+</sect1>
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect1 id="quickstart"><title>Quickstart to Using Privoxy</title>
+<para>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Install <application>Privoxy</application>. See the <link
+ linkend="installation">Installation Section</link> below for platform specific
+ information.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Advanced users and those who want to offer <application>Privoxy</application>
+ service to more than just their local machine should check the <link
+ linkend="config">main config file</link>, especially the <link
+ linkend="access-control">security-relevant</link> options. These are
+ off by default.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Start <application>Privoxy</application>, if the installation program has
+ not done this already (may vary according to platform). See the section
+ <link linkend="startup">Starting <application>Privoxy</application></link>.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Set your browser to use <application>Privoxy</application> as HTTP and
+ HTTPS (SSL) <ulink url="http://en.wikipedia.org/wiki/Proxy_server">proxy</ulink>
+ by setting the proxy configuration for address of
+ <literal>127.0.0.1</literal> and port <literal>8118</literal>.
+ <emphasis>DO NOT</emphasis> activate proxying for <literal>FTP</literal> or
+ any protocols besides HTTP and HTTPS (SSL) unless you intend to prevent your
+ browser from using these protocols.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Flush your browser's disk and memory caches, to remove any cached ad images.
+ If using <application>Privoxy</application> to manage
+ <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>,
+ you should remove any currently stored cookies too.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ A default installation should provide a reasonable starting point for
+ most. There will undoubtedly be occasions where you will want to adjust the
+ configuration, but that can be dealt with as the need arises. Little
+ to no initial configuration is required in most cases, you may want
+ to enable the
+ <ulink url="config.html#ENABLE-EDIT-ACTIONS">web-based action editor</ulink> though.
+ Be sure to read the warnings first.
+ </para>
+ <para>
+ See the <link linkend="configuration">Configuration section</link> for more
+ configuration options, and how to customize your installation.
+ You might also want to look at the <link
+ linkend="quickstart-ad-blocking">next section</link> for a quick
+ introduction to how <application>Privoxy</application> blocks ads and
+ banners.
+</para>
+ </listitem>
+
+ <listitem>
+ <para>
+ If you experience ads that slip through, innocent images that are
+ blocked, or otherwise feel the need to fine-tune
+ <application>Privoxy's</application> behavior, take a look at the <link
+ linkend="actions-file">actions files</link>. As a quick start, you might
+ find the <link linkend="act-examples">richly commented examples</link>
+ helpful. You can also view and edit the actions files through the <ulink
+ url="http://config.privoxy.org">web-based user interface</ulink>. The
+ Appendix <quote><link linkend="actionsanat">Troubleshooting: Anatomy of an
+ Action</link></quote> has hints on how to understand and debug actions that
+ <quote>misbehave</quote>.
+ </para>
+ </listitem>
+
+<!--
+ Did anyone test these lately?
+ fk 2007-11-10
+ <listitem>
+ <para>
+ For easy access to &my-app;'s most important controls, drag the provided
+ <link linkend="bookmarklets">Bookmarklets</link> into your browser's
+ personal toolbar.
+ </para>
+ </listitem>
+-->
+
+ <listitem>
+ <para>
+ Please see the section <link linkend="contact">Contacting the
+ Developers</link> on how to report bugs, problems with websites or to get
+ help.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Now enjoy surfing with enhanced control, comfort and privacy!
+ </para>
+ </listitem>
+
+ </itemizedlist>
+</para>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+
+<sect2 id="quickstart-ad-blocking">
+<title>Quickstart to Ad Blocking</title>
+<!--
+ NOTE: This section is deliberately redundant for those that don't
+ want to read the whole thing (which is getting lengthy).
+-->
+<para>
+ Ad blocking is but one of <application>Privoxy's</application>
+ array of features. Many of these features are for the technically minded advanced
+ user. But, ad and banner blocking is surely common ground for everybody.
+</para>
+<para>
+ This section will provide a quick summary of ad blocking so
+ you can get up to speed quickly without having to read the more extensive
+ information provided below, though this is highly recommended.
+</para>
+<para>
+ First a bit of a warning ... blocking ads is much like blocking SPAM: the
+ more aggressive you are about it, the more likely you are to block
+ things that were not intended. And the more likely that some things
+ may not work as intended. So there is a trade off here. If you want
+ extreme ad free browsing, be prepared to deal with more
+ <quote>problem</quote> sites, and to spend more time adjusting the
+ configuration to solve these unintended consequences. In short, there is
+ not an easy way to eliminate <emphasis>all</emphasis> ads. Either take
+ the easy way and settle for <emphasis>most</emphasis> ads blocked with the
+ default configuration, or jump in and tweak it for your personal surfing
+ habits and preferences.
+</para>
+<para>
+ Secondly, a brief explanation of <application>Privoxy's </application>
+ <quote>actions</quote>. <quote>Actions</quote> in this context, are
+ the directives we use to tell <application>Privoxy</application> to perform
+ some task relating to HTTP transactions (i.e. web browsing). We tell
+ <application>Privoxy</application> to take some <quote>action</quote>. Each
+ action has a unique name and function. While there are many potential
+ <application>actions</application> in <application>Privoxy's</application>
+ arsenal, only a few are used for ad blocking. <link
+ linkend="actions">Actions</link>, and <link linkend="actions-file">action
+ configuration files</link>, are explained in depth below.
+</para>
+<para>
+ Actions are specified in <application>Privoxy's</application> configuration,
+ followed by one or more URLs to which the action should apply. URLs
+ can actually be URL type <link linkend="af-patterns">patterns</link> that use
+ wildcards so they can apply potentially to a range of similar URLs. The
+ actions, together with the URL patterns are called a section.
+</para>
+<para>
+ When you connect to a website, the full URL will either match one or more
+ of the sections as defined in <application>Privoxy's</application> configuration,
+ or not. If so, then <application>Privoxy</application> will perform the
+ respective actions. If not, then nothing special happens. Furthermore, web
+ pages may contain embedded, secondary URLs that your web browser will
+ use to load additional components of the page, as it parses the
+ original page's HTML content. An ad image for instance, is just an URL
+ embedded in the page somewhere. The image itself may be on the same server,
+ or a server somewhere else on the Internet. Complex web pages will have many
+ such embedded URLs. &my-app; can deal with each URL individually, so, for
+ instance, the main page text is not touched, but images from such-and-such
+ server are blocked.
+</para>
+
+<para>
+ The most important actions for basic ad blocking are: <literal><link
+ linkend="block">block</link></literal>, <literal><link
+ linkend="handle-as-image">handle-as-image</link></literal>,
+ <literal><link
+ linkend="handle-as-empty-document">handle-as-empty-document</link></literal>,and
+ <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>:
+</para>
+
+<para>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ <literal><link linkend="block">block</link></literal> - this is perhaps
+ the single most used action, and is particularly important for ad blocking.
+ This action stops any contact between your browser and any URL patterns
+ that match this action's configuration. It can be used for blocking ads,
+ but also anything that is determined to be unwanted. By itself, it simply
+ stops any communication with the remote server and sends
+ <application>Privoxy</application>'s own built-in BLOCKED page instead to
+ let you now what has happened (with some exceptions, see below).
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <literal><link linkend="handle-as-image">handle-as-image</link></literal> -
+ tells <application>Privoxy</application> to treat this URL as an image.
+ <application>Privoxy</application>'s default configuration already does this
+ for all common image types (e.g. GIF), but there are many situations where this
+ is not so easy to determine. So we'll force it in these cases. This is particularly
+ important for ad blocking, since only if we know that it's an image of
+ some kind, can we replace it with an image of our choosing, instead of the
+ <application>Privoxy</application> BLOCKED page (which would only result in
+ a <quote>broken image</quote> icon). There are some limitations to this
+ though. For instance, you can't just brute-force an image substitution for
+ an entire HTML page in most situations.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <literal><link linkend="handle-as-empty-document">handle-as-empty-document</link></literal> -
+ sends an empty document instead of <application>Privoxy's</application>
+ normal BLOCKED HTML page. This is useful for file types that are neither
+ HTML nor images, such as blocking JavaScript files.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <literal><link
+ linkend="set-image-blocker">set-image-blocker</link></literal> - tells
+ <application>Privoxy</application> what to display in place of an ad image that
+ has hit a block rule. For this to come into play, the URL must match a
+ <literal><link linkend="block">block</link></literal> action somewhere in the
+ configuration, <emphasis>and</emphasis>, it must also match an
+ <literal><link linkend="handle-as-image">handle-as-image</link></literal> action.
+ </para>
+ <para>
+ The configuration options on what to display instead of the ad are:
+ </para>
+ <simplelist>
+ <member>
+ <emphasis>pattern</emphasis> - a checkerboard pattern, so that an ad
+ replacement is obvious. This is the default.
+ </member>
+ </simplelist>
+ <simplelist>
+ <member>
+ <emphasis>blank</emphasis> - A very small empty GIF image is displayed.
+ This is the so-called <quote>invisible</quote> configuration option.
+ </member>
+ </simplelist>
+ <simplelist>
+ <member>
+ <emphasis>http://<URL></emphasis> - A redirect to any image anywhere
+ of the user's choosing (advanced usage).
+ </member>
+ </simplelist>
+ </listitem>
+
+</itemizedlist>
+</para>
+
+<para>
+ Advanced users will eventually want to explore &my-app;
+ <literal><link linkend="filter">filters</link></literal> as well. Filters
+ are very different from <literal><link
+ linkend="block">blocks</link></literal>.
+ A <quote>block</quote> blocks a site, page, or unwanted contented. Filters
+ are a way of filtering or modifying what is actually on the page. An example
+ filter usage: a text replacement of <quote>no-no</quote> for
+ <quote>nasty-word</quote>. That is a very simple example. This process can be
+ used for ad blocking, but it is more in the realm of advanced usage and has
+ some pitfalls to be wary off.
+</para>
+
+<para>
+ The quickest way to adjust any of these settings is with your browser through
+ the special <application>Privoxy</application> editor at <ulink
+ url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
+ (shortcut: <ulink url="http://p.p/">http://p.p/show-status</ulink>). This
+ is an internal page, and does not require Internet access.
+</para>
+
+<para>
+ Note that as of <application>Privoxy</application> 3.0.7 beta the
+ action editor is disabled by default. Check the
+ <ulink url="config.html#ENABLE-EDIT-ACTIONS">enable-edit-actions
+ section in the configuration file</ulink> to learn why and in which
+ cases it's safe to enable again.
+</para>
+
+<para>
+ If you decided to enable the action editor, select the appropriate
+ <quote>actions</quote> file, and click
+ <quote><guibutton>Edit</guibutton></quote>. It is best to put personal or
+ local preferences in <filename>user.action</filename> since this is not
+ meant to be overwritten during upgrades, and will over-ride the settings in
+ other files. Here you can insert new <quote>actions</quote>, and URLs for ad
+ blocking or other purposes, and make other adjustments to the configuration.
+ <application>Privoxy</application> will detect these changes automatically.
+</para>
+
+<para>
+ A quick and simple step by step example:
+</para>
+
+<para>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Right click on the ad image to be blocked, then select
+ <quote><guimenuitem>Copy Link Location</guimenuitem></quote> from the
+ pop-up menu.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Set your browser to
+ <ulink
+ url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Find <filename>user.action</filename> in the top section, and click
+ on <quote><guibutton>Edit</guibutton></quote>:
+ </para>
+
+ <!-- image of editor and actions files selections -->
+ <para>
+ <figure pgwide="0" float="0"><title>Actions Files in Use</title>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="files-in-use.jpg" format="jpg">
+ </imageobject>
+ <textobject>
+ <phrase>[ Screenshot of Actions Files in Use ]</phrase>
+ </textobject>
+ </mediaobject>
+ </figure>
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ You should have a section with only
+ <literal><link linkend="block">block</link></literal> listed under
+ <quote>Actions:</quote>.
+ If not, click a <quote><guibutton>Insert new section below</guibutton></quote>
+ button, and in the new section that just appeared, click the
+ <guibutton>Edit</guibutton> button right under the word <quote>Actions:</quote>.
+ This will bring up a list of all actions. Find
+ <literal><link linkend="block">block</link></literal> near the top, and click
+ in the <quote>Enabled</quote> column, then <quote><guibutton>Submit</guibutton></quote>
+ just below the list.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Now, in the <literal><link linkend="block">block</link></literal> actions section,
+ click the <quote><guibutton>Add</guibutton></quote> button, and paste the URL the
+ browser got from <quote><guimenuitem>Copy Link Location</guimenuitem></quote>.
+ Remove the <literal>http://</literal> at the beginning of the URL. Then, click
+ <quote><guibutton>Submit</guibutton></quote> (or
+ <quote><guibutton>OK</guibutton></quote> if in a pop-up window).
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Now go back to the original page, and press <keycap>SHIFT-Reload</keycap>
+ (or flush all browser caches). The image should be gone now.
+ </para>
+ </listitem>
+
+ </itemizedlist>
+</para>
+
+<para>
+ This is a very crude and simple example. There might be good reasons to use a
+ wildcard pattern match to include potentially similar images from the same
+ site. For a more extensive explanation of <quote>patterns</quote>, and
+ the entire actions concept, see <link linkend="actions-file">the Actions
+ section</link>.
+</para>
+
+<para>
+ For advanced users who want to hand edit their config files, you might want
+ to now go to the <link linkend="act-examples">Actions Files Tutorial</link>.
+ The ideas explained therein also apply to the web-based editor.
+</para>
+<para>
+ There are also various
+ <link linkend="filter">filters</link> that can be used for ad blocking
+ (filters are a special subset of actions). These
+ fall into the <quote>advanced</quote> usage category, and are explained in
+ depth in later sections.
+</para>
+
+</sect2>
+
+</sect1>
+
+<!-- ~ End section ~ -->
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect1 id="startup">
+<title>Starting Privoxy</title>
+<para>
+ Before launching <application>Privoxy</application> for the first time, you
+ will want to configure your browser(s) to use
+ <application>Privoxy</application> as a HTTP and HTTPS (SSL)
+ <ulink url="http://en.wikipedia.org/wiki/Proxy_server">proxy</ulink>. The default is
+ 127.0.0.1 (or localhost) for the proxy address, and port 8118 (earlier versions
+ used port 8000). This is the one configuration step <emphasis>that must be done
+</emphasis>!
+</para>
+<para>
+ Please note that <application>Privoxy</application> can only proxy HTTP and
+ HTTPS traffic. It will not work with FTP or other protocols.
+</para>
+
+ <!-- image of Mozilla Proxy configuration -->
+ <para>
+ <figure pgwide="0" float="0"><title>Proxy Configuration Showing
+ Mozilla/Netscape HTTP and HTTPS (SSL) Settings</title>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="proxy_setup.jpg" format="jpg">
+ </imageobject>
+ <textobject>
+ <phrase>[ Screenshot of Mozilla Proxy Configuration ]</phrase>
+ </textobject>
+ </mediaobject>
+ </figure>
+ </para>
+
+
+<para>
+ With <application>Firefox</application>, this is typically set under:
+</para>
+
+<literallayout>
+ <guibutton>Tools</guibutton> -> <guibutton>Options</guibutton> -> <guibutton>Advanced</guibutton> -> <guibutton>Network</guibutton> -><guibutton>Connection</guibutton> -> <guibutton>Settings</guibutton>
+
+</literallayout>
+
+<para>
+ Or optionally on some platforms:
+</para>
+
+<literallayout>
+ <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>General</guibutton> -> <guibutton>Connection Settings</guibutton> -> <guibutton>Manual Proxy Configuration</guibutton>
+
+</literallayout>
+
+
+<para>
+ With <application>Netscape</application> (and
+ <application>Mozilla</application>), this can be set under:
+</para>
+
+
+<literallayout>
+<!-- Mix ascii and gui art, something for everybody -->
+<!-- spacing on this is tricky -->
+ <guibutton>Edit</guibutton> -> <guibutton>Preferences</guibutton> -> <guibutton>Advanced</guibutton> -> <guibutton>Proxies</guibutton> -> <guibutton>HTTP Proxy</guibutton>
+
+</literallayout>
+
+<para>
+ For <application>Internet Explorer v.5-7</application>:
+</para>
+
+<literallayout>
+ <guibutton>Tools</guibutton> -> <guibutton>Internet Options</guibutton> -> <guibutton>Connections</guibutton> -> <guibutton>LAN Settings</guibutton>
+</literallayout>
+
+<para>
+ Then, check <quote>Use Proxy</quote> and fill in the appropriate info
+ (Address: 127.0.0.1, Port: 8118). Include HTTPS (SSL), if you want HTTPS
+ proxy support too (sometimes labeled <quote>Secure</quote>). Make sure any
+ checkboxes like <quote>Use the same proxy server for all protocols</quote> is
+ <emphasis>UNCHECKED</emphasis>. You want only HTTP and HTTPS (SSL)!
+</para>
+
+ <!-- image of IE Proxy configuration -->
+ <para>
+ <figure pgwide="0" float="0"><title>Proxy Configuration Showing
+ Internet Explorer HTTP and HTTPS (Secure) Settings</title>
+ <mediaobject>
+ <imageobject>
+ <imagedata fileref="proxy2.jpg" format="jpg">
+ </imageobject>
+ <textobject>
+ <phrase>[ Screenshot of IE Proxy Configuration ]</phrase>
+ </textobject>
+ </mediaobject>
+ </figure>
+ </para>
+
+
+<para>
+ After doing this, flush your browser's disk and memory caches to force a
+ re-reading of all pages and to get rid of any ads that may be cached. Remove
+ any <ulink url="http://en.wikipedia.org/wiki/Browser_cookie">cookies</ulink>,
+ if you want <application>Privoxy</application> to manage that. You are now
+ ready to start enjoying the benefits of using
+ <application>Privoxy</application>!
+</para>
+
+<para>
+ <application>Privoxy</application> itself is typically started by specifying the
+ main configuration file to be used on the command line. If no configuration
+ file is specified on the command line, <application>Privoxy</application>
+ will look for a file named <filename>config</filename> in the current
+ directory. Except on Win32 where it will try <filename>config.txt</filename>.
+</para>
+
+<sect2 id="start-redhat">
+<title>Red Hat and Fedora</title>
+<para>
+ A default Red Hat installation may not start &my-app; upon boot. It will use
+ the file <filename>/etc/privoxy/config</filename> as its main configuration
+ file.
+</para>
+<para>
+ <screen>
+ # /etc/rc.d/init.d/privoxy start
+</screen>
+</para>
+<para>
+ Or ...
+</para>
+<para>
+ <screen>
+ # service privoxy start
+</screen>
+</para>
+</sect2>
+
+<sect2 id="start-debian">
+<title>Debian</title>
+<para>
+ We use a script. Note that Debian typically starts &my-app; upon booting per
+ default. It will use the file
+ <filename>/etc/privoxy/config</filename> as its main configuration
+ file.
+</para>
+<para>
+ <screen>
+ # /etc/init.d/privoxy start
+</screen>
+</para>
+</sect2>
+
+<sect2 id="start-windows">
+<title>Windows</title>
+<para>
+Click on the &my-app; Icon to start <application>Privoxy</application>. If no configuration file is
+ specified on the command line, <application>Privoxy</application> will look
+ for a file named <filename>config.txt</filename>. Note that Windows will
+ automatically start &my-app; when the system starts if you chose that option
+ when installing.
+</para>
+<para>
+ <application>Privoxy</application> can run with full Windows service functionality.
+ On Windows only, the &my-app; program has two new command line arguments
+ to install and uninstall &my-app; as a service. See the
+ <link linkend="installation-pack-win">Windows Installation
+ instructions</link> for details.
+</para>
+</sect2>
+
+<sect2 id="start-unices">
+<title>Solaris, NetBSD, FreeBSD, HP-UX and others</title>
+<para>
+Example Unix startup command:
+</para>
+<para>
+ <screen>
+ # /usr/sbin/privoxy /etc/privoxy/config
+</screen>
+</para>
+</sect2>
+
+<sect2 id="start-os2">
+<title>OS/2</title>
+<para>
+ During installation, <application>Privoxy</application> is configured to
+ start automatically when the system restarts. You can start it manually by
+ double-clicking on the <application>Privoxy</application> icon in the
+ <application>Privoxy</application> folder.
+</para>
+</sect2>
+
+<sect2 id="start-macosx">
+<title>Mac OS X</title>
+<para>
+ After downloading the privoxy software, unzip the downloaded file by
+ double-clicking on the zip file icon. Then, double-click on the
+ installer package icon and follow the installation process.
+</para>
+<para>
+ The privoxy service will automatically start after a successful
+ installation. In addition, the privoxy service will automatically
+ start every time your computer starts up.
+</para>
+<para>
+ To prevent the privoxy service from automatically starting when your
+ computer starts up, remove or rename the folder named
+ /Library/StartupItems/Privoxy.
+</para>
+<para>
+ A simple application named Privoxy Utility has been created which
+ enables administrators to easily start and stop the privoxy service.
+</para>
+<para>
+ In addition, the Privoxy Utility presents a simple way for
+ administrators to edit the various privoxy config files. A method
+ to uninstall the software is also available.
+</para>
+<para>
+ An administrator username and password must be supplied in order for
+ the Privoxy Utility to perform any of the tasks.
+</para>
+</sect2>
+
+
+<sect2 id="start-amigaos">
+<title>AmigaOS</title>
+<para>
+ Start <application>Privoxy</application> (with RUN <>NIL:) in your
+ <filename>startnet</filename> script (AmiTCP), in
+ <filename>s:user-startup</filename> (RoadShow), as startup program in your
+ startup script (Genesis), or as startup action (Miami and MiamiDx).
+ <application>Privoxy</application> will automatically quit when you quit your
+ TCP/IP stack (just ignore the harmless warning your TCP/IP stack may display that
+ <application>Privoxy</application> is still running).
+</para>
+</sect2>
+
+<sect2 id="start-gentoo">
+<title>Gentoo</title>
+<para>
+ A script is again used. It will use the file <filename>/etc/privoxy/config
+ </filename> as its main configuration file.
+</para>
+<para>
+ <screen>
+ /etc/init.d/privoxy start
+ </screen>
+</para>
+<para>
+ Note that <application>Privoxy</application> is not automatically started at
+ boot time by default. You can change this with the <literal>rc-update</literal>
+ command.
+</para>
+<para>
+ <screen>
+ rc-update add privoxy default
+ </screen>
+</para>
+</sect2>
+
+<!--
+
+<para>
+ See the section <link linkend="cmdoptions">Command line options</link> for
+ further info.
+</para>
+
+must find a better place for this paragraph
+
+<para>
+ The included default configuration files should give a reasonable starting
+ point. Most of the per site configuration is done in the
+ <ulink url="actions-file.html"><quote>actions</quote></ulink> files. These are
+ where various cookie actions are defined, ad and banner blocking, and other
+ aspects of <application>Privoxy</application> configuration. There are several
+ such files included, with varying levels of aggressiveness.
+</para>
+
+<para>
+ You will probably want to keep an eye out for sites for which you may prefer
+ persistent cookies, and add these to your actions configuration as needed. By
+ default, most of these will be accepted only during the current browser
+ session (aka <quote>session cookies</quote>), unless you add them to the
+ configuration. If you want the browser to handle this instead, you will need
+ to edit <filename>user.action</filename> (or through the web based interface)
+ and disable this feature. If you use more than one browser, it would make
+ more sense to let <application>Privoxy</application> handle this. In which
+ case, the browser(s) should be set to accept all cookies.
+</para>
+
+<para>
+ Another feature where you will probably want to define exceptions for trusted
+ sites is the popup-killing (through <ulink
+ url="actions-file.html#FILTER-POPUPS"><quote>+filter{popups}</quote></ulink>),
+ because your favorite shopping, banking, or leisure site may need
+ popups (explained below).
+</para>
+
+<para>
+ <application>Privoxy</application> does not support all of the optional HTTP/1.1
+ features yet. In the unlikely event that you experience inexplicable problems
+ with browsers that use HTTP/1.1 per default
+ (like <application>Mozilla</application> or recent versions of I.E.), you might
+ try to force HTTP/1.0 compatibility. For Mozilla, look under <literal>Edit ->
+ Preferences -> Debug -> Networking</literal>.
+ Alternatively, set the <quote>+downgrade-http-version</quote> config option in
+ <filename>default.action</filename> which will downgrade your browser's HTTP
+ requests from HTTP/1.1 to HTTP/1.0 before processing them.
+</para>
+
+<para>
+ After running <application>Privoxy</application> for a while, you can
+ start to fine tune the configuration to suit your personal, or site,
+ preferences and requirements. There are many, many aspects that can
+ be customized. <quote>Actions</quote>
+ can be adjusted by pointing your browser to
+ <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
+ (shortcut: <ulink url="http://p.p/">http://p.p/</ulink>),
+ and then follow the link to <quote>View & Change the Current Configuration</quote>.
+ (This is an internal page and does not require Internet access.)
+</para>
+
+<para>
+ In fact, various aspects of <application>Privoxy</application>
+ configuration can be viewed from this page, including
+ current configuration parameters, source code version numbers,
+ the browser's request headers, and <quote>actions</quote> that apply
+ to a given URL. In addition to the actions file
+ editor mentioned above, <application>Privoxy</application> can also
+ be turned <quote>on</quote> and <quote>off</quote> (toggled) from this page.
+</para>
+
+<para>
+ If you encounter problems, try loading the page without
+ <application>Privoxy</application>. If that helps, enter the URL where
+ you have the problems into <ulink url="http://p.p/show-url-info">the browser
+ based rule tracing utility</ulink>. See which rules apply and why, and
+ then try turning them off for that site one after the other, until the problem
+ is gone. When you have found the culprit, you might want to turn the rest on
+ again.
+</para>
+
+<para>
+ If the above paragraph sounds gibberish to you, you might want to <link
+ linkend="actions-file">read more about the actions concept</link>
+ or even dive deep into the <link linkend="actionsanat">Appendix
+ on actions</link>.
+</para>
+
+<para>
+ If you can't get rid of the problem at all, think you've found a bug in
+ Privoxy, want to propose a new feature or smarter rules, please see the
+ section <link linkend="contact"><quote>Contacting the
+ Developers</quote></link> below.
+</para>
+
+-->
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect2 id="cmdoptions">
+<title>Command Line Options</title>
+<para>
+ <application>Privoxy</application> may be invoked with the following
+ command-line options:
+</para>
+
+<para>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ <emphasis>--version</emphasis>
+ </para>
+ <para>
+ Print version info and exit. Unix only.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <emphasis>--help</emphasis>
+ </para>
+ <para>
+ Print short usage info and exit. Unix only.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <emphasis>--no-daemon</emphasis>
+ </para>
+ <para>
+ Don't become a daemon, i.e. don't fork and become process group
+ leader, and don't detach from controlling tty. Unix only.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <emphasis>--pidfile FILE</emphasis>
+ </para>
+ <para>
+ On startup, write the process ID to <emphasis>FILE</emphasis>. Delete the
+ <emphasis>FILE</emphasis> on exit. Failure to create or delete the
+ <emphasis>FILE</emphasis> is non-fatal. If no <emphasis>FILE</emphasis>
+ option is given, no PID file will be used. Unix only.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <emphasis>--user USER[.GROUP]</emphasis>
+ </para>
+ <para>
+ After (optionally) writing the PID file, assume the user ID of
+ <emphasis>USER</emphasis>, and if included the GID of GROUP. Exit if the
+ privileges are not sufficient to do so. Unix only.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <emphasis>--chroot</emphasis>
+ </para>
+ <para>
+ Before changing to the user ID given in the <emphasis>--user</emphasis> option,
+ chroot to that user's home directory, i.e. make the kernel pretend to the &my-app;
+ process that the directory tree starts there. If set up carefully, this can limit
+ the impact of possible vulnerabilities in &my-app; to the files contained in that hierarchy.
+ Unix only.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <emphasis>--pre-chroot-nslookup hostname</emphasis>
+ </para>
+ <para>
+ Specifies a hostname to look up before doing a chroot. On some systems, initializing the
+ resolver library involves reading config files from /etc and/or loading additional shared
+ libraries from /lib. On these systems, doing a hostname lookup before the chroot reduces
+ the number of files that must be copied into the chroot tree.
+ </para>
+ <para>
+ For fastest startup speed, a good value is a hostname that is not in /etc/hosts but that
+ your local name server (listed in /etc/resolv.conf) can resolve without recursion
+ (that is, without having to ask any other name servers). The hostname need not exist,
+ but if it doesn't, an error message (which can be ignored) will be output.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <emphasis>configfile</emphasis>
+ </para>
+ <para>
+ If no <emphasis>configfile</emphasis> is included on the command line,
+ <application>Privoxy</application> will look for a file named
+ <quote>config</quote> in the current directory (except on Win32
+ where it will look for <quote>config.txt</quote> instead). Specify
+ full path to avoid confusion. If no config file is found,
+ <application>Privoxy</application> will fail to start.
+ </para>
+ </listitem>
+
+ </itemizedlist>
+</para>
+
+<para>
+ On <application>MS Windows</application> only there are two additional
+ command-line options to allow <application>Privoxy</application> to install and
+ run as a <emphasis>service</emphasis>. See the
+<link linkend="installation-pack-win">Window Installation section</link>
+for details.
+</para>
+
+</sect2>
+
+</sect1>
+
+<!-- ~ End section ~ -->
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect1 id="configuration"><title>Privoxy Configuration</title>
+ <para>
+ All <application>Privoxy</application> configuration is stored
+ in text files. These files can be edited with a text editor.
+ Many important aspects of <application>Privoxy</application> can
+ also be controlled easily with a web browser.
+ </para>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+
+<sect2>
+<title>Controlling Privoxy with Your Web Browser</title>
+<para>
+ <application>Privoxy</application>'s user interface can be reached through the special
+ URL <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
+ (shortcut: <ulink url="http://p.p/">http://p.p/</ulink>),
+ which is a built-in page and works without Internet access.
+ You will see the following section:
+
+</para>
+
+<!-- Needs to be put in a table and colorized -->
+<screen>
+ <msgtext>
+ <bridgehead renderas="sect2"> Privoxy Menu</bridgehead>
+
+ <simplelist>
+ <member>
+ ▪ <ulink url="http://config.privoxy.org/show-status">View & change the current configuration</ulink>
+ </member>
+ <member>
+ ▪ <ulink url="http://config.privoxy.org/show-version">View the source code version numbers</ulink>
+ </member>
+ <member>
+ ▪ <ulink url="http://config.privoxy.org/show-request">View the request headers.</ulink>
+ </member>
+ <member>
+ ▪ <ulink url="http://config.privoxy.org/show-url-info">Look up which actions apply to a URL and why</ulink>
+ </member>
+ <member>
+ ▪ <ulink url="http://config.privoxy.org/toggle">Toggle Privoxy on or off</ulink>
+ </member>
+ <member>
+ ▪ <ulink
+ url="http://www.privoxy.org/&p-version;/user-manual/">Documentation</ulink>
+ </member>
+ </simplelist>
+ </msgtext>
+</screen>
+
+
+<para>
+ This should be self-explanatory. Note the first item leads to an editor for the
+ <link linkend="actions-file">actions files</link>, which is where the ad, banner,
+ cookie, and URL blocking magic is configured as well as other advanced features of
+ <application>Privoxy</application>. This is an easy way to adjust various
+ aspects of <application>Privoxy</application> configuration. The actions
+ file, and other configuration files, are explained in detail below.
+</para>
+
+<para>
+ <quote>Toggle Privoxy On or Off</quote> is handy for sites that might
+ have problems with your current actions and filters. You can in fact use
+ it as a test to see whether it is <application>Privoxy</application>
+ causing the problem or not. <application>Privoxy</application> continues
+ to run as a proxy in this case, but all manipulation is disabled, i.e.
+ <application>Privoxy</application> acts like a normal forwarding proxy. There
+ is even a toggle <link linkend="bookmarklets">Bookmarklet</link> offered, so
+ that you can toggle <application>Privoxy</application> with one click from
+ your browser.
+</para>
+
+<para>
+ Note that several of the features described above are disabled by default
+ in <application>Privoxy</application> 3.0.7 beta and later.
+ Check the
+ <ulink url="config.html">configuration file</ulink> to learn why
+ and in which cases it's safe to enable them again.
+</para>
+
+</sect2>
+
+<!-- ~ End section ~ -->
+
+
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+
+<sect2 id="confoverview">
+<title>Configuration Files Overview</title>
+<para>
+ For Unix, *BSD and Linux, all configuration files are located in
+ <filename>/etc/privoxy/</filename> by default. For MS Windows, OS/2, and
+ AmigaOS these are all in the same directory as the
+ <application>Privoxy</application> executable. <![%p-not-stable;[ The name
+ and number of configuration files has changed from previous versions, and is
+ subject to change as development progresses.]]>
+</para>
+
+<para>
+ The installed defaults provide a reasonable starting point, though
+ some settings may be aggressive by some standards. For the time being, the
+ principle configuration files are:
+</para>
+
+<para>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ The <link linkend="config">main configuration file</link> is named <filename>config</filename>
+ on Linux, Unix, BSD, OS/2, and AmigaOS and <filename>config.txt</filename>
+ on Windows. This is a required file.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <filename>match-all.action</filename> is used to define which <quote>actions</quote>
+ relating to banner-blocking, images, pop-ups, content modification, cookie handling
+ etc should be applied by default. It should be the first actions file loaded.
+ </para>
+ <para>
+ <filename>default.action</filename> defines many exceptions (both positive and negative)
+ from the default set of actions that's configured in <filename>match-all.action</filename>.
+ It should be the second actions file loaded and shouldn't be edited by the user.
+ </para>
+ <para>
+ Multiple actions files may be defined in <filename>config</filename>. These
+ are processed in the order they are defined. Local customizations and locally
+ preferred exceptions to the default policies as defined in
+ <filename>match-all.action</filename> (which you will most probably want
+ to define sooner or later) are best applied in <filename>user.action</filename>,
+ where you can preserve them across upgrades. The file isn't installed by all
+ installers, but you can easily create it yourself with a text editor.
+ </para>
+ <para>
+ There is also a web based editor that can be accessed from
+ <ulink
+ url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
+ (Shortcut: <ulink
+ url="http://p.p/show-status">http://p.p/show-status</ulink>) for the
+ various actions files.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <quote>Filter files</quote> (the <link linkend="filter-file">filter
+ file</link>) can be used to re-write the raw page content, including
+ viewable text as well as embedded HTML and JavaScript, and whatever else
+ lurks on any given web page. The filtering jobs are only pre-defined here;
+ whether to apply them or not is up to the actions files.
+ <filename>default.filter</filename> includes various filters made
+ available for use by the developers. Some are much more intrusive than
+ others, and all should be used with caution. You may define additional
+ filter files in <filename>config</filename> as you can with
+ actions files. We suggest <filename>user.filter</filename> for any
+ locally defined filters or customizations.
+ </para>
+ </listitem>
+
+ </itemizedlist>
+</para>
+
+<para>
+ The syntax of the configuration and filter files may change between different
+ Privoxy versions, unfortunately some enhancements cost backwards compatibility.
+ <!-- Add link to documentation-->
+</para>
+
+<para>
+ All files use the <quote><literal>#</literal></quote> character to denote a
+ comment (the rest of the line will be ignored) and understand line continuation
+ through placing a backslash ("<literal>\</literal>") as the very last character
+ in a line. If the <literal>#</literal> is preceded by a backslash, it looses
+ its special function. Placing a <literal>#</literal> in front of an otherwise
+ valid configuration line to prevent it from being interpreted is called "commenting
+ out" that line. Blank lines are ignored.
+</para>
+
+<para>
+ The actions files and filter files
+ can use Perl style <link linkend="regex">regular expressions</link> for
+ maximum flexibility.
+</para>
+
+<para>
+ After making any changes, there is no need to restart
+ <application>Privoxy</application> in order for the changes to take
+ effect. <application>Privoxy</application> detects such changes
+ automatically. Note, however, that it may take one or two additional
+ requests for the change to take effect. When changing the listening address
+ of <application>Privoxy</application>, these <quote>wake up</quote> requests
+ must obviously be sent to the <emphasis>old</emphasis> listening address.
+</para>
+
+<![%p-not-stable;[
+<para>
+ While under development, the configuration content is subject to change.
+ The below documentation may not be accurate by the time you read this.
+ Also, what constitutes a <quote>default</quote> setting, may change, so
+ please check all your configuration files on important issues.
+</para>
+]]>
+
+</sect2>
+</sect1>
+<!-- ~ End section ~ -->
+
+
+<!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
+
+<!-- **************************************************** -->
+<!-- Include config.sgml here -->
+<!-- This is where the entire config file is detailed. -->
+ &config;
+<!-- end include -->
+
+
+<!-- ~ End section ~ -->
+
+
+
+<!-- ~~~~~~~~ New section Header ~~~~~~~~~ -->
+
+<sect1 id="actions-file"><title>Actions Files</title>
+
+
+<!--
+ XXX: similar descriptions are in the Configuration Files sections.
+ We should only describe them at one place.
+-->
+<para>
+ The actions files are used to define what <emphasis>actions</emphasis>
+ <application>Privoxy</application> takes for which URLs, and thus determines
+ how ad images, cookies and various other aspects of HTTP content and
+ transactions are handled, and on which sites (or even parts thereof).
+ There are a number of such actions, with a wide range of functionality.
+ Each action does something a little different.
+ These actions give us a veritable arsenal of tools with which to exert
+ our control, preferences and independence. Actions can be combined so that
+ their effects are aggregated when applied against a given set of URLs.
+</para>
+<para>
+ There
+ are three action files included with <application>Privoxy</application> with
+ differing purposes:
+</para>
+<para>
+ <itemizedlist>
+ <listitem>
+ <para>
+ <filename>match-all.action</filename> - is used to define which
+ <quote>actions</quote> relating to banner-blocking, images, pop-ups,
+ content modification, cookie handling etc should be applied by default.
+ It should be the first actions file loaded
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <filename>default.action</filename> - defines many exceptions (both
+ positive and negative) from the default set of actions that's configured
+ in <filename>match-all.action</filename>. It is a set of rules that should
+ work reasonably well as-is for most users. This file is only supposed to
+ be edited by the developers. It should be the second actions file loaded.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <filename>user.action</filename> - is intended to be for local site
+ preferences and exceptions. As an example, if your ISP or your bank
+ has specific requirements, and need special handling, this kind of
+ thing should go here. This file will not be upgraded.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <guibutton>Edit</guibutton> <guibutton>Set to Cautious</guibutton> <guibutton>Set to Medium</guibutton> <guibutton>Set to Advanced</guibutton>
+ </para>
+ <para>
+ These have increasing levels of aggressiveness <emphasis>and have no
+ influence on your browsing unless you select them explicitly in the
+ editor</emphasis>. A default installation should be pre-set to
+ <literal>Cautious</literal>. New users should try this for a while before
+ adjusting the settings to more aggressive levels. The more aggressive
+ the settings, then the more likelihood there is of problems such as sites
+ not working as they should.
+ </para>
+ <para>
+ The <guibutton>Edit</guibutton> button allows you to turn each
+ action on/off individually for fine-tuning. The <guibutton>Cautious</guibutton>
+ button changes the actions list to low/safe settings which will activate
+ ad blocking and a minimal set of &my-app;'s features, and subsequently
+ there will be less of a chance for accidental problems. The
+ <guibutton>Medium</guibutton> button sets the list to a medium level of
+ other features and a low level set of privacy features. The
+ <guibutton>Advanced</guibutton> button sets the list to a high level of
+ ad blocking and medium level of privacy. See the chart below. The latter
+ three buttons over-ride any changes via with the
+ <guibutton>Edit</guibutton> button. More fine-tuning can be done in the
+ lower sections of this internal page.
+ </para>
+ <para>
+ While the actions file editor allows to enable these settings in all
+ actions files, they are only supposed to be enabled in the first one
+ to make sure you don't unintentionally overrule earlier rules.
+ </para>
+ <para>
+ The default profiles, and their associated actions, as pre-defined in
+ <filename>default.action</filename> are:
+ </para>
+ <para>
+ <table frame=all><title>Default Configurations</title>
+ <tgroup cols=4 align=left colsep=1 rowsep=1>
+ <colspec colname=c1>
+ <colspec colname=c2>
+ <colspec colname=c3>
+ <colspec colname=c4>
+ <thead>
+ <row>
+ <entry>Feature</entry>
+ <entry>Cautious</entry>
+ <entry>Medium</entry>
+ <entry>Advanced</entry>
+ </row>
+ </thead>
+ <!-- <tfoot> -->
+ <!-- <row> -->
+ <!-- <entry>f1</entry> -->
+ <!-- <entry>f2</entry> -->
+ <!-- <entry>f3</entry> -->
+ <!-- <entry>f4</entry> -->
+ <!-- </row> -->
+ <!-- </tfoot> -->
+ <tbody>
+
+ <row>
+ <entry>Ad-blocking Aggressiveness</entry>
+ <entry>medium</entry>
+ <entry>high</entry>
+ <entry>high</entry>
+ </row>
+
+ <row>
+ <entry>Ad-filtering by size</entry>
+ <entry>no</entry>
+ <entry>yes</entry>
+ <entry>yes</entry>
+ </row>
+
+ <row>
+ <entry>Ad-filtering by link</entry>
+ <entry>no</entry>
+ <entry>no</entry>
+ <entry>yes</entry>
+ </row>
+ <row>
+ <entry>Pop-up killing</entry>
+ <entry>blocks only</entry>
+ <entry>blocks only</entry>
+ <entry>blocks only</entry>
+ </row>
+
+ <row>
+ <entry>Privacy Features</entry>
+ <entry>low</entry>
+ <entry>medium</entry>
+ <entry>medium/high</entry>
+ </row>
+
+ <row>
+ <entry>Cookie handling</entry>
+ <entry>none</entry>
+ <entry>session-only</entry>
+ <entry>kill</entry>
+ </row>
+
+ <row>
+ <entry>Referer forging</entry>
+ <entry>no</entry>
+ <entry>yes</entry>
+ <entry>yes</entry>
+ </row>
+
+ <row>
+ <entry>GIF de-animation</entry>
+ <entry>no</entry>
+ <entry>yes</entry>
+ <entry>yes</entry>
+ </row>
+
+ <row>
+ <entry>Fast redirects</entry>
+ <entry>no</entry>
+ <entry>no</entry>
+ <entry>yes</entry>
+ </row>
+
+ <row>
+ <entry>HTML taming</entry>
+ <entry>no</entry>
+ <entry>no</entry>
+ <entry>yes</entry>
+ </row>
+
+ <row>
+ <entry>JavaScript taming</entry>
+ <entry>no</entry>
+ <entry>no</entry>
+ <entry>yes</entry>
+ </row>
+
+ <row>
+ <entry>Web-bug killing</entry>
+ <entry>no</entry>
+ <entry>yes</entry>
+ <entry>yes</entry>
+ </row>
+
+ <row>
+ <entry>Image tag reordering</entry>
+ <entry>no</entry>
+ <entry>yes</entry>
+ <entry>yes</entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+ </para>
+
+ </listitem>
+ </itemizedlist>
+</para>
+
+<para>
+ The list of actions files to be used are defined in the main configuration
+ file, and are processed in the order they are defined (e.g.
+ <filename>default.action</filename> is typically processed before
+ <filename>user.action</filename>). The content of these can all be viewed and
+ edited from <ulink
+ url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
+ The over-riding principle when applying actions, is that the last action that
+ matches a given URL wins. The broadest, most general rules go first
+ (defined in <filename>default.action</filename>),
+ followed by any exceptions (typically also in
+ <filename>default.action</filename>), which are then followed lastly by any
+ local preferences (typically in <emphasis>user</emphasis><filename>.action</filename>).
+ Generally, <filename>user.action</filename> has the last word.
+ </para>
+
+<para>
+ An actions file typically has multiple sections. If you want to use
+ <quote>aliases</quote> in an actions file, you have to place the (optional)
+ <link linkend="aliases">alias section</link> at the top of that file.
+ Then comes the default set of rules which will apply universally to all
+ sites and pages (be <emphasis>very careful</emphasis> with using such a
+ universal set in <filename>user.action</filename> or any other actions file after
+ <filename>default.action</filename>, because it will override the result
+ from consulting any previous file). And then below that,
+ exceptions to the defined universal policies. You can regard
+ <filename>user.action</filename> as an appendix to <filename>default.action</filename>,
+ with the advantage that it is a separate file, which makes preserving your
+ personal settings across <application>Privoxy</application> upgrades easier.
+</para>
+
+<para>
+ Actions can be used to block anything you want, including ads, banners, or
+ just some obnoxious URL whose content you would rather not see. Cookies can be accepted
+ or rejected, or accepted only during the current browser session (i.e. not
+ written to disk), content can be modified, some JavaScripts tamed, user-tracking
+ fooled, and much more. See below for a <link linkend="actions">complete list
+ of actions</link>.
+</para>
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect2>
+<title>Finding the Right Mix</title>
+<para>
+ Note that some <link linkend="actions">actions</link>, like cookie suppression
+ or script disabling, may render some sites unusable that rely on these
+ techniques to work properly. Finding the right mix of actions is not always easy and
+ certainly a matter of personal taste. And, things can always change, requiring
+ refinements in the configuration. In general, it can be said that the more
+ <quote>aggressive</quote> your default settings (in the top section of the
+ actions file) are, the more exceptions for <quote>trusted</quote> sites you
+ will have to make later. If, for example, you want to crunch all cookies per
+ default, you'll have to make exceptions from that rule for sites that you
+ regularly use and that require cookies for actually useful purposes, like maybe
+ your bank, favorite shop, or newspaper.
+</para>
+
+<para>
+ We have tried to provide you with reasonable rules to start from in the
+ distribution actions files. But there is no general rule of thumb on these
+ things. There just are too many variables, and sites are constantly changing.
+ Sooner or later you will want to change the rules (and read this chapter again :).
+</para>
+</sect2>
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect2>
+<title>How to Edit</title>
+<para>
+ The easiest way to edit the actions files is with a browser by
+ using our browser-based editor, which can be reached from <ulink
+ url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>.
+ Note: the config file option <link
+ linkend="enable-edit-actions">enable-edit-actions</link> must be enabled for
+ this to work. The editor allows both fine-grained control over every single
+ feature on a per-URL basis, and easy choosing from wholesale sets of defaults
+ like <quote>Cautious</quote>, <quote>Medium</quote> or
+ <quote>Advanced</quote>. Warning: the <quote>Advanced</quote> setting is more
+ aggressive, and will be more likely to cause problems for some sites.
+ Experienced users only!
+ </para>
+
+<para>
+ If you prefer plain text editing to GUIs, you can of course also directly edit the
+ the actions files with your favorite text editor. Look at
+ <filename>default.action</filename> which is richly commented with many
+ good examples.
+</para>
+</sect2>
+
+
+<sect2 id="actions-apply">
+<title>How Actions are Applied to Requests</title>
+<para>
+ Actions files are divided into sections. There are special sections,
+ like the <quote><link linkend="aliases">alias</link></quote> sections which will
+ be discussed later. For now let's concentrate on regular sections: They have a
+ heading line (often split up to multiple lines for readability) which consist
+ of a list of actions, separated by whitespace and enclosed in curly braces.
+ Below that, there is a list of URL and tag patterns, each on a separate line.
+</para>
+
+<para>
+ To determine which actions apply to a request, the URL of the request is
+ compared to all URL patterns in each <quote>action file</quote>.
+ Every time it matches, the list of applicable actions for the request is
+ incrementally updated, using the heading of the section in which the
+ pattern is located. The same is done again for tags and tag patterns later on.
+</para>
+
+<para>
+ If multiple applying sections set the same action differently,
+ the last match wins. If not, the effects are aggregated.
+ E.g. a URL might match a regular section with a heading line of <literal>{
+ +<link linkend="handle-as-image">handle-as-image</link> }</literal>,
+ then later another one with just <literal>{
+ +<link linkend="block">block</link> }</literal>, resulting
+ in <emphasis>both</emphasis> actions to apply. And there may well be
+ cases where you will want to combine actions together. Such a section then
+ might look like:
+</para>
+
+ <para>
+ <screen>
+ { +<literal>handle-as-image</literal> +<literal>block{Banner ads.}</literal> }
+ # Block these as if they were images. Send no block page.
+ banners.example.com
+ media.example.com/.*banners
+ .example.com/images/ads/</screen>
+ </para>
+
+<para>
+ You can trace this process for URL patterns and any given URL by visiting <ulink
+ url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>.
+</para>
+
+<para>
+ Examples and more detail on this is provided in the Appendix, <link linkend="ACTIONSANAT">
+ Troubleshooting: Anatomy of an Action</link> section.
+</para>
+</sect2>
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect2 id="af-patterns">
+<title>Patterns</title>
+<para>
+ As mentioned, <application>Privoxy</application> uses <quote>patterns</quote>
+ to determine what <emphasis>actions</emphasis> might apply to which sites and
+ pages your browser attempts to access. These <quote>patterns</quote> use wild
+ card type <emphasis>pattern</emphasis> matching to achieve a high degree of
+ flexibility. This allows one expression to be expanded and potentially match
+ against many similar patterns.
+</para>
+
+<para>
+ Generally, an URL pattern has the form
+ <literal><domain><port>/<path></literal>, where the
+ <literal><domain></literal>, the <literal><port></literal>
+ and the <literal><path></literal> are optional. (This is why the special
+ <literal>/</literal> pattern matches all URLs). Note that the protocol
+ portion of the URL pattern (e.g. <literal>http://</literal>) should
+ <emphasis>not</emphasis> be included in the pattern. This is assumed already!
+</para>
+<para>
+ The pattern matching syntax is different for the domain and path parts of
+ the URL. The domain part uses a simple globbing type matching technique,
+ while the path part uses more flexible
+ <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
+ Expressions</quote></ulink> (POSIX 1003.2).
+</para>
+<para>
+ The port part of a pattern is a decimal port number preceded by a colon
+ (<literal>:</literal>). If the domain part contains a numerical IPv6 address,
+ it has to be put into angle brackets
+ (<literal><</literal>, <literal>></literal>).
+</para>
+
+<variablelist>
+ <varlistentry>
+ <term><literal>www.example.com/</literal></term>
+ <listitem>
+ <para>
+ is a domain-only pattern and will match any request to <literal>www.example.com</literal>,
+ regardless of which document on that server is requested. So ALL pages in
+ this domain would be covered by the scope of this action. Note that a
+ simple <literal>example.com</literal> is different and would NOT match.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><literal>www.example.com</literal></term>
+ <listitem>
+ <para>
+ means exactly the same. For domain-only patterns, the trailing <literal>/</literal> may
+ be omitted.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><literal>www.example.com/index.html</literal></term>
+ <listitem>
+ <para>
+ matches all the documents on <literal>www.example.com</literal>
+ whose name starts with <literal>/index.html</literal>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><literal>www.example.com/index.html$</literal></term>
+ <listitem>
+ <para>
+ matches only the single document <literal>/index.html</literal>
+ on <literal>www.example.com</literal>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><literal>/index.html$</literal></term>
+ <listitem>
+ <para>
+ matches the document <literal>/index.html</literal>, regardless of the domain,
+ i.e. on <emphasis>any</emphasis> web server anywhere.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><literal>:8000/</literal></term>
+ <listitem>
+ <para>
+ Matches any URL pointing to TCP port 8000.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><literal><2001:db8::1>/</literal></term>
+ <listitem>
+ <para>
+ Matches any URL with the host address <literal>2001:db8::1</literal>.
+ (Note that the real URL uses plain brackets, not angle brackets.)
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><literal>index.html</literal></term>
+ <listitem>
+ <para>
+ matches nothing, since it would be interpreted as a domain name and
+ there is no top-level domain called <literal>.html</literal>. So its
+ a mistake.
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3><title>The Domain Pattern</title>
+
+<para>
+ The matching of the domain part offers some flexible options: if the
+ domain starts or ends with a dot, it becomes unanchored at that end.
+ For example:
+</para>
+
+<variablelist>
+ <varlistentry>
+ <term><literal>.example.com</literal></term>
+ <listitem>
+ <para>
+ matches any domain with first-level domain <literal>com</literal>
+ and second-level domain <literal>example</literal>.
+ For example <literal>www.example.com</literal>,
+ <literal>example.com</literal> and <literal>foo.bar.baz.example.com</literal>.
+ Note that it wouldn't match if the second-level domain was <literal>another-example</literal>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><literal>www.</literal></term>
+ <listitem>
+ <para>
+ matches any domain that <emphasis>STARTS</emphasis> with
+ <literal>www.</literal> (It also matches the domain
+ <literal>www</literal> but most of the time that doesn't matter.)
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><literal>.example.</literal></term>
+ <listitem>
+ <para>
+ matches any domain that <emphasis>CONTAINS</emphasis> <literal>.example.</literal>.
+ And, by the way, also included would be any files or documents that exist
+ within that domain since no path limitations are specified. (Correctly
+ speaking: It matches any FQDN that contains <literal>example</literal> as
+ a domain.) This might be <literal>www.example.com</literal>,
+ <literal>news.example.de</literal>, or
+ <literal>www.example.net/cgi/testing.pl</literal> for instance. All these
+ cases are matched.
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+
+<para>
+ Additionally, there are wild-cards that you can use in the domain names
+ themselves. These work similarly to shell globbing type wild-cards:
+ <quote>*</quote> represents zero or more arbitrary characters (this is
+ equivalent to the
+ <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
+ Expression</quote></ulink> based syntax of <quote>.*</quote>),
+ <quote>?</quote> represents any single character (this is equivalent to the
+ regular expression syntax of a simple <quote>.</quote>), and you can define
+ <quote>character classes</quote> in square brackets which is similar to
+ the same regular expression technique. All of this can be freely mixed:
+</para>
+
+<variablelist>
+ <varlistentry>
+ <term><literal>ad*.example.com</literal></term>
+ <listitem>
+ <para>
+ matches <quote>adserver.example.com</quote>,
+ <quote>ads.example.com</quote>, etc but not <quote>sfads.example.com</quote>
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><literal>*ad*.example.com</literal></term>
+ <listitem>
+ <para>
+ matches all of the above, and then some.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><literal>.?pix.com</literal></term>
+ <listitem>
+ <para>
+ matches <literal>www.ipix.com</literal>,
+ <literal>pictures.epix.com</literal>, <literal>a.b.c.d.e.upix.com</literal> etc.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><literal>www[1-9a-ez].example.c*</literal></term>
+ <listitem>
+ <para>
+ matches <literal>www1.example.com</literal>,
+ <literal>www4.example.cc</literal>, <literal>wwwd.example.cy</literal>,
+ <literal>wwwz.example.com</literal> etc., but <emphasis>not</emphasis>
+ <literal>wwww.example.com</literal>.
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+
+<para>
+ While flexible, this is not the sophistication of full regular expression based syntax.
+</para>
+
+</sect3>
+
+<!-- ~ End section ~ -->
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3><title>The Path Pattern</title>
+
+<para>
+ <application>Privoxy</application> uses <quote>modern</quote> POSIX 1003.2
+ <ulink url="http://en.wikipedia.org/wiki/Regular_expressions"><quote>Regular
+ Expressions</quote></ulink> for matching the path portion (after the slash),
+ and is thus more flexible.
+</para>
+
+<para>
+ There is an <link linkend="regex">Appendix</link> with a brief quick-start into regular
+ expressions, you also might want to have a look at your operating system's documentation
+ on regular expressions (try <literal>man re_format</literal>).
+</para>
+
+<para>
+ Note that the path pattern is automatically left-anchored at the <quote>/</quote>,
+ i.e. it matches as if it would start with a <quote>^</quote> (regular expression speak
+ for the beginning of a line).
+</para>
+
+<para>
+ Please also note that matching in the path is <emphasis>CASE INSENSITIVE</emphasis>
+ by default, but you can switch to case sensitive at any point in the pattern by using the
+ <quote>(?-i)</quote> switch: <literal>www.example.com/(?-i)PaTtErN.*</literal> will match
+ only documents whose path starts with <literal>PaTtErN</literal> in
+ <emphasis>exactly</emphasis> this capitalization.
+</para>
+
+<variablelist>
+ <varlistentry>
+ <term><literal>.example.com/.*</literal></term>
+ <listitem>
+ <para>
+ Is equivalent to just <quote>.example.com</quote>, since any documents
+ within that domain are matched with or without the <quote>.*</quote>
+ regular expression. This is redundant
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><literal>.example.com/.*/index.html$</literal></term>
+ <listitem>
+ <para>
+ Will match any page in the domain of <quote>example.com</quote> that is
+ named <quote>index.html</quote>, and that is part of some path. For
+ example, it matches <quote>www.example.com/testing/index.html</quote> but
+ NOT <quote>www.example.com/index.html</quote> because the regular
+ expression called for at least two <quote>/'s</quote>, thus the path
+ requirement. It also would match
+ <quote>www.example.com/testing/index_html</quote>, because of the
+ special meta-character <quote>.</quote>.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><literal>.example.com/(.*/)?index\.html$</literal></term>
+ <listitem>
+ <para>
+ This regular expression is conditional so it will match any page
+ named <quote>index.html</quote> regardless of path which in this case can
+ have one or more <quote>/'s</quote>. And this one must contain exactly
+ <quote>.html</quote> (but does not have to end with that!).
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><literal>.example.com/(.*/)(ads|banners?|junk)</literal></term>
+ <listitem>
+ <para>
+ This regular expression will match any path of <quote>example.com</quote>
+ that contains any of the words <quote>ads</quote>, <quote>banner</quote>,
+ <quote>banners</quote> (because of the <quote>?</quote>) or <quote>junk</quote>.
+ The path does not have to end in these words, just contain them.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><literal>.example.com/(.*/)(ads|banners?|junk)/.*\.(jpe?g|gif|png)$</literal></term>
+ <listitem>
+ <para>
+ This is very much the same as above, except now it must end in either
+ <quote>.jpg</quote>, <quote>.jpeg</quote>, <quote>.gif</quote> or <quote>.png</quote>. So this
+ one is limited to common image formats.
+ </para>
+ </listitem>
+ </varlistentry>
+
+</variablelist>
+<para>
+ There are many, many good examples to be found in <filename>default.action</filename>,
+ and more tutorials below in <link linkend="regex">Appendix on regular expressions</link>.
+</para>
+
+</sect3>
+
+<!-- ~ End section ~ -->
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 id="tag-pattern"><title>The Tag Pattern</title>
+
+<para>
+ Tag patterns are used to change the applying actions based on the
+ request's tags. Tags can be created with either the
+ <link linkend="CLIENT-HEADER-TAGGER">client-header-tagger</link>
+ or the <link linkend="SERVER-HEADER-TAGGER">server-header-tagger</link> action.
+</para>
+
+<para>
+ Tag patterns have to start with <quote>TAG:</quote>, so &my-app;
+ can tell them apart from URL patterns. Everything after the colon
+ including white space, is interpreted as a regular expression with
+ path pattern syntax, except that tag patterns aren't left-anchored
+ automatically (&my-app; doesn't silently add a <quote>^</quote>,
+ you have to do it yourself if you need it).
+</para>
+
+<para>
+ To match all requests that are tagged with <quote>foo</quote>
+ your pattern line should be <quote>TAG:^foo$</quote>,
+ <quote>TAG:foo</quote> would work as well, but it would also
+ match requests whose tags contain <quote>foo</quote> somewhere.
+ <quote>TAG: foo</quote> wouldn't work as it requires white space.
+</para>
+
+<para>
+ Sections can contain URL and tag patterns at the same time,
+ but tag patterns are checked after the URL patterns and thus
+ always overrule them, even if they are located before the URL patterns.
+</para>
+
+<para>
+ Once a new tag is added, Privoxy checks right away if it's matched by one
+ of the tag patterns and updates the action settings accordingly. As a result
+ tags can be used to activate other tagger actions, as long as these other
+ taggers look for headers that haven't already be parsed.
+</para>
+
+<para>
+ For example you could tag client requests which use the
+ <literal>POST</literal> method,
+ then use this tag to activate another tagger that adds a tag if cookies
+ are sent, and then use a block action based on the cookie tag. This allows
+ the outcome of one action, to be input into a subsequent action. However if
+ you'd reverse the position of the described taggers, and activated the
+ method tagger based on the cookie tagger, no method tags would be created.
+ The method tagger would look for the request line, but at the time
+ the cookie tag is created, the request line has already been parsed.
+</para>
+
+<para>
+ While this is a limitation you should be aware of, this kind of
+ indirection is seldom needed anyway and even the example doesn't
+ make too much sense.
+</para>
+
+</sect3>
+
+</sect2>
+
+<!-- ~ End section ~ -->
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+
+<sect2 id="actions">
+<title>Actions</title>
+<para>
+ All actions are disabled by default, until they are explicitly enabled
+ somewhere in an actions file. Actions are turned on if preceded with a
+ <quote>+</quote>, and turned off if preceded with a <quote>-</quote>. So a
+ <literal>+action</literal> means <quote>do that action</quote>, e.g.
+ <literal>+block</literal> means <quote>please block URLs that match the
+ following patterns</quote>, and <literal>-block</literal> means <quote>don't
+ block URLs that match the following patterns, even if <literal>+block</literal>
+ previously applied.</quote>
+
+</para>
+
+<para>
+ Again, actions are invoked by placing them on a line, enclosed in curly braces and
+ separated by whitespace, like in
+ <literal>{+some-action -some-other-action{some-parameter}}</literal>,
+ followed by a list of URL patterns, one per line, to which they apply.
+ Together, the actions line and the following pattern lines make up a section
+ of the actions file.
+</para>
+
+<para>
+ Actions fall into three categories:
+</para>
+
+<para>
+ <itemizedlist>
+ <listitem>
+ <para>
+ Boolean, i.e the action can only be <quote>enabled</quote> or
+ <quote>disabled</quote>. Syntax:
+ </para>
+ <para>
+ <screen>
+ +<replaceable class="function">name</replaceable> # enable action <replaceable class="parameter">name</replaceable>
+ -<replaceable class="function">name</replaceable> # disable action <replaceable class="parameter">name</replaceable></screen>
+ </para>
+ <para>
+ Example: <literal>+handle-as-image</literal>
+ </para>
+ </listitem>
+
+
+ <listitem>
+ <para>
+ Parameterized, where some value is required in order to enable this type of action.
+ Syntax:
+ </para>
+ <para>
+ <screen>
+ +<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # enable action and set parameter to <replaceable class="parameter">param</replaceable>,
+ # overwriting parameter from previous match if necessary
+ -<replaceable class="function">name</replaceable> # disable action. The parameter can be omitted</screen>
+ </para>
+ <para>
+ Note that if the URL matches multiple positive forms of a parameterized action,
+ the last match wins, i.e. the params from earlier matches are simply ignored.
+ </para>
+ <para>
+ Example: <literal>+hide-user-agent{Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.8.1.4) Gecko/20070602 Firefox/2.0.0.4}</literal>
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Multi-value. These look exactly like parameterized actions,
+ but they behave differently: If the action applies multiple times to the
+ same URL, but with different parameters, <emphasis>all</emphasis> the parameters
+ from <emphasis>all</emphasis> matches are remembered. This is used for actions
+ that can be executed for the same request repeatedly, like adding multiple
+ headers, or filtering through multiple filters. Syntax:
+ </para>
+ <para>
+ <screen>
+ +<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # enable action and add <replaceable class="parameter">param</replaceable> to the list of parameters
+ -<replaceable class="function">name</replaceable>{<replaceable class="parameter">param</replaceable>} # remove the parameter <replaceable class="parameter">param</replaceable> from the list of parameters
+ # If it was the last one left, disable the action.
+ <replaceable class="parameter">-name</replaceable> # disable this action completely and remove all parameters from the list</screen>
+ </para>
+ <para>
+ Examples: <literal>+add-header{X-Fun-Header: Some text}</literal> and
+ <literal>+filter{html-annoyances}</literal>
+ </para>
+ </listitem>
+
+ </itemizedlist>
+</para>
+
+<para>
+ If nothing is specified in any actions file, no <quote>actions</quote> are
+ taken. So in this case <application>Privoxy</application> would just be a
+ normal, non-blocking, non-filtering proxy. You must specifically enable the
+ privacy and blocking features you need (although the provided default actions
+ files will give a good starting point).
+</para>
+
+<para>
+ Later defined action sections always over-ride earlier ones of the same type.
+ So exceptions to any rules you make, should come in the latter part of the file (or
+ in a file that is processed later when using multiple actions files such
+ as <filename>user.action</filename>). For multi-valued actions, the actions
+ are applied in the order they are specified. Actions files are processed in
+ the order they are defined in <filename>config</filename> (the default
+ installation has three actions files). It also quite possible for any given
+ URL to match more than one <quote>pattern</quote> (because of wildcards and
+ regular expressions), and thus to trigger more than one set of actions! Last
+ match wins.
+</para>
+
+<!-- start actions listing -->
+<para>
+ The list of valid <application>Privoxy</application> actions are:
+</para>
+
+
+<!-- ********************************************************** -->
+<!-- Please note the below defined actions use id's that are -->
+<!-- probably linked from other places, so please don't change. -->
+<!-- -->
+<!-- ********************************************************** -->
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+
+<sect3 renderas="sect4" id="add-header">
+<title>add-header</title>
+
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>Confuse log analysis, custom applications</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ Sends a user defined HTTP header to the web server.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- boolean, parameterized, Multi-value -->
+ <listitem>
+ <para>Multi-value.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>
+ Any string value is possible. Validity of the defined HTTP headers is not checked.
+ It is recommended that you use the <quote><literal>X-</literal></quote> prefix
+ for custom headers.
+ </para>
+ </listitem>
+ </varlistentry>
+
+<varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ This action may be specified multiple times, in order to define multiple
+ headers. This is rarely needed for the typical user. If you don't know what
+ <quote>HTTP headers</quote> are, you definitely don't need to worry about this
+ one.
+ </para>
+ <para>
+ Headers added by this action are not modified by other actions.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage:</term>
+ <listitem>
+ <para>
+ <screen>+add-header{X-User-Tracking: sucks}</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="block">
+<title>block</title>
+
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>Block ads or other unwanted content</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ Requests for URLs to which this action applies are blocked, i.e. the
+ requests are trapped by &my-app; and the requested URL is never retrieved,
+ but is answered locally with a substitute page or image, as determined by
+ the <literal><link
+ linkend="handle-as-image">handle-as-image</link></literal>,
+ <literal><link
+ linkend="set-image-blocker">set-image-blocker</link></literal>, and
+ <literal><link
+ linkend="handle-as-empty-document">handle-as-empty-document</link></literal> actions.
+
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- boolean, parameterized, Multi-value -->
+ <listitem>
+ <para>Parameterized.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <para>A block reason that should be given to the user.</para>
+ </listitem>
+ </varlistentry>
+
+<varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ <application>Privoxy</application> sends a special <quote>BLOCKED</quote> page
+ for requests to blocked pages. This page contains the block reason given as
+ parameter, a link to find out why the block action applies, and a click-through
+ to the blocked content (the latter only if the force feature is available and
+ enabled).
+ </para>
+ <para>
+ A very important exception occurs if <emphasis>both</emphasis>
+ <literal>block</literal> and <literal><link linkend="handle-as-image">handle-as-image</link></literal>,
+ apply to the same request: it will then be replaced by an image. If
+ <literal><link linkend="set-image-blocker">set-image-blocker</link></literal>
+ (see below) also applies, the type of image will be determined by its parameter,
+ if not, the standard checkerboard pattern is sent.
+ </para>
+ <para>
+ It is important to understand this process, in order
+ to understand how <application>Privoxy</application> deals with
+ ads and other unwanted content. Blocking is a core feature, and one
+ upon which various other features depend.
+ </para>
+ <para>
+ The <literal><link linkend="filter">filter</link></literal>
+ action can perform a very similar task, by <quote>blocking</quote>
+ banner images and other content through rewriting the relevant URLs in the
+ document's HTML source, so they don't get requested in the first place.
+ Note that this is a totally different technique, and it's easy to confuse the two.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage (section):</term>
+ <listitem>
+ <para>
+ <screen>{+block{No nasty stuff for you.}}
+# Block and replace with "blocked" page
+ .nasty-stuff.example.com
+
+{+block{Doubleclick banners.} +handle-as-image}
+# Block and replace with image
+ .ad.doubleclick.net
+ .ads.r.us/banners/
+
+{+block{Layered ads.} +handle-as-empty-document}
+# Block and then ignore
+ adserver.example.net/.*\.js$</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+
+
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="change-x-forwarded-for">
+<title>change-x-forwarded-for</title>
+
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>Improve privacy by not forwarding the source of the request in the HTTP headers.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ Deletes the <quote>X-Forwarded-For:</quote> HTTP header from the client request,
+ or adds a new 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>block</quote> to delete the header.</para>
+ </listitem>
+ <listitem>
+ <para>
+ <quote>add</quote> to create the header (or append
+ the client's IP address to an already existing one).
+ </para>
+ </listitem>
+ </itemizedlist>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ It is safe and recommended to use <literal>block</literal>.
+ </para>
+ <para>
+ Forwarding the source address of the request may make
+ sense in some multi-user setups but is also a privacy risk.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term>Example usage:</term>
+ <listitem>
+ <para>
+ <screen>+change-x-forwarded-for{block}</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="client-header-filter">
+<title>client-header-filter</title>
+
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>
+ Rewrite or remove single client headers.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ All client headers to which this action applies are filtered on-the-fly through
+ the specified regular expression based substitutions.
+ </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 client-header filter, as defined in one of the
+ <link linkend="filter-file">filter files</link>.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ Client-header filters are applied to each header on its own, not to
+ 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.
+ You can do that by using tags though.
+ </para>
+ <para>
+ Client-header filters are executed after the other header actions have finished
+ and use their output as input.
+ </para>
+ <para>
+ If the request URL gets changed, &my-app; will detect that and use the new
+ one. This can be used to rewrite the request destination behind the client's
+ back, for example to specify a Tor exit relay for certain requests.
+ </para>
+ <para>
+ Please refer to the <link linkend="filter-file">filter file chapter</link>
+ to learn which client-header filters are available by default, and how to
+ create your own.
+ </para>
+
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage (section):</term>
+ <listitem>
+ <para>
+ <screen>
+# Hide Tor exit notation in Host and Referer Headers
+{+client-header-filter{hide-tor-exit-notation}}
+/
+ </screen>
+ </para>
+ </listitem>
+ </varlistentry>
+
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="client-header-tagger">
+<title>client-header-tagger</title>
+
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>
+ Block requests based on their headers.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ Client headers to which this action applies are filtered on-the-fly through
+ the specified regular expression based substitutions, the result is used as
+ tag.
+ </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 client-header tagger, as defined in one of the
+ <link linkend="filter-file">filter files</link>.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ Client-header taggers are applied to each header on its own,
+ and as the header isn't modified, each tagger <quote>sees</quote>
+ the original.
+ </para>
+ <para>
+ Client-header taggers are the first actions that are executed
+ and their tags can be used to control every other action.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage (section):</term>
+ <listitem>
+ <para>
+ <screen>
+# Tag every request with the User-Agent header
+{+client-header-tagger{user-agent}}
+/
+
+# Tagging itself doesn't change the action
+# settings, sections with TAG patterns do:
+#
+# If it's a download agent, use a different forwarding proxy,
+# show the real User-Agent and make sure resume works.
+{+forward-override{forward-socks5 10.0.0.2:2222 .} \
+ -hide-if-modified-since \
+ -overwrite-last-modified \
+ -hide-user-agent \
+ -filter \
+ -deanimate-gifs \
+}
+TAG:^User-Agent: NetBSD-ftp/
+TAG:^User-Agent: Novell ZYPP Installer
+TAG:^User-Agent: RPM APT-HTTP/
+TAG:^User-Agent: fetch libfetch/
+TAG:^User-Agent: Ubuntu APT-HTTP/
+TAG:^User-Agent: MPlayer/
+ </screen>
+ </para>
+ </listitem>
+ </varlistentry>
+
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect3 renderas="sect4" id="content-type-overwrite">
+<title>content-type-overwrite</title>
+
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>Stop useless download menus from popping up, or change the browser's rendering mode</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ Replaces the <quote>Content-Type:</quote> HTTP server header.
+ </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>
+ The <quote>Content-Type:</quote> HTTP server header is used by the
+ browser to decide what to do with the document. The value of this
+ header can cause the browser to open a download menu instead of
+ displaying the document by itself, even if the document's format is
+ supported by the browser.
+ </para>
+ <para>
+ The declared content type can also affect which rendering mode
+ the browser chooses. If XHTML is delivered as <quote>text/html</quote>,
+ many browsers treat it as yet another broken HTML document.
+ If it is send as <quote>application/xml</quote>, browsers with
+ XHTML support will only display it, if the syntax is correct.
+ </para>
+ <para>
+ If you see a web site that proudly uses XHTML buttons, but sets
+ <quote>Content-Type: text/html</quote>, you can use &my-app;
+ to overwrite it with <quote>application/xml</quote> and validate
+ the web master's claim inside your XHTML-supporting browser.
+ If the syntax is incorrect, the browser will complain loudly.
+ </para>
+ <para>
+ You can also go the opposite direction: if your browser prints
+ error messages instead of rendering a document falsely declared
+ as XHTML, you can overwrite the content type with
+ <quote>text/html</quote> and have it rendered as broken HTML document.
+ </para>
+ <para>
+ By default <literal>content-type-overwrite</literal> only replaces
+ <quote>Content-Type:</quote> headers that look like some kind of text.
+ If you want to overwrite it unconditionally, you have to combine it with
+ <literal><link linkend="force-text-mode">force-text-mode</link></literal>.
+ This limitation exists for a reason, think twice before circumventing it.
+ </para>
+ <para>
+ Most of the time it's easier to replace this action with a custom
+ <literal><link linkend="server-header-filter">server-header filter</link></literal>.
+ It allows you to activate it for every document of a certain site and it will still
+ only replace the content types you aimed at.
+ </para>
+ <para>
+ Of course you can apply <literal>content-type-overwrite</literal>
+ to a whole site and then make URL based exceptions, but it's a lot
+ more work to get the same precision.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage (sections):</term>
+ <listitem>
+ <para>
+ <screen># Check if www.example.net/ really uses valid XHTML
+{ +content-type-overwrite{application/xml} }
+www.example.net/
+
+# but leave the content type unmodified if the URL looks like a style sheet
+{-content-type-overwrite}
+www.example.net/.*\.css$
+www.example.net/.*style
+</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+</variablelist>
+</sect3>
+
+
+<!-- ~~~~~ 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 use a
+ <literal><link linkend="client-header-filter">client-header filter</link></literal>.
+ </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 (unlikely but possible).
+ </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 or missing 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 but don't
+# allow the server to use the revalidation headers for user tracking.
+{+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 HTTP 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> HTTP cookies. For
+ <emphasis>outgoing</emphasis> HTTP cookies, use
+ <literal><link linkend="crunch-outgoing-cookies">crunch-outgoing-cookies</link></literal>.
+ Use <emphasis>both</emphasis> to disable HTTP 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 use a custom
+ <literal><link linkend="server-header-filter">server-header filter</link></literal>.
+ </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 HTTP 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> HTTP cookies. For
+ <emphasis>incoming</emphasis> HTTP cookies, use
+ <literal><link linkend="crunch-incoming-cookies">crunch-incoming-cookies</link></literal>.
+ Use <emphasis>both</emphasis> to disable HTTP 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 HTTP/1.1 features and requirements 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. You can prevent this problem by
+ first using the <literal><link linkend="redirect">redirect</link></literal> action
+ to remove the last part of the URL, 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} }
+ one.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 instances 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.)
+ </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 content 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>
+ Compressed content can't be filtered either, unless &my-app;
+ is compiled with zlib support (requires at least &my-app; 3.0.7),
+ in which case &my-app; will decompress the content before filtering
+ it.
+ </para>
+ <para>
+ If you use a &my-app; version without zlib support, but want filtering to work on
+ as much documents as possible, 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>
+ Content 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 and timers (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 resizable.</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 saveable.</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. Note that this filter doesn't work reliably.</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} # Cure for site-specific problems. Don't apply generally!</screen>
+ </para>
+ <para>
+ <anchor id="filter-no-ping">
+ <screen>+filter{no-ping} # Removes non-standard ping attributes in <a> and <area> tags.</screen>
+ </para>
+ <para>
+ <anchor id="filter-google">
+ <screen>+filter{google} # CSS-based block for Google text ads. Also removes a width limitation and the toolbar advertisement.</screen>
+ </para>
+ <para>
+ <anchor id="filter-yahoo">
+ <screen>+filter{yahoo} # CSS-based block for Yahoo text ads. Also removes a width limitation.</screen>
+ </para>
+ <para>
+ <anchor id="filter-msn">
+ <screen>+filter{msn} # CSS-based block for MSN text ads. Also removes tracking URLs and a width limitation.</screen>
+ </para>
+ <para>
+ <anchor id="filter-blogspot">
+ <screen>+filter{blogspot} # Cleans up some Blogspot blogs. Read the fine print before using this.</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="forward-override">
+<title>forward-override</title>
+<!--
+new action
+-->
+<variablelist>
+ <varlistentry>
+ <term>Typical use:</term>
+ <listitem>
+ <para>Change the forwarding settings based on User-Agent or request origin</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Effect:</term>
+ <listitem>
+ <para>
+ Overrules the forward directives in the configuration file.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Type:</term>
+ <!-- Boolean, Parameterized, Multi-value -->
+ <listitem>
+ <para>Multi-value.</para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Parameter:</term>
+ <listitem>
+ <itemizedlist>
+ <listitem>
+ <para><quote>forward .</quote> to use a direct connection without any additional proxies.</para>
+ </listitem>
+ <listitem>
+ <para>
+ <quote>forward 127.0.0.1:8123</quote> to use the HTTP proxy listening at 127.0.0.1 port 8123.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <quote>forward-socks4a 127.0.0.1:9050 .</quote> to use the socks4a proxy listening at
+ 127.0.0.1 port 9050. Replace <quote>forward-socks4a</quote> with <quote>forward-socks4</quote>
+ to use a socks4 connection (with local DNS resolution) instead, use <quote>forward-socks5</quote>
+ for socks5 connections (with remote DNS resolution).
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <quote>forward-socks4a 127.0.0.1:9050 proxy.example.org:8000</quote> to use the socks4a proxy
+ listening at 127.0.0.1 port 9050 to reach the HTTP proxy listening at proxy.example.org port 8000.
+ Replace <quote>forward-socks4a</quote> with <quote>forward-socks4</quote> to use a socks4 connection
+ (with local DNS resolution) instead, use <quote>forward-socks5</quote>
+ for socks5 connections (with remote DNS resolution).
+ </para>
+ </listitem>
+ </itemizedlist>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Notes:</term>
+ <listitem>
+ <para>
+ This action takes parameters similar to the
+ <link linkend="forwarding">forward</link> directives in the configuration
+ file, but without the URL pattern. It can be used as replacement, but normally it's only
+ used in cases where matching based on the request URL isn't sufficient.
+ </para>
+ <warning>
+ <para>
+ Please read the description for the <link linkend="forwarding">forward</link> directives before
+ using this action. Forwarding to the wrong people will reduce your privacy and increase the
+ chances of man-in-the-middle attacks.
+ </para>
+ <para>
+ If the ports are missing or invalid, default values will be used. This might change
+ in the future and you shouldn't rely on it. Otherwise incorrect syntax causes Privoxy
+ to exit.
+ </para>
+ <para>
+ Use the <ulink url="http://config.privoxy.org/show-url-info">show-url-info CGI page</ulink>
+ to verify that your forward settings do what you thought the do.
+ </para>
+ </warning>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage:</term>
+ <listitem>
+ <para>
+ <screen>
+# Always use direct connections for requests previously tagged as
+# <quote>User-Agent: fetch libfetch/2.0</quote> and make sure
+# resuming downloads continues to work.
+# This way you can continue to use Tor for your normal browsing,
+# without overloading the Tor network with your FreeBSD ports updates
+# or downloads of bigger files like ISOs.
+# Note that HTTP headers are easy to fake and therefore their
+# values are as (un)trustworthy as your clients and users.
+{+forward-override{forward .} \
+ -hide-if-modified-since \
+ -overwrite-last-modified \
+}
+TAG:^User-Agent: fetch libfetch/2\.0$
+ </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.
+ And of course this action can also be used to eliminate the &my-app;
+ BLOCKED message in frames.
+ </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{Blocked JavaScript} +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{Nasty banners.} +handle-as-image}
+nasty-banner-server.example.com/junk.cgi\?output=trash
+</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>
+ <para>
+ This action will probably be removed in the future,
+ use server-header filters instead.
+ </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
+ it less likely that the server can use the time 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>,
+ otherwise it's more or less pointless.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>Example usage (section):</term>
+ <listitem>
+ <para>
+ <screen># Let the browser revalidate but make tracking based on the time less likely.
+{+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-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>conditional-forge</quote> to forge the header 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 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>Try to 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).
+ </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>
+ More information on known user-agent strings can be found at
+ <ulink url="http://www.user-agents.org/">http://www.user-agents.org/</ulink>
+ and
+ <ulink url="http://en.wikipedia.org/wiki/User_agent">http://en.wikipedia.org/wiki/User_agent</ulink>.
+ </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="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> allows HTTP CONNECT requests to all
+ ports. Use <literal>limit-connect</literal> if 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 means CONNECT-enabled proxies can be used 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.
+ </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} # Port 443 is OK.
++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 the <literal><link
+ linkend="filter">filter</link></literal> and
+ <literal><link linkend="deanimate-gifs">deanimate-gifs</link></literal>
+ actions need access to the uncompressed data.
+ </para>
+ <para>
+ When compiled with zlib support (available since &my-app; 3.0.7), content that should be
+ filtered is decompressed on-the-fly and you don't have to worry about this action.
+ If you are using an older &my-app; version, or one that hasn't been compiled with zlib
+ support, this action can be used to convince the server to send the content uncompressed.
+ </para>
+ <para>
+ Most text-based instances compress very well, the size is seldom decreased by less than 50%,
+ for markup-heavy instances like news feeds saving more than 90% of the original size isn't
+ unusual.
+ </para>
+ <para>
+ Not using compression will therefore slow down the transfer, and you should only
+ enable this action if you really need it. As of &my-app; 3.0.7 it's disabled in all
+ predefined action settings.
+ </para>
+ <para>
+ Note that some (rare) ill-configured sites don't handle requests for uncompressed
+ documents correctly. Broken PHP applications tend to send an empty document body,
+ some IIS versions only send the beginning of the content. If you enable
+ <literal>prevent-compression</literal> per default, you might want 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>
+# Selectively turn off compression, and enable a filter
+#
+{ +filter{tiny-textforms} +prevent-compression }
+# Match only these sites
+ .google.
+ sourceforge.net
+ sf.net
+
+# Or instead, we could set a universal default:
+#
+{ +prevent-compression }
+ / # Match all sites
+
+# Then maybe make exceptions for broken sites:
+#
+{ -prevent-compression }
+.compusa.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">hide-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>