size reduces the amount of memory Privoxy
+ needs to handle the request but increases the number of systemcalls
+ and may reduce the throughput.
+ </para>
+ <para>
+ A dtrace command like:
+ <quote>sudo dtrace -n 'syscall::read:return /execname == "privoxy"/ { @[execname] = llquantize(arg0, 10, 0, 5, 20); @m = max(arg0)}'</quote>
+ can be used to properly tune the receive-buffer-size.
+ On systems without dtrace, strace or truss may be used as
+ less convenient alternatives.
+ </para>
+ <para>
+ If the buffer is too large it will increase Privoxy's memory
+ footprint without any benefit. As the memory is (currently)
+ cleared before using it, a buffer that is too large can
+ actually reduce the throughput.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Examples:</term>
+ <listitem>
+ <screen>
+ # Increase the receive buffer size
+ receive-buffer-size 32768
+</screen>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+<!-- ~ End section ~ -->
+
+</sect2>
+
+
+<sect2 id="tls">
+<title>TLS/SSL</title>
+
+<!-- ~~~~~ New section ~~~~~ -->
+
+<sect3 renderas="sect4" id="ca-directory"><title>ca-directory</title>
+<variablelist>
+ <varlistentry>
+ <term>Specifies:</term>
+ <listitem>
+ <para>
+ Directory with the CA key, the CA certificate and the trusted CAs file.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Type of value:</term>
+ <listitem>
+ <para>
+ Text
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Default value:</term>
+ <listitem>
+ <para><emphasis>Empty string</emphasis></para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effect if unset:</term>
+ <listitem>
+ <para>
+ Default value is used.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ This directive specifies the directory where the
+ CA key, the CA certificate and the trusted CAs file
+ are located.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Examples:</term>
+ <listitem>
+ <para>
+ ca-directory /usr/local/etc/privoxy/CA
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+<![%config-file;[<literallayout>@@#ca-directory /usr/local/etc/privoxy/CA</literallayout>]]>
+</sect3>
+
+<!-- ~ End section ~ -->
+
+<!-- ~~~~~ New section ~~~~~ -->
+
+<sect3 renderas="sect4" id="ca-cert-file"><title>ca-cert-file</title>
+<variablelist>
+ <varlistentry>
+ <term>Specifies:</term>
+ <listitem>
+ <para>
+ The CA certificate file in ".crt" format.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Type of value:</term>
+ <listitem>
+ <para>
+ Text
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Default value:</term>
+ <listitem>
+ <para><emphasis>cacert.crt</emphasis></para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Effect if unset:</term>
+ <listitem>
+ <para>
+ Default value is used.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ This directive specifies the name of the CA certificate file
+ in ".crt" format.
+ </para>
+ <para>
+ It can be generated with: openssl req -new -x509 -extensions v3_ca -keyout cakey.pem -out cacert.crt -days 3650
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Examples:</term>
+ <listitem>
+ <para>
+ ca-cert-file root.crt
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+<![%config-file;[<literallayout>@@#ca-cert-file cacert.crt</literallayout>]]>
+</sect3>
+
+<!-- ~ End section ~ -->
+
+<!-- ~~~~~ New section ~~~~~ -->
+
+<sect3 renderas="sect4" id="ca-key-file"><title>ca-key-file</title>
+<variablelist>
+ <varlistentry>
+ <term>Specifies:</term>
+ <listitem>
+ <para>
+ The CA key file in ".pem" format.
+ </para>
+ </listitem>