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.
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:
This should be self-explanatory. Note the first item leads to an editor for the actions files, which is where 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 manipulation is disabled, i.e. Privoxy acts like a normal forwarding proxy.
Note that several of the features described above are disabled by default in Privoxy 3.0.7 beta and later. Check the configuration file to learn why and in which cases it's safe to enable them again.
For Unix, *BSD and GNU/Linux, all configuration files are located in /etc/privoxy/ by default. For MS Windows these are all in the same directory as the Privoxy executable.
The installed defaults provide a reasonable starting point, though some settings may be aggressive by some standards. For the time being, the principle configuration files are:
The main configuration file is named config on GNU/Linux, Unix, BSD, and config.txt on Windows. This is a required file.
match-all.action is used to define which "actions" relating to banner-blocking, images, pop-ups, content modification, cookie handling etc should be applied by default. It should be the first actions file loaded.
default.action defines many exceptions (both positive and negative) from the default set of actions that's configured in match-all.action. It should be the second actions file loaded and shouldn't be edited by the user.
Multiple actions files may be defined in config. These are processed in the order they are defined. Local customizations and locally preferred exceptions to the default policies as defined in match-all.action (which you will most probably want to define sooner or later) are best applied in user.action, where you can preserve them across upgrades. The file isn't installed by all installers, but you can easily create it yourself with a text editor.
There is also a web based editor that can be accessed from http://config.privoxy.org/show-status (Shortcut: http://p.p/show-status) for the various actions files.
The syntax of the configuration and filter files may change between different Privoxy versions, unfortunately some enhancements cost backwards compatibility.
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. Blank lines are ignored.
The actions files and filter files 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.