+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="crunch-client-header">
+<!--
+new action
+-->
+<title>crunch-client-header</title>
+
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>Remove a client header <application>Privoxy</application> has no dedicated action for.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ Deletes every header sent by the client that contains the string the user supplied as parameter.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- Boolean, Parameterized, Multi-value -->
+ <listitem>
+ <para>Parameterized.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>
+ Any string.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ This action allows you to block client headers for which no dedicated
+ <application>Privoxy</application> action exists.
+ <application>Privoxy</application> will remove every client header that
+ contains the string you supplied as parameter.
+ </para>
+ <para>
+ Regular expressions are <emphasis>not supported</emphasis> and you can't
+ use this action to block different headers in the same request, unless
+ they contain the same string.
+ </para>
+ <para>
+ <literal>crunch-client-header</literal> is only meant for quick tests.
+ If you have to block several different headers, or only want to modify
+ parts of them, you should enable
+ <literal><link linkend="filter-client-headers">filter-client-headers</link></literal>
+ and create your own filter.
+ </para>
+ <warning>
+ <para>
+ Don't block any header without understanding the consequences.
+ </para>
+ </warning>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage (section):</term>
+ <listitem>
+ <para>
+ <screen># Block the non-existent "Privacy-Violation:" client header
+{+crunch-client-header {Privacy-Violation:}}
+/
+ </screen>
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="crunch-if-none-match">
+<title>crunch-if-none-match</title>
+<!--
+new action
+-->
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>Prevent yet another way to track the user's steps between sessions.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ Deletes the <quote>If-None-Match:</quote> HTTP client header.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- Boolean, Parameterized, Multi-value -->
+ <listitem>
+ <para>Boolean.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>
+ N/A
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ Removing the <quote>If-None-Match:</quote> HTTP client header
+ is useful for filter testing, where you want to force a real
+ reload instead of getting status code <quote>304</quote> which
+ would cause the browser to use a cached copy of the page.
+ </para>
+ <para>
+ It is also useful to make sure the header isn't used as a cookie
+ replacement.
+ </para>
+ <para>
+ Blocking the <quote>If-None-Match:</quote> header shouldn't cause any
+ caching problems, as long as the <quote>If-Modified-Since:</quote> header
+ isn't blocked as well.
+ </para>
+ <para>
+ It is recommended to use this action together with
+ <literal><link linkend="hide-if-modified-since">hide-if-modified-since</link></literal>
+ and
+ <literal><link linkend="overwrite-last-modified">overwrite-last-modified</link></literal>.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage (section):</term>
+ <listitem>
+ <para>
+ <screen># Let the browser revalidate cached documents without being tracked across sessions
+{+hide-if-modified-since {-60} \
++overwrite-last-modified {randomize} \
++crunch-if-none-match}
+/ </screen>
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="crunch-incoming-cookies">
+<title>crunch-incoming-cookies</title>
+
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>
+ Prevent the web server from setting any cookies on your system
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ Deletes any <quote>Set-Cookie:</quote> HTTP headers from server replies.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- Boolean, Parameterized, Multi-value -->
+ <listitem>
+ <para>Boolean.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>
+ N/A
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ This action is only concerned with <emphasis>incoming</emphasis> cookies. For
+ <emphasis>outgoing</emphasis> cookies, use
+ <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>.
+ Use <emphasis>both</emphasis> to disable cookies completely.
+ </para>
+ <para>
+ It makes <emphasis>no sense at all</emphasis> to use this action in conjunction
+ with the <literal><link linkend="session-cookies-only">session-cookies-only</link></literal> action,
+ since it would prevent the session cookies from being set. See also
+ <literal><link linkend="filter-content-cookies">filter-content-cookies</link></literal>.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage:</term>
+ <listitem>
+ <para>
+ <screen>+crunch-incoming-cookies</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="crunch-server-header">
+<title>crunch-server-header</title>
+<!--
+new action
+-->
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>Remove a server header <application>Privoxy</application> has no dedicated action for.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ Deletes every header sent by the server that contains the string the user supplied as parameter.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- Boolean, Parameterized, Multi-value -->
+ <listitem>
+ <para>Parameterized.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>
+ Any string.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ This action allows you to block server headers for which no dedicated
+ <application>Privoxy</application> action exists. <application>Privoxy</application>
+ will remove every server header that contains the string you supplied as parameter.
+ </para>
+ <para>
+ Regular expressions are <emphasis>not supported</emphasis> and you can't
+ use this action to block different headers in the same request, unless
+ they contain the same string.
+ </para>
+ <para>
+ <literal>crunch-server-header</literal> is only meant for quick tests.
+ If you have to block several different headers, or only want to modify
+ parts of them, you should enable
+ <literal><link linkend="filter-server-headers">filter-server-headers</link></literal>
+ and create your own filter.
+ </para>
+ <warning>
+ <para>
+ Don't block any header without understanding the consequences.
+ </para>
+ </warning>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage (section):</term>
+ <listitem>
+ <para>
+ <screen># Crunch server headers that try to prevent caching
+{+crunch-server-header {no-cache}}
+/ </screen>
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="crunch-outgoing-cookies">
+<title>crunch-outgoing-cookies</title>
+
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>
+ Prevent the web server from reading any cookies from your system
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ Deletes any <quote>Cookie:</quote> HTTP headers from client requests.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- Boolean, Parameterized, Multi-value -->
+ <listitem>
+ <para>Boolean.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>
+ N/A
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ This action is only concerned with <emphasis>outgoing</emphasis> cookies. For
+ <emphasis>incoming</emphasis> cookies, use
+ <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal>.
+ Use <emphasis>both</emphasis> to disable cookies completely.
+ </para>
+ <para>
+ It makes <emphasis>no sense at all</emphasis> to use this action in conjunction
+ with the <literal><link linkend="session-cookies-only">session-cookies-only</link></literal> action,
+ since it would prevent the session cookies from being read.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage:</term>
+ <listitem>
+ <para>
+ <screen>+crunch-outgoing-cookies</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="deanimate-gifs">
+<title>deanimate-gifs</title>
+
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>Stop those annoying, distracting animated GIF images.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ De-animate GIF animations, i.e. reduce them to their first or last image.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- boolean, parameterized, Multi-value -->
+ <listitem>
+ <para>Parameterized.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>
+ <quote>last</quote> or <quote>first</quote>
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ This will also shrink the images considerably (in bytes, not pixels!). If
+ the option <quote>first</quote> is given, the first frame of the animation
+ is used as the replacement. If <quote>last</quote> is given, the last
+ frame of the animation is used instead, which probably makes more sense for
+ most banner animations, but also has the risk of not showing the entire
+ last frame (if it is only a delta to an earlier frame).
+ </para>
+ <para>
+ You can safely use this action with patterns that will also match non-GIF
+ objects, because no attempt will be made at anything that doesn't look like
+ a GIF.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage:</term>
+ <listitem>
+ <para>
+ <screen>+deanimate-gifs{last}</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="downgrade-http-version">
+<title>downgrade-http-version</title>
+
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>Work around (very rare) problems with HTTP/1.1</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ Downgrades HTTP/1.1 client requests and server replies to HTTP/1.0.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- boolean, parameterized, Multi-value -->
+ <listitem>
+ <para>Boolean.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>
+ N/A
+ </para>
+ </listitem>
+ </varlistentry>
+
+<varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ This is a left-over from the time when <application>Privoxy</application>
+ didn't support important HTTP/1.1 features well. It is left here for the
+ unlikely case that you experience HTTP/1.1 related problems with some server
+ out there. Not all (optional) HTTP/1.1 features are supported yet, so there
+ is a chance you might need this action.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage (section):</term>
+ <listitem>
+ <para>
+ <screen>{+downgrade-http-version}
+problem-host.example.com</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+
+</variablelist>
+</sect3>
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="fast-redirects">
+<title>fast-redirects</title>
+
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>Fool some click-tracking scripts and speed up indirect links.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ Detects redirection URLs and redirects the browser without contacting
+ the redirection server first.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- boolean, parameterized, Multi-value -->
+ <listitem>
+ <para>Parameterized.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <itemizedlist>
+ <listitem>
+ <para>
+ <quote>simple-check</quote> to just search for the string <quote>http://</quote>
+ to detect redirection URLs.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <quote>check-decoded-url</quote> to decode URLs (if necessary) before searching
+ for redirection URLs.
+ </para>
+ </listitem>
+ </itemizedlist>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ Many sites, like yahoo.com, don't just link to other sites. Instead, they
+ will link to some script on their own servers, giving the destination as a
+ parameter, which will then redirect you to the final target. URLs
+ resulting from this scheme typically look like:
+ <quote>http://www.example.org/click-tracker.cgi?target=http%3a//www.example.net/</quote>.
+ </para>
+ <para>
+ Sometimes, there are even multiple consecutive redirects encoded in the
+ URL. These redirections via scripts make your web browsing more traceable,
+ since the server from which you follow such a link can see where you go
+ to. Apart from that, valuable bandwidth and time is wasted, while your
+ browser asks the server for one redirect after the other. Plus, it feeds
+ the advertisers.
+ </para>
+ <para>
+ This feature is currently not very smart and is scheduled for improvement.
+ If it is enabled by default, you will have to create some exceptions to
+ this action. It can lead to failures in several ways:
+ </para>
+ <para>
+ Not every URLs with other URLs as parameters is evil.
+ Some sites offer a real service that requires this information to work.
+ For example a validation service needs to know, which document to validate.
+ <literal>fast-redirects</literal> assumes that every URL parameter that
+ looks like another URL is a redirection target, and will always redirect to
+ the last one. Most of the time the assumption is correct, but if it isn't,
+ the user gets redirected anyway.
+ </para>
+ <para>
+ Another failure occurs if the URL contains other parameters after the URL parameter.
+ The URL:
+ <quote>http://www.example.org/?redirect=http%3a//www.example.net/&foo=bar</quote>.
+ contains the redirection URL <quote>http://www.example.net/</quote>,
+ followed by another parameter. <literal>fast-redirects</literal> doesn't know that
+ and will cause a redirect to <quote>http://www.example.net/&foo=bar</quote>.
+ Depending on the target server configuration, the parameter will be silently ignored
+ or lead to a <quote>page not found</quote> error. It is possible to fix these redirected
+ requests with <literal><link linkend="filter-client-headers">filter-client-headers</link></literal>
+ but it requires a little effort.
+ </para>
+ <para>
+ To detect a redirection URL, <literal>fast-redirects</literal> only
+ looks for the string <quote>http://</quote>, either in plain text
+ (invalid but often used) or encoded as <quote>http%3a//</quote>.
+ Some sites use their own URL encoding scheme, encrypt the address
+ of the target server or replace it with a database id. In theses cases
+ <literal>fast-redirects</literal> is fooled and the request reaches the
+ redirection server where it probably gets logged.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage:</term>
+ <listitem>
+ <para>
+ <screen>
+ { +fast-redirects{simple-check} }
+ .example.com
+
+ { +fast-redirects{check-decoded-url} }
+ another.example.com/testing</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="filter">
+<title>filter</title>
+
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>Get rid of HTML and JavaScript annoyances, banner advertisements (by size),
+ do fun text replacements, add personalized effects, etc.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ All files of text-based type, most notably HTML and
+ JavaScript, to which this action applies, can be filtered on-the-fly
+ through the specified regular expression based substitutions. (Note: as of
+ version 3.0.3 plain text documents are exempted from filtering, because
+ web servers often use the <literal>text/plain</literal> MIME type for all
+ files whose type they don't know.) By default, filtering works only on the
+ raw document content itself (that which can be seen with <literal>View
+ Source</literal>),
+ not the headers.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- boolean, parameterized, Multi-value -->
+ <listitem>
+ <para>Parameterized.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>
+ The name of a filter, as defined in the <link linkend="filter-file">filter file</link>.
+ Filters can be defined in one or more files as defined by the
+ <literal><link linkend="filterfile">filterfile</link></literal>
+ option in the <link linkend="config">config file</link>.
+ <filename>default.filter</filename> is the collection of filters
+ supplied by the developers. Locally defined filters should go
+ in their own file, such as <filename>user.filter</filename>.
+ </para>
+ <para>
+ When used in its negative form,
+ and without parameters, <emphasis>all</emphasis> filtering is completely disabled.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ For your convenience, there are a number of pre-defined filters available
+ in the distribution filter file that you can use. See the examples below for
+ a list.
+ </para>
+ <para>
+ Filtering requires buffering the page content, which may appear to
+ slow down page rendering since nothing is displayed until all content has
+ passed the filters. (It does not really take longer, but seems that way
+ since the page is not incrementally displayed.) This effect will be more
+ noticeable on slower connections.
+ </para>
+ <para>
+ <quote>Rolling your own</quote>
+ filters requires a knowledge of
+ <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
+ Expressions</quote></ulink> and
+ <ulink url="http://en.wikipedia.org/wiki/Html"><quote>HTML</quote></ulink>.
+ This is very powerful feature, and potentially very intrusive.
+ Filters should be used with caution, and where an equivalent
+ <quote>action</quote> is not available.
+ </para>
+ <para>
+ The amount of data that can be filtered is limited to the
+ <literal><link linkend="buffer-limit">buffer-limit</link></literal>
+ option in the main <link linkend="config">config file</link>. The
+ default is 4096 KB (4 Megs). Once this limit is exceeded, the buffered
+ data, and all pending data, is passed through unfiltered.
+ </para>
+ <para>
+ Inappropriate MIME types, such as zipped files, are not filtered at all.
+ (Again, only text-based types except plain text). Encrypted SSL data
+ (from HTTPS servers) cannot be filtered either, since this would violate
+ the integrity of the secure transaction. In some situations it might
+ be necessary to protect certain text, like source code, from filtering
+ by defining appropriate <literal>-filter</literal> exceptions.
+ </para>
+ <para>
+ At this time, <application>Privoxy</application> cannot uncompress compressed
+ documents. If you want filtering to work on all documents, even those that
+ would normally be sent compressed, you must use the
+ <literal><link linkend="prevent-compression">prevent-compression</link></literal>
+ action in conjunction with <literal>filter</literal>.
+ </para>
+ <para>
+ Filtering can achieve some of the same effects as the
+ <literal><link linkend="block">block</link></literal>
+ action, i.e. it can be used to block ads and banners. But the mechanism
+ works quite differently. One effective use, is to block ad banners
+ based on their size (see below), since many of these seem to be somewhat
+ standardized.
+ </para>
+ <para>
+ <link linkend="contact">Feedback</link> with suggestions for new or
+ improved filters is particularly welcome!
+ </para>
+ <para>
+ The below list has only the names and a one-line description of each
+ predefined filter. There are <link linkend="predefined-filters">more
+ verbose explanations</link> of what these filters do in the <link
+ linkend="filter-file">filter file chapter</link>.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage (with filters from the distribution <filename>default.filter</filename> file).
+ See <link linkend="PREDEFINED-FILTERS">the Predefined Filters section</link> for
+ more explanation on each:</term>
+ <listitem>
+ <para>
+ <anchor id="filter-js-annoyances">
+ <screen>+filter{js-annoyances} # Get rid of particularly annoying JavaScript abuse</screen>
+ </para>
+ <para>
+ <anchor id="filter-js-events">
+ <screen>+filter{js-events} # Kill all JS event bindings (Radically destructive! Only for extra nasty sites)</screen>
+ </para>
+ <para>
+ <anchor id="filter-html-annoyances">
+ <screen>+filter{html-annoyances} # Get rid of particularly annoying HTML abuse</screen>
+ </para>
+ <para>
+ <anchor id="filter-content-cookies">
+ <screen>+filter{content-cookies} # Kill cookies that come in the HTML or JS content</screen>
+ </para>
+ <para>
+ <anchor id="filter-refresh-tags">
+ <screen>+filter{refresh-tags} # Kill automatic refresh tags (for dial-on-demand setups)</screen>
+ </para>
+ <para>
+ <anchor id="filter-unsolicited-popups">
+ <screen>+filter{unsolicited-popups} # Disable only unsolicited pop-up windows. Useful if your browser lacks this ability.</screen>
+ </para>
+ <para>
+ <anchor id="filter-all-popups">
+ <screen>+filter{all-popups} # Kill all popups in JavaScript and HTML. Useful if your browser lacks this ability.</screen>
+ </para>
+ <para>
+ <anchor id="filter-img-reorder">
+ <screen>+filter{img-reorder} # Reorder attributes in <img> tags to make the banners-by-* filters more effective</screen>
+ </para>
+ <para>
+ <anchor id="filter-banners-by-size">
+ <screen>+filter{banners-by-size} # Kill banners by size</screen>
+ </para>
+ <para>
+ <anchor id="filter-banners-by-link">
+ <screen>+filter{banners-by-link} # Kill banners by their links to known clicktrackers</screen>
+ </para>
+ <para>
+ <anchor id="filter-webbugs">
+ <screen>+filter{webbugs} # Squish WebBugs (1x1 invisible GIFs used for user tracking)</screen>
+ </para>
+ <para>
+ <anchor id="filter-tiny-textforms">
+ <screen>+filter{tiny-textforms} # Extend those tiny textareas up to 40x80 and kill the hard wrap</screen>
+ </para>
+ <para>
+ <anchor id="filter-jumping-windows">
+ <screen>+filter{jumping-windows} # Prevent windows from resizing and moving themselves</screen>
+ </para>
+ <para>
+ <anchor id="filter-frameset-borders">
+ <screen>+filter{frameset-borders} # Give frames a border and make them resizeable</screen>
+ </para>
+ <para>
+ <anchor id="filter-demoronizer">
+ <screen>+filter{demoronizer} # Fix MS's non-standard use of standard charsets</screen>
+ </para>
+ <para>
+ <anchor id="filter-shockwave-flash">
+ <screen>+filter{shockwave-flash} # Kill embedded Shockwave Flash objects</screen>
+ </para>
+ <para>
+ <anchor id="filter-quicktime-kioskmode">
+ <screen>+filter{quicktime-kioskmode} # Make Quicktime movies savable</screen>
+ </para>
+ <para>
+ <anchor id="filter-fun">
+ <screen>+filter{fun} # Text replacements for subversive browsing fun!</screen>
+ </para>
+ <para>
+ <anchor id="filter-crude-parental">
+ <screen>+filter{crude-parental} # Crude parental filtering (demo only)</screen>
+ </para>
+ <para>
+ <anchor id="filter-ie-exploits">
+ <screen>+filter{ie-exploits} # Disable some known Internet Explorer bug exploits</screen>
+ </para>
+ <para>
+ <anchor id="filter-site-specifics">
+ <screen>+filter{site-specifics} # Custom filters for specific site related problems</screen>
+ </para>
+ <para>
+ <anchor id="filter-google">
+ <screen>+filter{google} # Removes text ads and other Google specific improvements</screen>
+ </para>
+ <para>
+ <anchor id="filter-yahoo">
+ <screen>+filter{yahoo} # Removes text ads and other Yahoo specific improvements</screen>
+ </para>
+ <para>
+ <anchor id="filter-msn">
+ <screen>+filter{msn} # Removes text ads and other MSN specific improvements</screen>
+ </para>
+ <para>
+ <anchor id="filter-blogspot">
+ <screen>+filter{blogspot} # Cleans up Blogspot blogs</screen>
+ </para>
+ <para>
+ <anchor id="filter-html-to-xml">
+ <screen>+filter{html-to-xml} # Header filter to change the Content-Type from html to xml</screen>
+ </para>
+ <para>
+ <anchor id="filter-xml-to-html">
+ <screen>+filter{xml-to-html} # Header filter to change the Content-Type from xml to html</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="filter-client-headers">
+<title>filter-client-headers</title>
+
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>
+ To apply filtering to the client's (browser's) headers
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ By default, <application>Privoxy's</application> filters only apply
+ to the document content itself. This will extend those filters to
+ include the client's headers as well.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- boolean, parameterized, Multi-value -->
+ <listitem>
+ <para>Boolean.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>
+ N/A
+ </para>
+ </listitem>
+ </varlistentry>
+
+<varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ Regular expressions can be used to filter headers as well. Check your
+ filters closely before activating this action, as it can easily lead to broken
+ requests.
+ </para>
+ <para>
+ These filters are applied to each header on its own, not to them
+ all at once. This makes it easier to diagnose problems, but on the downside
+ you can't write filters that only change header x if header y's value is
+ z.
+ </para>
+ <para>
+ The filters are used after the other header actions have finished and can
+ use their output as input.
+ </para>
+
+ <para>
+ Whenever possible one should specify <literal>^</literal>,
+ <literal>$</literal>, the whole header name and the colon, to make sure
+ the filter doesn't cause havoc to other headers or the
+ page itself. For example if you want to transform
+ <application>Galeon</application> User-Agents to
+ <application>Firefox</application> User-Agents you
+ shouldn't use:
+</para>
+<para>
+<screen>
+s@Galeon/\d\.\d\.\d @@
+</screen>
+</para><para>
+ but:
+</para><para>
+<screen>
+s@^(User-Agent:.*) Galeon/\d\.\d\.\d (Firefox/\d\.\d\.\d\.\d)$@$1 $2@
+</screen>
+</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage (section):</term>
+ <listitem>
+ <para>
+ <screen>
+{+filter-client-headers +filter{test_filter}}
+problem-host.example.com
+ </screen>
+ </para>
+ </listitem>
+ </varlistentry>
+
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="filter-server-headers">
+<title>filter-server-headers</title>
+
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>
+ To apply filtering to the server's headers
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ By default, <application>Privoxy's</application> filters only apply
+ to the document content itself. This will extend those filters to
+ include the server's headers as well.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- boolean, parameterized, Multi-value -->
+ <listitem>
+ <para>Boolean.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>
+ N/A
+ </para>
+ </listitem>
+ </varlistentry>
+
+<varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ Similar to <literal>filter-client-headers</literal>, but works on
+ the server instead. To filter both server and client, use both.
+ </para>
+ <para>
+ As with <literal>filter-client-headers</literal>, check your
+ filters before activating this action, as it can easily lead to broken
+ requests.
+ </para>
+ <para>
+ These filters are applied to each header on its own, not to them
+ all at once. This makes it easier to diagnose problems, but on the downside
+ you can't write filters that only change header x if header y's value is
+ z.
+ </para>
+ <para>
+ The filters are used after the other header actions have finished and can
+ use their output as input.
+ </para>
+ <para>
+ Remember too, whenever possible one should specify <literal>^</literal>,
+ <literal>$</literal>, the whole header name and the colon, to make sure
+ the filter doesn't cause havoc to other headers or the
+ page itself. See above for example.
+ </para>
+
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage (section):</term>
+ <listitem>
+ <para>
+ <screen>
+{+filter-server-headers +filter{test_filter}}
+problem-host.example.com
+ </screen>
+ </para>
+ </listitem>
+ </varlistentry>
+
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="force-text-mode">
+<title>force-text-mode</title>
+<!--
+new action
+-->
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>Force <application>Privoxy</application> to treat a document as if it was in some kind of <emphasis>text</emphasis> format. </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ Declares a document as text, even if the <quote>Content-Type:</quote> isn't detected as such.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- Boolean, Parameterized, Multi-value -->
+ <listitem>
+ <para>Boolean.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>
+ N/A
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ As explained <literal><link linkend="filter">above</link></literal>,
+ <application>Privoxy</application> tries to only filter files that are
+ in some kind of text format. The same restrictions apply to
+ <literal><link linkend="content-type-overwrite">content-type-overwrite</link></literal>.
+ <literal>force-text-mode</literal> declares a document as text,
+ without looking at the <quote>Content-Type:</quote> first.
+ </para>
+ <warning>
+ <para>
+ Think twice before activating this action. Filtering binary data
+ with regular expressions can cause file damage.
+ </para>
+ </warning>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage:</term>
+ <listitem>
+ <para>
+ <screen>
++force-text-mode
+ </screen>
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="handle-as-empty-document">
+<title>handle-as-empty-document</title>
+<!--
+new action
+-->
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>Mark URLs that should be replaced by empty documents <emphasis>if they get blocked</emphasis></para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ This action alone doesn't do anything noticeable. It just marks URLs.
+ If the <literal><link linkend="block">block</link></literal> action <emphasis>also applies</emphasis>,
+ the presence or absence of this mark decides whether an HTML <quote>blocked</quote>
+ page, or an empty document will be sent to the client as a substitute for the blocked content.
+ The <emphasis>empty</emphasis> document isn't literally empty, but actually contains a single space.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- Boolean, Parameterized, Multi-value -->
+ <listitem>
+ <para>Boolean.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>
+ N/A
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ Some browsers complain about syntax errors if JavaScript documents
+ are blocked with <application>Privoxy's</application>
+ default HTML page; this option can be used to silence them.
+ </para>
+ <para>
+ The content type for the empty document can be specified with
+ <literal><link linkend="content-type-overwrite">content-type-overwrite{}</link></literal>,
+ but usually this isn't necessary.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage:</term>
+ <listitem>
+ <para>
+ <screen># Block all documents on example.org that end with ".js",
+# but send an empty document instead of the usual HTML message.
+{+block +handle-as-empty-document}
+example.org/.*\.js$
+ </screen>
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="handle-as-image">
+<title>handle-as-image</title>
+
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>Mark URLs as belonging to images (so they'll be replaced by images <emphasis>if they do get blocked</emphasis>, rather than HTML pages)</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ This action alone doesn't do anything noticeable. It just marks URLs as images.
+ If the <literal><link linkend="block">block</link></literal> action <emphasis>also applies</emphasis>,
+ the presence or absence of this mark decides whether an HTML <quote>blocked</quote>
+ page, or a replacement image (as determined by the <literal><link
+ linkend="set-image-blocker">set-image-blocker</link></literal> action) will be sent to the
+ client as a substitute for the blocked content.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- Boolean, Parameterized, Multi-value -->
+ <listitem>
+ <para>Boolean.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>
+ N/A
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ The below generic example section is actually part of <filename>default.action</filename>.
+ It marks all URLs with well-known image file name extensions as images and should
+ be left intact.
+ </para>
+ <para>
+ Users will probably only want to use the handle-as-image action in conjunction with
+ <literal><link linkend="block">block</link></literal>, to block sources of banners, whose URLs don't
+ reflect the file type, like in the second example section.
+ </para>
+ <para>
+ Note that you cannot treat HTML pages as images in most cases. For instance, (in-line) ad
+ frames require an HTML page to be sent, or they won't display properly.
+ Forcing <literal>handle-as-image</literal> in this situation will not replace the
+ ad frame with an image, but lead to error messages.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage (sections):</term>
+ <listitem>
+ <para>
+ <screen># Generic image extensions:
+#
+{+handle-as-image}
+/.*\.(gif|jpg|jpeg|png|bmp|ico)$
+
+# These don't look like images, but they're banners and should be
+# blocked as images:
+#
+{+block +handle-as-image}
+some.nasty-banner-server.com/junk.cgi?output=trash
+
+# Banner source! Who cares if they also have non-image content?
+ad.doubleclick.net
+</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="hide-accept-language">
+<title>hide-accept-language</title>
+<!--
+new action
+-->
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>Pretend to use different language settings.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ Deletes or replaces the <quote>Accept-Language:</quote> HTTP header in client requests.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- Boolean, Parameterized, Multi-value -->
+ <listitem>
+ <para>Parameterized.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>
+ Keyword: <quote>block</quote>, or any user defined value.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ Faking the browser's language settings can be useful to make a
+ foreign User-Agent set with
+ <literal><link linkend="hide-user-agent">hide-user-agent</link></literal>
+ more believable.
+ </para>
+ <para>
+ However some sites with content in different languages check the
+ <quote>Accept-Language:</quote> to decide which one to take by default.
+ Sometimes it isn't possible to later switch to another language without
+ changing the <quote>Accept-Language:</quote> header first.
+ </para>
+ <para>
+ Therefore it's a good idea to either only change the
+ <quote>Accept-Language:</quote> header to languages you understand,
+ or to languages that aren't wide spread.
+ </para>
+ <para>
+ Before setting the <quote>Accept-Language:</quote> header
+ to a rare language, you should consider that it helps to
+ make your requests unique and thus easier to trace.
+ If you don't plan to change this header frequently,
+ you should stick to a common language.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage (section):</term>
+ <listitem>
+ <para>
+ <screen># Pretend to use Canadian language settings.
+{+hide-accept-language{en-ca} \
++hide-user-agent{Mozilla/5.0 (X11; U; OpenBSD i386; en-CA; rv:1.8.0.4) Gecko/20060628 Firefox/1.5.0.4} \
+}
+/ </screen>
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="hide-content-disposition">
+<title>hide-content-disposition</title>
+<!--
+new action
+-->
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>Prevent download menus for content you prefer to view inside the browser.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ Deletes or replaces the <quote>Content-Disposition:</quote> HTTP header set by some servers.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- Boolean, Parameterized, Multi-value -->
+ <listitem>
+ <para>Parameterized.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>
+ Keyword: <quote>block</quote>, or any user defined value.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ Some servers set the <quote>Content-Disposition:</quote> HTTP header for
+ documents they assume you want to save locally before viewing them.
+ The <quote>Content-Disposition:</quote> header contains the file name
+ the browser is supposed to use by default.
+ </para>
+ <para>
+ In most browsers that understand this header, it makes it impossible to
+ <emphasis>just view</emphasis> the document, without downloading it first,
+ even if it's just a simple text file or an image.
+ </para>
+ <para>
+ Removing the <quote>Content-Disposition:</quote> header helps
+ to prevent this annoyance, but some browsers additionally check the
+ <quote>Content-Type:</quote> header, before they decide if they can
+ display a document without saving it first. In these cases, you have
+ to change this header as well, before the browser stops displaying
+ download menus.
+ </para>
+ <para>
+ It is also possible to change the server's file name suggestion
+ to another one, but in most cases it isn't worth the time to set
+ it up.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage:</term>
+ <listitem>
+ <para>
+ <screen># Disarm the download link in Sourceforge's patch tracker
+{-filter\
++content-type-overwrite {text/plain}\
++hide-content-disposition {block} }
+.sourceforge.net/tracker/download.php</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="hide-if-modified-since">
+<title>hide-if-modified-since</title>
+<!--
+new action
+-->
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>Prevent yet another way to track the user's steps between sessions.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ Deletes the <quote>If-Modified-Since:</quote> HTTP client header or modifies its value.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- Boolean, Parameterized, Multi-value -->
+ <listitem>
+ <para>Parameterized.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>
+ Keyword: <quote>block</quote>, or a user defined value that specifies a range of hours.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ Removing this header is useful for filter testing, where you want to force a real
+ reload instead of getting status code <quote>304</quote>, which would cause the
+ browser to use a cached copy of the page.
+ </para>
+ <para>
+ Instead of removing the header, <literal>hide-if-modified-since</literal> can
+ also add or subtract a random amount of time to/from the header's value.
+ You specify a range of minutes where the random factor should be chosen from and
+ <application>Privoxy</application> does the rest. A negative value means
+ subtracting, a positive value adding.
+ </para>
+ <para>
+ Randomizing the value of the <quote>If-Modified-Since:</quote> makes
+ sure it isn't used as a cookie replacement, but you will run into
+ caching problems if the random range is too high.
+ </para>
+ <para>
+ It is a good idea to only use a small negative value and let
+ <literal><link linkend="overwrite-last-modified">overwrite-last-modified</link></literal>
+ handle the greater changes.
+ </para>
+ <para>
+ It is also recommended to use this action together with
+ <literal><link linkend="crunch-if-none-match">crunch-if-none-match</link></literal>.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage (section):</term>
+ <listitem>
+ <para>
+ <screen># Let the browser revalidate without being tracked across sessions
+{+hide-if-modified-since {-60}\
++overwrite-last-modified {randomize}\
++crunch-if-none-match}
+/</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="hide-forwarded-for-headers">
+<title>hide-forwarded-for-headers</title>
+<!--
+new action
+-->
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>Improve privacy by hiding the true source of the request</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ Deletes any existing <quote>X-Forwarded-for:</quote> HTTP header from client requests,
+ and prevents adding a new one.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- Boolean, Parameterized, Multi-value -->
+ <listitem>
+ <para>Boolean.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>
+ N/A
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ It is fairly safe to leave this on.
+ </para>
+ <para>
+ This action is scheduled for improvement: It should be able to generate forged
+ <quote>X-Forwarded-for:</quote> headers using random IP addresses from a specified network,
+ to make successive requests from the same client look like requests from a pool of different
+ users sharing the same proxy.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage:</term>
+ <listitem>
+ <para>
+ <screen>+hide-forwarded-for-headers</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="hide-from-header">
+<title>hide-from-header</title>
+
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>Keep your (old and ill) browser from telling web servers your email address</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ Deletes any existing <quote>From:</quote> HTTP header, or replaces it with the
+ specified string.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- Boolean, Parameterized, Multi-value -->
+ <listitem>
+ <para>Parameterized.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>
+ Keyword: <quote>block</quote>, or any user defined value.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ The keyword <quote>block</quote> will completely remove the header
+ (not to be confused with the <literal><link linkend="block">block</link></literal>
+ action).
+ </para>
+ <para>
+ Alternately, you can specify any value you prefer to be sent to the web
+ server. If you do, it is a matter of fairness not to use any address that
+ is actually used by a real person.
+ </para>
+ <para>
+ This action is rarely needed, as modern web browsers don't send
+ <quote>From:</quote> headers anymore.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage:</term>
+ <listitem>
+ <para>
+ <screen>+hide-from-header{block}</screen> or
+ <screen>+hide-from-header{spam-me-senseless@sittingduck.example.com}</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="hide-referrer">
+<title>hide-referrer</title>
+<anchor id="hide-referer">
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>Conceal which link you followed to get to a particular site</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ Deletes the <quote>Referer:</quote> (sic) HTTP header from the client request,
+ or replaces it with a forged one.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- Boolean, Parameterized, Multi-value -->
+ <listitem>
+ <para>Parameterized.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <itemizedlist>
+ <listitem>
+ <para><quote>conditional-block</quote> to delete the header completely if the host has changed.</para>
+ </listitem>
+ <listitem>
+ <para><quote>block</quote> to delete the header unconditionally.</para>
+ </listitem>
+ <listitem>
+ <para><quote>forge</quote> to pretend to be coming from the homepage of the server we are talking to.</para>
+ </listitem>
+ <listitem>
+ <para>Any other string to set a user defined referrer.</para>
+ </listitem>
+ </itemizedlist>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ <literal>conditional-block</literal> is the only parameter,
+ that isn't easily detected in the server's log file. If it blocks the
+ referrer, the request will look like the visitor used a bookmark or
+ typed in the address directly.
+ </para>
+ <para>
+ Leaving the referrer unmodified for requests on the same host
+ allows the server owner to see the visitor's <quote>click path</quote>,
+ but in most cases she could also get that information by comparing
+ other parts of the log file: for example the User-Agent if it isn't
+ a very common one, or the user's IP address if it doesn't change between
+ different requests.
+ </para>
+ <para>
+ Always blocking the referrer, or using a custom one, can lead to
+ failures on servers that check the referrer before they answer any
+ requests, in an attempt to prevent their valuable content from being
+ embedded or linked to elsewhere.
+ </para>
+ <para>
+ Both <literal>conditional-block</literal> and <literal>forge</literal>
+ will work with referrer checks, as long as content and valid referring page
+ are on the same host. Most of the time that's the case.
+ </para>
+ <para>
+ <literal>hide-referer</literal> is an alternate spelling of
+ <literal>hide-referrer</literal> and the two can be can be freely
+ substituted with each other. (<quote>referrer</quote> is the
+ correct English spelling, however the HTTP specification has a bug - it
+ requires it to be spelled as <quote>referer</quote>.)
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage:</term>
+ <listitem>
+ <para>
+ <screen>+hide-referrer{forge}</screen> or
+ <screen>+hide-referrer{http://www.yahoo.com/}</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="hide-user-agent">
+<title>hide-user-agent</title>
+
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>Conceal your type of browser and client operating system</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ Replaces the value of the <quote>User-Agent:</quote> HTTP header
+ in client requests with the specified value.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- Boolean, Parameterized, Multi-value -->
+ <listitem>
+ <para>Parameterized.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>
+ Any user-defined string.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <warning>
+ <para>
+ This can lead to problems on web sites that depend on looking at this header in
+ order to customize their content for different browsers (which, by the
+ way, is <emphasis>NOT</emphasis> the right thing to do: good web sites
+ work browser-independently).
+ <!--
+ <ulink url="http://www.javascriptkit.com/javaindex.shtml">smart way to do
+ that</ulink>!).
+ -->
+ </para>
+ </warning>
+ <para>
+ Using this action in multi-user setups or wherever different types of
+ browsers will access the same <application>Privoxy</application> is
+ <emphasis>not recommended</emphasis>. In single-user, single-browser
+ setups, you might use it to delete your OS version information from
+ the headers, because it is an invitation to exploit known bugs for your
+ OS. It is also occasionally useful to forge this in order to access
+ sites that won't let you in otherwise (though there may be a good
+ reason in some cases). Example of this: some MSN sites will not
+ let <application>Mozilla</application> enter, yet forging to a
+ <application>Netscape 6.1</application> user-agent works just fine.
+ (Must be just a silly MS goof, I'm sure :-).
+ </para>
+ <para>
+ This action is scheduled for improvement.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage:</term>
+ <listitem>
+ <para>
+ <screen>+hide-user-agent{Netscape 6.1 (X11; I; Linux 2.4.18 i686)}</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="inspect-jpegs">
+<title>inspect-jpegs</title>
+<!--
+new action
+-->
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>To protect against the MS buffer over-run in JPEG processing</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ Protect against a known exploit
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- Boolean, Parameterized, Multi-value -->
+ <listitem>
+ <para>Boolean.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>
+ N/A
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ See Microsoft Security Bulletin MS04-028. JPEG images are one of the most
+ common image types found across the Internet. The exploit as described can
+ allow execution of code on the target system, giving an attacker access
+ to the system in question by merely planting an altered JPEG image, which
+ would have no obvious indications of what lurks inside. This action
+ prevents unwanted intrusion.
+ </para>
+
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage:</term>
+ <listitem>
+ <para><screen>+inspect-jpegs</screen></para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="kill-popups">
+<title>kill-popups<anchor id="kill-popup"></title>
+
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>Eliminate those annoying pop-up windows (deprecated)</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ While loading the document, replace JavaScript code that opens
+ pop-up windows with (syntactically neutral) dummy code on the fly.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- Boolean, Parameterized, Multi-value -->
+ <listitem>
+ <para>Boolean.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>
+ N/A
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ This action is basically a built-in, hardwired special-purpose filter
+ action, but there are important differences: For <literal>kill-popups</literal>,
+ the document need not be buffered, so it can be incrementally rendered while
+ downloading. But <literal>kill-popups</literal> doesn't catch as many pop-ups as
+ <literal><link
+ linkend="FILTER-ALL-POPUPS">filter{<replaceable>all-popups</replaceable>}</link></literal>
+ does and is not as smart as <literal><link
+ linkend="FILTER-UNSOLICITED-POPUPS">filter{<replaceable>unsolicited-popups</replaceable>}</link>
+ </literal>is.
+ </para>
+ <para>
+ Think of it as a fast and efficient replacement for a filter that you
+ can use if you don't want any filtering at all. Note that it doesn't make
+ sense to combine it with any <literal><link linkend="filter">filter</link></literal> action,
+ since as soon as one <literal><link linkend="filter">filter</link></literal> applies,
+ the whole document needs to be buffered anyway, which destroys the advantage of
+ the <literal>kill-popups</literal> action over its filter equivalent.
+ </para>
+ <para>
+ Killing all pop-ups unconditionally is problematic. Many shops and banks rely on
+ pop-ups to display forms, shopping carts etc, and the <literal><link
+ linkend="FILTER-UNSOLICITED-POPUPS">filter{<replaceable>unsolicited-popups</replaceable>}</link>
+ </literal> does a better job of catching only the unwanted ones.
+ </para>
+ <para>
+ If the only kind of pop-ups that you want to kill are exit consoles (those
+ <emphasis>really nasty</emphasis> windows that appear when you close an other
+ one), you might want to use
+ <literal><link
+ linkend="filter">filter</link>{<replaceable>js-annoyances</replaceable>}</literal>
+ instead.
+ </para>
+ <para>
+ This action is most appropriate for browsers that don't have any controls
+ for unwanted pop-ups. Not recommended for general usage.
+ </para>
+
+ <!--
+ <para>
+ An alternate spelling is <literal>+kill-popup</literal>, which is
+ interchangeable.
+ </para>
+ -->
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage:</term>
+ <listitem>
+ <para><screen>+kill-popups</screen></para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="limit-connect">
+<title>limit-connect</title>
+
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>Prevent abuse of <application>Privoxy</application> as a TCP proxy relay or disable SSL for untrusted sites</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ Specifies to which ports HTTP CONNECT requests are allowable.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- Boolean, Parameterized, Multi-value -->
+ <listitem>
+ <para>Parameterized.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>
+ A comma-separated list of ports or port ranges (the latter using dashes, with the minimum
+ defaulting to 0 and the maximum to 65K).
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ By default, i.e. if no <literal>limit-connect</literal> action applies,
+ <application>Privoxy</application> only allows HTTP CONNECT
+ requests to port 443 (the standard, secure HTTPS port). Use
+ <literal>limit-connect</literal> if more fine-grained control is desired
+ for some or all destinations.
+ </para>
+ <para>
+ The CONNECT methods exists in HTTP to allow access to secure websites
+ (<quote>https://</quote> URLs) through proxies. It works very simply:
+ the proxy connects to the server on the specified port, and then
+ short-circuits its connections to the client and to the remote server.
+ This can be a big security hole, since CONNECT-enabled proxies can be
+ abused as TCP relays very easily.
+ </para>
+ <para>
+ <application>Privoxy</application> relays HTTPS traffic without seeing
+ the decoded content. Websites can leverage this limitation to circumvent &my-app;'s
+ filters. By specifying an invalid port range you can disable HTTPS entirely.
+ If you plan to disable SSL by default, consider enabling
+ <literal><link linkend="treat-forbidden-connects-like-blocks ">treat-forbidden-connects-like-blocks</link></literal>
+ as well, to be able to quickly create exceptions.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usages:</term>
+ <listitem>
+ <!-- I had trouble getting the spacing to look right in my browser -->
+ <!-- I probably have the wrong font setup, bollocks. -->
+ <!-- Apparently the emphasis tag uses a proportional font no matter what -->
+ <para>
+ <screen>+limit-connect{443} # This is the default and need not be specified.
++limit-connect{80,443} # Ports 80 and 443 are OK.
++limit-connect{-3, 7, 20-100, 500-} # Ports less than 3, 7, 20 to 100 and above 500 are OK.
++limit-connect{-} # All ports are OK
++limit-connect{,} # No HTTPS/SSL traffic is allowed</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="prevent-compression">
+<title>prevent-compression</title>
+
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>
+ Ensure that servers send the content uncompressed, so it can be
+ passed through <literal><link linkend="filter">filter</link></literal>s.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ Removes the Accept-Encoding header which can be used to ask for compressed transfer.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- Boolean, Parameterized, Multi-value -->
+ <listitem>
+ <para>Boolean.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>
+ N/A
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ More and more websites send their content compressed by default, which
+ is generally a good idea and saves bandwidth. But for the <literal><link
+ linkend="filter">filter</link></literal>, <literal><link linkend="deanimate-gifs">deanimate-gifs</link></literal>
+ and <literal><link linkend="kill-popups">kill-popups</link></literal> actions to work,
+ <application>Privoxy</application> needs access to the uncompressed data.
+ Unfortunately, <application>Privoxy</application> can't yet(!) uncompress, filter, and
+ re-compress the content on the fly. So if you want to ensure that all websites, including
+ those that normally compress, can be filtered, you need to use this action.
+ </para>
+ <para>
+ This will slow down transfers from those websites, though. If you use any of the above-mentioned
+ actions, you will typically want to use <literal>prevent-compression</literal> in conjunction
+ with them.
+ </para>
+ <para>
+ Note that some (rare) ill-configured sites don't handle requests for uncompressed
+ documents correctly (they send an empty document body). If you use <literal>prevent-compression</literal>
+ per default, you'll have to add exceptions for those sites. See the example for how to do that.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage (sections):</term>
+ <listitem>
+ <para>
+ <screen># Set default:
+#
+{+prevent-compression}
+/ # Match all sites
+
+# Make exceptions for ill sites:
+#
+{-prevent-compression}
+www.debianhelp.org
+www.pclinuxonline.com</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="overwrite-last-modified">
+<title>overwrite-last-modified</title>
+<!--
+new action
+-->
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>Prevent yet another way to track the user's steps between sessions.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ Deletes the <quote>Last-Modified:</quote> HTTP server header or modifies its value.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- Boolean, Parameterized, Multi-value -->
+ <listitem>
+ <para>Parameterized.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>
+ One of the keywords: <quote>block</quote>, <quote>reset-to-request-time</quote>
+ and <quote>randomize</quote>
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ Removing the <quote>Last-Modified:</quote> header is useful for filter
+ testing, where you want to force a real reload instead of getting status
+ code <quote>304</quote>, which would cause the browser to reuse the old
+ version of the page.
+ </para>
+ <para>
+ The <quote>randomize</quote> option overwrites the value of the
+ <quote>Last-Modified:</quote> header with a randomly chosen time
+ between the original value and the current time. In theory the server
+ could send each document with a different <quote>Last-Modified:</quote>
+ header to track visits without using cookies. <quote>Randomize</quote>
+ makes it impossible and the browser can still revalidate cached documents.
+ </para>
+ <para>
+ <quote>reset-to-request-time</quote> overwrites the value of the
+ <quote>Last-Modified:</quote> header with the current time. You could use
+ this option together with
+ <literal><link linkend="hide-if-modified-since">hided-if-modified-since</link></literal>
+ to further customize your random range.
+ </para>
+ <para>
+ The preferred parameter here is <quote>randomize</quote>. It is safe
+ to use, as long as the time settings are more or less correct.
+ If the server sets the <quote>Last-Modified:</quote> header to the time
+ of the request, the random range becomes zero and the value stays the same.
+ Therefore you should later randomize it a second time with
+ <literal><link linkend="hide-if-modified-since">hided-if-modified-since</link></literal>,
+ just to be sure.
+ </para>
+ <para>
+ It is also recommended to use this action together with
+ <literal><link linkend="crunch-if-none-match">crunch-if-none-match</link></literal>.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage:</term>
+ <listitem>
+ <para>
+ <screen># Let the browser revalidate without being tracked across sessions
+{+hide-if-modified-since {-60}\
++overwrite-last-modified {randomize}\
++crunch-if-none-match}
+/</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="redirect">
+<title>redirect</title>
+<!--
+new action
+-->
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>
+ Redirect requests to other sites.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ Convinces the browser that the requested document has been moved
+ to another location and the browser should get it from there.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- Boolean, Parameterized, Multi-value -->
+ <listitem>
+ <para>Parameterized</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>
+ Any URL.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ This action is useful to replace whole documents with ones of your
+ choosing. This can be used to enforce safe surfing, or just as a simple
+ convenience.
+ </para>
+ <para>
+ You can do the same by combining the actions
+ <literal><link linkend="block">block</link></literal>,
+ <literal><link linkend="handle-as-image">handle-as-image</link></literal> and
+ <literal><link linkend="set-image-blocker">set-image-blocker{URL}</link></literal>.
+ It doesn't sound right for non-image documents, and that's why this action
+ was created.
+ </para>
+ <para>
+ This action will be ignored if you use it together with
+ <literal><link linkend="block">block</link></literal>.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usages:</term>
+ <listitem>
+ <para>
+ <screen># Replace example.com's style sheet with another one
+{ +redirect{http://localhost/css-replacements/example.com.css} }
+ example.com/stylesheet.css
+
+# Create a short, easy to remember nickname for a favorite site
+{ +redirect{http://www.privoxy.org/user-manual/actions-file.html} }
+ a</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="send-vanilla-wafer">
+<title>send-vanilla-wafer</title>
+
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>
+ Feed log analysis scripts with useless data.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ Sends a cookie with each request stating that you do not accept any copyright
+ on cookies sent to you, and asking the site operator not to track you.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- Boolean, Parameterized, Multi-value -->
+ <listitem>
+ <para>Boolean.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>
+ N/A
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ The vanilla wafer is a (relatively) unique header and could conceivably be used to track you.
+ </para>
+ <para>
+ This action is rarely used and not enabled in the default configuration.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage:</term>
+ <listitem>
+ <para>
+ <screen>+send-vanilla-wafer</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="send-wafer">
+<title>send-wafer</title>
+
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>
+ Send custom cookies or feed log analysis scripts with even more useless data.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ Sends a custom, user-defined cookie with each request.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- Boolean, Parameterized, Multi-value -->
+ <listitem>
+ <para>Multi-value.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>
+ A string of the form <quote><replaceable class="option">name</replaceable>=<replaceable
+ class="parameter">value</replaceable></quote>.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ Being multi-valued, multiple instances of this action can apply to the same request,
+ resulting in multiple cookies being sent.
+ </para>
+ <para>
+ This action is rarely used and not enabled in the default configuration.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Example usage (section):</term>
+ <listitem>
+ <para>
+ <screen>{+send-wafer{UsingPrivoxy=true}}
+my-internal-testing-server.void</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="session-cookies-only">
+<title>session-cookies-only</title>
+
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>
+ Allow only temporary <quote>session</quote> cookies (for the current
+ browser session <emphasis>only</emphasis>).
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ Deletes the <quote>expires</quote> field from <quote>Set-Cookie:</quote>
+ server headers. Most browsers will not store such cookies permanently and
+ forget them in between sessions.
+ </para>
+ </listitem>
+ </varlistentry>
+
+<varlistentry>
+ <term>Type:</term>
+ <!-- Boolean, Parameterized, Multi-value -->
+ <listitem>
+ <para>Boolean.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>
+ N/A
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ This is less strict than <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal> /
+ <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal> and allows you to browse
+ websites that insist or rely on setting cookies, without compromising your privacy too badly.
+ </para>
+ <para>
+ Most browsers will not permanently store cookies that have been processed by
+ <literal>session-cookies-only</literal> and will forget about them between sessions.
+ This makes profiling cookies useless, but won't break sites which require cookies so
+ that you can log in for transactions. This is generally turned on for all
+ sites, and is the recommended setting.
+ </para>
+ <para>
+ It makes <emphasis>no sense at all</emphasis> to use <literal>session-cookies-only</literal>
+ together with <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal> or
+ <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>. If you do, cookies
+ will be plainly killed.
+ </para>
+ <para>
+ Note that it is up to the browser how it handles such cookies without an <quote>expires</quote>
+ field. If you use an exotic browser, you might want to try it out to be sure.
+ </para>
+ <para>
+ This setting also has no effect on cookies that may have been stored
+ previously by the browser before starting <application>Privoxy</application>.
+ These would have to be removed manually.
+ </para>
+ <para>
+ <application>Privoxy</application> also uses
+ the <link linkend="filter-content-cookies">content-cookies filter</link>
+ to block some types of cookies. Content cookies are not effected by
+ <literal>session-cookies-only</literal>.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage:</term>
+ <listitem>
+ <para>
+ <screen>+session-cookies-only</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="set-image-blocker">
+<title>set-image-blocker</title>
+
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>Choose the replacement for blocked images</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ This action alone doesn't do anything noticeable. If <emphasis>both</emphasis>
+ <literal><link linkend="block">block</link></literal> <emphasis>and</emphasis> <literal><link
+ linkend="handle-as-image">handle-as-image</link></literal> <emphasis>also</emphasis>
+ apply, i.e. if the request is to be blocked as an image,
+ <emphasis>then</emphasis> the parameter of this action decides what will be
+ sent as a replacement.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- Boolean, Parameterized, Multi-value -->
+ <listitem>
+ <para>Parameterized.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <itemizedlist>
+ <listitem>
+ <para>
+ <quote>pattern</quote> to send a built-in checkerboard pattern image. The image is visually
+ decent, scales very well, and makes it obvious where banners were busted.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <quote>blank</quote> to send a built-in transparent image. This makes banners disappear
+ completely, but makes it hard to detect where <application>Privoxy</application> has blocked
+ images on a given page and complicates troubleshooting if <application>Privoxy</application>
+ has blocked innocent images, like navigation icons.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <quote><replaceable class="parameter">target-url</replaceable></quote> to
+ send a redirect to <replaceable class="parameter">target-url</replaceable>. You can redirect
+ to any image anywhere, even in your local filesystem via <quote>file:///</quote> URL.
+ (But note that not all browsers support redirecting to a local file system).
+ </para>
+ <para>
+ A good application of redirects is to use special <application>Privoxy</application>-built-in
+ URLs, which send the built-in images, as <replaceable class="parameter">target-url</replaceable>.
+ This has the same visual effect as specifying <quote>blank</quote> or <quote>pattern</quote> in
+ the first place, but enables your browser to cache the replacement image, instead of requesting
+ it over and over again.
+ </para>
+ </listitem>
+ </itemizedlist>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ The URLs for the built-in images are <quote>http://config.privoxy.org/send-banner?type=<replaceable
+ class="parameter">type</replaceable></quote>, where <replaceable class="parameter">type</replaceable> is
+ either <quote>blank</quote> or <quote>pattern</quote>.
+ </para>
+ <para>
+ There is a third (advanced) type, called <quote>auto</quote>. It is <emphasis>NOT</emphasis> to be
+ used in <literal>set-image-blocker</literal>, but meant for use from <link linkend="filter-file">filters</link>.
+ Auto will select the type of image that would have applied to the referring page, had it been an image.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage:</term>
+ <listitem>
+ <para>
+ Built-in pattern:
+ </para>
+ <para>
+ <screen>+set-image-blocker{pattern}</screen>
+ </para>
+ <para>
+ Redirect to the BSD devil:
+ </para>
+ <para>
+ <screen>+set-image-blocker{http://www.freebsd.org/gifs/dae_up3.gif}</screen>
+ </para>
+ <para>
+ Redirect to the built-in pattern for better caching:
+ </para>
+ <para>
+ <screen>+set-image-blocker{http://config.privoxy.org/send-banner?type=pattern}</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>