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Privoxy User Manual $Id: user-manual.sgml,v 1.87 2002/04/23 02:53:15 david__schmidt Exp $ By: Privoxy Developers This is here to keep vim syntax file from breaking :/ If I knew enough to fix it, I would. PLEASE DO NOT REMOVE! HB: hal@foobox.net ]]> The user manual gives users information on how to install, configure and use Privoxy. &p-intro; You can find the latest version of the user manual at http://www.privoxy.org/user-manual/. Please see the Contact section on how to contact the developers. Introduction This documentation is included with the current &p-status; version of Privoxy, v.&p-version;soon ;-)]]>. Since this is a &p-status; version, not all new features are well tested. This documentation may be slightly out of sync as a result (especially with CVS sources). And there may be bugs, though hopefully not many! ]]> New Features In addition to Internet Junkbuster's traditional features of ad and banner blocking and cookie management, Privoxy provides new features: &newfeatures; Installation Privoxy is available both in convenient pre-compiled packages for a wide range of operating systems, and as raw source code. For most users, we recommend using the packages, which can be downloaded from our Privoxy Project Page. If you like to live on the bleeding edge and are not afraid of using possibly unstable development versions, you can check out the up-to-the-minute version directly from the CVS repository or simply download the nightly CVS tarball. &supported; Binary Packages Note: If you have a previous Junkbuster or Privoxy installation on your system, you will need to remove it. Some platforms do this for you as part of their installation procedure. (See below for your platform). In any case be sure to backup your old configuration if it is valuable to you. See the note to upgraders. How to install the binary packages depends on your operating system: Red Hat and SuSE RPMs RPMs can be installed with rpm -Uvh privoxy-&p-version;-1.rpm, and will use /etc/privoxy for the location of configuration files. If you have problems with failed dependencies, try rebuilding the SRC RPM: rpm --rebuild privoxy-&p-version;-1.src.rpm;. This will use your locally installed libraries and RPM version. Note that if you have a Junkbuster RPM installed on your system, you need to remove it first, because the packages conflict. Otherwise, RPM will try to remove Junkbuster automatically, before installing Privoxy. Debian FIXME. Windows Just double-click the installer, which will guide you through the installation process. Solaris, NetBSD, FreeBSD, HP-UX Create a new directory, cd to it, then unzip and untar the archive. For the most part, you'll have to figure out where things go. FIXME. OS/2 First, make sure that no previous installations of Junkbuster and / or Privoxy are left on your system. You can do this by Then, just double-click the WarpIN self-installing archive, which will guide you through the installation process. A shadow of the Privoxy executable will be placed in your startup folder so it will start automatically whenever OS/2 starts. The directory you choose to install Privoxy into will contain all of the configuration files. Max OSX Unzip the downloaded package (you can either double-click on the file in the finder, or on the desktop if you downloaded it there). Then, double-click on the package installer icon and follow the installation process. Privoxy will be installed in the subdirectory /Applications/Privoxy.app. Privoxy will set itself up to start automatically on system bringup via /System/Library/StartupItems/Privoxy. AmigaOS Copy and then unpack the lha archive to a suitable location. All necessary files will be installed into Privoxy directory, including all configuration and log files. To uninstall, just remove this directory. Start Privoxy (with RUN <>NIL:) in your startnet script (AmiTCP), in s:user-startup (RoadShow), as startup program in your startup script (Genesis), or as startup action (Miami and MiamiDx). Privoxy will automatically quit when you quit your TCP/IP stack (just ignore the harmless warning your TCP/IP stack may display that Privoxy is still running). Building from Source &buildsource; Quickstart to Using <application>Privoxy</application> Note to Upgraders There are very significant changes from older versions of Junkbuster to the current Privoxy. Configuration is substantially changed. Junkbuster 2.0.x and earlier configuration files will not migrate. The functionality of the old blockfile, cookiefile and imagelist, are now combined into the actions file (default.action for most installations). A filter file (typically default.filter) is new as of Privoxy 2.9.x, and provides some of the new sophistication (explained below). config is much the same as before. If upgrading from a 2.0.x version, you will have to use the new config files, and possibly adapt any personal rules from your older files. When porting personal rules over from the old blockfile to the new actions file, please note that even the pattern syntax has changed. If upgrading from 2.9.x development versions, it is still recommended to use the new configuration files. A quick list of things to be aware of before upgrading: The default listening port is now 8118 due to a conflict with another service (NAS). Some installers may remove earlier versions completely. Save any important configuration files! Privoxy is controllable with a web browser at the special URL: http://config.privoxy.org/ (Shortcut: http://p.p/). Many aspects of configuration can be done here, including temporarily disabling Privoxy. The primary configuration file for cookie management, ad and banner blocking, and many other aspects of Privoxy configuration is default.action. It is strongly recommended to become familiar with the new actions concept below, before modifying this file. Some installers may not automatically start Privoxy after installation. Starting <application>Privoxy</application> Before launching Privoxy for the first time, you will want to configure your browser(s) to use Privoxy as a HTTP and HTTPS proxy. The default is localhost for the proxy address, and port 8118 (earlier versions used port 8000). This is the one configuration step that must be done! With Netscape (and Mozilla), this can be set under Edit -> Preferences -> Advanced -> Proxies -> HTTP Proxy. For Internet Explorer: Tools -> Internet Properties -> Connections -> LAN Setting. Then, check Use Proxy and fill in the appropriate info (Address: localhost, Port: 8118). Include if HTTPS proxy support too. After doing this, flush your browser's disk and memory caches to force a re-reading of all pages and to get rid of any ads that may be cached. You are now ready to start enjoying the benefits of using Privoxy! Privoxy is typically started by specifying the main configuration file to be used on the command line. Example Unix startup command: # /usr/sbin/privoxy /etc/privoxy/config See below for other command line options. An init script is provided for SuSE and Red Hat. For for SuSE: rcprivoxy start For Red Hat and Debian: /etc/rc.d/init.d/privoxy start If no configuration file is specified on the command line, Privoxy will look for a file named config in the current directory. Except on Win32 where it will try config.txt. If no file is specified on the command line and no default configuration file can be found, Privoxy will fail to start. The included default configuration files should give a reasonable starting point. Most of the per site configuration is done in the actions files. These are where various cookie actions are defined, ad and banner blocking, and other aspects of Privoxy configuration. There are several such files included, with varying levels of aggressiveness. You will probably want to keep an eye out for sites that require persistent cookies, and add these to default.action as needed. By default, most of these will be accepted only during the current browser session (aka session cookies), until you add them to the configuration. If you want the browser to handle this instead, you will need to edit default.action and disable this feature. If you use more than one browser, it would make more sense to let Privoxy handle this. In which case, the browser(s) should be set to accept all cookies. Another feature where you will probably want to define exceptions for trusted sites is the popup-killing (through the +popup and +filter{popups} actions), because your favorite shopping, banking, or leisure site may need popups. Privoxy is HTTP/1.1 compliant, but not all of the optional 1.1 features are as yet supported. In the unlikely event that you experience inexplicable problems with browsers that use HTTP/1.1 per default (like Mozilla or recent versions of I.E.), you might try to force HTTP/1.0 compatibility. For Mozilla, look under Edit -> Preferences -> Debug -> Networking. Alternatively, set the +downgrade config option in default.action which will downgrade your browser's HTTP requests from HTTP/1.1 to HTTP/1.0 before processing them. After running Privoxy for a while, you can start to fine tune the configuration to suit your personal, or site, preferences and requirements. There are many, many aspects that can be customized. Actions (as specified in default.action) can be adjusted by pointing your browser to http://config.privoxy.org/ (shortcut: http://p.p/), and then follow the link to edit the actions list. (This is an internal page and does not require Internet access.) In fact, various aspects of Privoxy configuration can be viewed from this page, including current configuration parameters, source code version numbers, the browser's request headers, and actions that apply to a given URL. In addition to the default.action file editor mentioned above, Privoxy can also be turned on and off (toggled) from this page. If you encounter problems, try loading the page without Privoxy. If that helps, enter the URL where you have the problems into the browser based rule tracing utility. See which rules apply and why, and then try turning them off for that site one after the other, until the problem is gone. When you have found the culprit, you might want to turn the rest on again. If the above paragraph sounds gibberish to you, you might want to read more about the actions concept or even dive deep into the Appendix on actions. If you can't get rid of the problem at all, think you've found a bug in Privoxy, want to propose a new feature or smarter rules, please see the chapter "Contacting the Developers, .." below. Command Line Options Privoxy may be invoked with the following command-line options: --version Print version info and exit. Unix only. --help Print short usage info and exit. Unix only. --no-daemon Don't become a daemon, i.e. don't fork and become process group leader, and don't detach from controlling tty. Unix only. --pidfile FILE On startup, write the process ID to FILE. Delete the FILE on exit. Failure to create or delete the FILE is non-fatal. If no FILE option is given, no PID file will be used. Unix only. --user USER[.GROUP] After (optionally) writing the PID file, assume the user ID of USER, and if included the GID of GROUP. Exit if the privileges are not sufficient to do so. Unix only. configfile If no configfile is included on the command line, Privoxy will look for a file named config in the current directory (except on Win32 where it will look for config.txt instead). Specify full path to avoid confusion. If no config file is found, Privoxy will fail to start. <application>Privoxy</application> Configuration All Privoxy configuration is stored in text files. These files can be edited with a text editor. Many important aspects of Privoxy can also be controlled easily with a web browser. Controlling <application>Privoxy</application> with Your Web Browser Privoxy's user interface can be reached through the special URL http://config.privoxy.org/ (shortcut: http://p.p/), which is a built-in page and works without Internet access. You will see the following section: Please choose from the following options: * Privoxy main page * Show information about the current configuration * Show the source code version numbers * Show the request headers. * Show which actions apply to a URL and why * Toggle Privoxy on or off * Edit the actions list This should be self-explanatory. Note the last item is an editor for the actions list, which is where much of the ad, banner, cookie, and URL blocking magic is configured as well as other advanced features of Privoxy. This is an easy way to adjust various aspects of Privoxy configuration. The actions file, and other configuration files, are explained in detail below. Toggle Privoxy On or Off is handy for sites that might have problems with your current actions and filters. You can in fact use it as a test to see whether it is Privoxy causing the problem or not. Privoxy continues to run as a proxy in this case, but all filtering is disabled. There is even a toggle Bookmarklet offered, so that you can toggle Privoxy with one click from your browser. Configuration Files Overview For Unix, *BSD and Linux, all configuration files are located in /etc/privoxy/ by default. For MS Windows, OS/2, and AmigaOS these are all in the same directory as the Privoxy executable. The installed defaults provide a reasonable starting point, though possibly aggressive by some standards. For the time being, there are only three default configuration files (this may change in time): The main configuration file is named config on Linux, Unix, BSD, OS/2, and AmigaOS and config.txt on Windows. default.action (the actions file) is used to define which of a set of various actions relating to images, banners, pop-ups, access restrictions, banners and cookies are to be applied, and where. There is a web based editor for this file that can be accessed at http://config.privoxy.org/edit-actions/ (Shortcut: http://p.p/edit-actions/). (Other actions files are included as well with differing levels of filtering and blocking, e.g. basic.action.) default.filter (the filter file) can be used to re-write the raw page content, including viewable text as well as embedded HTML and JavaScript, and whatever else lurks on any given web page. The filtering jobs are only pre-defined here; whether to apply them or not is up to the actions file. All files use the # character to denote a comment (the rest of the line will be ignored) and understand line continuation through placing a backslash ("\") as the very last character in a line. If the # is preceded by a backslash, it looses its special function. Placing a # in front of an otherwise valid configuration line to prevent it from being interpreted is called "commenting out" that line. default.action and default.filter can use Perl style regular expressions for maximum flexibility. After making any changes, there is no need to restart Privoxy in order for the changes to take effect. Privoxy detects such changes automatically. Note, however, that it may take one or two additional requests for the change to take effect. When changing the listening address of Privoxy, these wake up requests must obviously be sent to the old listening address. While under development, the configuration content is subject to change. The below documentation may not be accurate by the time you read this. Also, what constitutes a default setting, may change, so please check all your configuration files on important issues. ]]> The Main Configuration File Again, the main configuration file is named config on Linux/Unix/BSD and OS/2, and config.txt on Windows. Configuration lines consist of an initial keyword followed by a list of values, all separated by whitespace (any number of spaces or tabs). For example: confdir /etc/privoxy Assigns the value /etc/privoxy to the option confdir and thus indicates that the configuration directory is named /etc/privoxy/. All options in the config file except for confdir and logdir are optional. Watch out in the below description for what happens if you leave them unset. The main config file controls all aspects of Privoxy's operation that are not location dependent (i.e. they apply universally, no matter where you may be surfing). Configuration and Log File Locations Privoxy can (and normally does) use a number of other files for additional configuration and logging. This section of the configuration file tells Privoxy where to find those other files. confdir Specifies: The directory where the other configuration files are located Type of value: Path name Default value: /etc/privoxy (Unix) or Privoxy installation dir (Windows) Effect if unset: Mandatory Notes: No trailing /, please When development goes modular and multi-user, the blocker, filter, and per-user config will be stored in subdirectories of confdir. For now, the configuration directory structure is flat, except for confdir/templates, where the HTML templates for CGI output reside (e.g. Privoxy's 404 error page). logdir Specifies: The directory where all logging takes place (i.e. where logfile and jarfile are located) Type of value: Path name Default value: /var/log/privoxy (Unix) or Privoxy installation dir (Windows) Effect if unset: Mandatory Notes: No trailing /, please actionsfile Specifies: The actions file to use Type of value: File name, relative to confdir Default value: default.action (Unix) or default.action.txt (Windows) Effect if unset: No action is taken at all. Simple neutral proxying. Notes: There is no point in using Privoxy without an actions file. There are three different actions files included in the distribution, with varying degrees of aggressiveness: default.action, intermediate.action and advanced.action. filterfile Specifies: The filter file to use Type of value: File name, relative to confdir Default value: default.filter (Unix) or default.filter.txt (Windows) Effect if unset: No textual content filtering takes place, i.e. all +filter{name} actions in the actions file are turned off Notes: The default.filter file contains content modification rules that use regular expressions. These rules permit powerful changes on the content of Web pages, e.g., you could disable your favorite JavaScript annoyances, re-write the actual displayed text, or just have some fun replacing Microsoft with MicroSuck wherever it appears on a Web page. logfile Specifies: The log file to use Type of value: File name, relative to logdir Default value: logfile (Unix) or privoxy.log (Windows) Effect if unset: No log file is used, all log messages go to the console (stderr). Notes: The windows version will additionally log to the console. The logfile is where all logging and error messages are written. The level of detail and number of messages are set with the debug option (see below). The logfile can be useful for tracking down a problem with Privoxy (e.g., it's not blocking an ad you think it should block) but in most cases you probably will never look at it. Your logfile will grow indefinitely, and you will probably want to periodically remove it. On Unix systems, you can do this with a cron job (see man cron). For Red Hat, a logrotate script has been included. On SuSE Linux systems, you can place a line like /var/log/privoxy.* +1024k 644 nobody.nogroup in /etc/logfiles, with the effect that cron.daily will automatically archive, gzip, and empty the log, when it exceeds 1M size. jarfile Specifies: The file to store intercepted cookies in Type of value: File name, relative to logdir Default value: jarfile (Unix) or privoxy.jar (Windows) Effect if unset: Intercepted cookies are not stored at all. Notes: The jarfile may grow to ridiculous sizes over time. trustfile Specifies: The trust file to use Type of value: File name, relative to confdir Default value: Unset (commented out). When activated: trust (Unix) or trust.txt (Windows) Effect if unset: The whole trust mechanism is turned off. Notes: The trust mechanism is an experimental feature for building white-lists and should be used with care. It is NOT recommended for the casual user. If you specify a trust file, Privoxy will only allow access to sites that are named in the trustfile. You can also mark sites as trusted referrers (with +), with the effect that access to untrusted sites will be granted, if a link from a trusted referrer was used. The link target will then be added to the trustfile. Possible applications include limiting Internet access for children. If you use + operator in the trust file, it may grow considerably over time. Local Set-up Documentation If you intend to operate Privoxy for more users that just yourself, it might be a good idea to let them know how to reach you, what you block and why you do that, your policies etc. trust-info-url Specifies: A URL to be displayed in the error page that users will see if access to an untrusted page is denied. Type of value: URL Default value: Two example URL are provided Effect if unset: No links are displayed on the "untrusted" error page. Notes: The value of this option only matters if the experimental trust mechanism has been activated. (See trustfile above.) If you use the trust mechanism, it is a good idea to write up some on-line documentation about your trust policy and to specify the URL(s) here. Use multiple times for multiple URLs. The URL(s) should be added to the trustfile as well, so users don't end up locked out from the information on why they were locked out in the first place! admin-address Specifies: An email address to reach the proxy administrator. Type of value: Email address Default value: Unset Effect if unset: No email address is displayed on error pages and the CGI user interface. Notes: If both admin-address and proxy-info-url are unset, the whole "Local Privoxy Support" box on all generated pages will not be shown. proxy-info-url Specifies: A URL to documentation about the local Privoxy setup, configuration or policies. Type of value: URL Default value: Unset Effect if unset: No link to local documentation is displayed on error pages and the CGI user interface. Notes: If both admin-address and proxy-info-url are unset, the whole "Local Privoxy Support" box on all generated pages will not be shown. This URL shouldn't be blocked ;-) Debugging These options are mainly useful when tracing a problem. Note that you might also want to invoke Privoxy with the --no-daemon command line option when debugging. debug Specifies: Key values that determine what information gets logged. Type of value: Integer values Default value: 12289 (i.e.: URLs plus informational and warning messages) Effect if unset: Nothing gets logged. Notes: The available debug levels are: debug 1 # show each GET/POST/CONNECT request debug 2 # show each connection status debug 4 # show I/O status debug 8 # show header parsing debug 16 # log all data into the logfile debug 32 # debug force feature debug 64 # debug regular expression filter debug 128 # debug fast redirects debug 256 # debug GIF de-animation debug 512 # Common Log Format debug 1024 # debug kill pop-ups debug 4096 # Startup banner and warnings. debug 8192 # Non-fatal errors To select multiple debug levels, you can either add them or use multiple debug lines. A debug level of 1 is informative because it will show you each request as it happens. 1, 4096 and 8192 are highly recommended so that you will notice when things go wrong. The other levels are probably only of interest if you are hunting down a specific problem. They can produce a hell of an output (especially 16). The reporting of fatal errors (i.e. ones which crash Privoxy) is always on and cannot be disabled. If you want to use CLF (Common Log Format), you should set debug 512 ONLY and not enable anything else. single-threaded Specifies: Whether to run only one server thread Type of value: None Default value: Unset Effect if unset: Multi-threaded (or, where unavailable: forked) operation, i.e. the ability to serve multiple requests simultaneously. Notes: This option is only there for debug purposes and you should never need to use it. It will drastically reduce performance. Access Control and Security This section of the config file controls the security-relevant aspects of Privoxy's configuration. listen-address Specifies: The IP address and TCP port on which Privoxy will listen for client requests. Type of value: [IP-Address]:Port Default value: localhost:8118 Effect if unset: Bind to localhost (127.0.0.1), port 8118. This is suitable and recommended for home users who run Privoxy on the same machine as their browser. Notes: You will need to configure your browser(s) to this proxy address and port. If you already have another service running on port 8118, or if you want to serve requests from other machines (e.g. on your local network) as well, you will need to override the default. If you leave out the IP address, Privoxy will bind to all interfaces (addresses) on your machine and may become reachable from the Internet. In that case, consider using access control lists (acl's) (see ACLs below), or a firewall. Example: Suppose you are running Privoxy on a machine which has the address 192.168.0.1 on your local private network (192.168.0.0) and has another outside connection with a different address. You want it to serve requests from inside only: listen-address 192.168.0.1:8118 toggle Specifies: Initial state of "toggle" status Type of value: 1 or 0 Default value: 1 Effect if unset: Act as if toggled on Notes: If set to 0, Privoxy will start in toggled off mode, i.e. behave like a normal, content-neutral proxy. See enable-remote-toggle below. This is not really useful anymore, since toggling is much easier via the web interface then via editing the conf file. The windows version will only display the toggle icon in the system tray if this option is present. enable-remote-toggle Specifies: Whether or not the web-based toggle feature may be used Type of value: 0 or 1 Default value: 1 Effect if unset: The web-based toggle feature is disabled. Notes: When toggled off, Privoxy acts like a normal, content-neutral proxy, i.e. it acts as if none of the actions applied to any URL. For the time being, access to the toggle feature can not be controlled separately by ACLs or HTTP authentication, so that everybody who can access Privoxy (see ACLs and listen-address above) can toggle it for all users. So this option is not recommended for multi-user environments with untrusted users. Note that you must have compiled Privoxy with support for this feature, otherwise this option has no effect. enable-edit-actions Specifies: Whether or not the web-based actions file editor may be used Type of value: 0 or 1 Default value: 1 Effect if unset: The web-based actions file editor is disabled. Notes: For the time being, access to the editor can not be controlled separately by ACLs or HTTP authentication, so that everybody who can access Privoxy (see ACLs and listen-address above) can modify its configuration for all users. So this option is not recommended for multi-user environments with untrusted users. Note that you must have compiled Privoxy with support for this feature, otherwise this option has no effect. ACLs: permit-access and deny-access 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 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 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. 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. 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 actions 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 . 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 actions 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 . 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. 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 The Actions File The actions file (default.action, formerly: actionsfile or ijb.action) is 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 on which sites (or even parts thereof). Anything you want can blocked, 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 available actions. An actions file typically has sections. At the top, aliases are defined (discussed below), then the default set of rules which will apply universally to all sites and pages. And then below that is generally a lengthy set of exceptions to the defined universal policies. 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 file. 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). How to Edit The easiest way to edit the actions file is with a browser by using our browser-based editor, which is available at http://config.privoxy.org/edit-actions. If you prefer plain text editing to GUIs, you can of course also directly edit the default.action file. How Actions are Applied to URLs The actions file is 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. 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. 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. 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. 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 ^. 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. Actions Actions are enabled if preceded with a +, and disabled if preceded with a -. 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}} ot {+/-wafer{name=value}}), where some value needs to be defined in addition to simply enabling the actino. 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 this 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 default.action file 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. For multi-valued actions, the actions are applied in the order they are specified. The list of valid Privoxy actions are: <emphasis>+add-header{Name: value}</emphasis> 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. <emphasis>+block</emphasis> 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} .example.com .ads.r.us Notes: Privoxy will display its special BLOCKED page if a URL matches one of the blocked patterns. 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. One exception is if the URL matches both +block and +image, then it can be handled by +image-blocker (see below). <emphasis>+deanimate-gifs</emphasis> 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). <emphasis>+downgrade</emphasis> Type: Boolean. Typical uses: +downgrade will downgrade HTTP/1.1 client requests to HTTP/1.0 and downgrade the responses as well. Possible values: N/A Example usage: {+downgrade} .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 problem sites only. <emphasis>+fast-redirects</emphasis> 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 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. <emphasis>+filter</emphasis> 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. 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 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. <emphasis>+hide-forwarded</emphasis> 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} .example.com Notes: It is fairly safe to leave this on. It does not seem to break many sites. <emphasis>+hide-from</emphasis> 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{block}} .example.com Notes: The keyword block will completely remove the header. Alternately, you can specify any value you prefer to send to the web server. <emphasis>+hide-referer</emphasis> 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.) <emphasis>+hide-user-agent</emphasis> 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. <emphasis>+image</emphasis> Type: Boolean. Typical uses: To define what Privoxy should treat automatically as an image. Possible values: N/A Example usage: {+image} /.*\.(gif|jpg|jpeg|png|bmp|ico) Notes: This only has meaning if the URL (or pattern) also is +blocked, in which case a blocked image can be sent rather than a HTML page. (See +image-blocker{} below for the control over what is actually sent.) There is little reason to change the default definition for this. <emphasis>+image-blocker</emphasis> Type: Parameterized. Typical uses: Decide what to do with URLs that end up tagged with both {+block} and {+image}, e.g an advertisement. Possible values: There are four available options: -image-blocker will send a HTML blocked page, usually resulting in a broken image icon. +image-blocker{blank} will send a 1x1 transparent GIF image. +image-blocker{pattern} will send a checkerboard type pattern (the default). And finally, +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: {+image-blocker{blank}} .example.com Notes: If you want invisible ads, they need to be both defined as images and blocked. 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, cannot be treated as an image. Forcing an image in this situation just will not work. <emphasis>+limit-connect</emphasis> 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. <emphasis>+no-compression</emphasis> Type: Boolean. Typical uses: Prevent the specified websites from compressing HTTP data. Possible values: N/A Example usage: {+no-compression} .example.com Notes: Some websites do this, which can be a problem for Privoxy, since +filter, +no-popup and +gif-deanimate will not work on compressed data. This will slow down connections to those websites, though. Default typically is to turn no-compression on. <emphasis>+no-cookies-keep</emphasis> Type: Boolean. Typical uses: Allow cookies for the current browser session only. Possible values: N/A Example usage: {+no-cookies-keep} .example.com Notes: If websites set cookies, no-cookies-keep 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. Sometimes referred to as session cookies. <emphasis>+no-cookies-read</emphasis> Type: Boolean. Typical uses: Explicitly prevent the web server from reading any cookies on your system. Possible values: N/A Example usage: {+no-cookies-read} .example.com Notes: Often used in conjunction with +no-cookies-set to disable persistant cookies completely. <emphasis>+no-cookies-set</emphasis> Type: Boolean. Typical uses: Explicitly block the web server from sending cookies to your system. Possible values: N/A Example usage: {+no-cookies-set} .example.com Notes: Often used in conjunction with +no-cookies-read to disable persistant cookies completely. <emphasis>+no-popup</emphasis> Type: Boolean. Typical uses: Stop those annoying JavaScript pop-up windows! Possible values: N/A Example usage: {+no-popup} .example.com Notes: +no-popup uses a built in filter to disable pop-ups that use the window.open() function, etc. An alternate spelling is +no-popups, which is interchangeable. <emphasis>+vanilla-wafer</emphasis> 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: {+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 be used to track you. <emphasis>+wafer</emphasis> 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: {+wafer{name=value}} .example.com Notes: This can be specified multiple times in order to add as many cookies as you like. 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. Some actions that are turned on the default section do typically require exceptions to be listed in the lower sections of actions file. Some examples: Turn off cookies by default, then allow a few through for specified sites: # Turn off all persistent cookies { +no-cookies-read } { +no-cookies-set } # Allow cookies for this browser session ONLY { +no-cookies-keep } # Exceptions to the above, sites that benefit from persistent cookies # that saved from one browser session to the next. { -no-cookies-read } { -no-cookies-set } { -no-cookies-keep } .javasoft.com .sun.com .yahoo.com .msdn.microsoft.com .redhat.com # Alternative way of saying the same thing {-no-cookies-set -no-cookies-read -no-cookies-keep} .sourceforge.net .sf.net Now turn off fast redirects, and then we allow two exceptions: # Turn them off! {+fast-redirects} # 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 the # specified sections: +filter{html-annoyances} +filter{js-annoyances} +filter{no-popups}\ +filter{webbugs} +filter{nimda} +filter{banners-by-size} # Then disable filtering of code from sourceforge! {-filter} .cvs.sourceforge.net Now some URLs that we want blocked (normally generates the blocked banner). Many of these use regular expressions that will expand to match multiple URLs: # Blocklist: {+block} /.*/(.*[-_.])?ads?[0-9]?(/|[-_.].*|\.(gif|jpe?g)) /.*/(.*[-_.])?count(er)?(\.cgi|\.dll|\.exe|[?/]) /.*/(ng)?adclient\.cgi /.*/(plain|live|rotate)[-_.]?ads?/ /.*/(sponsor)s?[0-9]?/ /.*/_?(plain|live)?ads?(-banners)?/ /.*/abanners/ /.*/ad(sdna_image|gifs?)/ /.*/ad(server|stream|juggler)\.(cgi|pl|dll|exe) /.*/adbanners/ /.*/adserver /.*/adstream\.cgi /.*/adv((er)?ts?|ertis(ing|ements?))?/ /.*/banner_?ads/ /.*/banners?/ /.*/banners?\.cgi/ /.*/cgi-bin/centralad/getimage /.*/images/addver\.gif /.*/images/marketing/.*\.(gif|jpe?g) /.*/popupads/ /.*/siteads/ /.*/sponsor.*\.gif /.*/sponsors?[0-9]?/ /.*/advert[0-9]+\.jpg /Media/Images/Adds/ /ad_images/ /adimages/ /.*/ads/ /bannerfarm/ /grafikk/annonse/ /graphics/defaultAd/ /image\.ng/AdType /image\.ng/transactionID /images/.*/.*_anim\.gif # alvin brattli /ip_img/.*\.(gif|jpe?g) /rotateads/ /rotations/ /worldnet/ad\.cgi /cgi-bin/nph-adclick.exe/ /.*/Image/BannerAdvertising/ /.*/ad-bin/ /.*/adlib/server\.cgi /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 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. 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 anything else in the default.actionfile! And there can only be one set of aliases defined. Now let's define a few aliases: # Useful custom aliases we can use later. These must come first! {{alias}} +no-cookies = +no-cookies-set +no-cookies-read -no-cookies = -no-cookies-set -no-cookies-read fragile = -block -no-cookies -filter -fast-redirects -hide-referer -no-popups shop = -no-cookies -filter -fast-redirects +imageblock = +block +image #For people who don't like to type too much: ;-) c0 = +no-cookies c1 = -no-cookies c2 = -no-cookies-set +no-cookies-read c3 = +no-cookies-set -no-cookies-read #... etc. Customize to your heart's content. Some examples using our shop and fragile aliases from above: # 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 .jungle.com .scan.co.uk # These shops require pop-ups also {shop -no-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. 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 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. Contacting the Developers, Bug Reporting and Feature Requests &contacting; Submitting Ads and <quote>Action</quote> Problems Ads and banners that are not stopped by Privoxy can be submitted to the developers by accessing a special page and filling out the brief, required form. Conversely, you can also report pages, images, etc. that Privoxy is blocking, but should not. The form itself does require Internet access. To do this, point your browser to Privoxy at http://config.privoxy.org/ (shortcut: http://p.p/), and then select Actions file feedback system, near the bottom of the page. Paste in the URL that is the cause of the unwanted behavior, and follow the prompts. The developers will try to incorporate a fix for the problem you reported into future versions. New default.actions files will occasionally be made available based on your feedback. These will be announced on the ijbswa-announce list. Copyright and History Copyright ©right; History &history; See Also &seealso; Appendix 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 metacharacter 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 <application>Privoxy</application>'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/
Alternately, this may be reached at http://p.p/, but this variation may not work as reliably as the above in some configurations.
Show information about the current configuration:
http://config.privoxy.org/show-status
Show the source code version numbers:
http://config.privoxy.org/show-version
Show the client's request headers:
http://config.privoxy.org/show-request
Show which actions apply to a URL and why:
http://config.privoxy.org/show-url-info
Toggle Privoxy on or off. In this case, Privoxy continues to run, but only as a pass-through proxy, with no actions taking place:
http://config.privoxy.org/toggle
Short cuts. Turn off, then on:
http://config.privoxy.org/toggle?set=disable
http://config.privoxy.org/toggle?set=enable
Edit the actions list file:
http://config.privoxy.org/edit-actions
These may be bookmarked for quick reference. See next. Bookmarklets Below are some bookmarklets to allow you to easily access a mini version of some of Privoxy's special pages. They are designed for MS Internet Explorer, but should work equally well in Netscape, Mozilla, and other browsers which support JavaScript. They are designed to run directly from your bookmarks - not by clicking the links below (although that should work for testing). To save them, right-click the link and choose Add to Favorites (IE) or Add Bookmark (Netscape). You will get a warning that the bookmark may not be safe - just click OK. Then you can run the Bookmarklet directly from your favorites/bookmarks. For even faster access, you can put them on the Links bar (IE) or the Personal Toolbar (Netscape), and run them with a single click. Enable Privoxy Disable Privoxy Toggle Privoxy (Toggles between enabled and disabled) View Privoxy Status Actions file feedback system Credit: The site which gave me the general idea for these bookmarklets is www.bookmarklets.com. They have more information about bookmarklets.
Anatomy of an Action The way Privoxy applies actions and filters to any given URL can be complex, and not always so easy to understand what is happening. And sometimes we need to be able to see just what Privoxy is doing. Especially, if something Privoxy is doing is causing us a problem inadvertently. It can be a little daunting to look at the actions and filters files themselves, since they tend to be filled with regular expressions whose consequences are not always so obvious. One quick test to see if Privoxy is causing a problem or not, is to disable it temporarily. This should be the first troubleshooting step. See the Bookmarklets section on a quick and easy way to do this (be sure to flush caches afterwards!). Privoxy also provides the http://config.privoxy.org/show-url-info page that can show us very specifically how actions are being applied to any given URL. This is a big help for troubleshooting. First, enter one URL (or partial URL) at the prompt, and then Privoxy will tell us how the current configuration will handle it. This will not help with filtering effects from the default.filter file! It also will not tell you about any other URLs that may be embedded within the URL you are testing (i.e. a web page). For instance, images such as ads are expressed as URLs within the raw page source of HTML pages. So you will only get info for the actual URL that is pasted into the prompt area -- not any sub-URLs. If you want to know about embedded URLs like ads, you will have to dig those out of the HTML source. Use your browser's View Page Source option for this. Or right click on the ad, and grab the URL. Let's look at an example, google.com, one section at a time: System default actions: { -add-header -block -deanimate-gifs -downgrade -fast-redirects -filter -hide-forwarded -hide-from -hide-referer -hide-user-agent -image -image-blocker -limit-connect -no-compression -no-cookies-keep -no-cookies-read -no-cookies-set -no-popups -vanilla-wafer -wafer } This is the top section, and only tells us of the compiled in defaults. This is basically what Privoxy would do if there were not any actions defined, i.e. it does nothing. Every action is disabled. This is not particularly informative for our purposes here. OK, next section: Matches for http://google.com: { -add-header -block +deanimate-gifs -downgrade +fast-redirects +filter{html-annoyances} +filter{js-annoyances} +filter{no-popups} +filter{webbugs} +filter{nimda} +filter{banners-by-size} +filter{hal} +filter{fun} +hide-forwarded +hide-from{block} +hide-referer{forge} -hide-user-agent -image +image-blocker{blank} +no-compression +no-cookies-keep -no-cookies-read -no-cookies-set +no-popups -vanilla-wafer -wafer } / { -no-cookies-keep -no-cookies-read -no-cookies-set } .google.com { -fast-redirects } .google.com This is much more informative, and tells us how we have defined our actions, and which ones match for our example, google.com. The first grouping shows our default settings, which would apply to all URLs. If you look at your actions file, this would be the section just below the aliases section near the top. This applies to all URLs as signified by the single forward slash -- /. These are the default actions we have enabled. But we can define additional actions that would be exceptions to these general rules, and then list specific URLs that these exceptions would apply to. Last match wins. Just below this then are two explicit matches for .google.com. The first is negating our various cookie blocking actions (i.e. we will allow cookies here). The second is allowing fast-redirects. Note that there is a leading dot here -- .google.com. This will match any hosts and sub-domains, in the google.com domain also, such as www.google.com. So, apparently, we have these actions defined somewhere in the lower part of our actions file, and google.com is referenced in these sections. And now we pull it altogether in the bottom section and summarize how Privoxy is applying all its actions to google.com: Final results: -add-header -block -deanimate-gifs -downgrade -fast-redirects +filter{html-annoyances} +filter{js-annoyances} +filter{no-popups} +filter{webbugs} +filter{nimda} +filter{banners-by-size} +filter{hal} +filter{fun} +hide-forwarded +hide-from{block} +hide-referer{forge} -hide-user-agent -image +image-blocker{blank} -limit-connect +no-compression -no-cookies-keep -no-cookies-read -no-cookies-set +no-popups -vanilla-wafer -wafer Now another example, ad.doubleclick.net: { +block +image } .ad.doubleclick.net { +block +image } ad*. { +block +image } .doubleclick.net We'll just show the interesting part here, the explicit matches. It is matched three different times. Each as an +block +image, which is the expanded form of one of our aliases that had been defined as: +imageblock. (Aliases are defined in the first section of the actions file and typically used to combine more than one action.) Any one of these would have done the trick and blocked this as an unwanted image. This is unnecessarily redundant since the last case effectively would also cover the first. No point in taking chances with these guys though ;-) Note that if you want an ad or obnoxious URL to be invisible, it should be defined as ad.doubleclick.net is done here -- as both a +block and an +image. The custom alias +imageblock does this for us. One last example. Let's try http://www.rhapsodyk.net/adsl/HOWTO/. This one is giving us problems. We are getting a blank page. Hmmm... Matches for http://www.rhapsodyk.net/adsl/HOWTO/: { -add-header -block +deanimate-gifs -downgrade +fast-redirects +filter{html-annoyances} +filter{js-annoyances} +filter{no-popups} +filter{webbugs} +filter{nimda} +filter{banners-by-size} +filter{hal} +filter{fun} +hide-forwarded +hide-from{block} +hide-referer{forge} -hide-user-agent -image +image-blocker{blank} +no-compression +no-cookies-keep -no-cookies-read -no-cookies-set +no-popups -vanilla-wafer -wafer } / { +block +image } /ads Ooops, the /adsl/ is matching /ads! But we did not want this at all! Now we see why we get the blank page. We could now add a new action below this that explicitly does not block (-block) pages with adsl. There are various ways to handle such exceptions. Example: { -block } /adsl Now the page displays ;-) Be sure to flush your browser's caches when making such changes. Or, try using Shift+Reload. But now what about a situation where we get no explicit matches like we did with: { -block } /adsl That actually was very telling and pointed us quickly to where the problem was. If you don't get this kind of match, then it means one of the default rules in the first section is causing the problem. This would require some guesswork, and maybe a little trial and error to isolate the offending rule. One likely cause would be one of the {+filter} actions. Try adding the URL for the site to one of aliases that turn off +filter: {shop} .quietpc.com .worldpay.com # for quietpc.com .jungle.com .scan.co.uk .forbes.com {shop} is an alias that expands to { -filter -no-cookies -no-cookies-keep }. Or you could do your own exception to negate filtering: {-filter} .forbes.com {fragile} is an alias that disables most actions. This can be used as a last resort for problem sites. Remember to flush caches! If this still does not work, you will have to go through the remaining actions one by one to find which one(s) is causing the problem.