+ <application>Privoxy</application> can use <quote>regular expressions</quote>
+ in various config files. Assuming support for <quote>pcre</quote> (Perl
+ Compatible Regular Expressions) is compiled in, which is the default. Such
+ configuration directives do not require regular expressions, but they can be
+ used to increase flexibility by matching a pattern with wild-cards against
+ URLs.
+</para>
+
+<para>
+ If you are reading this, you probably don't understand what <quote>regular
+ expressions</quote> are, or what they can do. So this will be a very brief
+ introduction only. A full explanation would require a book ;-)
+</para>
+
+<para>
+ <quote>Regular expressions</quote> is a way of matching one character
+ expression against another to see if it matches or not. One of the
+ <quote>expressions</quote> is a literal string of readable characters
+ (letter, numbers, etc), and the other is a complex string of literal
+ characters combined with wild-cards, and other special characters, called
+ meta-characters. The <quote>meta-characters</quote> have special meanings and
+ are used to build the complex pattern to be matched against. Perl Compatible
+ Regular Expressions is an enhanced form of the regular expression language
+ with backward compatibility.
+</para>
+
+<para>
+ To make a simple analogy, we do something similar when we use wild-card
+ characters when listing files with the <command>dir</command> command in DOS.
+ <literal>*.*</literal> matches all filenames. The <quote>special</quote>
+ character here is the asterisk which matches any and all characters. We can be
+ more specific and use <literal>?</literal> to match just individual
+ characters. So <quote>dir file?.text</quote> would match
+ <quote>file1.txt</quote>, <quote>file2.txt</quote>, etc. We are pattern
+ matching, using a similar technique to <quote>regular expressions</quote>!
+</para>
+
+<para>
+ Regular expressions do essentially the same thing, but are much, much more
+ powerful. There are many more <quote>special characters</quote> and ways of
+ building complex patterns however. Let's look at a few of the common ones,
+ and then some examples:
+</para>
+
+<simplelist>
+ <member>
+ <emphasis>.</emphasis> - Matches any single character, e.g. <quote>a</quote>,
+ <quote>A</quote>, <quote>4</quote>, <quote>:</quote>, or <quote>@</quote>.
+ </member>
+</simplelist>
+
+<simplelist>
+ <member>
+ <emphasis>?</emphasis> - The preceding character or expression is matched ZERO or ONE
+ times. Either/or.
+ </member>
+</simplelist>
+
+<simplelist>
+ <member>
+ <emphasis>+</emphasis> - The preceding character or expression is matched ONE or MORE
+ times.
+ </member>
+</simplelist>
+
+<simplelist>
+ <member>
+ <emphasis>*</emphasis> - The preceding character or expression is matched ZERO or MORE
+ times.
+ </member>
+</simplelist>
+
+<simplelist>
+ <member>
+ <emphasis>\</emphasis> - The <quote>escape</quote> character denotes that
+ the following character should be taken literally. This is used where one of the
+ special characters (e.g. <quote>.</quote>) needs to be taken literally and
+ not as a special meta-character.
+ </member>
+</simplelist>
+
+<simplelist>
+ <member>
+ <emphasis>[]</emphasis> - Characters enclosed in brackets will be matched if
+ any of the enclosed characters are encountered.
+ </member>
+</simplelist>
+
+<simplelist>
+ <member>
+ <emphasis>()</emphasis> - parentheses are used to group a sub-expression,
+ or multiple sub-expressions.
+ </member>
+</simplelist>
+
+<simplelist>
+ <member>
+ <emphasis>|</emphasis> - The <quote>bar</quote> character works like an
+ <quote>or</quote> conditional statement. A match is successful if the
+ sub-expression on either side of <quote>|</quote> matches.
+ </member>
+</simplelist>
+
+<simplelist>
+ <member>
+ <emphasis>s/string1/string2/g</emphasis> - This is used to rewrite strings of text.
+ <quote>string1</quote> is replaced by <quote>string2</quote> in this
+ example.
+ </member>
+</simplelist>
+
+<para>
+ These are just some of the ones you are likely to use when matching URLs with
+ <application>Privoxy</application>, and is a long way from a definitive
+ list. This is enough to get us started with a few simple examples which may
+ be more illuminating:
+</para>
+
+<para>
+ <emphasis><literal>/.*/banners/.*</literal></emphasis> - A simple example
+ that uses the common combination of <quote>.</quote> and <quote>*</quote> to
+ denote any character, zero or more times. In other words, any string at all.
+ So we start with a literal forward slash, then our regular expression pattern
+ (<quote>.*</quote>) another literal forward slash, the string
+ <quote>banners</quote>, another forward slash, and lastly another
+ <quote>.*</quote>. We are building
+ a directory path here. This will match any file with the path that has a
+ directory named <quote>banners</quote> in it. The <quote>.*</quote> matches
+ any characters, and this could conceivably be more forward slashes, so it
+ might expand into a much longer looking path. For example, this could match:
+ <quote>/eye/hate/spammers/banners/annoy_me_please.gif</quote>, or just
+ <quote>/banners/annoying.html</quote>, or almost an infinite number of other
+ possible combinations, just so it has <quote>banners</quote> in the path
+ somewhere.
+</para>
+
+<para>
+ A now something a little more complex:
+</para>
+
+<para>
+ <emphasis><literal>/.*/adv((er)?ts?|ertis(ing|ements?))?/</literal></emphasis> -
+ We have several literal forward slashes again (<quote>/</quote>), so we are
+ building another expression that is a file path statement. We have another
+ <quote>.*</quote>, so we are matching against any conceivable sub-path, just so
+ it matches our expression. The only true literal that <emphasis>must
+ match</emphasis> our pattern is <application>adv</application>, together with
+ the forward slashes. What comes after the <quote>adv</quote> string is the
+ interesting part.
+</para>
+
+<para>
+ Remember the <quote>?</quote> means the preceding expression (either a
+ literal character or anything grouped with <quote>(...)</quote> in this case)
+ can exist or not, since this means either zero or one match. So
+ <quote>((er)?ts?|ertis(ing|ements?))</quote> is optional, as are the
+ individual sub-expressions: <quote>(er)</quote>,
+ <quote>(ing|ements?)</quote>, and the <quote>s</quote>. The <quote>|</quote>
+ means <quote>or</quote>. We have two of those. For instance,
+ <quote>(ing|ements?)</quote>, can expand to match either <quote>ing</quote>
+ <emphasis>OR</emphasis> <quote>ements?</quote>. What is being done here, is an
+ attempt at matching as many variations of <quote>advertisement</quote>, and
+ similar, as possible. So this would expand to match just <quote>adv</quote>,
+ or <quote>advert</quote>, or <quote>adverts</quote>, or
+ <quote>advertising</quote>, or <quote>advertisement</quote>, or
+ <quote>advertisements</quote>. You get the idea. But it would not match
+ <quote>advertizements</quote> (with a <quote>z</quote>). We could fix that by
+ changing our regular expression to:
+ <quote>/.*/adv((er)?ts?|erti(s|z)(ing|ements?))?/</quote>, which would then match
+ either spelling.
+</para>
+
+<para>
+ <emphasis><literal>/.*/advert[0-9]+\.(gif|jpe?g)</literal></emphasis> - Again
+ another path statement with forward slashes. Anything in the square brackets
+ <quote>[]</quote> can be matched. This is using <quote>0-9</quote> as a
+ shorthand expression to mean any digit one through nine. It is the same as
+ saying <quote>0123456789</quote>. So any digit matches. The <quote>+</quote>
+ means one or more of the preceding expression must be included. The preceding
+ expression here is what is in the square brackets -- in this case, any digit
+ one through nine. Then, at the end, we have a grouping: <quote>(gif|jpe?g)</quote>.
+ This includes a <quote>|</quote>, so this needs to match the expression on
+ either side of that bar character also. A simple <quote>gif</quote> on one side, and the other
+ side will in turn match either <quote>jpeg</quote> or <quote>jpg</quote>,
+ since the <quote>?</quote> means the letter <quote>e</quote> is optional and
+ can be matched once or not at all. So we are building an expression here to
+ match image GIF or JPEG type image file. It must include the literal
+ string <quote>advert</quote>, then one or more digits, and a <quote>.</quote>
+ (which is now a literal, and not a special character, since it is escaped
+ with <quote>\</quote>), and lastly either <quote>gif</quote>, or
+ <quote>jpeg</quote>, or <quote>jpg</quote>. Some possible matches would
+ include: <quote>//advert1.jpg</quote>,
+ <quote>/nasty/ads/advert1234.gif</quote>,
+ <quote>/banners/from/hell/advert99.jpg</quote>. It would not match
+ <quote>advert1.gif</quote> (no leading slash), or
+ <quote>/adverts232.jpg</quote> (the expression does not include an
+ <quote>s</quote>), or <quote>/advert1.jsp</quote> (<quote>jsp</quote> is not
+ in the expression anywhere).
+</para>
+
+<para>
+ <emphasis><literal>s/microsoft(?!.com)/MicroSuck/i</literal></emphasis> - This is
+ a substitution. <quote>MicroSuck</quote> will replace any occurrence of
+ <quote>microsoft</quote>. The <quote>i</quote> at the end of the expression
+ means ignore case. The <quote>(?!.com)</quote> means
+ the match should fail if <quote>microsoft</quote> is followed by
+ <quote>.com</quote>. In other words, this acts like a <quote>NOT</quote>
+ modifier. In case this is a hyperlink, we don't want to break it ;-).
+</para>
+
+<para>
+ We are barely scratching the surface of regular expressions here so that you
+ can understand the default <application>Privoxy</application>
+ configuration files, and maybe use this knowledge to customize your own
+ installation. There is much, much more that can be done with regular
+ expressions. Now that you know enough to get started, you can learn more on
+ your own :/
+</para>
+
+<para>
+ More reading on Perl Compatible Regular expressions:
+ <ulink url="http://www.perldoc.com/perl5.6/pod/perlre.html">http://www.perldoc.com/perl5.6/pod/perlre.html</ulink>
+</para>
+
+</sect2>
+
+<!-- ~ End section ~ -->
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect2>
+<title><application>Privoxy</application>'s Internal Pages</title>
+
+<para>
+ Since <application>Privoxy</application> proxies each requested
+ web page, it is easy for <application>Privoxy</application> to
+ trap certain special URLs. In this way, we can talk directly to
+ <application>Privoxy</application>, and see how it is
+ configured, see how our rules are being applied, change these
+ rules and other configuration options, and even turn
+ <application>Privoxy's</application> filtering off, all with
+ a web browser.
+
+</para>
+
+<para>
+ The URLs listed below are the special ones that allow direct access
+ to <application>Privoxy</application>. Of course,
+ <application>Privoxy</application> must be running to access these. If
+ not, you will get a friendly error message. Internet access is not
+ necessary either.
+</para>
+
+<para>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Privoxy main page:
+ </para>
+ <blockquote>
+ <para>
+ <ulink url="http://config.privoxy.org/">http://config.privoxy.org/</ulink>
+ </para>
+ </blockquote>
+ <para>
+ Alternately, this may be reached at <ulink
+ url="http://p.p/">http://p.p/</ulink>, but this
+ variation may not work as reliably as the above in some configurations.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Show information about the current configuration:
+ </para>
+ <blockquote>
+ <para>
+ <ulink url="http://config.privoxy.org/show-status">http://config.privoxy.org/show-status</ulink>
+ </para>
+ </blockquote>
+ </listitem>
+
+ <listitem>
+ <para>
+ Show the source code version numbers:
+ </para>
+ <blockquote>
+ <para>
+ <ulink url="http://config.privoxy.org/show-version">http://config.privoxy.org/show-version</ulink>
+ </para>
+ </blockquote>
+ </listitem>
+
+ <listitem>
+ <para>
+ Show the client's request headers:
+ </para>
+ <blockquote>
+ <para>
+ <ulink url="http://config.privoxy.org/show-request">http://config.privoxy.org/show-request</ulink>
+ </para>
+ </blockquote>
+ </listitem>
+
+ <listitem>
+ <para>
+ Show which actions apply to a URL and why:
+ </para>
+ <blockquote>
+ <para>
+ <ulink url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
+ </para>
+ </blockquote>
+ </listitem>
+
+ <listitem>
+ <para>
+ Toggle Privoxy on or off. In this case, <quote>Privoxy</quote> continues
+ to run, but only as a pass-through proxy, with no actions taking place:
+ </para>
+ <blockquote>
+ <para>
+ <ulink url="http://config.privoxy.org/toggle">http://config.privoxy.org/toggle</ulink>
+ </para>
+ </blockquote>
+ <para>
+ Short cuts. Turn off, then on:
+ </para>
+ <blockquote>
+ <para>
+ <ulink url="http://config.privoxy.org/toggle?set=disable">http://config.privoxy.org/toggle?set=disable</ulink>
+ </para>
+ </blockquote>
+ <blockquote>
+ <para>
+ <ulink url="http://config.privoxy.org/toggle?set=enable">http://config.privoxy.org/toggle?set=enable</ulink>
+ </para>
+ </blockquote>
+ </listitem>
+
+ <listitem>
+ <para>
+ Edit the actions list file:
+ </para>
+ <blockquote>
+ <para>
+ <ulink url="http://config.privoxy.org/edit-actions">http://config.privoxy.org/edit-actions</ulink>
+ </para>
+ </blockquote>
+ </listitem>
+
+ </itemizedlist>
+</para>
+
+<para>
+ These may be bookmarked for quick reference.
+
+</para>
+
+<sect3 id="bookmarklets">
+<title>Bookmarklets</title>
+<para>
+ Here are some bookmarklets to allow you to easily access a
+ <quote>mini</quote> version of this page. They are designed for MS Internet
+ Explorer, but should work equally well in Netscape, Mozilla, and other
+ browsers which support JavaScript. They are designed to run directly from
+ your bookmarks - not by clicking the links below (although that will work for
+ testing).
+</para>
+<para>
+ To save them, right-click the link and choose <quote>Add to Favorites</quote>
+ (IE) or <quote>Add Bookmark</quote> (Netscape). You will get a warning that
+ the bookmark <quote>may not be safe</quote> - just click OK. Then you can run the
+ Bookmarklet directly from your favourites/bookmarks. For even faster access,
+ you can put them on the <quote>Links</quote> bar (IE) or the <quote>Personal
+ Toolbar</quote> (Netscape), and run them with a single click.
+</para>
+
+<para>
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ <ulink url="javascript:void(window.open('http://config.privoxy.org/toggle?mini=y&set=enabled','ijbstatus','width=250,height=100,resizable=yes,scrollbars=no,toolbar=no,location=no,directories=no,status=no,menubar=no,copyhistory=no').focus());">Enable Privoxy</ulink>
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <ulink url="javascript:void(window.open('http://config.privoxy.org/toggle?mini=y&set=disabled','ijbstatus','width=250,height=100,resizable=yes,scrollbars=no,toolbar=no,location=no,directories=no,status=no,menubar=no,copyhistory=no').focus());">Disable Privoxy</ulink>
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <ulink url="javascript:void(window.open('http://config.privoxy.org/toggle?mini=y&set=toggle','ijbstatus','width=250,height=100,resizable=yes,scrollbars=no,toolbar=no,location=no,directories=no,status=no,menubar=no,copyhistory=no').focus());">Toggle Privoxy</ulink> (Toggles between enabled and disabled)
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ <ulink url="javascript:void(window.open('http://config.privoxy.org/toggle?mini=y','ijbstatus','width=250,height=2,resizable=yes,scrollbars=no,toolbar=no,location=no,directories=no,status=no,menubar=no,copyhistory=no').focus());">View Privoxy Status</ulink>
+ </para>
+ </listitem>
+
+ </itemizedlist>
+</para>
+
+<para>
+ Credit: The site which gave me the general idea for these bookmarklets is
+ <ulink url="http://www.bookmarklets.com">www.bookmarklets.com</ulink>. They
+ have more information about bookmarklets.
+</para>
+
+
+</sect3>
+
+</sect2>
+
+
+<!-- ~~~~~ New section ~~~~~ -->
+<sect2 id="actionsanat">
+<title>Anatomy of an Action</title>
+
+<para>
+ The way <application>Privoxy</application> applies <quote>actions</quote>
+ and <quote>filters</quote> to any given URL can be complex, and not always so
+ easy to understand what is happening. And sometimes we need to be able to
+ <emphasis>see</emphasis> just what <application>Privoxy</application> is
+ doing. Especially, if something <application>Privoxy</application> is doing
+ is causing us a problem inadvertantly. It can be a little daunting to look at
+ the actions and filters files themselves, since they tend to be filled with
+ <quote>regular expressions</quote> whose consequences are not always
+ so obvious. <application>Privoxy</application> provides the
+ <ulink url="http://config.privoxy.org/show-url-info">http://config.privoxy.org/show-url-info</ulink>
+ page that can show us very specifically how <application>actions</application>
+ are being applied to any given URL. This is a big help for troubleshooting.
+ </para>
+
+<para>
+ First, enter one URL (or partial URL) at the prompt, and then
+ <application>Privoxy</application> will tell us
+ how the current configuration will handle it. This will not
+ help with filtering effects from the <filename>default.filter</filename> file! It
+ also will not tell you about any other URLs that may be embedded within the
+ URL you are testing. For instance, images such as ads are expressed as URLs
+ within the raw page source of HTML pages. So you will only get info for the
+ actual URL that is pasted into the prompt area -- not any sub-URLs. If you
+ want to know about embedded URLs like ads, you will have to dig those out of
+ the HTML source. Use your browser's <quote>View Page Source</quote> option
+ for this.
+</para>
+
+<para>
+ Let's look at an example, <ulink url="http://google.com">google.com</ulink>,
+ one section at a time:
+</para>
+
+<para>
+ <screen>
+ System default actions:
+
+ { -add-header -block -deanimate-gifs -downgrade -fast-redirects -filter
+ -hide-forwarded -hide-from -hide-referer -hide-user-agent -image
+ -image-blocker -limit-connect -no-compression -no-cookies-keep
+ -no-cookies-read -no-cookies-set -no-popups -vanilla-wafer -wafer }
+
+ </screen>
+</para>
+
+<para>
+ This is the top section, and only tells us of the compiled in defaults. This
+ is basically what <application>Privoxy</application> would do if there
+ were not any <quote>actions</quote> defined, i.e. it does nothing. Every action
+ is disabled. This is not particularly informative for our purposes here. OK,
+ next section:
+</para>
+
+<para>
+ <screen>
+
+ Matches for http://google.com:
+
+ { -add-header -block +deanimate-gifs -downgrade +fast-redirects
+ +filter{html-annoyances} +filter{js-annoyances} +filter{no-popups}
+ +filter{webbugs} +filter{nimda} +filter{banners-by-size} +filter{hal}
+ +filter{fun} +hide-forwarded +hide-from{block} +hide-referer{forge}
+ -hide-user-agent -image +image-blocker{blank} +no-compression
+ +no-cookies-keep -no-cookies-read -no-cookies-set +no-popups
+ -vanilla-wafer -wafer }
+ /
+
+ { -no-cookies-keep -no-cookies-read -no-cookies-set }
+ .google.com
+
+ { -fast-redirects }
+ .google.com
+
+ </screen>
+</para>
+
+<para>
+ This is much more informative, and tells us how we have defined our
+ <quote>actions</quote>, and which ones match for our example,
+ <quote>google.com</quote>. The first grouping shows our default
+ settings, which would apply to all URLs. If you look at your <quote>actions</quote>
+ file, this would be the section just below the <quote>aliases</quote> section
+ near the top. This applies to all URLs as signified by the single forward
+ slash -- <quote>/</quote>.
+
+</para>
+
+<para>
+ These are the default actions we have enabled. But we can define additional
+ actions that would be exceptions to these general rules, and then list
+ specific URLs that these exceptions would apply to. Last match wins.
+ Just below this then are two explict matches for <quote>.google.com</quote>.
+ The first is negating our various cookie blocking actions (i.e. we will allow
+ cookies here). The second is allowing <quote>fast-redirects</quote>. Note
+ that there is a leading dot here -- <quote>.google.com</quote>. This will
+ match any hosts and sub-domains, in the google.com domain also, such as
+ <quote>www.google.com</quote>. So, apparently, we have these actions defined
+ somewhere in the lower part of our actions file, and
+ <quote>google.com</quote> is referenced in these sections.
+
+</para>
+
+<para>
+ And now we pull it altogether in the bottom section and summarize how
+ <application>Privoxy</application> is appying all its <quote>actions</quote>
+ to <quote>google.com</quote>:
+
+</para>
+
+<para>
+ <screen>
+
+ Final results:
+
+ -add-header -block -deanimate-gifs -downgrade -fast-redirects
+ +filter{html-annoyances} +filter{js-annoyances} +filter{no-popups}
+ +filter{webbugs} +filter{nimda} +filter{banners-by-size} +filter{hal}
+ +filter{fun} +hide-forwarded +hide-from{block} +hide-referer{forge}
+ -hide-user-agent -image +image-blocker{blank} -limit-connect +no-compression
+ -no-cookies-keep -no-cookies-read -no-cookies-set +no-popups -vanilla-wafer
+ -wafer
+
+ </screen>
+</para>
+
+<para>
+ Now another example, <quote>ad.doubleclick.net</quote>:
+</para>
+
+<para>
+ <screen>
+
+ { +block +image }
+ .ad.doubleclick.net
+
+ { +block +image }
+ ad*.
+
+ { +block +image }
+ .doubleclick.net
+
+ </screen>
+</para>
+
+<para>
+ We'll just show the interesting part here, the explicit matches. It is
+ matched three different times. Each as an <quote>+block +image</quote>,
+ which is the expanded form of one of our aliases that had been defined as:
+ <quote>+imageblock</quote>. (<quote>Aliases</quote> are defined in the
+ first section of the actions file and typically used to combine more
+ than one action.)
+</para>
+
+<para>
+ Any one of these would have done the trick and blocked this as an unwanted
+ image. This is unnecessarily redundant since the last case effectively
+ would also cover the first. No point in taking chances with these guys
+ though ;-) Note that if you want an ad or obnoxious
+ URL to be invisible, it should be defined as <quote>ad.doubleclick.net</quote>
+ is done here -- as both a <quote>+block</quote> <emphasis>and</emphasis> an
+ <quote>+image</quote>. The custom alias <quote>+imageblock</quote> does this
+ for us.
+</para>
+
+<para>
+ One last example. Let's try <quote>http://www.rhapsodyk.net/adsl/HOWTO/</quote>.
+ This one is giving us problems. We are getting a blank page. Hmmm...
+</para>
+
+<para>
+ <screen>
+
+ Matches for http://www.rhapsodyk.net/adsl/HOWTO/:
+
+ { -add-header -block +deanimate-gifs -downgrade +fast-redirects
+ +filter{html-annoyances} +filter{js-annoyances} +filter{no-popups}
+ +filter{webbugs} +filter{nimda} +filter{banners-by-size} +filter{hal}
+ +filter{fun} +hide-forwarded +hide-from{block} +hide-referer{forge}
+ -hide-user-agent -image +image-blocker{blank} +no-compression
+ +no-cookies-keep -no-cookies-read -no-cookies-set +no-popups
+ -vanilla-wafer -wafer }
+ /
+
+ { +block +image }
+ /ads
+
+ </screen>
+</para>
+
+<para>
+ Ooops, the <quote>/adsl/</quote> is matching <quote>/ads</quote>! But
+ we did not want this at all! Now we see why we get the blank page. We could
+ now add a new action below this that explictly does <emphasis>not</emphasis>
+ block (-block) pages with <quote>adsl</quote>. There are various ways to
+ handle such exceptions. Example:
+</para>
+
+<para>
+ <screen>
+
+ { -block }
+ /adsl
+
+ </screen>
+</para>
+
+<para>
+ Now the page displays ;-) Be sure to flush your browser's caches when
+ making such changes. Or, try using <literal>Shift+Reload</literal>.
+
+</para>
+
+<para>
+ But now what about a situation where we get no explicit matches like
+ we did with:
+
+</para>
+
+<para>
+ <screen>
+
+ { -block }
+ /adsl
+
+ </screen>
+</para>
+
+<para>
+ That actually was very telling and pointed us quickly to where the problem
+ was. If you don't get this kind of match, then it means one of the default
+ rules in the first section is causing the problem. This would require some
+ guesswork, and maybe a little trial and error to isolate the offending rule.
+ One likely cause would be one of the <quote>{+filter}</quote> actions. Try
+ adding the URL for the site to one of aliases that turn off <quote>+filter</quote>:
+</para>
+
+<para>
+ <screen>
+
+ {shop}
+ .quietpc.com
+ .worldpay.com # for quietpc.com
+ .jungle.com
+ .scan.co.uk
+ .forbes.com
+
+ </screen>
+</para>
+
+<para>
+ <quote>{shop}</quote> is an <quote>alias</quote> that expands to
+ <quote>{ -filter -no-cookies -no-cookies-keep }</quote>. Or you could do
+ your own exception to negate filtering:
+
+</para>
+
+<para>
+ <screen>
+
+ {-filter}
+ .forbes.com
+
+ </screen>
+</para>
+
+<para>
+ <quote>{fragile}</quote> is an alias that disables most actions. This can be
+ used as a last resort for problem sites. Remember to flush caches! If this
+ still does not work, you will have to go through the remaining actions one by
+ one to find which one(s) is causing the problem.