+ Where target_domain is a domain name pattern (see the chapter on domain
+ matching in the default.action file), http_parent and socks_proxy are IP
+ addresses in dotted decimal notation or valid DNS names (http_parent may be
+ "." to denote "no HTTP forwarding"), and the optional port parameters are
+ TCP ports, i.e. integer values from 1 to 64535
+
+Default value:
+
+ Unset
+
+Effect if unset:
+
+ Don't use SOCKS proxies.
+
+Notes:
+
+ Multiple lines are OK, they are checked in sequence, and the last match
+ wins.
+
+ The difference between forward-socks4 and forward-socks4a is that in the
+ SOCKS 4A protocol, the DNS resolution of the target hostname happens on the
+ SOCKS server, while in SOCKS 4 it happens locally.
+
+ If http_parent is ".", then requests are not forwarded to another HTTP
+ proxy but are made (HTTP-wise) directly to the web servers, albeit through
+ a SOCKS proxy.
+
+Examples:
+
+ From the company example.com, direct connections are made to all "internal"
+ domains, but everything outbound goes through their ISP's proxy by way of
+ example.com's corporate SOCKS 4A gateway to the Internet.
+
+ forward-socks4a .*. socks-gw.example.com:1080 www-cache.example-isp.net:8080
+ forward .example.com .
+
+ A rule that uses a SOCKS 4 gateway for all destinations but no HTTP parent
+ looks like this:
+
+ forward-socks4 .*. socks-gw.example.com:1080 .
+
+-------------------------------------------------------------------------------
+
+7.3.5.3. Advanced Forwarding Examples
+
+If you have links to multiple ISPs that provide various special content only to
+their subscribers, you can configure multiple Privoxies which have connections
+to the respective ISPs to act as forwarders to each other, so that your users
+can see the internal content of all ISPs.
+
+Assume that host-a has a PPP connection to isp-a.net. And host-b has a PPP
+connection to isp-b.net. Both run Privoxy. Their forwarding configuration can
+look like this:
+
+host-a:
+
+ forward .*. .
+ forward .isp-b.net host-b:8118
+
+host-b:
+
+ forward .*. .
+ forward .isp-a.net host-a:8118
+
+Now, your users can set their browser's proxy to use either host-a or host-b
+and be able to browse the internal content of both isp-a and isp-b.
+
+If you intend to chain Privoxy and squid locally, then chain as browser ->
+squid -> privoxy is the recommended way.
+
+Assuming that Privoxy and squid run on the same box, your squid configuration
+could then look like this:
+
+ # Define Privoxy as parent proxy (without ICP)
+ cache_peer 127.0.0.1 parent 8118 7 no-query
+
+ # Define ACL for protocol FTP
+ acl ftp proto FTP
+
+ # Do not forward FTP requests to Privoxy
+ always_direct allow ftp
+
+ # Forward all the rest to Privoxy
+ never_direct allow all
+
+You would then need to change your browser's proxy settings to squid's address
+and port. Squid normally uses port 3128. If unsure consult http_port in
+squid.conf.
+
+-------------------------------------------------------------------------------
+
+7.3.6. Windows GUI Options
+
+Privoxy has a number of options specific to the Windows GUI interface:
+
+If "activity-animation" is set to 1, the Privoxy icon will animate when
+"Privoxy" is active. To turn off, set to 0.
+
+ activity-animation 1
+
+
+If "log-messages" is set to 1, Privoxy will log messages to the console window:
+
+ log-messages 1
+
+
+If "log-buffer-size" is set to 1, the size of the log buffer, i.e. the amount
+of memory used for the log messages displayed in the console window, will be
+limited to "log-max-lines" (see below).
+
+Warning: Setting this to 0 will result in the buffer to grow infinitely and eat
+up all your memory!
+
+ log-buffer-size 1
+
+
+log-max-lines is the maximum number of lines held in the log buffer. See above.
+
+ log-max-lines 200
+
+
+If "log-highlight-messages" is set to 1, Privoxy will highlight portions of the
+log messages with a bold-faced font:
+
+ log-highlight-messages 1
+
+
+The font used in the console window:
+
+ log-font-name Comic Sans MS
+
+
+Font size used in the console window:
+
+ log-font-size 8
+
+
+"show-on-task-bar" controls whether or not Privoxy will appear as a button on
+the Task bar when minimized:
+
+ show-on-task-bar 0
+
+
+If "close-button-minimizes" is set to 1, the Windows close button will minimize
+Privoxy instead of closing the program (close with the exit option on the File
+menu).
+
+ close-button-minimizes 1
+
+
+The "hide-console" option is specific to the MS-Win console version of Privoxy.
+If this option is used, Privoxy will disconnect from and hide the command
+console.
+
+ #hide-console
+
+
+-------------------------------------------------------------------------------
+
+7.4. Actions Files
+
+The actions files are used to define what actions Privoxy 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 three such files included with Privoxy, with slightly
+different purposes. default.action sets the default policies. standard.action
+is used by Privoxy and the web based editor to set pre-defined values (and
+normally should not be edited). Local exceptions are best done in user.action.
+The content of these can all be viewed and edited from http://
+config.privoxy.org/show-status.
+
+Anything you want can be blocked, including ads, banners, or just some
+obnoxious URL that you would rather not see is done here. Cookies can be
+accepted or rejected, or accepted only during the current browser session (i.e.
+not written to disk), content can be modified, JavaScripts tamed, user-tracking
+fooled, and much more. See below for a complete list of available actions.
+
+An actions file typically has sections. Near the top, "aliases" are optionally
+defined (discussed below), then the default set of rules which will apply
+universally to all sites and pages. And then below that, exceptions to the
+defined universal policies.
+
+-------------------------------------------------------------------------------
+
+7.4.1. Finding the Right Mix
+
+Note that some actions like cookie suppression or script disabling may render
+some sites unusable, which rely on these techniques to work properly. Finding
+the right mix of actions is not easy and certainly a matter of personal taste.
+In general, it can be said that the more "aggressive" your default settings (in
+the top section of the actions file) are, the more exceptions for "trusted"
+sites you will have to make later. If, for example, you want to kill popup
+windows per default, you'll have to make exceptions from that rule for sites
+that you regularly use and that require popups for actually useful content,
+like maybe your bank, favorite shop, or newspaper.
+
+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
+:).
+
+-------------------------------------------------------------------------------
+
+7.4.2. How to Edit
+
+The easiest way to edit the "actions" files is with a browser by using our
+browser-based editor, which can be reached from http://config.privoxy.org/
+show-status.
+
+If you prefer plain text editing to GUIs, you can of course also directly edit
+the the actions files.
+
+-------------------------------------------------------------------------------
+
+7.4.3. How Actions are Applied to URLs
+
+Actions files are divided into sections. There are special sections, like the "
+alias" 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 patterns, each
+on a separate line.
+
+To determine which actions apply to a request, the URL of the request is
+compared to all patterns in this file. Every time it matches, the list of
+applicable actions for the URL is incrementally updated, using the heading of
+the section in which the pattern is located. If multiple matches for the same
+URL set the same action differently, the last match wins. If not, the effects
+are aggregated (e.g. a URL might match both the "+handle-as-image" and "+block"
+actions).
+
+You can trace this process by visiting http://config.privoxy.org/show-url-info.
+
+More detail on this is provided in the Appendix, Anatomy of an Action.
+
+-------------------------------------------------------------------------------
+
+7.4.4. Patterns
+
+Generally, a pattern has the form <domain>/<path>, where both the <domain> and
+<path> are optional. (This is why the pattern / matches all URLs).
+
+www.example.com/
+
+ is a domain-only pattern and will match any request to www.example.com,
+ regardless of which document on that server is requested.
+
+www.example.com
+
+ means exactly the same. For domain-only patterns, the trailing / may be
+ omitted.
+
+www.example.com/index.html
+
+ matches only the single document /index.html on www.example.com.
+
+/index.html
+
+ matches the document /index.html, regardless of the domain, i.e. on any web
+ server.
+
+index.html
+
+ matches nothing, since it would be interpreted as a domain name and there
+ is no top-level domain called .html.
+
+-------------------------------------------------------------------------------
+
+7.4.4.1. The Domain Pattern
+
+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:
+
+.example.com
+
+ matches any domain that ENDS in .example.com
+
+www.
+
+ matches any domain that STARTS with www.
+
+.example.
+
+ matches any domain that CONTAINS .example. (Correctly speaking: It matches
+ any FQDN that contains example as a domain.)
+
+Additionally, there are wild-cards that you can use in the domain names
+themselves. They work pretty similar to shell wild-cards: "*" stands for zero
+or more arbitrary characters, "?" stands for any single character, you can
+define character classes in square brackets and all of that can be freely
+mixed:
+
+ad*.example.com
+
+ matches "adserver.example.com", "ads.example.com", etc but not
+ "sfads.example.com"
+
+*ad*.example.com
+
+ matches all of the above, and then some.
+
+.?pix.com
+
+ matches www.ipix.com, pictures.epix.com, a.b.c.d.e.upix.com etc.
+
+www[1-9a-ez].example.c*
+
+ matches www1.example.com, www4.example.cc, wwwd.example.cy,
+ wwwz.example.com etc., but not wwww.example.com.
+
+-------------------------------------------------------------------------------
+
+7.4.4.2. The Path Pattern
+
+Privoxy uses Perl compatible regular expressions (through the PCRE library) for
+matching the path.
+
+There is an Appendix with a brief quick-start into regular expressions, and
+full (very technical) documentation on PCRE regex syntax is available on-line
+at http://www.pcre.org/man.txt. You might also find the Perl man page on
+regular expressions (man perlre) useful, which is available on-line at http://
+www.perldoc.com/perl5.6/pod/perlre.html.
+
+Note that the path pattern is automatically left-anchored at the "/", i.e. it
+matches as if it would start with a "^" (regular expression speak for the
+beginning of a line).
+
+Please also note that matching in the path is case INSENSITIVE by default, but
+you can switch to case sensitive at any point in the pattern by using the "(?
+-i)" switch: www.example.com/(?-i)PaTtErN.* will match only documents whose
+path starts with PaTtErN in exactly this capitalization.
+
+-------------------------------------------------------------------------------
+
+7.4.5. Actions
+
+All actions are disabled by default, until they are explicitly enabled
+somewhere in an actions file. Actions are turned on if preceded with a "+", and
+turned off if preceded with a "-". So a "+action" means "do that action", e.g.
+"+block" means please "block the following URL patterns".
+
+Actions are invoked by enclosing the action name in curly braces (e.g.
+{+some_action}), followed by a list of URLs (or patterns that match URLs) to
+which the action applies. There are three classes of actions:
+
+ * Boolean, i.e the action can only be "on" or "off". Examples:
+
+ {+name} # enable this action
+ {-name} # disable this action
+
+
+ * Parameterized, e.g. "+/-hide-user-agent{ Mozilla 1.0 }", where some value
+ is required in order to enable this type of action. Examples:
+
+ {+name{param}} # enable action and set parameter to "param"
+ {-name} # disable action ("parameter") can be omitted
+
+
+ * Multi-value, e.g. "{+/-add-header{Name: value}}" or "{+/-send-wafer{name=
+ value}}"), where some value needs to be defined in addition to simply
+ enabling the action. Examples:
+
+ {+name{param=value}} # enable action and set "param" to "value"
+ {-name{param=value}} # remove the parameter "param" completely
+ {-name} # disable this action totally and remove param too
+
+
+If nothing is specified in any actions file, no "actions" are taken. So in this
+case Privoxy would just be a normal, non-blocking, non-anonymizing proxy. You
+must specifically enable the privacy and blocking features you need (although
+the provided default actions files will give a good starting point).
+
+Later defined actions always over-ride earlier ones. 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). 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 config (the default installation has
+three actions files). It also quite possible for any given URL pattern to match
+more than one action!
+
+The list of valid Privoxy "actions" are:
+
+-------------------------------------------------------------------------------
+
+7.4.5.1. +add-header
+
+Type:
+
+ Multi-value.
+
+Typical uses:
+
+ Send a user defined HTTP header to the web server.
+
+Possible values:
+
+ Any value is possible. Validity of the defined HTTP headers is not checked.
+
+Example usage:
+
+ {+add-header{X-User-Tracking: sucks}}
+ .example.com
+
+
+Notes:
+
+ 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
+ "HTTP headers" are, you definitely don't need to worry about this one.
+
+-------------------------------------------------------------------------------
+
+7.4.5.2. +block
+
+Type:
+
+ Boolean.
+
+Typical uses:
+
+ Used to block a URL from reaching your browser. The URL may be anything,
+ but is typically used to block ads or other obnoxious content.
+
+Possible values:
+
+ N/A
+
+Example usage:
+
+ {+block}
+ .banners.example.com
+ .ads.r.us
+
+
+Notes:
+
+ If a URL matches one of the blocked patterns, Privoxy will intercept the
+ URL and display its special "BLOCKED" page instead. If there is sufficient
+ space, a large red banner will appear with a friendly message about why the
+ page was blocked, and a way to go there anyway. If there is insufficient
+ space a smaller "BLOCKED" page will appear without the red banner. Click
+ here to view the default blocked HTML page (Privoxy must be running for
+ this to work as intended!).
+
+ A very important exception is if the URL matches both "+block" and
+ "+handle-as-image", then it will be handled by "+set-image-blocker" (see
+ below). It is important to understand this process, in order to understand
+ how Privoxy is able to deal with ads and other objectionable content.
+
+ The "+filter" action can also perform some of the same functionality as
+ "+block", but by virtue of very different programming techniques, and is
+ most often used for different reasons.
+
+-------------------------------------------------------------------------------
+
+7.4.5.3. +deanimate-gifs
+
+Type:
+
+ Parameterized.
+
+Typical uses:
+
+ To stop those annoying, distracting animated GIF images.
+
+Possible values:
+
+ "last" or "first"
+
+Example usage:
+
+ {+deanimate-gifs{last}}
+ .example.com
+
+
+Notes:
+
+ De-animate all animated GIF images, i.e. reduce them to their last frame.
+ This will also shrink the images considerably (in bytes, not pixels!). If
+ the option "first" is given, the first frame of the animation is used as
+ the replacement. If "last" 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).
+
+-------------------------------------------------------------------------------
+
+7.4.5.4. +downgrade-http-version
+
+Type:
+
+ Boolean.
+
+Typical uses:
+
+ "+downgrade-http-version" will downgrade HTTP/1.1 client requests to HTTP/
+ 1.0 and downgrade the responses as well.
+
+Possible values:
+
+ N/A
+
+Example usage:
+
+ {+downgrade-http-version}
+ .example.com
+
+
+Notes:
+
+ Use this action for servers that use HTTP/1.1 protocol features that
+ Privoxy doesn't handle well yet. HTTP/1.1 is only partially implemented.
+ Default is not to downgrade requests. This is an infrequently needed
+ action, and is used to help with rare problem sites only.
+
+-------------------------------------------------------------------------------
+
+7.4.5.5. +fast-redirects
+
+Type:
+
+ Boolean.
+
+Typical uses:
+
+ The "+fast-redirects" action enables interception of "redirect" requests
+ from one server to another, which are used to track users.Privoxy can cut
+ off all but the last valid URL in a redirect request and send a local
+ redirect back to your browser without contacting the intermediate site(s).
+
+Possible values:
+
+ N/A
+
+Example usage:
+
+ {+fast-redirects}
+ .example.com
+
+
+Notes:
+
+ Many sites, like yahoo.com, don't just link to other sites. Instead, they
+ will link to some script on their own server, giving the destination as a
+ parameter, which will then redirect you to the final target. URLs resulting
+ from this scheme typically look like: http://some.place/some_script?http://
+ some.where-else.
+
+ 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
+ ask the server for one redirect after the other. Plus, it feeds the
+ advertisers.
+
+ This is a normally "on" feature, and often requires exceptions for sites
+ that are sensitive to defeating this mechanism.
+
+-------------------------------------------------------------------------------
+
+7.4.5.6. +filter
+
+Type:
+
+ Parameterized.
+
+Typical uses:
+
+ Apply page filtering as defined by named sections of the default.filter
+ file to the specified site(s). "Filtering" can be any modification of the
+ raw page content, including re-writing or deletion of content.
+
+Possible values:
+
+ "+filter" must include the name of one of the section identifiers from
+ default.filter (or whatever filterfile is specified in config).
+
+Example usage (from the current default.filter):
+
+ +filter{html-annoyances}: Get rid of particularly annoying HTML abuse.
+
+ +filter{js-annoyances}: Get rid of particularly annoying JavaScript abuse
+
+ +filter{content-cookies}: Kill cookies that come in the HTML or JS content
+
+ +filter{popups}: Kill all popups in JS and HTML
+
+ +filter{frameset-borders}: Give frames a border and make them resizable
+
+ +filter{webbugs}: Squish WebBugs (1x1 invisible GIFs used for user
+ tracking)
+
+ +filter{refresh-tags}: Kill automatic refresh tags (for dial-on-demand
+ setups)
+
+ +filter{fun}: Text replacements for subversive browsing fun!
+
+ +filter{nimda}: Remove Nimda (virus) code.
+
+ +filter{banners-by-size}: Kill banners by size (very efficient!)
+
+ +filter{shockwave-flash}: Kill embedded Shockwave Flash objects
+
+ +filter{crude-parental}: Kill all web pages that contain the words "sex" or
+ "warez"
+
+Notes:
+
+ This is potentially a very powerful feature! And requires a knowledge of
+ regular expressions if you want to "roll your own". Filtering operates on a
+ line by line basis throughout the entire page.
+
+ 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.
+
+ Filtering can achieve some of the effects as the "+block" action, i.e. it
+ can be used to block ads and banners. In the overall scheme of things,
+ filtering is one of the first things "Privoxy" does with a web page. So
+ other most other actions are applied to the already "filtered" page.
+
+-------------------------------------------------------------------------------
+
+7.4.5.7. +hide-forwarded-for-headers
+
+Type:
+
+ Boolean.
+
+Typical uses:
+
+ Block any existing X-Forwarded-for HTTP header, and do not add a new one.
+
+Possible values:
+
+ N/A
+
+Example usage:
+
+ {+hide-forwarded-for-headers}
+ .example.com
+
+
+Notes:
+
+ It is fairly safe to leave this on. It does not seem to break many sites.
+
+-------------------------------------------------------------------------------
+
+7.4.5.8. +hide-from-header
+
+Type:
+
+ Parameterized.
+
+Typical uses:
+
+ To block the browser from sending your email address in a "From:" header.
+
+Possible values:
+
+ Keyword: "block", or any user defined value.
+
+Example usage:
+
+ {+hide-from-header{block}}
+ .example.com
+
+
+Notes:
+
+ The keyword "block" will completely remove the header (not to be confused
+ with the "+block" action). Alternately, you can specify any value you
+ prefer to send to the web server.
+
+-------------------------------------------------------------------------------
+
+7.4.5.9. +hide-referer
+
+Type:
+
+ Parameterized.
+
+Typical uses:
+
+ Don't send the "Referer:" (sic) HTTP header to the web site. Or,
+ alternately send a forged header instead.
+
+Possible values:
+
+ Prevent the header from being sent with the keyword, "block". Or, "forge" a
+ URL to one from the same server as the request. Or, set to user defined
+ value of your choice.
+
+Example usage:
+
+ {+hide-referer{forge}}
+ .example.com
+
+
+Notes:
+
+ "forge" is the preferred option here, since some servers will not send
+ images back otherwise.
+
+ "+hide-referrer" is an alternate spelling of "+hide-referer". It has the
+ exact same parameters, and can be freely mixed with, "+hide-referer".
+ ("referrer" is the correct English spelling, however the HTTP specification
+ has a bug - it requires it to be spelled as "referer".)
+
+-------------------------------------------------------------------------------
+
+7.4.5.10. +hide-user-agent
+
+Type:
+
+ Parameterized.
+
+Typical uses:
+
+ To change the "User-Agent:" header so web servers can't tell your browser
+ type. Who's business is it anyway?
+
+Possible values:
+
+ Any user defined string.
+
+Example usage:
+
+ {+hide-user-agent{Netscape 6.1 (X11; I; Linux 2.4.18 i686)}}
+ .msn.com
+
+
+Notes:
+
+ Warning! This breaks many web sites that depend on this in order to
+ determine how the target browser will respond to various requests. Use with
+ caution.
+
+-------------------------------------------------------------------------------
+
+7.4.5.11. +handle-as-image
+
+Type:
+
+ Boolean.
+
+Typical uses:
+
+ To define what Privoxy should treat automatically as an image, and is an
+ important ingredient of how ads are handled.
+
+Possible values:
+
+ N/A
+
+Example usage:
+
+ {+handle-as-image}
+ /.*\.(gif|jpg|jpeg|png|bmp|ico)
+
+
+Notes:
+
+ This only has meaning if the URL (or pattern) also is "+block"ed, in which
+ case a user definable image can be sent rather than a HTML page. This is
+ integral to the whole concept of ad blocking: the URL must match both a
+ "+block" rule, and "+handle-as-image". (See "+set-image-blocker" below for
+ control over what will actually be displayed by the browser.)
+
+ There is little reason to change the default definition for this action.
+
+-------------------------------------------------------------------------------
+
+7.4.5.12. +set-image-blocker
+
+Type:
+
+ Parameterized.
+
+Typical uses:
+
+ Decide what to do with URLs that end up tagged with both "+block" and
+ "+handle-as-image", e.g an advertisement.
+
+Possible values:
+
+ There are four available options: "-set-image-blocker" will send a HTML
+ "blocked" page, usually resulting in a "broken image" icon.
+ "+set-image-blocker{blank}" will send a 1x1 transparent GIF image.
+ "+set-image-blocker{pattern}" will send a checkerboard type pattern (the
+ default). And finally, "+set-image-blocker{http://xyz.com}" will send a
+ HTTP temporary redirect to the specified image. This has the advantage of
+ the icon being being cached by the browser, which will speed up the
+ display.
+
+Example usage:
+
+ {+set-image-blocker{blank}}
+ .example.com
+
+
+Notes:
+
+ If you want invisible ads, they need to meet criteria as matching both
+ images and blocked actions. And then, "image-blocker" should be set to
+ "blank" for invisibility. Note you cannot treat HTML pages as images in
+ most cases. For instance, frames require an HTML page to display. So a
+ frame that is an ad, typically cannot be treated as an image. Forcing an
+ "image" in this situation just will not work reliably.
+
+-------------------------------------------------------------------------------
+
+7.4.5.13. +limit-connect
+
+Type:
+
+ Parameterized.
+
+Typical uses:
+
+ By default, Privoxy only allows HTTP CONNECT requests to port 443 (the
+ standard, secure HTTPS port). Use "+limit-connect" to disable this
+ altogether, or to allow more ports.
+
+Possible values:
+
+ Any valid port number, or port number range.
+
+Example usages:
+
+ +limit-connect{443} #
+ This is the default and need not be specified.
+ +limit-connect{80,443} # Ports 80 and 443 are OK.
+ +limit-connect{-3, 7, 20-100, 500-} #
+ Port less than 3, 7, 20 to 100 and above 500 are OK.
+
+
+Notes:
+
+ The CONNECT methods exists in HTTP to allow access to secure websites
+ (https:// 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 proxy. This can be a big
+ security hole, since CONNECT-enabled proxies can be abused as TCP relays
+ very easily.
+
+ If you want to allow CONNECT for more ports than this, or want to forbid
+ CONNECT altogether, you can specify a comma separated list of ports and
+ port ranges (the latter using dashes, with the minimum defaulting to 0 and
+ max to 65K).
+
+ If you don't know what any of this means, there probably is no reason to
+ change this one.
+
+-------------------------------------------------------------------------------
+
+7.4.5.14. +prevent-compression
+
+Type:
+
+ Boolean.
+
+Typical uses:
+
+ Prevent the specified websites from compressing HTTP data.
+
+Possible values:
+
+ N/A
+
+Example usage:
+
+ {+prevent-compression}
+ .example.com
+
+
+Notes:
+
+ Some websites do this, which can be a problem for Privoxy, since "+filter",
+ "+kill-popups" and "+gif-deanimate" will not work on compressed data. This
+ will slow down connections to those websites, though. Default typically is
+ to turn "prevent-compression" on.
+
+-------------------------------------------------------------------------------
+
+7.4.5.15. +session-cookies-only
+
+Type:
+
+ Boolean.
+
+Typical uses:
+
+ Allow cookies for the current browser session only.
+
+Possible values:
+
+ N/A
+
+Example usage (disabling):
+
+ {-session-cookies-only}
+ .example.com
+
+
+Notes:
+
+ If websites set cookies, "+session-cookies-only" will make sure they are
+ erased when you exit and restart your web browser. This makes profiling
+ cookies useless, but won't break sites which require cookies so that you
+ can log in for transactions. This is generally turned on for all sites, and
+ is the recommended setting.
+
+ "+prevent-*-cookies" actions should be turned off as well (see below), for
+ "+session-cookies-only" to work. Or, else no cookies will get through at
+ all. For, "persistent" cookies that survive across browser sessions, see
+ below as well.
+
+-------------------------------------------------------------------------------
+
+7.4.5.16. +prevent-reading-cookies
+
+Type:
+
+ Boolean.
+
+Typical uses:
+
+ Explicitly prevent the web server from reading any cookies on your system.
+
+Possible values:
+
+ N/A
+
+Example usage:
+
+ {+prevent-reading-cookies}
+ .example.com
+
+
+Notes:
+
+ Often used in conjunction with "+prevent-setting-cookies" to disable
+ cookies completely. Note that "+session-cookies-only" requires these to
+ both be disabled (or else it never gets any cookies to cache).
+
+ For "persistent" cookies to work (i.e. they survive across browser sessions
+ and reboots), all three cookie settings should be "off" for the specified
+ sites.
+
+-------------------------------------------------------------------------------
+
+7.4.5.17. +prevent-setting-cookies
+
+Type:
+
+ Boolean.
+
+Typical uses:
+
+ Explicitly block the web server from storing cookies on your system.
+
+Possible values:
+
+ N/A
+
+Example usage:
+
+ {+prevent-setting-cookies}
+ .example.com
+
+
+Notes:
+
+ Often used in conjunction with "+prevent-reading-cookies" to disable
+ cookies completely (see above).
+
+-------------------------------------------------------------------------------
+
+7.4.5.18. +kill-popups
+
+Type:
+
+ Boolean.
+
+Typical uses:
+
+ Stop those annoying JavaScript pop-up windows!
+
+Possible values:
+
+ N/A
+
+Example usage:
+
+ {+kill-popups}
+ .example.com
+
+
+Notes:
+
+ "+kill-popups" uses a built in filter to disable pop-ups that use the
+ window.open() function, etc. This is one of the first actions processed by
+ Privoxy as it contacts the remote web server. This action is not always
+ 100% reliable, and is supplemented by "+filter{popups}".
+
+-------------------------------------------------------------------------------
+
+7.4.5.19. +send-vanilla-wafer
+
+Type:
+
+ Boolean.
+
+Typical uses:
+
+ Sends a cookie for every site stating that you do not accept any copyright
+ on cookies sent to you, and asking them not to track you.
+
+Possible values:
+
+ N/A
+
+Example usage:
+
+ {+send-vanilla-wafer}
+ .example.com
+
+
+Notes:
+
+ This action only applies if you are using a jarfile for saving cookies. Of
+ course, this is a (relatively) unique header and could conceivably be used
+ to track you.
+
+-------------------------------------------------------------------------------
+
+7.4.5.20. +send-wafer
+
+Type:
+
+ Multi-value.
+
+Typical uses:
+
+ This allows you to send an arbitrary, user definable cookie.
+
+Possible values:
+
+ User specified cookie name and corresponding value.
+
+Example usage:
+
+ {+send-wafer{name=value}}
+ .example.com
+
+
+Notes:
+
+ This can be specified multiple times in order to add as many cookies as you
+ like.
+
+-------------------------------------------------------------------------------
+
+7.4.5.21. Actions Examples
+
+Note that the meaning of any of the above examples is reversed by preceding the
+action with a "-", in place of the "+". Also, that some actions are turned on
+in the default section of the actions file, and require little to no additional
+configuration. These are just "on". But, other actions that are turned on the
+default section do typically require exceptions to be listed in the latter
+sections of one of our actions file. For instance, by default no URLs are
+"blocked" (i.e. in the default definitions of default.action). We need
+exceptions to this in order to enable ad blocking in the lower sections. But we
+need to be very selective about what we do block.
+
+Below is a liberally commented default.action file to demonstrate the pieces
+all come together. And to show how exceptions to the default policies can be
+handled. This is followed by a user.action with similar examples.
+
+
+##########################################################################
+# Aliases must be defined *before* they are used. These are
+# easier to remember, and combine several actions into one:
+##########################################################################
+
+# Some useful aliases.
+ +prevent-cookies = +prevent-setting-cookies +prevent-reading-cookies
+ -prevent-cookies = -prevent-setting-cookies -prevent-reading-cookies
+ +imageblock = +block +handle-as-image
+
+# Fragile sites should have the minimum changes:
+ fragile = -block -deanimate-gifs -fast-redirects -filter -hide-referer \
+ -prevent-cookies -kill-popups
+
+# Shops should be allowed to set persistent cookies
+ shop = -filter -prevent-cookies -prevent-keeping-cookies
+
+
+##########################################################################
+# Begin default action settings. Anything in this section will match
+# all URLs -- UNLESS we have exceptions defined below this section.
+# We will show all potential actions here whether they are on or off.
+# We could omit any disabled action if we wanted, since all actions are
+# 'off' by default anyway. Shown for completeness only.
+##########################################################################
+ { \
+ -add-header \
+ -block \
+ -deanimate-gifs \
+ -downgrade-http-version \
+ +fast-redirects \
+ +filter{html-annoyances} \
+ +filter{js-annoyances} \
+ -filter{content-cookies} \
+ -filter{popups} \
+ +filter{webbugs} \
+ -filter{refresh-tags} \
+ -filter{fun} \
+ +filter{nimda} \
+ +filter{banners-by-size} \
+ -filter{shockwave-flash} \
+ -filter{crude-prental} \
+ +hide-forwarded-for-headers \
+ +hide-from-header{block} \
+ -hide-referrer \
+ -hide-user-agent \
+ -handle-as-image \
+ +set-image-blocker{pattern} \
+ -limit-connect \
+ +prevent-compression \
+ -session-cookies-only \
+ -prevent-reading-cookies \
+ -prevent-setting-cookies \
+ -kill-popups \
+ -send-vanilla-wafer \
+ -send-wafer \
+ }
+ / # forward slash will match all potential URLs patterns.
+
+##########################################################################
+# Default behavior is now set. Time for some exceptions to our
+# default actions.
+##########################################################################
+
+# These sites are very complex and require very minimal interference.
+# We'll disable most actions with our 'fragile' alias.
+ {fragile}
+ .office.microsoft.com
+ .windowsupdate.microsoft.com
+
+
+# Shopping sites - not as fragile. We still want to block ads.
+ {shop}
+ .quietpc.com
+ .worldpay.com # for quietpc.com
+ .jungle.com
+ .scan.co.uk
+
+
+# These sites require pop-ups too :( We'll combine our 'shop'
+# alias with two other actions into one rule to allow all popups.
+ {shop -no-popups -filter{popups}}
+ .dabs.com
+ .overclockers.co.uk
+
+
+# The 'Fast-redirects' action breaks some sites. Disable this action
+# for these known sensitive sites.
+ {-fast-redirects}
+ www.ukc.ac.uk/cgi-bin/wac\.cgi\?
+ login.yahoo.com
+ edit.europe.yahoo.com
+ .google.com
+ .altavista.com/.*(like|url|link):http
+ .altavista.com/trans.*urltext=http
+ .nytimes.com
+
+
+# Define which file types will be treated as images. Important
+# for ad blocking.
+ {+handle-as-image}
+ /.*\.(gif|jpe?g|png|bmp|ico)
+
+
+# Now lets list some domains that are known ad generators. And
+# our alias here will block these as well as force them to be
+# treated as images. This combination of actions is important
+# for ad blocking. What the browser will show instead is
+# determined by the setting of "+set-image-blocker"
+ {+imageblock}
+ ar.atwola.com
+ .ad.doubleclick.net
+ .a.yimg.com/(?:(?!/i/).)*$
+ .a[0-9].yimg.com/(?:(?!/i/).)*$
+ bs*.gsanet.com
+ bs*.einets.com
+ .qkimg.net
+ ad.*.doubleclick.net
+
+
+# These will just simply be blocked. They will generate the BLOCKED
+# banner page, if matched. Heavy use of wildcards and regular
+# expressions in this example.
+ {+block}
+ ad*.
+ .*ads.
+ banner?.
+ count*.
+ /.*count(er)?\.(pl|cgi|exe|dll|asp|php[34]?)
+ /(?:.*/)?(publicite|werbung|rekla(ma|me|am)|annonse|maino(kset|nta|s)?)/
+ .hitbox.com
+
+
+# The above block section will catch some sites we DO NOT want
+# blocked via wildcards and regular expressions. Now set exceptions
+# to the exceptions so the good guys get better treatment.
+ {-block}
+ advogato.org
+ adsl.
+ ad[ud]*.
+ advice.
+# Let's just trust universities
+ .edu
+ www.ugu.com/sui/ugu/adv
+# We'll need to access to path names containing 'download'
+ .*downloads.
+ /downloads/
+# 'adv' is for globalintersec means advanced, not advertisement
+ www.globalintersec.com/adv
+
+
+# Don't filter *anything* from our friends at sourceforge.
+# Notice we don't have to name the individual filter
+# identifiers -- we just turn them all off.
+ {-filter}
+ .sourceforge.net
+
+
+
+Some examples:
+
+Turn off cookies by default, then allow a few through for specified sites
+(showing an excerpt from the "default" section of an actions file ONLY):
+
+ # Excerpt only:
+ # Allow cookies to and from the server, but
+ # for this browser session ONLY
+ {
+ # other actions normally listed here...
+ -prevent-setting-cookies \
+ -prevent-reading-cookies \
+ +session-cookies-only \
+ }
+ / # match all URLs
+
+ # Exceptions to the above, sites that benefit from persistent cookies
+ # that are saved from one browser session to the next.
+ { -session-cookies-only }
+ .javasoft.com
+ .sun.com
+ .yahoo.com
+ .msdn.microsoft.com
+ .redhat.com
+
+
+
+Now turn off "fast redirects", and then we allow two exceptions:
+
+ # Turn them off (excerpt only)!
+ {
+ # other actions normally listed here...
+ +fast-redirects
+ }
+ / # match all URLs
+
+ # Reverse it for these two sites, which don't work right without it.
+ {-fast-redirects}
+ www.ukc.ac.uk/cgi-bin/wac\.cgi\?
+ login.yahoo.com
+
+
+Turn on page filtering according to rules in the defined sections of
+default.filter, and make one exception for Sourceforge:
+
+ # Run everything through the filter file, using only certain
+ # specified sections:
+ {
+ # other actions normally listed here...
+ +filter{html-annoyances} +filter{js-annoyances} +filter{kill-popups}\
+ +filter{webbugs} +filter{nimda} +filter{banners-by-size}
+ }
+ / #match all URLs
+
+ # Then disable filtering of code from all sourceforge domains!
+ {-filter}
+ .sourceforge.net
+
+
+Now some URLs that we want "blocked" (normally generates the "blocked" banner).
+Typically, the "block" action is off by default in the upper section of an
+actions file, then enabled against certain URLs and patterns in the lower part
+of the file. Many of these use regular expressions that will expand to match
+multiple URLs:
+
+ # Blocklist:
+ {+block}
+ ad*.
+ .*ads.
+ banner?.
+ count*.
+ /.*count(er)?\.(pl|cgi|exe|dll|asp|php[34]?)
+ /(?:.*/)?(publicite|werbung|rekla(ma|me|am)|annonse|maino(kset|nta|s)?)/
+ .hitbox.com
+ /.*/(ng)?adclient\.cgi
+ /.*/(plain|live|rotate)[-_.]?ads?/
+ /.*/abanners/
+ /autoads/
+
+
+Note that many of these actions have the potential to cause a page to
+misbehave, possibly even not to display at all. There are many ways a site
+designer may choose to design his site, and what HTTP header content, and other
+criteria, he may depend on. There is no way to have hard and fast rules for all
+sites. See the Appendix for a brief example on troubleshooting actions.
+
+-------------------------------------------------------------------------------
+
+7.4.6. Aliases
+
+Custom "actions", known to Privoxy as "aliases", can be defined by combining
+other "actions". These can in turn be invoked just like the built-in "actions".
+Currently, an alias can contain any character except space, tab, "=", "{" or "}
+". But please use only "a"- "z", "0"-"9", "+", and "-". Alias names are not
+case sensitive, and must be defined before other actions in the actions file!
+And there can only be one set of "aliases" defined per file. Each actions file
+may have its own aliases, but they are only visible within that file.
+
+Now let's define a few aliases:
+
+ # Useful custom aliases we can use later. These must come first!
+ {{alias}}
+ +prevent-cookies = +prevent-setting-cookies +prevent-reading-cookies
+ -prevent-cookies = -prevent-setting-cookies -prevent-reading-cookies
+ fragile =
+ -block -prevent-cookies -filter -fast-redirects -hide-referer -kill-popups
+ shop = -prevent-cookies -filter -fast-redirects
+ +imageblock = +block +handle-as-image
+
+ # Aliases defined from other aliases, for people who don't like to type
+ # too much: ;-)
+ c0 = +prevent-cookies
+ c1 = -prevent-cookies
+ #... etc. Customize to your heart's content.
+
+
+Some examples using our "shop" and "fragile" aliases from above. These would
+appear in the lower sections of an actions file as exceptions to the default
+actions (as defined in the upper section):
+
+ # These sites are very complex and require
+ # minimal interference.
+ {fragile}
+ .office.microsoft.com
+ .windowsupdate.microsoft.com
+ .nytimes.com
+
+ # Shopping sites - but we still want to block ads.
+ {shop}
+ .quietpc.com
+ .worldpay.com # for quietpc.com
+ .scan.co.uk
+
+ # These shops require pop-ups also
+ {shop -kill-popups}
+ .dabs.com
+ .overclockers.co.uk
+
+
+The "shop" and "fragile" aliases are often used for "problem" sites that
+require most actions to be disabled in order to function properly.
+
+-------------------------------------------------------------------------------
+
+7.5. The Filter File
+
+Any web page can be dynamically modified with the filter file. This
+modification can be removal, or re-writing, of any web page content, including
+tags and non-visible content. The default filter file is default.filter,
+located in the config directory.
+
+This is potentially a very powerful feature, and requires knowledge of both
+"regular expression" and HTML in order create custom filters. But, there are a
+number of useful filters included with Privoxy for many common situations.
+
+The included example file is divided into sections. Each section begins with
+the FILTER keyword, followed by the identifier for that section, e.g. "FILTER:
+webbugs". Each section performs a similar type of filtering, such as
+"html-annoyances".
+
+This file uses regular expressions to alter or remove any string in the target
+page. The expressions can only operate on one line at a time. Some examples
+from the included default default.filter:
+
+Stop web pages from displaying annoying messages in the status bar by deleting
+such references:
+
+ FILTER: html-annoyances
+
+ # New browser windows should be resizeable and have a location and status
+ # bar. Make it so.
+ #
+ s/resizable="?(no|0)"?/resizable=1/ig s/noresize/yesresize/ig
+ s/location="?(no|0)"?/location=1/ig s/status="?(no|0)"?/status=1/ig
+ s/scrolling="?(no|0|Auto)"?/scrolling=1/ig
+ s/menubar="?(no|0)"?/menubar=1/ig
+
+ # The <BLINK> tag was a crime!
+ #
+ s*<blink>|</blink>**ig
+
+ # Is this evil?
+ #
+ #s/framespacing="?(no|0)"?//ig
+ #s/margin(height|width)=[0-9]*//gi
+
+
+Just for kicks, replace any occurrence of "Microsoft" with "MicroSuck", and
+have a little fun with topical buzzwords:
+
+ FILTER: fun
+
+ s/microsoft(?!.com)/MicroSuck/ig
+
+ # Buzzword Bingo:
+ #
+ s/industry-leading|cutting-edge|award-winning/<font color=red><b>BINGO!</b></
+font>/ig
+
+
+Kill those pesky little web-bugs:
+
+ # webbugs: Squish WebBugs (1x1 invisible GIFs used for user tracking)
+ FILTER: webbugs
+
+ s/<img\s+[^>]*?(width|height)\s*=\s*['"]?1\D[^>]*?(width|height)\s*=\s*['"]?1
+(\D[^>]*?)?>/<!-- Squished WebBug -->/sig
+
+
+-------------------------------------------------------------------------------
+
+7.5.1. The +filter Action
+
+Filters are enabled with the "+filter" action from within one of the actions
+files. "+filter" requires one parameter, which should match one of the section
+identifiers in the filter file itself. Example:
+
+ +filter{html-annoyances}
+
+
+This would activate that particular filter. Similarly, "+filter" can be turned
+off for selected sites as: "-filter{html-annoyances}". Remember, all actions
+are off by default, unless they are explicity enabled in one of the actions
+files.
+
+-------------------------------------------------------------------------------
+
+7.6. Templates
+
+When Privoxy displays one of its internal pages, such as a 404 Not Found error
+page, it uses the appropriate template. On Linux, BSD, and Unix, these are
+located in /etc/privoxy/templates by default. These may be customized, if
+desired. cgi-style.css is used to control the HTML attributes (fonts, etc).
+
+The default "Blocked" banner page with the bright red top banner, is called
+just "blocked". This may be customized or replaced with something else if
+desired.
+
+-------------------------------------------------------------------------------
+
+8. Contacting the Developers, Bug Reporting and Feature Requests
+
+We value your feedback. However, to provide you with the best support, please
+note the following sections.
+
+-------------------------------------------------------------------------------
+
+8.1. Get Support
+
+To get support, use the Sourceforge Support Forum:
+
+ http://sourceforge.net/tracker/?group_id=11118&atid=211118
+
+
+-------------------------------------------------------------------------------
+
+8.2. Report bugs
+
+To submit bugs, use the Sourceforge Bug Forum:
+
+ http://sourceforge.net/tracker/?group_id=11118&atid=111118.
+
+
+Make sure that the bug has not already been submitted. Please try to verify
+that it is a Privoxy bug, and not a browser or site bug first. If you are using
+your own custom configuration, please try the stock configs to see if the
+problem is a configuration related bug. And if not using the latest development
+snapshot, please try the latest one. Or even better, CVS sources. Please be
+sure to include the Privoxy version, platform, browser, any pertinent log data,
+any other relevant details (please be specific) and, if possible, some way to
+reproduce the bug.
+
+-------------------------------------------------------------------------------
+
+8.3. Request new features
+
+To submit ideas on new features, use the Sourceforge feature request forum:
+
+ http://sourceforge.net/tracker/?atid=361118&group_id=11118&func=browse.
+
+
+-------------------------------------------------------------------------------
+
+8.4. Report ads or other filter problems
+
+You can also send feedback on websites that Privoxy has problems with. Please
+bookmark the following link: "Privoxy - Submit Filter Feedback". Once you surf
+to a page with problems, use the bookmark to send us feedback. We will look
+into the issue as soon as possible.
+
+New, improved default.action files will occasionally be made available based on
+your feedback. These will be announced on the ijbswa-announce list.
+
+-------------------------------------------------------------------------------
+
+8.5. Other
+
+For any other issues, feel free to use the mailing lists:
+
+ http://sourceforge.net/mail/?group_id=11118.
+
+
+Anyone interested in actively participating in development and related
+discussions can also join the appropriate mailing list. Archives are available,
+too. See the page on Sourceforge.
+
+-------------------------------------------------------------------------------
+
+9. Copyright and History
+
+9.1. Copyright
+
+Privoxy is free software; you can redistribute it and/or modify it under the
+terms of the GNU General Public License as published by the Free Software
+Foundation; either version 2 of the License, or (at your option) any later
+version.
+
+This program is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+PARTICULAR PURPOSE. See the GNU General Public License for more details, which
+is available from the Free Software Foundation, Inc, 59 Temple Place - Suite
+330, Boston, MA 02111-1307, USA.
+
+You should have received a copy of the GNU General Public License along with
+this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+Place, Suite 330, Boston, MA 02111-1307 USA.
+
+-------------------------------------------------------------------------------
+
+9.2. History
+
+Privoxy is evolved, and derived from, the Internet Junkbuster, with many
+improvments and enhancements over the original.
+
+Junkbuster was originally written by Anonymous Coders and Junkbusters
+Corporation, and was released as free open-source software under the GNU GPL.
+Stefan Waldherr made many improvements, and started the SourceForge project
+Privoxy to rekindle development. There are now several active developers
+contributing. The last stable release of Junkbuster was v2.0.2, which has now
+grown whiskers ;-).
+
+-------------------------------------------------------------------------------
+
+10. See Also
+
+Other references and sites of interest to Privoxy users:
+
+http://www.privoxy.org/, The Privoxy Home page.
+
+http://sourceforge.net/projects/ijbswa, the Project Page for Privoxy on
+Sourceforge.
+
+http://p.p/, access Privoxy from your browser. Alternately, http://
+config.privoxy.org may work in some situations where the first does not.
+
+http://p.p/, and select "actions file feedback system" to submit "misses" to
+the developers.
+
+http://www.junkbusters.com/ht/en/cookies.html
+
+http://www.waldherr.org/junkbuster/
+
+http://privacy.net/analyze/
+
+http://www.squid-cache.org/
+
+
+
+-------------------------------------------------------------------------------
+
+11. Appendix
+
+11.1. Regular Expressions
+
+Privoxy can use "regular expressions" in various config files. Assuming support
+for "pcre" (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.
+
+If you are reading this, you probably don't understand what "regular
+expressions" are, or what they can do. So this will be a very brief
+introduction only. A full explanation would require a book ;-)
+
+"Regular expressions" is a way of matching one character expression against
+another to see if it matches or not. One of the "expressions" 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 "meta-characters" 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.
+
+To make a simple analogy, we do something similar when we use wild-card
+characters when listing files with the dir command in DOS. *.* matches all
+filenames. The "special" character here is the asterisk which matches any and
+all characters. We can be more specific and use ? to match just individual
+characters. So "dir file?.text" would match "file1.txt", "file2.txt", etc. We
+are pattern matching, using a similar technique to "regular expressions"!
+
+Regular expressions do essentially the same thing, but are much, much more
+powerful. There are many more "special characters" and ways of building complex
+patterns however. Let's look at a few of the common ones, and then some
+examples:
+
+. - Matches any single character, e.g. "a", "A", "4", ":", or "@".
+
+? - The preceding character or expression is matched ZERO or ONE times. Either/
+or.
+
++ - The preceding character or expression is matched ONE or MORE times.
+
+* - The preceding character or expression is matched ZERO or MORE times.
+
+\ - The "escape" character denotes that the following character should be taken
+literally. This is used where one of the special characters (e.g. ".") needs to
+be taken literally and not as a special meta-character. Example: "example
+\.com", makes sure the period is recognized only as a period (and not expanded
+to its meta-character meaning of any single character).
+
+[] - Characters enclosed in brackets will be matched if any of the enclosed
+characters are encountered. For instance, "[0-9]" matches any numeric digit
+(zero through nine). As an example, we can combine this with "+" to match any
+digit one of more times: "[0-9]+".
+
+() - parentheses are used to group a sub-expression, or multiple
+sub-expressions.
+
+| - The "bar" character works like an "or" conditional statement. A match is
+successful if the sub-expression on either side of "|" matches. As an example:
+"/(this|that) example/" uses grouping and the bar character and would match
+either "this example" or "that example", and nothing else.
+
+s/string1/string2/g - This is used to rewrite strings of text. "string1" is
+replaced by "string2" in this example. There must of course be a match on
+"string1" first.
+
+These are just some of the ones you are likely to use when matching URLs with
+Privoxy, 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:
+
+/.*/banners/.* - A simple example that uses the common combination of "." and "
+*" 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 (".*") another literal forward slash, the string "banners", another
+forward slash, and lastly another ".*". We are building a directory path here.
+This will match any file with the path that has a directory named "banners" in
+it. The ".*" 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: "/eye/hate/spammers/banners/annoy_me_please.gif", or just "/
+banners/annoying.html", or almost an infinite number of other possible
+combinations, just so it has "banners" in the path somewhere.
+
+A now something a little more complex:
+
+/.*/adv((er)?ts?|ertis(ing|ements?))?/ - We have several literal forward
+slashes again ("/"), so we are building another expression that is a file path
+statement. We have another ".*", so we are matching against any conceivable
+sub-path, just so it matches our expression. The only true literal that must
+match our pattern is adv, together with the forward slashes. What comes after
+the "adv" string is the interesting part.
+
+Remember the "?" means the preceding expression (either a literal character or
+anything grouped with "(...)" in this case) can exist or not, since this means
+either zero or one match. So "((er)?ts?|ertis(ing|ements?))" is optional, as
+are the individual sub-expressions: "(er)", "(ing|ements?)", and the "s". The "
+|" means "or". We have two of those. For instance, "(ing|ements?)", can expand
+to match either "ing" OR "ements?". What is being done here, is an attempt at
+matching as many variations of "advertisement", and similar, as possible. So
+this would expand to match just "adv", or "advert", or "adverts", or
+"advertising", or "advertisement", or "advertisements". You get the idea. But
+it would not match "advertizements" (with a "z"). We could fix that by changing
+our regular expression to: "/.*/adv((er)?ts?|erti(s|z)(ing|ements?))?/", which
+would then match either spelling.
+
+/.*/advert[0-9]+\.(gif|jpe?g) - Again another path statement with forward
+slashes. Anything in the square brackets "[]" can be matched. This is using
+"0-9" as a shorthand expression to mean any digit one through nine. It is the
+same as saying "0123456789". So any digit matches. The "+" 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: "(gif|jpe?g)". This includes a "|", so
+this needs to match the expression on either side of that bar character also. A
+simple "gif" on one side, and the other side will in turn match either "jpeg"
+or "jpg", since the "?" means the letter "e" 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 "advert", then one or
+more digits, and a "." (which is now a literal, and not a special character,
+since it is escaped with "\"), and lastly either "gif", or "jpeg", or "jpg".
+Some possible matches would include: "//advert1.jpg", "/nasty/ads/
+advert1234.gif", "/banners/from/hell/advert99.jpg". It would not match
+"advert1.gif" (no leading slash), or "/adverts232.jpg" (the expression does not
+include an "s"), or "/advert1.jsp" ("jsp" is not in the expression anywhere).
+
+s/microsoft(?!.com)/MicroSuck/i - This is a substitution. "MicroSuck" will
+replace any occurrence of "microsoft". The "i" at the end of the expression
+means ignore case. The "(?!.com)" means the match should fail if "microsoft" is
+followed by ".com". In other words, this acts like a "NOT" modifier. In case
+this is a hyperlink, we don't want to break it ;-).
+
+We are barely scratching the surface of regular expressions here so that you
+can understand the default Privoxy 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 :/
+
+More reading on Perl Compatible Regular expressions: http://www.perldoc.com/
+perl5.6/pod/perlre.html
+
+-------------------------------------------------------------------------------
+
+11.2. Privoxy's Internal Pages
+
+Since Privoxy proxies each requested web page, it is easy for Privoxy to trap
+certain special URLs. In this way, we can talk directly to Privoxy, and see how
+it is configured, see how our rules are being applied, change these rules and
+other configuration options, and even turn Privoxy's filtering off, all with a
+web browser.
+
+The URLs listed below are the special ones that allow direct access to Privoxy.
+Of course, Privoxy must be running to access these. If not, you will get a
+friendly error message. Internet access is not necessary either.
+
+ * Privoxy main page:
+
+ http://config.privoxy.org/