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-Junkbuster Frequently Asked Questions +Privoxy Frequently Asked Questions + + + + + + Copyright &my-copy; 2001, 2002 by + Privoxy Developers + + + +$Id: faq.sgml,v 1.60 2002/05/22 17:17:48 oes Exp $ + + + + + + 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 FAQ document gives users and developers alike answers to frequently asked -questions about the Internet Junkbuster. Internet -Junkbuster is a web proxy with advanced filtering capabilities -for protecting privacy, filtering web page content, managing cookies, -controlling access, and removing ads, banners, pop-ups and other obnoxious -Internet Junk. Junkbuster has a very flexible configuration and can be -customized to suit individual needs and tastes. Internet -Junkbuster has application for both stand-alone systems and -multi-user networks. + This FAQ gives quick answers to frequently asked questions about + Privoxy + . It can't and doesn't replace the + user manual. + + + &p-intro; + + -You can find the latest version of the document at http://ijbswa.sourceforge.net/faq/. -Please see the Contact section in the user-manual if you want to contact the developers. + You can find the latest version of the document at http://www.privoxy.org/faq/. + Please see the Contact section if you want to contact the developers. @@ -56,628 +136,1421 @@ Please see the Contact section in the user-manual if you want to contact the dev - + &history; + + + + + + +Why <quote>Privoxy</quote>? Why a name change at all? - Fillme. + Privoxy is the + Privacy Enhancing Proxy. Also, its content + modification and junk suppression allow you to browse your + private edition of the web. - ---> - + + Junkbusters Corporation + continues to offer their original version of the Internet + Junkbuster, so publishing our + Junkbuster-derived software under the same name + led to confusion. + + + There are also potential legal complications from the continued use of the + Junkbuster name, which is a registered trademark of + Junkbusters Corporation. + There are, however, no objections from Junkbusters Corporation to the + Privoxy project itself, and they, in fact, still + share our ideals and goals. + + + The developers also believed that there are so many changes from the original + code, that it was time to make a clean break from the past and make + a name in their own right. + + -Frequently Asked Questions - +How does <application>Privoxy</application> differ +from the old <application>Junkbuster?</application> + + Privoxy picks up where + Junkbuster left off. All the old features remain. + The new Privoxy still blocks ads and banners, + still manages cookies, and still helps protect your privacy. But, these are + all enhanced, and many new features have been added, all in the same vein. + + + The configuration has changed significantly as well. This is something that + users will notice right off the bat if upgrading from + Junkbuster 2.0.x. The blocklist + cookielist, imagelist and much more has been + combined into the actions files, with a completely different + syntax. See the note to + upgraders for details. + + + Privoxy's new features include: + -General Information + + &newfeatures; + + + -What is this new <application>Junkbuster</application>? +What is a <quote>proxy</quote>? How does +<application>Privoxy</application> work? - The original Junkbuster was a product of - Junkbusters Corporation (tm). Development of this effort stopped - as of version 2.0.2. Stefan Walherr started the ijbswa project on - Sourceforge to - rekindle development. Other developers subsequently joined with - Stefan, and have since added many new features and enhancements. + A web proxy is a service, based on a software such as Privoxy, + that clients (i.e. browsers) can use instead of connecting directly to the web + servers on the Internet. The clients then ask the proxy to fetch the objects + they need (web pages, images, movies etc) on their behalf, and when the proxy + has done so, it hands the results back to the client. - - -How does it differ from the old <application>Junkbuster?</application> - All the old features remain. The new Junkbuster - still blocks ads and banners, still manages cookies, and protects - privacy. But, these are all enhanced, and many new features have been - added, all in the same vein. + There are many reasons to use web proxies, such as security (firewalling), + efficiency (caching) and others, and there are just as many different proxies + to accommodate those needs. - The configuration has changed significantly. This is something that users - will notice right off the bat. The blocklist file does - not exist any more. This is replaced by actions - files, such as ijb.actions. This is where most of - the per site configuration is now. - + Privoxy is a proxy that is solely focused on privacy + protection and junk elimination. Sitting between your browser(s) and the Internet, + it is in a perfect position to filter outbound personal information that your + browser is leaking, as well as inbound junk. It uses a variety of techniques to do + this, all of which are under your control via the various configuration + files and options. - - -What are some of the new features? - - - - - - - Integrated browser based configuration and control utility (http://i.j.b). Browser-based tracing of rule - and filter effects. - - - - - - Blocking of annoying pop-up browser windows. - - - - - - HTTP/1.1 compliant (most, but not all 1.1 features are supported). - - - - - - Support for Perl Compatible Regular Expressions in the configuration files, and - generally a more sophisticated and flexible configuration syntax over - previous versions. - - - - - - GIF de-animation. - - - - - - Web page content filtering (removes banners based on size, - invisible web-bugs, JavaScript, pop-ups, status bar abuse, - etc.) - - - - - - Bypass many click-tracking scripts (avoids script redirection). - - - - - - - Multi-threaded (POSIX and native threads). - - - - - - Auto-detection and re-reading of config file changes. - - - - - - User-customizable HTML templates (e.g. 404 error page). - - - - - - Improved cookie management features (e.g. session based cookies). - - - - - - Builds from source on most UNIX-like systems. Packages available for: Linux - (RedHat, SuSE, or Debian), Windows, Sun Solaris, Mac OSX, OS/2, HP-UX 11 and AmigaOS. - - - + - - - In addition, the configuration is much more powerful and versatile over-all. - - - + +How does <application>Privoxy</application> know what is +an ad, and what is not? + + Privoxy's approach to blocking ads is twofold: + + First, there are certain patterns in the locations (URLs) + of banner images. This applies to both the path (you wouldn't guess how many + web sites serve their banners from a directory called banners!) + and the host (blocking the big banner hosting services like doublecklick.net + already helps a lot). Privoxy takes advantage of this + fact by using URL + patterns to sort out and block the requests for banners. + + + Second, banners tend to come in certain sizes. But you + can't tell the size of an image by its URL without downloading it, and if you + do, it's too late to save bandwidth. Therefore, Privoxy + also inspects the HTML sources of web pages while they are loaded, and replaces + references to images with standard banner sizes by dummy references, so that + your browser doesn't request them anymore in the first place. + + + Both of this involves a certain amount of guesswork and is, of course, freely + configurable. + + - - -How does <application>Junkbuster</application> - work? What is a <quote>proxy</quote>? - - When you connect to a web site with Junkbuster, - you are really connecting to your locally running version of - Junkbuster. Junkbuster - intercepts your requests for the web page, and relays that to the - real web site. The web site sends the HTTP data stream - back to Junkbuster, where - Junkbuster can work its magic before it - relays this data back to your web browser. + +Can <application>Privoxy</application> make mistakes? +This does not sound very scientific. + + Actually, it's a black art ;-) And yes, it is always possible to have a broad + rule accidentally block or change something by mistake. There is a good chance + you may run into such a situation at some point. It is tricky writing rules to + cover every conceivable possibility, and not occasionally get false positives. + - + + But this should not be a big concern since the + Privoxy configuration is very flexible, and + includes tools to help identify these types of situations so they can be + addressed as needed, allowing you to customize your installation. + (See the Troubleshooting section below.) + - - Since Junkbuster sits between you and the - WWW, it is in a position to intercept and completely manage all web traffic and - HTTP content before it gets to your browser. - Junkbuster uses various programming methods to do - this, all of which is under your control via the various configuration - files. + - - -My browser does the same things as -Junkbuster. Why should I use Junkbuster at all? +My browser does the same things as +<application>Privoxy</application>. Why should I use +<application>Privoxy</application> at all? Modern browsers do indeed have some of the same - functionality as Junkbuster. Maybe this is - adequate for you. But Junkbuster is much more - verstatile and flexible, and can do some things that browsers just can't. + functionality as Privoxy. Maybe this is + adequate for you. But Privoxy is much more + versatile and powerful, and can do a number of things that browsers just can't. In addition, a proxy is good choice if you use multiple browsers, or have a LAN with multiple computers. This way all the configuration is in one place, and you don't have to maintain a similar configuration for possibly many browsers. - - + -Is there is a license or fee? What about a +<sect2 renderas="sect3" id="license"><title>Is there is a license or fee? What about a warranty? Registration? - Junkbuster is licensed under the - GNU General Public License (GPL). It is free to use, copy, - modify or distribute as you wish. + Privoxy is licensed under the GNU General Public License (GPL). + It is free to use, copy, modify or distribute as you wish under the terms of this + license. Please see the Copyright section for more + information on the license and copyright. Or the LICENSE file + that should be included. - There is no warranty of any kind, expressed, implied or otherwise. That is something - that would cost real money ;-) There is no registration either. - Junkbuster really is free + There is no warranty of any kind, expressed, implied or otherwise. + That is something that would cost real money ;-) There is no registration either. + Privoxy really is free in every respect! - + + + +I would like to help you, what do I do? + +Money Money Money + + We, of course, welcome donations and could use money for domain registering, + buying software to test Privoxy with, and, of course, + for regular world-wide get-togethers (hahaha). If you enjoy the software and feel + like helping us with a donation, just drop us a note. + + + +Software + + If you are a vendor of a web-related software like a browser, web server + or proxy, and would like us to ensure that Privoxy + runs smoothly with your product, you might consider supplying us with a + copy or license. We can't, however, guarantee that we will fix all potential + compatibility issues as a result. + +You want to work with us? + + Well, helping the team is always a good idea. We welcome new developers, + packaging gurus or documentation writers. Simply get an account on SourceForge.net + and mail your id to the developers + mailing list. Then read the Developer's Manual. + + + Once we have added you to the team, you'll have write access to the CVS repository, and + together we'll find a suitable task for you. + + + + + -Installation -Can I install the new - <application>Junkbuster</application> over the old one? +Installation + + +Which browsers are supported by <application>Privoxy</application>? + + Any browser that can be configured to use a proxy, which + should be virtually all browsers. Direct browser support is not necessary + since Privoxy runs as a separate application and + talks to the browser in the standardized HTTP protocol, just like a web server + does. + + + + +Which operating systems are supported? + +&supported; + + +Can I install + <application>Privoxy</application> over <application>Junkbuster</application>? - We recommend you uninstall the old Junkbuster + We recommend you un-install Junkbuster first to minimize conflicts and confusion. You may want to - save your old configuration files for future reference. + save your old configuration files for future reference. The configuration + files and syntax have substantially changed, so you will need to manually + port your old patterns. See the note + to upgraders and installation + chapter in the user manual + for details. - See the user-manual for platform specific installation instructions. - + Note: Some installers may automatically un-install + Junkbuster, if present! - - -What is the proxy address of Junkbuster? + + + +I just installed <application>Privoxy</application>. Is there anything +special I have to do now? + + + All browsers must be told to use Privoxy + as a proxy by specifying the correct proxy address and port number + in the appropriate configuration area for the browser. See below. + You should also flush your browser's memory and disk cache to get rid of any + cached junk items. + + + + + + +What is the proxy address of <application>Privoxy</application>? - If you set up the Junkbuster to run on + If you set up the Privoxy to run on the computer you browse from (rather than your ISP's server or some - networked computer on a LAN), the proxy will be on localhost - (which is the special name used by every computer on the Internet to refer - to itself) and the port will be 8118 (unless you have told the Internet - Junkbuster to run on a different port with the - listen-address config option). + networked computer on a LAN), the proxy will be on 127.0.0.1 + (sometimes referred to as localhost, + which is the special name used by every computer on the Internet to refer + to itself) and the port will be 8118 (unless you have Privoxy + to run on a different port with the listen-address config option). - So you when configuring your browser's proxy settings you typically enter - the word localhost in the boxes next to HTTP - and Secure (HTTPS) and then the number 8118 - for port. + When configuring your browser's proxy settings you typically enter + the word localhost or the IP address 127.0.0.1 + in the boxes next to HTTP and Secure (HTTPS) and + then the number 8118 for port. + This tells your browser to send all web requests to Privoxy + instead of directly to the Internet. - Junkbuster can also be used to proxy for + Privoxy can also be used to proxy for a Local Area Network. In this case, your would enter either the IP - address of the LAN host where Junkbuster + address of the LAN host where Privoxy is running, or the equivalent hostname. Port assignment would be - same as above. + same as above. Note that Privoxy doesn't + listen on any LAN interfaces by default. - Junkbuster does not currently handle + Privoxy does not currently handle protocols such as FTP, SMTP, IM, IRC, ICQ, or other Internet protocols. - + + + +I just installed <application>Privoxy</application>, and nothing is happening. +All the ads are there. What's wrong? + + + Did you configure your browser to use Privoxy + as a proxy? It does not sound like it. See above. You might also try flushing + the browser's caches to force a full re-reading of pages. You can verify + that Privoxy is running, and your browser + is correctly configured by entering the special URL: + http://config.privoxy.org/. + This should take you to a page titled This is Privoxy.. with + access to Privoxy's internal configuration. + If you see this, then you are good to go. If you receive a page saying + Privoxy is not running, then the browser is not set up to use + your Privoxy installation. + If you receive anything else (probably nothing at all), it could either + be that the browser is not set up correctly, or that + Privoxy is not running at all. Check the log file. + + + + + + -Configuration +Configuration -Can I use my old config files? +Can I use my old config files? - No. These will not work. You will need to re-enter your old - data into the new configuration structure. + The syntax, number, and purpose of configuration files has substantially + changed from Junkbuster and earlier versions + of Privoxy. The old files, like blocklist + will not work at all. If you are upgrading from a 2.0.x version, you will + need to port your configuration data to the new format. Note that even the + pattern syntax has changed! Even configuration files from the 2.9.x versions + will need to be adapted, as configuration syntax has been very much in flow + in the 2.9.x series. - + + +What is an <quote>actions</quote> file? -How can I make my Yahoo account work? - - Fillme. - - + + Actions files + are where various actions + that Privoxy might take while processing a certain + request, are configured. Typically, you would define a set of default actions + that apply to all URLs, then add exceptions to these defaults where needed. + + + + Actions can be defined on a URL pattern basis, i.e. + for single URLs, whole web sites, groups or parts thereof etc. Actions can also be + grouped together and then applied to requests matching one or more patterns. + There are many possible actions that might apply to any given site. As an example, + if you are blocking cookies as one of your default actions, but need to accept + cookies from a given site, you would need to define an exception for this + site in one of your actions files, preferably in user.action + - How can I make my Hotmail account work? - - Fillme. - - + + + +The <quote>actions</quote> concept confuses me. Please list +some of these <quote>actions</quote>. + + For a comprehensive discussion of the actions concept, please refer + to the actions file + chapter in the user + manual. It includes a list of all actions + and an actions + file tutorial to get you started. + + + + + +How are actions files configured? What is the easiest +way to do this? - How can I make my GMX account work? + + Actions files are just text files in a special syntax and can be edited + with a text editor. The probably easiest way is to access + Privoxy's user interface with your web browser + at http://config.privoxy.org/ + (Shortcut: http://p.p/) and then select + View & + change the current configuration from the menu. + + + + + + +There are several different <quote>actions</quote> files. What are +the differences? + + As of Privoxy v2.9.15, three actions files + are being included, to be used for + different purposes: These are + default.action, the main actions file + which is actively maintained by the Privoxy + developers, user.action, where users are encouraged + to make their private customizations, and standard.action, + which is for internal Privoxy use only. + Please see the actions chapter + in the user manual for a more + detailed explanation. + + + + Earlier versions included three different versions of the + default.action file. The new scheme allows for + greater flexibility of local configuration, and for browser based + selection of pre-defined aggressiveness levels. + + + + +How can I make my Yahoo/Hotmail/GMX account work? - Fillme. + The default configuration shouldn't impact the usability of any of these services. + It will, however, make all cookies temporary, so that your browser will forget your + login credentials in between browser sessions. If you would like not to have to log + in manually each time you access those websites, simply turn off all cookie handling + for them in the user.action file. An example for yahoo might + look like: - + + # Allow all cookies for Yahoo login: +# +{ -crunch-incoming-cookies -crunch-outgoing-cookies -session-cookies-only } +.login.yahoo.com + + + - What are the differences between -ijb-intermediate.action, ijb-basic.action, etc.? + What's the difference between the +<quote>Cautious</quote>, <quote>Medium</quote> and <quote>Advenced</quote> defaults? -Configuring the Internet Junkbuster is not easy. To help you get started, we -provide you with three different default configurations. The following table -shows you, which features are enabled in each configuration. + Configuring Privoxy is not entirely trivial. To help you get + started, we provide you with three different default action packages in + the web based actions file editor at http://config.privoxy.org/show-status. + The following table shows you, which of the most important features are enabled in each + configuration: Default Configurations - + - Feature - ijb.action - ijb-basic.action - ijb-intermediate.action - ijb-advanced.action + Cautious + Intermadiate + Advanced - - - - - - ad-filtering - ? - x - x - x - - - - blank image - ? - x - x - x - - + - de-animate GIFs - ? - x - x - x + Ad-blocking by URL + yes + yes + yes - + - referer forging - ? - x - x - x + Ad-filtering by size + yes + yes + yes - + - jon's +no-cookies-keep (i.e. session cookies only) - ? - x - x - x + GIF de-animation + no + yes + yes - + - no-popup windows - ? - - x - x + Referer forging + no + yes + yes - + - fast redirects - ? - - x - x + Cookie handling + none + session-only + kill - + - hide-referrer - ? - - x - x + Pop-up killing + no + no + yes - + - hide-useragent - ? - - x - x + Fast redirects + no + no + yes - + - content-modification - ? - - - x + HTML taming + yes + yes + yes - + - feature-x - ? - - - + JavaScript taming + yes + yes + yes - + - feature-y - ? - - - + Web-bug killing + yes + yes + yes - + - feature-z - ? - - - + Fun text replacements + no + no + yes - +
- + + Where the defaults are likely to break some sites, exceptions for + known popular problem sites are included, but in + general, the more aggressive your default settings are, the more + exceptions you will have to make later. See the user manual for a more + deatiled discussion. + - Why can I change the configuration with a -browser? Does that not raise security issues? + + + Why can I change the configuration +with a browser? Does that not raise security issues? -What I don't understand, is how I can browser edit the config file as a -regular user, while the whole /etc/junkbuster hierarchy belongs to the user -"junkbuster", with only 644 perms. + It may seem strange that regular users can edit the config files with their + browsers, although the whole /etc/privoxy hierarchy + belongs to the user privoxy, with only 644 permissions. -When you use the browser-based editor, JunkBuster itself is writing to the -config files. Because JunkBuster is running as the user "junkbuster", it can -update the config files. + When you use the browser-based editor, Privoxy + itself is writing to the config files. Because + Privoxy is running as the user privoxy, + it can update the config files. -If you don't like this, setting "enable-edit-actions 0" in the config file -will disable the browser-based editor. If you're that paranoid, you should -also consider setting "enable-remote-toggle 0" to prevent browser-based -enabling/disabling of JunkBuster. + If you run Privoxy for multiple untrusted users (e.g. in + a LAN), you will probably want to turn the web-based editor and remote toggle + features off by setting enable-edit-actions + 0 and enable-remote-toggle + 0 in the main configuration file. -Note that normally only local users can connect to JunkBuster, so this is not -(normally) a security problem. + Note that in the default configuration, only local users (i.e. those on + localhost) can connect to Privoxy, + so this is not (normally) a security problem. - - - - -Misc -I noticed considerable -delays in page requests compared to the old IJB. What's wrong? - -Using the default filtering configuration, I noticed considerable delays in -page requests compared to the old IJB. Loading pages with large contents -seemed to take forever, then suddenly delivering all the content at once. - + +What is the <filename>default.filter</filename> file? -The whole content must be loaded in order to filter, and nothing is is -sent to the browser during this time. The loading time does not really -change in real numbers, but the feeling is different, because most -browsers are able to start rendering incomplete content, giving the -user a feeling of "it works". - - -To modify the content of a page (i.e. make frames resizeable again, etc.) and -not just replace ads, the Internet Junkbuster needs to download the entire -page first, do its content magic and then send the page to the browser. + The default.filter + file is where filters are defined, which can be used to modify or + remove, web page content on the fly. This applies to anything + in the page source, including HTML tags, and JavaScript. Regular expressions are used + to accomplish this. There are a number of pre-defined filters to deal with common + annoyances. The filters are only defined here, to invoke them, you need to use the + filter action. - + + If you are familiar with regular expressions, and HTML, you can look at + the provided default.filter with a text editor and define + your own filters. This is potentially a very powerful feature, but + requires some expertise. + -What is the "http://i.j.b/"? -Since JunkBuster sits between your web browser and the Internet, it can be -programmed to handle certain pages specially. + Presently, there is no GUI editor option for this part of the configuration, + but you can disable/enable the various pre-defined filters of the included + default.filter file with the web-based actions file editor. + + + +How can I set up <application>Privoxy</application> to act as a proxy for my + LAN? -With recent versions of JunkBuster (version 2.9.x), you can get some -information about JunkBuster and change some settings by going to -http://i.j.b/ or, equivalently, http://ijbswa.sourceforge.net/config/ -(Note that i.j.b is far easier to type but may not work in some -configurations). + By default, Privoxy only responds to requests + from 127.0.0.1 (localhost). To have it act as a server for + a network, this needs to be changed in the main configuration file. Look for + the listen-address + option, which may be commented out with a # symbol. Make sure + it is uncommented, and assign it the address of the LAN gateway interface, + and port number to use. Assuming your LAN address is 192.168.1.1 and you + wish to run Privoxy on port 8118, this line + schould look like: -These pages are *not* forwarded to a server on the internet - instead they are -handled by a special web server which is built in to JunkBuster. + + listen-address 192.168.1.1:8118 -If you are not running JunkBuster, then http://i.j.b/ will fail, and -http://ijbswa.sourceforge.net/config/ will return a web page telling you -you're not running JunkBuster. + Save the file, and restart Privoxy. Configure + all browsers on the network then to use this address and port number. -If you have version 2.0.2, then the equivalent is -http://example.com/show-proxy-args (but you get far less information, and you -should really consider upgrading to 2.9.x). + If you run Privoxy on a LAN with untrusted users, + we recommend that you double-check the access control and security + options! - + + -I get the message 'Bad File Descriptor', why? + +Instead of ads, now I get a checkerboard pattern. I don't want to see anything. - Fillme. + The replacement for blocked images can be controlled with the set-image-blocker + action. You have the choice of a checkerboard pattern, a transparent 1x1 GIF + image (aka blank), or a redirect to a custom image of your choice. + Note that this choice only has effect for images which are blocked as images, i.e. + whose URLs match both a handle-as-image + and block action. - - -How do I chain Junkbuster with other proxies -(e.g. squid)? - Fillme. + If you want to see nothing, then change the set-image-blocker + action to blank. This can be done by editing the + default.action file, or trough the web-based actions file editor. - -I would like to help you, what do I do? + + + +Why would anybody want to see a checkerboard pattern? - Well, helping the team is always a good idea. We welcome new developers, - RPM gurus or documentation makers. Simply get an account on sourceforge.net - and mail your id to the developer mailing list. Once we have added you to - the team, you'll have write access to the CVS repository, and together - we'll find a suitable task for you. + Remember that telling which image is an ad and which + isn't, is mostly guesswork. While we hope that the standard configuration + is rather smart, it can and will make errors. The checkerboard image is visually + decent, but it shows you that and where images were blocked, which can be very + helpful in case some navigation aid or otherwise innocent image was + erraneously blocked. Some people might also enjoy seeing how many banners + they don't have to see.. - -Do you still maintain the blocklists? + + + + + +I see some images being replaced by a text +instead of the checkerboard image. Why and how do I get rid of this? + + This happens when the banners are not embedded in the HTML code of the + page itself, but in separate HTML (sub)documents that are loaded into (i)frames + or (i)layers, and these external HTML documents are blocked. Being non-images + they get replaced by a substitute HTML page rather than a substitute image, + which wouldn't work out technically, since the browser expects and accepts + only HTML when it has requested an HTML document. + + + The substitute page adapts to the available space and shows itself as a + miniature two-liner if loaded into small frames, or full-blown with a + large red "BLOCKED" banner if space allows. + + + If you prefer the banners to be blocked by images, you must see to it that + the HTML documents in which they are embedded are not blocked. Clicking + the See why link offered in the substitute page will show + you which rule blocked the page. After changing the rule and un-blocking + the HTML documents, the browser will try to load the actual banner images + and the usual image blocking will (hopefully!) kick in. + + + + + +Can <application>Privoxy</application> run as a service +on Win2K/NT? + + Yes, it can run as a system service using srvany.exe. + The only catch is that this will effectively disable the + Privoxy icon (and its menu!) in the taskbar. You can have + one or the other, but not both at this time :( + + + There is a pending feature request for this functionality. See the discussion + at http://sourceforge.net/tracker/?func=detail&atid=361118&aid=485617&group_id=11118, + for details, and a sample configuration. + + + + + + +How can I make <application>Privoxy</application> work with other +proxies like <application>Squid</application>? + + This can be done and is often useful to combine the benefits of + Privoxy with those of a caching proxy. + See the forwarding chapter + in the user manual which + describes how to do this. + + - - - - - - - + +Can <application>Privoxy</application> run as a <quote>transparent +</quote> proxy? + + No, Privoxy currently does not have this ability, + though it is planned for a future release. Transparent proxies require + special handling of the request headers beyond what + Privoxy is now capable of. + + + + Chaining Privoxy behind another proxy that has + this ability should work though. + See the forwarding chapter + in the user manual. As + a transparent proxy to be used for chaining we recommend Transproxy + (http://www.transproxy.nlc.net.au/). + + + + -Known Issues + +Miscellaneous + + +How much does <application>Privoxy</application> slow my browsing down? This +has to add extra time to browsing. + + It should not slow you down any in real terms, and may actually help + speed things up since ads, banners and other junk are not being displayed. + The actual processing time required by Privoxy + itself for each page, is relatively small in the overall scheme of things, + and happens very quickly. This is typically more than offset by time saved + not downloading and rendering ad images. + + + + Filtering content via the filter or + deanimate-gifs + actions may cause a perceived slowdown, since the entire document needs to be buffered + before displaying. See below. + + + + + +I noticed considerable +delays in page requests compared to the old Junkbuster. What's wrong? + + If you use any filter action, + such as filtering banners by size, web-bugs etc, or the deanimate-gifs + action, the entire document must be loaded into memory in order for the filtering + mechanism to work, and nothing is sent to the browser during this time. + + + The loading time does not really change in real numbers, but the feeling is + different, because most browsers are able to start rendering incomplete + content, giving the user a feeling of "it works". This effect is especially + noticeable on slow dialup connections. + + + + +What are "http://config.privoxy.org/" and +"http://p.p/"? + + http://config.privoxy.org/ is the + address of Privoxy's built-in user interface, and + http://p.p/ is a shortcut for it. + + + Since Privoxy sits between your web browser and the Internet, + it can simply intercept requests for these addresses and answer them with its built-in + web server. + + + This also makes for a good test for your browser configuration: If entering the + URL http://config.privoxy.org/ + takes you to a page saying This is Privoxy.., everything is OK. + If you get a page saying Privoxy is not working instead, then + your browser didn't use Privoxy for the request, + hence it could not be intercepted, and you have accessed the real + web site at config.privoxy.org. + + + With recent versions of Privoxy (version 2.9.x and + later), the user interface features information on the run time status, the + configuration, and even a built-in editor for the actions files. + + + + Note that the built-in URLs from earlier versions of Junkbuster + / Privoxy, http://example.com/show-proxy-args and http://i.j.b/, + are no longer supported. If you still use such an old version, you should really consider + upgrading to &p-version;. + + + + + +Do you still maintain the blocklists? + + No. The patterns for blocking now reside (among other things) in the actions files, which are + actively maintained instead. See next question ... + + + +How can I submit new ads? + +Yes, absolutely! Please see the Contact section for +how to do that. Please note that you (technically) need the latest +Privoxy version for this to work. + + + + +How can I hide my IP address? + + If you run both the browser and the proxy locally, you cannot hide your IP + address with Privoxy or any other software. The + server needs to know your IP address to send the answers back to you. + + + Fortunately there are many publicly usable anonymous proxies out there, which + solve the problem by providing a further level of indirection between you and + the web server, shared by many people, and thus letting your requests "drown" + in white noise of unrelated requests as far as user tracking is concerned. + + + Most of them will, however, log your IP address and make it available to the + authorities in case you abuse that anonymity for criminal purposes. In fact + you can't even rule out that some of them only exist to *collect* information + on (those suspicious) people with a more than average preference for privacy. + + + You can find a list of anonymous public proxies at multiproxy.org and many + more through Google. A particularly interesting project is the JAP service + offered by the Technical University of Dresden (http://anon.inf.tu-dresden.de/index_en.html. + + + There is, however, even in the single-machine case the possibility to make the + server believe that your machine is in fact a shared proxy serving a whole big + LAN, and we are looking into that. + + + + +Can <application>Privoxy</application> guarantee I am anonymous? + + No. Your chances of remaining anonymous are greatly improved, but unless you + are an expert on Internet security it would be safest to assume that + everything you do on the Web can be traced back to you. + + + Privoxy can remove various information about you, + and allows you more freedom to decide which sites + you can trust, and what details you want to reveal. But it's still possible + that web sites can find out who you are. Here's one way this can happen. + + + A few browsers disclose the user's email address in certain situations, such + as when transferring a file by FTP. Privoxy + does not filter FTP. If you need this feature, or are concerned about the + mail handler of your browser disclosing your email address, you might + consider products such as NSClean. + + + Browsers available only as binaries could use non-standard headers to give + out any information they can have access to: see the manufacturer's license + agreement. It's impossible to anticipate and prevent every breach of privacy + that might occur. The professionally paranoid prefer browsers available as + source code, because anticipating their behavior is easier. Trust the source, + Luke! + + + + + +Might some things break because header information or +content is being altered? + + + Definitely. More and more sites use HTTP header content to decide what to + display and how to display it. There is many ways that this can be handled, + so having hard and fast rules, is tricky. + + + + User-Agent in particular is often used in this way to identify + the browser, and adjust content accordingly. Changing this now (at least not + further than removing the OS information) is not recommended, since so many + sites do look for it. You may get undesirable results by changing this. + + + + For instance, different browsers use different encodings of Russian and Czech + characters, certain web servers convert pages on-the-fly according to the + User Agent header. Giving a User Agent with the wrong + operating system or browser manufacturer causes some sites in these languages + to be garbled; Surfers to Eastern European sites should change it to + something closer. And then some page access counters work by looking at the + Referer header; they may fail or break if unavailable. The + weather maps of Intellicast have been blocked by their server when no + Referer or cookie is provided, is another example. (But you + can forge both headers without giving information away). There are + many other ways things can go wrong when trying to fool a web server. + + + + Similar thoughts apply to modifying JavaScript, and, to a lesser degree, + HTML elements. + + + + If you have problems with a site, you will have to adjust your configuration + accordingly. Cookies are probably the most likely adjustment that may + be required, but by no means the only one. + + + + + + +Can <application>Privoxy</application> act as a <quote>caching</quote> proxy to +speed up web browsing? + + No, it does not have this ability at all. You want something like + Squid for this. And, yes, + before you ask, Privoxy can co-exist + with other kinds of proxies like Squid. + See the forwarding + chapter in the user + manual for details. + + + + +What about as a firewall? Can <application>Privoxy</application> protect me? + + Not in the way you mean, or in the way a true firewall can. + Privoxy can help protect your privacy, but not + protect you from intrusion attempts. It is, of course, perfectly possible + and recommended to use both. + + + + + + +I have large empty spaces / a checkerboard pattern now where +ads used to be. Why? + + It would be technically possible eliminate the banners in a way that frees + their screen estate in many cases, by doing all banner blocking with filters, + i.e. eliminating the whole image references from the HTML pages instead + of letting them stay in, and blocking the resulting requests for the + banners themselves. + + + But this would consume considerable CPU resources, would likely destroy + the layout of many web pages which rely on the banners consuming a certain + amount of screen space, and would fail in other cases, where the screen space + is reserved e.g. by tables anyway. Also, making the banners disappear without + a visual trace complicates troubleshooting. + + + So we won't support this in the default configuration, but you can of course + define appropriate filters yourself. + + + + +How can <application>Privoxy</application> filter Secure (HTTPS) URLs? + + Since secure HTTP connections are encrypted SSL sessions between your browser + and the secure site, and are meant to be reliably secure, + there is little that Privoxy can do but hand the raw + gibberish data though from one end to the other unprocessed. + + + The only exception to this is blocking by host patterns, as the client needs + to tell Privoxy the name of the remote server, + so that Privoxy can establish the connection. + If that name matches a host-only pattern, the connection will be blocked. + + + As far as ad blocking is concerned, this is less of a restriction than it may + seem, since ad sources are often identifiable by the host name, and often + the banners to be placed in an encrypted page come unencrypted nonetheless + for efficiency reasons, which exposes them to the full power of + Privoxy's ad blocking. + + + + + +<application>Privoxy</application> runs as a <quote>server</quote>. How +secure is it? Do I need to take any special precautions? + + There are no known exploits that might affect + Privoxy. On Unix-like systems, + Privoxy can run as a non-privileged + user, which is how we recommend it be run. Also, by default + Privoxy only listens to requests + from localhost only. The server aspect of + Privoxy is not itself directly exposed to the + Internet in this configuration. If you want to have + Privoxy serve as a LAN proxy, this will have to + be opened up to allow for LAN requests. In this case, we'd recommend + you specify only the LAN gateway address, e.g. 192.168.1.1, in the main + Privoxy configuration file and check all access control and security + options. All LAN hosts can then use this as their proxy address + in the browser proxy configuration, but Privoxy + will not listen on any external interfaces. ACLs can be defined in addition, + and using a firewall is always good too. Better safe than sorry. + + + + + +How can I temporarily disable <application>Privoxy</application>? + + The easiest way is to access Privoxy with your + browser by using the remote toggle URL: http://config.privoxy.org/toggle. + + + + +Where can I find more information about <application>Privoxy</application> +and related issues? + + &seealso; + + + + + + -Contact the developers -Please see the user manual for information on how to contact the developers. + + +Troubleshooting + + +I just upgraded and am getting <quote>connection refused</quote> +with every web page? + + Either Privoxy is not running, or your + browser is configured for a different port than what + Privoxy is using. + + + + The old Privoxy (and also + Junkbuster) used port 8000 by + default. This has been changed to port 8118 now, due to a conflict + with NAS (Network Audio Service), which uses port 8000. If you haven't, + you need to change your browser to the new port number, or alternately + change the listen-address + option in Privoxy's main configuration file. + + + + + +I just added a new rule, but the steenkin ad is +still getting through. How? + + If the ad had been displayed before you added its URL, it will probably be + held in the browser's cache for some time, so it will be displayed without + the need for any request to the server, and Privoxy + will not be in the picture. The best thing to do is try flushing the browser's + caches. And then try again. + + + + If this doesn't help, you probably have an error in the rule you + applied. Try pasting the full URL of the offending ad into http://config.privoxy.org/show-url-info + and see if it really matches your new rule. + + + + + +One of my favorite sites does not work with <application>Privoxy</application>. +What can I do? + + + First verify that it is indeed a Privoxy problem, + by toggling off Privoxy through http://config.privoxy.org/toggle, + and then shift-reloading the problem page (i.e. holding down the shift key + while clicking reload. Alternatively, flush your browser's disk and memory + caches). + + + + If still a problem, go to http://config.privoxy.org/show-url-info + and paste the full URL of the page in question into the prompt. See which actions + are being applied to the URL, and which matches in which actions files are + responsible for that. Now, armed with this information, go to http://config.privoxy.org/show-status + and select the appropriate actions files for editing. + + + You can now either look for a section which disables the actions that + you suspect to cause the problem and add a pattern for your site there, + or make up a completely new section for your site. In any case, the recommended + way is to disable only the prime suspect, reload the problem page, and only + if the problem persists, disable more and more actions until you have + identified the culprit. You may or may not want to turn the other actions + on again. Remember to flush your browser's caches in between any such changes! + + + Alternately, if you are comfortable with a text editor, you can accomplish + the same thing by editing the appropriate actions file. Probably the easiest + way to deal with such problems when editing by hand is to add your + site to a { fragile } section in user.action, + which is an alias that turns off most dangerous + actions, but is also likely to turn off more actions then needed, and thus lower + your privacy and protection more than necessary, + + Troubleshooting actions is discussed in more detail in the user-manual appendix. + There is also an actions tutorial. + + + + + -Copyright and History -Please see the user manual for information on Copyright and History. + + + + Contacting the developers, Bug Reporting and Feature Requests + + &contacting; + + + + +Privoxy Copyright, License and History + + ©right; + + + + Portions of this document are borrowed from the original + Junkbuster (tm) FAQ, and modified as + appropriate for Privoxy. + + + + License + + &license; + + + + + + History + + &history; + + + + + + + + + + + +