+Specifies:
+
+ Who can access what.
+
+Type of value:
+
+ src_addr[/src_masklen] [dst_addr[/dst_masklen]]
+
+ Where src_addr and dst_addr are IP addresses in dotted decimal notation or
+ valid DNS names, and src_masklen and dst_masklen are subnet masks in CIDR
+ notation, i.e. integer values from 2 to 30 representing the length (in
+ bits) of the network address. The masks and the whole destination part are
+ optional.
+
+Default value:
+
+ Unset
+
+Effect if unset:
+
+ Don't restrict access further than implied by listen-address
+
+Notes:
+
+ Access controls are included at the request of ISPs and systems
+ administrators, and are not usually needed by individual users. For a
+ typical home user, it will normally suffice to ensure that Privoxy only
+ listens on the localhost (127.0.0.1) or internal (home) network address by
+ means of the listen-address option.
+
+ Please see the warnings in the FAQ that this proxy is not intended to be a
+ substitute for a firewall or to encourage anyone to defer addressing basic
+ security weaknesses.
+
+ Multiple ACL lines are OK. If any ACLs are specified, then the Privoxy
+ talks only to IP addresses that match at least one permit-access line and
+ don't match any subsequent deny-access line. In other words, the last match
+ wins, with the default being deny-access.
+
+ If Privoxy is using a forwarder (see forward below) for a particular
+ destination URL, the dst_addr that is examined is the address of the
+ forwarder and NOT the address of the ultimate target. This is necessary
+ because it may be impossible for the local Privoxy to determine the IP
+ address of the ultimate target (that's often what gateways are used for).
+
+ You should prefer using IP addresses over DNS names, because the address
+ lookups take time. All DNS names must resolve! You can not use domain
+ patterns like "*.org" or partial domain names. If a DNS name resolves to
+ multiple IP addresses, only the first one is used.
+
+ Denying access to particular sites by ACL may have undesired side effects
+ if the site in question is hosted on a machine which also hosts other
+ sites.
+
+Examples:
+
+ Explicitly define the default behavior if no ACL and listen-address are
+ set: "localhost" is OK. The absence of a dst_addr implies that all
+ destination addresses are OK:
+
+ permit-access localhost
+
+ Allow any host on the same class C subnet as www.privoxy.org access to
+ nothing but www.example.com:
+
+ permit-access www.privoxy.org/24 www.example.com/32
+
+ Allow access from any host on the 26-bit subnet 192.168.45.64 to anywhere,
+ with the exception that 192.168.45.73 may not access
+ www.dirty-stuff.example.com:
+
+ permit-access 192.168.45.64/26
+ deny-access 192.168.45.73 www.dirty-stuff.example.com
+
+-------------------------------------------------------------------------------
+
+7.4.6. buffer-limit
+
+Specifies:
+
+ Maximum size of the buffer for content filtering.
+
+Type of value:
+
+ Size in Kbytes
+
+Default value:
+
+ 4096
+
+Effect if unset:
+
+ Use a 4MB (4096 KB) limit.
+
+Notes:
+
+ For content filtering, i.e. the +filter and +deanimate-gif actions, it is
+ necessary that Privoxy buffers the entire document body. This can be
+ potentially dangerous, since a server could just keep sending data
+ indefinitely and wait for your RAM to exhaust -- with nasty consequences.
+ Hence this option.
+
+ When a document buffer size reaches the buffer-limit, it is flushed to the
+ client unfiltered and no further attempt to filter the rest of the document
+ is made. Remember that there may be multiple threads running, which might
+ require up to buffer-limit Kbytes each, unless you have enabled
+ "single-threaded" above.
+
+-------------------------------------------------------------------------------
+
+7.5. Forwarding
+
+This feature allows routing of HTTP requests through a chain of multiple
+proxies. It can be used to better protect privacy and confidentiality when
+accessing specific domains by routing requests to those domains through an
+anonymous public proxy (see e.g. http://www.multiproxy.org/anon_list.htm) Or to
+use a caching proxy to speed up browsing. Or chaining to a parent proxy may be
+necessary because the machine that Privoxy runs on has no direct Internet
+access.
+
+Also specified here are SOCKS proxies. Privoxy supports the SOCKS 4 and SOCKS
+4A protocols.
+
+-------------------------------------------------------------------------------
+
+7.5.1. forward
+
+Specifies:
+
+ To which parent HTTP proxy specific requests should be routed.
+
+Type of value:
+
+ target_domain[:port] http_parent[/port]
+
+ Where target_domain is a domain name pattern (see the chapter on domain
+ matching in the default.action file), http_parent is the address of the
+ parent HTTP proxy as an IP addresses in dotted decimal notation or as a
+ valid DNS name (or "." to denote "no 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 parent HTTP proxies.
+
+Notes:
+
+ If http_parent is ".", then requests are not forwarded to another HTTP
+ proxy but are made directly to the web servers.
+
+ Multiple lines are OK, they are checked in sequence, and the last match
+ wins.
+
+Examples:
+
+ Everything goes to an example anonymizing proxy, except SSL on port 443
+ (which it doesn't handle):
+
+ forward .* anon-proxy.example.org:8080
+ forward :443 .
+
+ Everything goes to our example ISP's caching proxy, except for requests to
+ that ISP's sites:
+
+ forward .*. caching-proxy.example-isp.net:8000
+ forward .example-isp.net .
+
+-------------------------------------------------------------------------------
+
+7.5.2. forward-socks4 and forward-socks4a
+
+Specifies:
+
+ Through which SOCKS proxy (and to which parent HTTP proxy) specific
+ requests should be routed.
+
+Type of value:
+
+ target_domain[:port] socks_proxy[/port] http_parent[/port]
+
+ 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 .
+
+-------------------------------------------------------------------------------
+
+7.5.3. 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.
+
+-------------------------------------------------------------------------------
+
+7.6. 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
+
+
+-------------------------------------------------------------------------------
+
+8. Actions Files
+
+The actions files are used to define what actions Privoxy takes for which URLs,
+and thus determine 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 (as of version
+2.9.15), with differing purposes:
+
+ * standard.action - is used by the web based editor, to set various
+ pre-defined sets of rules for the default actions section in
+ default.action. These have increasing levels of aggressiveness and have no
+ influence on your browsing unless you select them explicitly in the editor.
+ It is not recommend to edit this file.
+
+ * default.action - is the primary action file that sets the initial values
+ for all actions. It is intended to provide a base level of functionality
+ for Privoxy's array of features. So it is a set of broad rules that should
+ work reasonably well for users everywhere. This is the file that the
+ developers are keeping updated, and making available to users.
+
+ * user.action - 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.
+
+The list of actions files to be used are defined in the main configuration
+file, and are processed in the order they are defined. The content of these can
+all be viewed and edited from http://config.privoxy.org/show-status.
+
+An actions file typically has multiple sections. If you want to use "aliases"
+in an actions file, you have to place the (optional) alias section at the top
+of that file. Then comes the default set of rules which will apply universally
+to all sites and pages (be very careful with using such a universal set in
+user.action or any other actions file after default.action, because it will
+override the result from consulting any previous file). And then below that,
+exceptions to the defined universal policies. You can regard user.action as an
+appendix to default.action, with the advantage that is a separate file, which
+makes preserving your personal settings across Privoxy upgrades easier.
+
+Actions can be used to block anything you want, including ads, banners, or just
+some obnoxious URL that 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, JavaScripts tamed, user-tracking fooled, and
+much more. See below for a complete list of actions.
+
+-------------------------------------------------------------------------------
+
+8.1. Finding the Right Mix
+
+Note that some actions, 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. 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
+:).
+
+-------------------------------------------------------------------------------
+
+8.2. 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. 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 "Cautious", "Medium" or "Advanced".
+
+If you prefer plain text editing to GUIs, you can of course also directly edit
+the the actions files. Look at default.action which is richly commented.
+
+-------------------------------------------------------------------------------
+
+8.3. 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 each action file 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 for any given URL by visiting http://
+config.privoxy.org/show-url-info.
+
+More detail on this is provided in the Appendix, Anatomy of an Action.
+
+-------------------------------------------------------------------------------
+
+8.4. 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.
+
+-------------------------------------------------------------------------------
+
+8.4.1. 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.
+
+-------------------------------------------------------------------------------
+
+8.4.2. 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.
+
+-------------------------------------------------------------------------------
+
+8.5. 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 URLs that match the following patterns", and -block
+means "don't block URLs that match the following patterns, even if +block
+previously applied."
+
+Again, actions are invoked by placing them on a line, enclosed in curly braces
+and separated by whitespace, like in {+some-action -some-other-action
+{some-parameter}}, 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.
+
+There are three classes of actions:
+
+ * Boolean, i.e the action can only be "enabled" or "disabled". Syntax:
+
+ +name # enable action name
+ -name # disable action name
+
+ Example: +block
+
+ * Parameterized, where some value is required in order to enable this type of
+ action. Syntax:
+
+ +name{param} # enable action and set parameter to param,
+ # overwriting parameter from previous match if necessary
+ -name # disable action. The parameter can be omitted
+
+ 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.
+
+ Example: +hide-user-agent{ Mozilla 1.0 }
+
+ * 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, all the parameters from all 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:
+
+ +name{param} # enable action and add param to the list of parameters
+ -name{param} # remove the parameter param from the list of parameters
+ # If it was the last one left, disable the action.
+ -name # disable this action completely and remove all parameters from the list
+
+ Examples: +add-header{X-Fun-Header: Some text} and +filter{html-annoyances}
+
+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 pattern and thus more than one set of actions!
+
+The list of valid Privoxy actions are:
+
+-------------------------------------------------------------------------------
+
+8.5.1. add-header
+
+Typical use:
+
+ Confuse log analysis, custom applications
+
+Effect:
+
+ Sends a user defined HTTP header to the web server.
+
+Type:
+
+ Multi-value.
+
+Parameter:
+
+ Any string value is possible. Validity of the defined HTTP headers is not
+ checked. It is recommended that you use the "X-" prefix for custom headers.
+
+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.
+
+Example usage:
+
+ +add-header{X-User-Tracking: sucks}
+
+-------------------------------------------------------------------------------
+
+8.5.2. block
+
+Typical use:
+
+ Block ads or other obnoxious content
+
+Effect:
+
+ Requests for URLs to which this action applies are blocked, i.e. the
+ requests are not forwarded to the remote server, but answered locally with
+ a substitute page or image, as determined by the handle-as-image and
+ set-image-blocker actions.
+
+Type:
+
+ Boolean.
+
+Parameter:
+
+ N/A
+
+Notes:
+
+ Privoxy sends a special "BLOCKED" page for requests to blocked pages. This
+ page contains links to find out why the request was blocked, and a
+ click-through to the blocked content (the latter only if compiled with the
+ force feature enabled). The "BLOCKED" page adapts to the available screen
+ space -- it displays full-blown if space allows, or miniaturized and
+ text-only if loaded into a small frame or window. If you are using Privoxy
+ right now, you can take a look at the "BLOCKED" page.
+
+ A very important exception occurs if both block and handle-as-image, apply
+ to the same request: it will then be replaced by an image. If
+ set-image-blocker (see below) also applies, the type of image will be
+ determined by its parameter, if not, the standard checkerboard pattern is
+ sent.
+
+ It is important to understand this process, in order to understand how
+ Privoxy deals with ads and other unwanted content.
+
+ The filter action can perform a very similar task, by "blocking" 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.
+
+Example usage (section):
+
+ {+block} # Block and replace with "blocked" page
+ .nasty-stuff.example.com
+
+ {+block +handle-as-image} # Block and replace with image
+ .ad.doubleclick.net
+ .ads.r.us
+
+-------------------------------------------------------------------------------
+
+8.5.3. crunch-incoming-cookies
+
+Typical use:
+
+ Prevent the web server from setting any cookies on your system
+
+Effect:
+
+ Deletes any "Set-Cookie:" HTTP headers from server replies.
+
+Type:
+
+ Boolean.
+
+Parameter:
+
+ N/A
+
+Notes:
+
+ This action is only concerned with incoming cookies. For outgoing cookies,
+ use crunch-outgoing-cookies. Use both to disable cookies completely.
+
+ It makes no sense at all to use this action in conjunction with the
+ session-cookies-only action, since it would prevent the session cookies
+ from being set.
+
+Example usage:
+
+ +crunch-incoming-cookies
+
+-------------------------------------------------------------------------------
+
+8.5.4. crunch-outgoing-cookies
+
+Typical use:
+
+ Prevent the web server from reading any cookies from your system
+
+Effect:
+
+ Deletes any "Cookie:" HTTP headers from client requests.
+
+Type:
+
+ Boolean.
+
+Parameter:
+
+ N/A
+
+Notes:
+
+ This action is only concerned with outgoing cookies. For incoming cookies,
+ use crunch-incoming-cookies. Use both to disable cookies completely.
+
+ It makes no sense at all to use this action in conjunction with the
+ session-cookies-only action, since it would prevent the session cookies
+ from being read.
+
+Example usage:
+
+ +crunch-outgoing-cookies
+
+-------------------------------------------------------------------------------
+
+8.5.5. deanimate-gifs
+
+Typical use:
+
+ Stop those annoying, distracting animated GIF images.
+
+Effect:
+
+ De-animate GIF animations, i.e. reduce them to their first or last image.
+
+Type:
+
+ Parameterized.
+
+Parameter:
+
+ "last" or "first"
+
+Notes:
+
+ 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).
+
+ 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.
+
+Example usage:
+
+ +deanimate-gifs{last}
+
+-------------------------------------------------------------------------------
+
+8.5.6. downgrade-http-version
+
+Typical use:
+
+ Work around (very rare) problems with HTTP/1.1
+
+Effect:
+
+ Downgrades HTTP/1.1 client requests and server replies to HTTP/1.0.
+
+Type:
+
+ Boolean.
+
+Parameter:
+
+ N/A
+
+Notes:
+
+ This is a left-over from the time when Privoxy didn't support important
+ HTTP/1.1 features well. It is left here for the unlikely case that you
+ experience HTTP/1.1 related problems with some server out there. Not all
+ (optional) HTTP/1.1 features are supported yet, so there is a chance you
+ might need this action.
+
+Example usage (section):
+
+ {+downgrade-http-version}
+ problem-host.example.com
+
+-------------------------------------------------------------------------------
+
+8.5.7. fast-redirects
+
+Typical use:
+
+ Fool some click-tracking scripts and speed up indirect links
+
+Effect:
+
+ Cut off all but the last valid URL from requests.
+
+Type:
+
+ Boolean.
+
+Parameter:
+
+ N/A
+
+Notes:
+
+ 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: http://some.place/click-tracker.cgi?
+ target=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 feature is currently not very smart and is scheduled for improvement.
+ It is likely to break some sites. You should expect to need possibly many
+ exceptions to this action, if it is enabled by default in default.action.
+ Some sites just don't work without it.
+
+Example usage:
+
+ {+fast-redirects}
+
+-------------------------------------------------------------------------------
+
+8.5.8. filter
+
+Typical use:
+
+ Get rid of HTML and JavaScript annoyances, banner advertisements (by size),
+ do fun text replacements, etc.
+
+Effect:
+
+ Text documents, including HTML and JavaScript, to which this action
+ applies, are filtered on-the-fly through the specified regular expression
+ based substitutions.
+
+Type:
+
+ Parameterized.
+
+Parameter:
+
+ The name of a filter, as defined in the filter file (typically
+ default.filter, set by the filterfile option in the config file)
+
+Notes:
+
+ For your convenience, there are a bunch of pre-defined filters available in
+ the distribution filter file that you can use. See the example below for a
+ list.
+
+ This is potentially a very powerful feature! But "rolling your own" filters
+ requires a knowledge of regular expressions and HTML.
+
+ 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.
+
+ At this time, Privoxy cannot (yet!) uncompress compressed documents. If you
+ want filtering to work on all documents, even those that would normally be
+ sent compressed, use the prevent-compression action in conjunction with
+ filter.
+
+ Filtering can achieve some of the effects as the block action, i.e. it can
+ be used to block ads and banners.
+
+ Feedback with suggestions for new or improved filters is particularly
+ welcome!
+
+Example usage (with filters from the distribution default.filter file):
+
+ +filter{html-annoyances} # Get rid of particularly annoying HTML abuse.
+
+ +filter{js-annoyances} # Get rid of particularly annoying JavaScript abuse
+
+ +filter{banners-by-size} # Kill banners by size (very efficient!)
+
+ +filter{content-cookies} # Kill cookies that come sneaking in the HTML or JS content
+
+ +filter{popups} # Kill all popups in JS and HTML
+
+ +filter{webbugs} # Squish WebBugs (1x1 invisible GIFs used for user tracking)
+
+ +filter{fun} # Text replacements for subversive browsing fun!
+
+ +filter{frameset-borders} # Give frames a border and make them resizeable
+
+ +filter{refresh-tags} # Kill automatic refresh tags (for dial-on-demand setups)
+
+ +filter{nimda} # Remove Nimda (virus) code.
+
+ +filter{shockwave-flash} # Kill embedded Shockwave Flash objects
+
+ +filter{crude-parental} # Kill all web pages that contain the words "sex" or "warez"
+
+-------------------------------------------------------------------------------
+
+8.5.9. handle-as-image
+
+Typical use:
+
+ Mark URLs as belonging to images (so they'll be replaced by images if they
+ get blocked)
+
+Effect:
+
+ This action alone doesn't do anything noticeable. It just marks URLs as
+ images. If the block action also applies, the presence or absence of this
+ mark decides whether an HTML "blocked" page, or a replacement image (as
+ determined by the set-image-blocker action) will be sent to the client as a
+ substitute for the blocked content.
+
+Type:
+
+ Boolean.
+
+Parameter:
+
+ N/A
+
+Notes:
+
+ The below generic example section is actually part of default.action. It
+ marks all URLs with well-known image file name extensions as images and
+ should be left intact.
+
+ Users will probably only want to use the handle-as-image action in
+ conjunction with block, to block sources of banners, whose URLs don't
+ reflect the file type, like in the second example section.
+
+ Note that you cannot treat HTML pages as images in most cases. For
+ instance, (inline) ad frames require an HTML page to be sent, or they won't
+ display properly. Forcing handle-as-image in this situation will not
+ replace the ad frame with an image, but lead to error messages.
+
+Example usage (sections):
+
+ # Generic image extensions:
+ #
+ {+handle-as-image}
+ /.*\.(gif|jpg|jpeg|png|bmp|ico)$
+
+ # These don't look like images, but they're banners and should be
+ # blocked as images:
+ #
+ {+block +handle-as-image}
+ some.nasty-banner-server.com/junk.cgi?output=trash
+
+ # Banner source! Who cares if they also have non-image content?
+ ad.doubleclick.net
+
+-------------------------------------------------------------------------------
+
+8.5.10. hide-forwarded-for-headers
+
+Typical use:
+
+ Improve privacy by hiding the true source of the request
+
+Effect:
+
+ Deletes any existing "X-Forwarded-for:" HTTP header from client requests,
+ and prevents adding a new one.
+
+Type:
+
+ Boolean.
+
+Parameter:
+
+ N/A
+
+Notes:
+
+ It is fairly safe to leave this on.
+
+ This action is scheduled for improvement: It should be able to generate
+ forged "X-Forwarded-for:" headers using random IP addresses from a
+ specified network, to make successive requests from the same client look
+ like requests from a pool of different users sharing the same proxy.
+
+Example usage:
+
+ +hide-forwarded-for-headers
+
+-------------------------------------------------------------------------------
+
+8.5.11. hide-from-header
+
+Typical use:
+
+ Keep your (old and ill) browser from telling web servers your email address
+
+Effect:
+
+ Deletes any existing "From:" HTTP header, or replaces it with the specified
+ string.
+
+Type:
+
+ Parameterized.
+
+Parameter:
+
+ Keyword: "block", or any user defined value.
+
+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 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.
+
+ This action is rarely needed, as modern web browsers don't send "From:"
+ headers anymore.
+
+Example usage:
+
+ +hide-from-header{block}
+
+ or
+
+ +hide-from-header{spam-me-senseless@sittingduck.example.com}
+
+-------------------------------------------------------------------------------
+
+8.5.12. hide-referrer
+
+Typical use:
+
+ Conceal which link you followed to get to a particular site
+
+Effect:
+
+ Deletes the "Referer:" (sic) HTTP header from the client request, or
+ replaces it with a forged one.
+
+Type:
+
+ Parameterized.
+
+Parameter:
+
+ + "block" to delete the header completely.
+
+ + "forge" to pretend to be coming from the homepage of the server we are
+ talking to.
+
+ + Any other string to set a user defined referrer.
+
+Notes:
+
+ "forge" is the preferred option here, since some servers will not send
+ images back otherwise, in an attempt to prevent their valuable content from
+ being embedded elsewhere (and hence, without being surrounded by their
+ banners).
+
+ hide-referer is an alternate spelling of hide-referrer and the two can be
+ can be freely substituted with each other. ("referrer" is the correct
+ English spelling, however the HTTP specification has a bug - it requires it
+ to be spelled as "referer".)
+
+Example usage:
+
+ +hide-referrer{forge}
+
+ or
+
+ +hide-referrer{http://www.yahoo.com/}
+
+-------------------------------------------------------------------------------
+
+8.5.13. hide-user-agent
+
+Typical use:
+
+ Conceal your type of browser and client operating system
+
+Effect:
+
+ Replaces the value of the "User-Agent:" HTTP header in client requests with
+ the specified value.
+
+Type:
+
+ Parameterized.
+
+Parameter:
+
+ Any user-defined string.
+
+Notes:
+
+ +-----------------------------------------------------------------+
+ | Warning |
+ |-----------------------------------------------------------------|
+ |This breaks many web sites that depend on looking at this header |
+ |in order to customize their content for different browsers |
+ |(which, by the way, is NOT a smart way to do that!). |
+ +-----------------------------------------------------------------+
+
+ Using this action in multi-user setups or wherever different types of
+ browsers will access the same Privoxy is not recommended. 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 Mozilla
+ enter, yet forging to a Netscape 6.1 user-agent works just fine. (Must be
+ just a silly MS goof, I'm sure :-).
+
+ This action is scheduled for improvement.
+
+Example usage:
+
+ +hide-user-agent{Netscape 6.1 (X11; I; Linux 2.4.18 i686)}
+
+-------------------------------------------------------------------------------
+
+8.5.14. kill-popups
+
+Typical use:
+
+ Eliminate those annoying pop-up windows
+
+Effect:
+
+ While loading the document, replace JavaScript code that opens pop-up
+ windows with (syntactically neutral) dummy code on the fly.
+
+Type:
+
+ Boolean.
+
+Parameter:
+
+ N/A
+
+Notes:
+
+ This action is easily confused with the built-in, hardwired filter action,
+ but there are important differences: For kill-popups, the document need not
+ be buffered, so it can be incrementally rendered while downloading. But
+ kill-popups doesn't catch as many pop-ups as filter{popups} does.
+
+ Think of it as a fast and efficient replacement for a filter that you can
+ use if you don't want any filtering at all. Note that it doesn't make sense
+ to combine it with any filter action, since as soon as one filter applies,
+ the whole document needs to be buffered anyway, which destroys the
+ advantage of the kill-popups action over it's filter equivalent.
+
+ Killing all pop-ups is a dangerous business. Many shops and banks rely on
+ pop-ups to display forms, shopping carts etc, and killing only the unwanted
+ pop-ups would require artificial intelligence in Privoxy. If the only kind
+ of pop-ups that you want to kill are exit consoles (those really nasty
+ windows that appear when you close an other one), you might want to use
+ filter{js-annoyances} instead.
+
+Example usage:
+
+ +kill-popups
+