Junkbuster Frequently Asked Questions

+ +

-Junkbuster Frequently Asked Questions +Privoxy Frequently Asked Questions + + + + + + Copyright &my-copy; 2001-2014 by + Privoxy Developers + + + +$Id: faq.sgml,v 2.117 2016/03/04 13:21:33 fabiankeil 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. The Internet Junkbuster is an application -that provides privacy and security to the user of the world wide web. - - -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. + This FAQ gives quick answers to frequently asked questions about + Privoxy. + It is not a substitute for the + Privoxy User Manual. + + + What is Privoxy? &p-intro; + + - Feel free to send a note to the developers at ijbswa-developers@lists.sourceforge.net. + Please note that this document is a work in progress. This copy represents + the state at the release of version &p-version;. + 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. + + + + - -Introduction - - Fillme. - - - -Frequently Asked Questions +General Information +Who should give &my-app; a try? + + Anyone who is interested in security, privacy, or in + finer-grained control over their web and Internet experience. + + - +Is Privoxy the best choice for +me? + + &my-app; is certainly a good choice, especially for those who want more + control and security. Those with the willingness to read the documentation + and the ability to fine-tune their installation will benefit the most. + + + One of Privoxy's + strengths is that it is highly configurable giving you the ability to + completely personalize your installation. Being familiar with, or at least + having an interest in learning about HTTP and other networking + protocols, HTML, and + Regular + Expressions + will be a big plus and will help you get the most out of &my-app;. + A new installation just includes a very basic configuration. The user + should take this as a starting point only, and enhance it as he or she + sees fit. In fact, the user is encouraged, and expected to, fine-tune the + configuration. + + + Much of Privoxy's configuration can be done + with a Web browser. + But there are areas where configuration is done using a + text editor + to edit configuration files. Also note that the web-based action editor + doesn't use authentication and should only be enabled in environments + where all clients with access to &my-app; listening port can be trusted. + + -Installation +What is a <quote>proxy</quote>? How does +Privoxy work? + + A web proxy + is a service, based on a software such as &my-app;, that clients + (i.e. browsers) can use instead of connecting to web servers directly. + The clients then ask the proxy to request objects (web pages, images, movies etc) + on their behalf and to forward the data to the clients. + It is a go-between. For details, see + Wikipedia's proxy definition. + + + There are many reasons to use web proxies, such as security (firewalling), + efficiency (caching) and others, and there are any number of proxies + to accommodate those needs. + - Fillme. + &my-app; is a proxy that is primarily focused on + privacy enhancement, ad and junk elimination and freeing the user from + restrictions placed on his activities. 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 complete control via the various configuration + files and options. Being a proxy also makes it easier to share + configurations among multiple browsers and/or users. - + +Does Privoxy do anything more than ad blocking? + + Yes, ad blocking is but one possible use. There are many, many ways &my-app; + can be used to sanitize and customize web browsing. + + -Configuration +What is this new version of +<quote><citetitle>Junkbuster</citetitle></quote>? -How can I make my Yahoo account work? - - Fillme. + + &history; + + + + + + +Why <quote>Privoxy</quote>? Why change the name from +Junkbuster at all? + + Though outdated, Junkbusters Corporation continued to offer their original + version of the Internet Junkbuster for a while, + so publishing our Junkbuster-derived software + under the same name would have led to confusion. + + + There were also potential legal reasons not to use the + Junkbuster name, as it was (and maybe still is) + a registered trademark of Junkbusters Corporation. + There were, however, no objections from Junkbusters Corporation to the + Privoxy project itself, and they, in fact, + shared our ideals and goals. + + + The Privoxy developers also believed that there were so many improvements + over the original code, that it was time to make a clean break from the past + and make a name in their own right. + + + Privoxy is the + Privacy Enhancing Proxy. Also, its content + modification and junk suppression gives you, the user, more + control, more freedom, and allows you to browse your personal and + private edition of the web. + + + +How does Privoxy differ +from the old Junkbuster? + + Privoxy picks up where + Junkbuster left off. + Privoxy still blocks ads and banners, + still manages cookies, and still + helps protect your privacy. But, most of these features have been enhanced, + and many new ones have been added, all in the same vein. - + + Privoxy's new features include: + - How can I make my Hotmail account work? - - Fillme. - - + + &newfeatures; + + + + + +How does Privoxy 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 things that sound + like they would be ads or 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 + and readily configurable. + + + + +Can Privoxy 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. You will almost surely + run into such situations 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.) + + + + + +Will I have to configure Privoxy + before I can use it? + + That depends on your expectations. + The default installation should give you a good starting + point, and block most ads and unwanted content, + but many of the more advanced features are off by default, and require + you to activate them. + + + You do have to set up your browser to use + Privoxy (see the Installation section below). + + + And you will certainly run into situations where there are false positives, + or ads not being blocked that you may not want to see. In these cases, you + would certainly benefit by customizing Privoxy's + configuration to more closely match your individual situation. And we + encourage you to do this. This is where the real power of + Privoxy lies! + + + - How can I make my GMX account work? + +Can Privoxy run as a server on a network? - Fillme. - - + Yes, &my-app; runs as a server already, and can easily be configured to + serve more than one client. See + How can I set up Privoxy to act as a proxy for my LAN below. + + - Why can I change the configuration with a -browser? Does that not raise security issues? +My browser does the same things as +Privoxy. Why should I use Privoxy at all? -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. + Modern browsers do indeed have some of the same + functionality as Privoxy. Maybe this is + adequate for you. But Privoxy is very + versatile and powerful, and can probably do a number of things + your browser just can't. -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. + In addition, a proxy is good choice if you use multiple browsers, or + have a LAN with multiple computers since &my-app; can run as a server + application. This way all the configuration is in one place, and you don't + have to maintain a similar configuration for possibly many browsers or + users. -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. + Note, however, that it's recommended to leverage both your browser's + and Privoxy's privacy enhancing features + at the same time. While your browser probably lacks some features + &my-app; offers, it should also be able to do some things more + reliably, for example restricting and suppressing JavaScript. + + +Why should I trust Privoxy? -Note that normally only local users can connect to JunkBuster, so this is not -(normally) a security problem. + The most important reason is because you have access to + everything, and you can control everything. You can + check every line of every configuration file yourself. You can check every + last bit of source code should you desire. And even if you can't read code, + there should be some comfort in knowing that other people can, + and do read it. You can build the software from scratch, if you want, + so that you know the executable is clean, and that it is + yours. In fact, we encourage this level of scrutiny. It + is one reason we use &my-app; ourselves. + + + +Is there is a license or fee? What about a +warranty? Registration? + + Privoxy is free software and licensed under the GNU General Public License (GPL) version 2. + 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. - - + +Can Privoxy remove spyware? Adware? Viruses? + + No, at least not reliably enough to trust it. &my-app; is not designed to be + a malware removal tool and the default configuration doesn't even try to + filter out any malware. + + + &my-app; could help prevent contact from (known) sites that use such + tactics with appropriate configuration rules, and thus could conceivably + prevent contamination from such sites. However, keeping such a configuration + up to date would require a lot of time and effort that would be better spend + on keeping your software itself up to date so it doesn't have known + vulnerabilities. + + -Misc -I noticed considerable -delays in page requests compared to the old IJB. What's wrong? + +Can I use Privoxy with other ad-blocking software? -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. - + &my-app; should work fine with other proxies and other software in general. + -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". - + But it is probably not necessary to use &my-app; in conjunction with other + ad-blocking products, and this could conceivably cause undesirable results. + It might be better to choose one software or the other and work a little to + tweak its configuration to your liking. + -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. + Note that this is an advice specific to ad blocking. - + +I would like to help you, what can I do? -What is the "http://i.j.b/"? +Would you like to participate? -Since JunkBuster sits between your web browser and the Internet, it can be -programmed to handle certain pages specially. + Well, we always need help. There is something for + everybody who wants to help us. We welcome new developers, packagers, + testers, documentation writers or really anyone with a desire to help in + any way. You DO NOT need to be a + programmer. There are many other tasks available. In fact, + the programmers often can't spend as much time programming because of some + of the other, more mundane things that need to be done, like checking the + Tracker feedback sections or responding to user questions on the mailing + lists. + + + So first thing, subscribe to the Privoxy Users + or the Privoxy + Developers mailing list, join the discussion, help out other users, provide general + feedback or report problems you noticed. + + + If you intend to help out with the trackers, you also might want to get an account on SourceForge.net + so we don't confuse you with the other name-less users. + + + We also have a Developer's Manual. + While it is partly out of date, it's still worth reading. + + + Our TODO list + may be of interest to you as well. + Please let us know if you want to work on one of the items listed. + +Would you like to donate? -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). + Donations are welcome. Our + TODO list + is rather long and being able to pay one (or more) developers to work on Privoxy + would make a huge difference, even if it was only for a couple of weeks. Donations may + also be used for Privoxy-related travel expenses (for example to attend conferences), + for hardware used for Privoxy development and for hosting expenses etc. -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. + Privoxy is an associated + project of Software + in the Public Interest (SPI), which allows us to receive + tax-deductible donations in the United States. If you want to donate through + SPI, please use SPI's donation page + to see what the options are. -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. + You can also donate to Privoxy using a bank account or a "Paypal" address: + + + Name on account: Zwiebelfreunde e.V. + IBAN: DE95430609671126825604 + BIC: GENODEM1GLS + Bank: GLS Bank + + + "Paypal" address: privoxy@zwiebelfreunde.de + + + Donations made through Zwiebelfreunde e.V. are tax-deductible in Germany + and other countries that recognize German charitable clubs. Feel free to + use the Subject field to provide a name to be credited and a list of TODO + list items you are interested in the most. For example: Max Mustermann: #16, #1, #14. -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). + Note that donations made through Zwiebelfreunde e.V. currently can't be checked + automatically so you may not get credited right away. The credits currently + reflect donations received before 2016-01-14. + + + If you have any questions regarding donations please mail to either the + public user mailing list or, if it's a private matter, to + Fabian Keil (Privoxy's SPI liason) + directly. + + + + + + + +Installation -I get the message 'Bad File Descriptor', why? + +Which browsers are supported by Privoxy? - Fillme. + Any browser that can be configured to use a proxy, which + should be virtually all browsers, including + Firefox, Internet + Explorer, Opera, and + Safari among others. + Direct browser support is not an absolute requirement 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; + -How do I chain Junkbuster with other proxies -(e.g. squid)? + +Can I use Privoxy with my email client? - Fillme. + As long as there is some way to set a HTTP proxy for the client, then yes, + any application can be used, whether it is strictly speaking a + browser or not. Though this may not be the best approach for + dealing with some of the common abuses of HTML in email. See How can I configure Privoxy + with Outlook? below for more on + this. - - -I would like to help you, what do I do? - 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 we'll find a - suitable task for you together. + Be aware that HTML email presents a number of unique security and privacy + related issues, that can require advanced skills to overcome. The developers + recommend using email clients that can be configured to convert HTML to plain + text for these reasons. - + + + + + +I just installed Privoxy. Is there anything +special I have to do now? -Do you still maintain the blocklists? - No. The format of the blocklists has changed significantly in the versions - 2.9.x. Once we have released the new version, there will again be - blocklists that you can update automatically. + All browsers should 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. It's possible + to combine &my-app; with a packet filter to intercept HTTP requests + even if the client isn't explicitly configured to use &my-app;, + but where possible, configuring the client is recommended. See + the User Manual for more + details. You should also flush your browser's memory and disk + cache to get rid of any cached junk items, and remove any stored + cookies. + - -How can I submit new ads? + + +What is the proxy address of Privoxy? + + 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 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 used the listen-address + config option to tell Privoxy to run on + a different 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. + + + 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 Privoxy + is running, or the equivalent hostname, e.g. 192.168.1.1. + Port assignment would be same as above. Note that + Privoxy doesn't listen on any LAN interfaces by + default. + + + Privoxy does not currently handle + any other protocols such as FTP, SMTP, IM, IRC, ICQ, etc. + + + + +I just installed Privoxy, and nothing is happening. +All the ads are there. What's wrong? + - As of now, please discontinue to submit new ad blocking infos. Once we - have released the new version, there will again be a form on the website, - which you can use to contribute new ads. + 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://p.p/. + + 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. For instructions + on starting Privoxy and browser configuration, + see the chapter + on starting Privoxy in the + User Manual. - -How can I hide my IP address? + + + +I get a <quote>Privoxy is not being used</quote> dummy page although +Privoxy is running and being used. + - You cannot hide your IP address with Junkbuster. + First, make sure that Privoxy is really running and + being used by visiting http://p.p/. You + should see the Privoxy main page. If not, see + the chapter + on starting Privoxy in the + User Manual. - -What is the imagefile (simage.ini, etc.) for? - Anytime the Junkbuster determines (with the help of the blocklist) that a URL - contains an advertisement, it has to decide whether this advertisement is an - image or not. The Junkbuster uses the imagefile for that purpose. + Now if http://p.p/ works for you, but + other parts of Privoxy's web interface show + the dummy page, your browser has cached a redirection it encountered before + Privoxy was being used. You need to clear your + browser's cache. Note that shift-reloading the dummy page won't help, since + that'll only refresh the dummy page, not the redirection that lead you there. - + + The procedure for clearing the cache varies from browser to browser. For + example, Mozilla/Netscape users would click + Edit --> Preferences --> + Advanced --> Cache and + then click both Clear Memory Cache + and Clear Disk Cache. + In some Firefox versions it's + Tools --> Options --> + Privacy --> Cache and + then click Clear Cache Now. + + + -Contact the developers -Please see the user manual for information on how to contact the developers. + +Configuration + +What exactly is an <quote>actions</quote> file? + + + &my-app; utilizes the concept of + actions + that are used to manipulate and control web page data. + Actions files + are where these actions + that Privoxy could take while processing a certain + request, are configured. Typically, you would define a set of default actions + that apply globally to all URLs, then add exceptions to these defaults where needed. + There is a wide array of actions available that give the user a high degree + of control and flexibility on how to process each and every web page. - - -Copyright and History -Please see the user manual for information on Copyright and History. + + 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. - - -See also -Please see the user manual for information on references. + + + +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 can I have separate rules just for HTML mail? + + The short answer is, you can't. Privoxy has no way + of knowing which particular application makes a request, so there is no way to + distinguish between web pages and HTML mail. + Privoxy just blindly proxies all requests. In the + case of Outlook Express (see above), OE uses + IE anyway, and there is no way for Privoxy to ever + be able to distinguish between them (nor could any other proxy type application for + that matter). + + + For a good discussion of some of the issues involved (including privacy and + security issues), see + http://sourceforge.net/tracker/?func=detail&atid=211118&aid=629518&group_id=11118. + + + + +I sometimes notice cookies sneaking through. How? + + Cookies can be + set in several ways. The classic method is via the + Set-Cookie HTTP header. This is straightforward, and an + easy one to manipulate, such as the &my-app; concept of + session-cookies-only. + There is also the possibility of using + Javascript to + set cookies (&my-app; calls these content-cookies). This + is trickier because the syntax can vary widely, and thus requires a certain + amount of guesswork. It is not realistic to catch all of these short of + disabling Javascript, which would break many sites. And lastly, if the + cookies are embedded in a HTTPS/SSL secure session via Javascript, they are beyond + Privoxy's reach. + + + All in all, &my-app; can help manage cookies in general, can help minimize + the loss of privacy posed by cookies, but can't realistically stop all + cookies. + + + + +Are all cookies bad? Why? + + No, in fact there are many beneficial uses of + cookies. Cookies are just a + method that browsers can use to store data between pages, or between browser + sessions. Sometimes there is a good reason for this, and the user's life is a + bit easier as a result. But there is a long history of some websites taking + advantage of this layer of trust, and using the data they glean from you and + your browsing habits for their own purposes, and maybe to your potential + detriment. Such sites are using you and storing their data on your system. + That is why the privacy conscious watch from whom those cookies come, and why + they really need to be there. + + + See the + Wikipedia cookie + definition for more. + + + + +How can I allow permanent cookies for my trusted sites? + + + There are several actions that relate to cookies. The default behavior is to + allow only session cookies, which means the cookies only last + for the current browser session. This eliminates most kinds of abuse related + to cookies. But there may be cases where you want cookies to last. + + + To disable all cookie actions, so that cookies are allowed unrestricted, + both in and out, for example.com: + + + + { -crunch-incoming-cookies -crunch-outgoing-cookies -session-cookies-only -filter{content-cookies} } + .example.com + + + Place the above in user.action. Note that some of these may + be off by default anyway, so this might be redundant, but there is no harm + being explicit in what you want to happen. user.action + includes an alias for this situation, called + allow-all-cookies. + + + + +Can I have separate configurations for different users? + + Each instance of Privoxy has its own + configuration, including such attributes as the TCP port that it listens on. + What you can do is run multiple instances of Privoxy, each with + a unique + listen-address + configuration setting, and configuration path, and then + each of these can have their own configurations. Think of it as per-port + configuration. + + + Simple enough for a few users, but for large installations, consider having + groups of users that might share like configurations. + + + + +Can I set-up Privoxy as a whitelist of +<quote>good</quote> sites? + + Sure. There are a couple of things you can do for simple white-listing. + Here's one real easy one: + + + ############################################################ + # Blacklist + ############################################################ + { +block } + / # Block *all* URLs + + ############################################################ + # Whitelist + ############################################################ + { -block } + kids.example.com + toys.example.com + games.example.com + + This allows access to only those three sites by first blocking all URLs, and + then subsequently allowing three specific exceptions. + + + Another approach is Privoxy's + trustfile concept, which incorporates the notion of + trusted referrers. See the Trust documentation + for details. + + + These are fairly simple approaches and are not completely foolproof. There + are various other configuration options that should be disabled (described + elsewhere here and in the User Manual) + so that users can't modify their own configuration and easily circumvent the + whitelist. + + + + +How can I turn off ad-blocking? + + Ad blocking is achieved through a complex application of various &my-app; + actions. These + actions are deployed against simple images, banners, flash animations, + text pages, JavaScript, pop-ups and pop-unders, etc., so its not as simple as + just turning one or two actions off. The various actions that make up + &my-app; ad blocking are hard-coded into the default configuration files. It + has been assumed that everyone using &my-app; is interested in this + particular feature. + + + If you want to do without this, there are several approaches you can take: + You can manually undo the many block rules in + default.action. Or even easier, just create your own + default.action file from scratch without the many ad + blocking rules, and corresponding exceptions. Or lastly, if you are not + concerned about the additional blocks that are done for privacy reasons, you + can very easily over-ride all blocking with the + following very simple rule in your user.action: + + + + # Unblock everybody, everywhere + { -block } + / # UN-Block *all* URLs + + + Or even a more comprehensive reversing of various ad related actions: + + + + # Unblock everybody, everywhere, and turn off appropriate filtering, etc + { -block \ + -filter{banners-by-size} \ + -filter{banners-by-link} \ + allow-popups \ + } + / # UN-Block *all* URLs and allow ads + + + This last action in this compound statement, + allow-popups, is an alias that disables + various pop-up blocking features. + + + + +How can I have custom template pages, like the +<emphasis>BLOCKED</emphasis> page? + + &my-app; templates are specialized text files utilized by + &my-app; for various purposes and can easily be modified using any text + editor. All the template pages are installed in a sub-directory appropriately + named: templates. Knowing something about HTML syntax + will of course be helpful. + + + Be forewarned that the default templates are subject to being overwritten + during upgrades. You can, however, create completely new templates, + place them in another directory and specify the alternate path in the main + config. For details, have a look at the templdir option. + + + + +How can I remove the <quote>Go There Anyway</quote> link from +the <emphasis>BLOCKED</emphasis> page? + + There is more than one way to do it (although Perl is not involved). + + + Editing the BLOCKED template page (see above) may dissuade some users, but + this method is easily circumvented. Where you need this level of control, you + might want to build &my-app; from source, and disable various features that are + available as compile-time options. You should + configure the sources as follows: + + + + ./configure --disable-toggle --disable-editor --disable-force + + + This will create an executable with hard-coded security features so that + &my-app; does not allow easy bypassing of blocked sites, or changing the + current configuration via any connected user's web browser. + + + Finally, all of these features can also be toggled on/off via options in + Privoxy's main config file which + means you don't have to recompile anything. + + + + + + + + + + +Miscellaneous + + +How much does Privoxy slow my browsing down? This +has to add extra time to browsing. + + How much of an impact depends on many things, including the CPU of the host + system, how aggressive the configuration is, which specific actions are being triggered, + the size of the page, the bandwidth of the connection, etc. + + + Overall, 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 typically being + retrieved and 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 and + other junk content (if ad blocking is being used). + + + + Filtering content via the filter or + deanimate-gifs + actions may cause a perceived slowdown, since the entire document + needs to be buffered before displaying. And on very large documents, + filtering may have some measurable impact. How much depends on the page size, + the actual definition of the filter(s), etc. See below. Most other actions + have little to no impact on speed. + + + Also, when filtering is enabled but zlib support isn't available, compression + is often disabled (see prevent-compression). + This can have an impact on speed as well, although it's probably smaller than + you might think. Again, the page size, etc. will determine how much of an impact. + + + + + +I notice considerable +delays in page requests. 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 typically does not really change much 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 + more noticeable on slower dialup connections. Extremely large documents + may have some impact on the time to load the page where there is filtering + being done. But overall, the difference should be very minimal. If there is a + big impact, then probably some other situation is contributing (like + anti-virus software). + + + Filtering is automatically disabled for inappropriate MIME types. But note + that if the web server mis-reports the MIME type, then content that should + not be filtered, could be. Privoxy only knows how + to differentiate filterable content because of the MIME type as reported by + the server, or because of some configuration setting that enables/disables + filtering. + + + +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. + + + Note that config.privoxy.org resolves to a public IP address. + If you use config.privoxy.org as ping or traceroute target you will + reach the system on the Internet (Privoxy can't intercept ICMP requests). + If you want to ping the system Privoxy runs on, + you should use its IP address or local DNS name (if it has got one). + + + + + +How can I submit new ads, or report +problems? + +Please see the Contact section for +various ways to interact with the developers. + + + + +If I do submit missed ads, will +they be included in future updates? + + Whether such submissions are eventually included in the + default.action configuration file depends on how + significant the issue is. We of course want to address any potential + problem with major, high-profile sites such as Google, + Yahoo, etc. Any site with global or regional reach, + has a good chance of being a candidate. But at the other end of the spectrum + are any number of smaller, low-profile sites such as for local clubs or + schools. Since their reach and impact are much less, they are best handled by + inclusion in the user's user.action, and thus would be + unlikely to be included. + + + + + +Why doesn't anyone answer my support +request? + +Rest assured that it has been read and considered. Why it is not answered, +could be for various reasons, including no one has a good answer for it, no +one has had time to yet investigate it thoroughly, it has been reported +numerous times already, or because not enough information was provided to help +us help you. Your efforts are not wasted, and we do appreciate them. + + + + + +How can I hide my IP address? + + If you run both the browser and &my-app; locally, you cannot hide your IP + address with Privoxy or ultimately any other + software alone. The server needs to know your IP address so that it knows + where to send the responses back. + + + There are many publicly usable "anonymous" proxies out there, which + provide a further level of indirection between you and the web server. + + + However, these proxies are called "anonymous" because you don't need + to authenticate, not because they would offer any real anonymity. + Most of them will log your IP address and make it available to the + authorities in case you violate the law of the country they run in. 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. + + + If you want to hide your IP address from most adversaries, + you should consider chaining Privoxy + with Tor. + The configuration details can be found in + How do I use Privoxy together + with Tor section + just below. + + + + +Can Privoxy guarantee I am anonymous? + + No. Your chances of remaining anonymous are improved, but unless you + chain Privoxy with Tor + or a similar proxy and know what you're doing when it comes to configuring + the rest of your system, you should 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 neither + hides your IP address, nor can it guarantee that the rest of the system + behaves correctly. There are several possibilities how a web sites can find + out who you are, even if you are using a strict Privoxy + configuration and chained it with Tor. + + + Most of Privoxy's privacy-enhancing features can be easily subverted + by an insecure browser configuration, therefore you should use a browser that can + be configured to only execute code from trusted sites, and be careful which sites you trust. + For example there is no point in having Privoxy + modify the User-Agent header, if websites can get all the information they want + through JavaScript, ActiveX, Flash, Java etc. + + + 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! + + + + + +A test site says I am not using a Proxy. + + Good! Actually, they are probably testing for some other kinds of proxies. + Hiding yourself completely would require additional steps. + + + +How do I use Privoxy + together with Tor? + + Before you configure Privoxy to use + Tor, + please follow the User Manual chapters + 2. Installation and + 5. Startup to make sure + Privoxy itself is setup correctly. + + + If it is, refer to Tor's + extensive documentation to learn how to install Tor, + and make sure Tor's logfile says that + Tor has successfully opened a circuit and it + looks like client functionality is working. + + + If either Tor or Privoxy + isn't working, their combination most likely will neither. Testing them on their + own will also help you to direct problem reports to the right audience. + If Privoxy isn't working, don't bother the + Tor developers. If Tor + isn't working, don't send bug reports to the Privoxy Team. + + + If you verified that Privoxy and Tor + are working, it is time to connect them. As far as Privoxy + is concerned, Tor is just another proxy that can be reached + by socks4, socks4a and socks5. Most likely you are interested in Tor + to increase your anonymity level, therefore you should use socks5, to make sure DNS + requests are done through Tor and thus invisible to your + local network. Using socks4a would work too, but with socks5 you get more precise error + messages. + + + + Privoxy's + main configuration file + is already prepared for Tor, if you are using a + default Tor configuration and run it on the same + system as &my-app;, you just have to edit the + forwarding section + and uncomment the line: + + + +# forward-socks5t / 127.0.0.1:9050 . + + + + Note that if you got Tor through one of the bundles, you may + have to change the port from 9050 to 9150 (or even another one). + For details, please check the documentation on the + Tor website. + + + + This is enough to reach the Internet, but additionally you might want to + uncomment the following forward rules, to make sure your local network is still + reachable through Privoxy: + + + +# forward 192.168.*.*/ . +# forward 10.*.*.*/ . +# forward 127.*.*.*/ . + + + + Unencrypted connections to systems in these address ranges will + be as (un)secure as the local network is, but the alternative is + that your browser can't reach the network at all. Then again, + that may actually be desired and if you don't know for sure + that your browser has to be able to reach the local network, + there's no reason to allow it. + + + If you want your browser to be able to reach servers in your local + network by using their names, you will need additional exceptions + that look like this: + + + +# forward localhost/ . + + + + Save the modified configuration file and open + http://config.privoxy.org/show-status + in your browser, confirm that Privoxy has reloaded its configuration + and that there are no other forward lines, unless you know that you need them. If everything looks good, + refer to + Tor + Faq 4.2 to learn how to verify that you are really using Tor. + + + Afterward, please take the time to at least skim through the rest + of Tor's documentation. Make sure you understand + what Tor does, why it is no replacement for + application level security, and why you probably don't want to + use it for unencrypted logins. + + + + +Might some things break because header information or +content is being altered? + + + Definitely. It is common for sites to use browser type, browser version, + HTTP header content, and various other techniques in order to dynamically + decide what to display and how to display it. What you see, and what I see, + might be very different. There are many, many ways that this can be handled, + so having hard and fast rules, is tricky. + + + + The User-Agent is sometimes used in this way to identify + the browser, and adjust content accordingly. + + + + Also, different browsers use different encodings of non-English + 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. The + results of which could inadvertently cause pages to load incorrectly, + partially, or even not at all. And there may be no obvious clues as to just + what went wrong, or why. Nowhere will there be a message that says + Turn off fast-redirects or else! + + + + + 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 Privoxy 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 or + Polipo 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 Privoxy protect me? + + Not in the way you mean, or in the way some firewall vendors claim they can. + Privoxy can help protect your privacy, but can't + protect your system from intrusion attempts. It is, of course, perfectly possible + to use both. + + + + +I have large empty spaces / a checkerboard pattern now where +ads used to be. Why? + + It is technically possible to eliminate banners and ads in a way that frees + their allocated page space. This could easily be done by blocking with + Privoxy's filters, + and eliminating the entire image references from the + HTML page source. + + + But, this would consume considerably more CPU resources (IOW, slow things + down), would likely destroy the layout of some web pages which rely on the + banners utilizing a certain amount of page space, and might fail in other + cases, where the screen space is reserved (e.g. by HTML tables for instance). + Also, making ads and banners disappear without any trace complicates + troubleshooting, and would sooner or later be problematic. + + + The better alternative is to instead let them stay, and block the resulting + requests for the banners themselves as is now the case. This leaves either + empty space, or the familiar checkerboard pattern. + + + So the developers won't support this in the default configuration, but you + can of course define appropriate filters yourself to achieve this. + + + + +How can Privoxy 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. + + + Content cookies (those that are embedded in the actual HTML or + JS page content, see filter{content-cookies}), + in an SSL transaction will be impossible to block under these conditions. + Fortunately, this does not seem to be a very common scenario since most + cookies come by traditional means. + + + + + +Privoxy runs as a <quote>server</quote>. How +secure is it? Do I need to take any special precautions? + + On Unix-like systems, Privoxy can run as a non-privileged + user, which is how we recommend it be run. Also, by default + Privoxy 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. + + + + + +Can I temporarily disable Privoxy? + + &my-app; doesn't have a transparent proxy mode, + but you can toggle off blocking and content filtering. + + + The easiest way to do that is to point your browser + to the remote toggle URL: http://config.privoxy.org/toggle. + + + See the Bookmarklets section + of the User Manual for an easy way to access this + feature. Note that this is a feature that may need to be enabled in the main + config file. + + + + + +When <quote>disabled</quote> is Privoxy totally +out of the picture? + + No, this just means all optional filtering and actions are disabled. + Privoxy is still acting as a proxy, but just + doing less of the things that Privoxy would + normally be expected to do. It is still a middle-man in + the interaction between your browser and web sites. See below to bypass + the proxy. + + + + +How can I tell Privoxy to totally ignore certain sites? + + Bypassing a proxy, or proxying based on arbitrary criteria, is purely a browser + configuration issue, not a &my-app; issue. Modern browsers typically do have + settings for not proxying certain sites. Check your browser's help files. + + + + + +My logs show Privoxy <quote>crunches</quote> +ads, but also its own internal CGI pages. What is a <quote>crunch</quote>? + + A crunch simply means Privoxy intercepted + something, nothing more. Often this is indeed ads or + banners, but Privoxy uses the same mechanism for + trapping requests for its own internal pages. For instance, a request for + Privoxy's configuration page at: http://config.privoxy.org, is + intercepted (i.e. it does not go out to the 'net), and the familiar CGI + configuration is returned to the browser, and the log consequently will show + a crunch. + + + Since version 3.0.7, Privoxy will also log the crunch reason. + If you are using an older version you might want to upgrade. + + + + +Can Privoxy affect files that I download +from a webserver? FTP server? + + From the webserver's perspective, there is no difference between + viewing a document (i.e. a page), and downloading a file. The same is true of + Privoxy. If there is a match for a block pattern, + it will still be blocked, and of course this is obvious. + + + Filtering is potentially more of a concern since the results are not always + so obvious, and the effects of filtering are there whether the file is simply + viewed, or downloaded. And potentially whether the content is some obnoxious + advertisement, or Mr. Jimmy's latest/greatest source code jewel. Of course, + one of these presumably is bad content that we don't want, and + the other is good content that we do want. + Privoxy is blind to the differences, and can only + distinguish good from bad by the configuration parameters + we give it. + + + Privoxy knows the differences in files according + to the Content Type as reported by the webserver. If this is + reported accurately (e.g. application/zip for a zip archive), + then Privoxy knows to ignore these where + appropriate. Privoxy potentially can filter HTML + as well as plain text documents, subject to configuration parameters of + course. Also, documents that are of an unknown type (generally assumed to be + text/plain) can be filtered, as will those that might be + incorrectly reported by the webserver. If such a file is a downloaded file + that is intended to be saved to disk, then any content that might have been + altered by filtering, will be saved too, for these (probably rare) cases. + + + Note that versions later than 3.0.2 do NOT filter document types reported as + text/plain. Prior to this, Privoxy + did filter this document type. + + + In short, filtering is ON if a) the content type as reported + by the webserver is appropriate and b) the configuration + allows it (or at least does not disallow it). That's it. There is no magic + cookie anywhere to say this is good and this is + bad. It's the configuration that lets it all happen or not. + + + If you download text files, you probably do not want these to be filtered, + particularly if the content is source code, or other critical content. Source + code sometimes might be mistaken for Javascript (i.e. the kind that might + open a pop-up window). It is recommended to turn off filtering for download + sites (particularly if the content may be plain text files and you are using + version 3.0.2 or earlier) in your user.action file. And + also, for any site or page where making any changes at + all to the content is to be avoided. + + + Privoxy does not do FTP at all, only HTTP + and HTTPS (SSL) protocols. + + + + +I just downloaded a Perl script, and Privoxy +altered it! Yikes, what is wrong! + + Please read above. + + + + +Should I continue to use a <quote>HOSTS</quote> file for ad-blocking? + + One time-tested technique to defeat common ads is to trick the local DNS + system by giving a phony IP address for the ad generator in the local + HOSTS file, typically using 127.0.0.1, aka + localhost. This effectively blocks the ad. + + + There is no reason to use this technique in conjunction with + Privoxy. Privoxy + does essentially the same thing, much more elegantly and with much more + flexibility. A large HOSTS file, in fact, not only + duplicates effort, but may get in the way and seriously slow down your system. + It is recommended to remove such entries from your HOSTS file. If you think + your hosts list is neglected by Privoxy's + configuration, consider adding your list to your user.action file: + + + + { +block } + www.ad.example1.com + ad.example2.com + ads.galore.example.com + etc.example.com + + + + +Where can I find more information about Privoxy +and related issues? + + &seealso; + + + + + + +I've noticed that Privoxy changes <quote>Microsoft</quote> to +<quote>MicroSuck</quote>! Why are you manipulating my browsing? + + + We're not. The text substitutions that you are seeing are disabled + in the default configuration as shipped. You have either manually + activated the fun filter which + is clearly labeled Text replacements for subversive browsing + fun! or you are using an older Privoxy version and have implicitly + activated it by choosing the Advanced profile in the + web-based editor. Please upgrade. + + + + +Does Privoxy produce <quote>valid</quote> HTML (or XHTML)? + + + Privoxy generates HTML in both its own templates, and possibly + whenever there are text substitutions via a &my-app; filter. While this + should always conform to the HTML 4.01 specifications, it has not been + validated against this or any other standard. + + + + +How did you manage to get Privoxy on my computer without my consent? + + + We didn't. We make Privoxy available for download, but we don't go + around installing it on other people's systems behind their back. + If you discover Privoxy running on your system and are sure you didn't + install it yourself, somebody else did. You may not even be running + the real Privoxy, but maybe something else that only pretends to be + Privoxy, or maybe something that is based on the real Privoxy, + but has been modified. + + + Lately there have been reports of problems with some kind of + "parental control" software based on Privoxy that came preinstalled on + certain ASUS Netbooks. + The problems described are inconsistent with the behaviour of official + Privoxy versions, which suggests that the preinstalled software may + contain vendor modifications that we don't know about and thus can't debug. + + + Privoxy's license allows vendor + modifications, but the vendor has to comply with the license, + which involves informing the user about the changes and to make + the changes available under the same license as Privoxy itself. + + + If you are having trouble with a modified Privoxy version, + please try to talk to whoever made the modifications before + reporting the problem to us. Please also try to convince + whoever made the modifications to talk to us. If you think + somebody gave you a modified Privoxy version without complying + to the license, please let us know. + + + + + + + + + + +Troubleshooting + + +I cannot connect to any websites. Or, I am getting +<quote>connection refused</quote> message with every web page. Why? + + There are several possibilities: + + + + +Privoxy is not running. Solution: verify + that &my-app; is installed correctly, has not crashed, and is indeed running. + Turn on Privoxy's logging, and look at the logs to see what they say. + + Or your browser is configured for a different port than what + Privoxy is using. Solution: verify that &my-app; + and your browser are set to the same port (listen-address). + + Or if using a forwarding rule, you have a configuration problem or a + problem with a host in the forwarding chain. Solution: temporarily alter your + configuration and take the forwarders out of the equation. + + + Or you have a firewall that is interfering and blocking you. Solution: + try disabling or removing the firewall as a simple test. + + + + + + + + +Why am I getting a 503 Error (WSAECONNREFUSED) on every page? + + More than likely this is a problem with your TCP/IP networking. ZoneAlarm has + been reported to cause this symptom -- even if not running! The solution is + to either fight the ZA configuration, or uninstall ZoneAlarm, and then find + something better behaved in its place. Other personal firewall type products + may cause similar type problems if not configured correctly. + + + + +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 involved. Flush 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. Blocking ads is like blocking + spam: a lot of tinkering is required to stay ahead of the game. And + remember you need to block the URL of the ad in question, which may be + entirely different from the site URL itself. Most ads are hosted on different + servers than the main site itself. If you right-click on the ad, you should + be able to get all the relevant information you need. Alternately, you can + find the correct URL by looking at Privoxy's logs + (you may need to enable logging in the main config file if its disabled). + + + Below is a slightly modified real-life log snippet that originates with one + requested URL: www.example.com (name of site was changed + for this example, the number of requests is real). You can see in this the + complexity of what goes into making up this one page. There + are eight different domains involved here, with thirty two separate URLs + requested in all, making up all manner of images, Shockwave Flash, + JavaScript, CSS stylesheets, scripts, and other related content. Some of this + content is obviously good or bad, but not all. + Many of the more questionable looking requests, are going to outside domains + that seem to be identifying themselves with suspicious looking names, making + our job a little easier. &my-app; has crunched (meaning caught + and BLOCKED) quite a few items in this example, but perhaps missed a few as well. + + + + + + + + Despite 12 out of 32 requests being blocked, the page looked, and seemed to + behave perfectly normal (minus some ads, of course). + + + + + +One of my favorite sites does not work with Privoxy. +What can I do? + + + First verify that it is indeed a Privoxy problem, + by toggling off Privoxy through http://config.privoxy.org/toggle + (the toggle feature may need to be enabled in the main + config), + 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 the problem went away, we know we have a configuration related problem. + Now 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. It might be helpful also to look at your logs + for this site too, to see what else might be happening (note: logging may need + to be enabled in the main config file). Many sites are + complex and require a number of related pages to help present their content. + Look at what else might be used by the page in question, and what of that + might be required. + 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, + Troubleshooting: the Anatomy of an Action. + There is also an actions tutorial + with general configuration information and examples. + + + As a last resort, you can always see if your browser has a setting that will + bypass the proxy setting for selective sites. Modern browsers can do this. + + + + + + + +After installing Privoxy, I have to log in +every time I start IE. What gives? + + + This is a quirk that affects the installation of + Privoxy, in conjunction with Internet Explorer and + Internet Connection Sharing on Windows 2000 and Windows XP. The symptoms may + appear to be corrupted or invalid DUN settings, or passwords. + + + + When setting up an NT based Windows system with + Privoxy you may find that things do not seem to be + doing what you expect. When you set your system up you will probably have set + up Internet Connection Sharing (ICS) with Dial up Networking (DUN) when + logged in with administrator privileges. You will probably have made this DUN + connection available to other accounts that you may have set-up on your + system. E.g. Mum or Dad sets up the system and makes accounts suitably + configured for the kids. + + + + When setting up Privoxy in this environment you + will have to alter the proxy set-up of Internet Explorer (IE) for the + specific DUN connection on which you wish to use + Privoxy. When you do this the ICS DUN set-up + becomes user specific. In this instance you will see no difference if you + change the DUN connection under the account used to set-up the connection. + However when you do this from another user you will notice that the DUN + connection changes to make available to "Me only". You will also find that + you have to store the password under each different user! + + + + The reason for this is that each user's set-up for IE is user specific. Each + set-up DUN connection and each LAN connection in IE store the settings for + each user individually. As such this enforces individual configurations + rather than common ones. Hence the first time you use a DUN connection after + re-booting your system it may not perform as you expect, and prompt you for + the password. Just set and save the password again and all should be OK. + + + +[Thanks to Ray Griffith for this submission.] + + + + + + +I cannot connect to any FTP sites. Privoxy + is blocking me. + + Privoxy cannot act as a proxy for FTP traffic, + so do not configure your browser to use Privoxy + as an FTP proxy. The same is true for any protocol other than HTTP + or HTTPS (SSL). + + + Most browsers understand FTP as well as HTTP. If you connect to a site, with + a URL like ftp://ftp.example.com, your browser is making + an FTP connection, and not a HTTP connection. So while your browser may + speak FTP, Privoxy does not, and cannot proxy + such traffic. + + + To complicate matters, some systems may have a generic proxy + setting, which will enable various protocols, including + both HTTP and FTP proxying! So it is possible to + accidentally enable FTP proxying in these cases. And of course, if this + happens, Privoxy will indeed cause problems since + it does not know FTP. Just disable the FTP setting + and all will be well again. + + + Will Privoxy ever proxy FTP traffic? Unlikely. + There just is not much reason, and the work to make this happen is more than + it may seem. + + + + + +In Mac OS X, I can't configure Microsoft Internet Explorer to use + Privoxy as the HTTP proxy. + + Microsoft Internet Explorer (in versions like 5.1) respects system-wide + network settings. In order to change the HTTP proxy, open System + Preferences, and click on the Network icon. In the settings pane that + comes up, click on the Proxies tab. Ensure the "Web Proxy (HTTP)" checkbox + is checked and enter 127.0.0.1 in the entry field. + Enter 8118 in the Port field. The next time you start + IE, it should reflect these values. + + + + + +In Mac OS X, I dragged the Privoxy folder to the trash in order to + uninstall it. Now the finder tells me I don't have sufficient privileges to + empty the trash. + + Note: This ONLY applies to privoxy 3.0.6 and earlier. + + + Just dragging the Privoxy folder to the trash is + not enough to delete it. Privoxy supplies an + uninstall.command file that takes care of + these details. Open the trash, drag the uninstall.command + file out of the trash and double-click on it. You will be prompted for + confirmation and the administration password. + + + The trash may still appear full after this command; emptying the trash + from the desktop should make it appear empty again. + + + + + +In Mac OS X Panther (10.3), images often fail to load and/or I + experience random delays in page loading. I'm using + <literal>localhost</literal> as my browser's proxy setting. + + We believe this is due to an IPv6-related bug in Mac OS X, but don't fully + understand the issue yet. In any case, changing the proxy setting to + 127.0.0.1 instead of localhost + works around the problem. + + + + + +I just upgraded to Mac OS X 10.9 (Mavericks) and now &my-app; has stopped + working. + + The upgrade process to Mac OS X Mavericks (10.9) from an earlier version of OS + X deletes all user accounts that are either not part of OS X itself or are + not interactive user accounts (ones you log in with). Since, for the sake of + security, &my-app; runs as a non-privileged user that is created by its + installer (_privoxy), it can no longer start up once that account gets deleted. + The solution is to perform a complete uninstall using the supplied + uninstall.command script (either back up your + configuration files or select to not have the uninstaller remove them when it + prompts you) and then reinstall &my-app; using the installer package and merge + in your configuration. + + + + + + +I get a completely blank page at one site. <quote>View Source</quote> + shows only: <markup><![CDATA[<html><body></body></html>]]></markup>. Without + Privoxy the page loads fine. + + Chances are that the site suffers from a bug in + PHP, + which results in empty pages being sent if the client explicitly requests + an uncompressed page, like Privoxy does. + This bug has been fixed in PHP 4.2.3. + + + To find out if this is in fact the source of the problem, try adding + the site to a -prevent-compression section in + user.action: + + + # Make exceptions for ill-behaved sites: + # + {-prevent-compression} + .example.com + + If that works, you may also want to report the problem to the + site's webmasters, telling them to use zlib.output_compression + instead of ob_gzhandler in their PHP applications (workaround) + or upgrade to PHP 4.2.3 or later (fix). + + + + +My logs show many <quote>Unable to get my own hostname</quote> lines. +Why? + + Privoxy tries to get the hostname of the system + its running on from the IP address of the system interface it is bound to + (from the config file + listen-address setting). If the system cannot supply + this information, Privoxy logs this condition. + + + Typically, this would be considered a minor system configuration error. It is + not a fatal error to Privoxy however, but may + result in a much slower response from Privoxy on + some platforms due to DNS timeouts. + + + This can be caused by a problem with the local hosts + file. If this file has been changed from the original, try reverting it to + see if that helps. Make sure whatever name(s) are used for the local system, + that they resolve both ways. + + + You should also be able to work around the problem with the + hostname option. + + + + +When I try to launch Privoxy, I get an +error message <quote>port 8118 is already in use</quote> (or similar wording). +Why? + + Port 8118 is Privoxy's default TCP + listening port. Typically this message would mean that there + is already one instance of Privoxy running, and + your system is actually trying to start a second + Privoxy on the same port, which will not work. + (You can have multiple instances but they must be assigned different ports.) + How and why this might happen varies from platform to platform, but you need + to check your installation and start-up procedures. + + + + + + Pages with UTF-8 fonts are garbled. + + + This may be the result of an overly aggressive filter. The filters that + are enabled in the default configuration aren't expected to cause problems + like this. If you enabled the demoronizer filter, please + try temporarily disabling it. + + + If that doesn't help, temporarily disable all filters to see if another + filter could be the culprit. If the problem disappears, enable the filters + one by one, until the problem reappears and the offending filter is found. + + + Once the problem-causing filter is known, it can be fixed or disabled. + + + Upgrading Privoxy, or going to the most recent + default.action file available from SourceForge + might be worth a try, too. + + + + + + Why are binary files (such as images) corrupted when Privoxy + is used? + + + This may also be caused by an (overly aggressive + filter in conjunction with a web server that is misreporting the content + type. By default binary files are exempted from + Privoxy's filtering + (unless the web server by mistake says the file is something else). + + + + + + What is the <quote>demoronizer</quote> and why is it there? + + + The original demoronizer was a Perl script that cleaned up HTML pages which + were created with certain Microsoft products. MS has used proprietary extensions + to standardized font encodings (ISO 8859-1), which has caused problems for pages + that are viewed with non-Microsoft products (and are expecting to see a + standard set of fonts). The demoronizer corrected these errors so the pages + displayed correctly. Privoxy borrowed from this + script, introducing a filter based on the original demoronizer, which in turn could + correct these errors on the fly. + + + But this is only needed in some situations, and will cause serious problems in some + other situations. + + + If you are using Microsoft products, you do not need it. If you need to view + pages with UTF-8 characters (such as Cyrillic or Chinese), then it will + cause corruption of the fonts, and thus should not be on. + + + On the other hand, if you use non-Microsoft products, and you occasionally + notice weird characters on pages, you might want to try it. + + + + + + Why do I keep seeing <quote>PrivoxyWindowOpen()</quote> in raw source code? + + + Privoxy is attempting to disable malicious + Javascript + in this case, with the unsolicited-popups + filter. Privoxy cannot tell very well + good code snippets from bad code snippets. + + + If you see this in HTML source, and the page displays without problems, then + this is good, and likely some pop-up window was disabled. If you see this + where it is causing a problem, such as a downloaded program source code file, + then you should set an exception for this site or page such that the + integrity of the page stays in tact by disabling all filtering. + + + + + + I am getting too many DNS errors like <quote>404 No Such Domain</quote>. Why + can't Privoxy do this better? + + + There are potentially several factors here. First of all, the DNS resolution + is done by the underlying operating system -- not + Privoxy itself. Privoxy + merely initiates the process and hands it off, and then later reports + whatever the outcome was and tries to give a coherent message if there seems + to be a problem. In some cases, this might otherwise be mitigated by the + browser itself which might try some work-arounds and alternate approaches (e.g + adding www. to the URL). + + + In other cases, if Privoxy is being chained + with another proxy, this could complicate the issue, and cause undue + delays and timeouts. In the case of a socks4a proxy, the socks + server handles all the DNS. Privoxy would just be + the messenger which is reporting whatever problem occurred + downstream, and not the root cause of the error. + + + In any case, versions newer than 3.0.3 include various improvements to help + Privoxy better handle these cases. +]]> + + + + + At one site Privoxy just hangs, and starts taking + all CPU. Why is this? + + + This is probably a manifestation of the 100% cpu problem that + occurs on pages containing many (thousands upon thousands) of blank lines. The blank lines + are in the raw HTML source of the page, and the browser just ignores them. But the + pattern matching in Privoxy's page filtering + mechanism is trying to match against absurdly long strings and this becomes + very CPU-intensive, taking a long, long time to complete. + + + Until a better solution comes along, disable filtering on these pages, + particularly the js-annoyances and + unsolicited-popups filters. If you run into this problem + with a recent &my-app; version, please send a problem report. + + + + +I just installed Privoxy, and all my +browsing has slowed to a crawl. What gives? + + This should not happen, and for the overwhelming number of users world-wide, + it does not happen. I would suspect some inadvertent interaction of software + components such as anti-virus software, spyware protectors, personal + firewalls or similar components. Try disabling (or uninstalling) these one + at a time and see if that helps. Either way, if you are using a + recent &my-app; version, please report the problem. + + + + +Why do my filters work on some sites but not on others? + + It's probably due to compression. It is a common practice for web servers to + send their content compressed in order to speed things up, and + then let the browser uncompress them. When compiled with zlib support + &my-app; can decompress content before filtering, otherwise you may want to enable +prevent-compression. + + + As of &my-app; 3.0.9, zlib support is enabled in the default builds. + + + + + +On some HTTPS sites my browser warns me about unauthenticated content, + the URL bar doesn't get highlighted and the lock symbol appears to be broken. + What's going on? + + Probably the browser is requesting ads through HTTPS and &my-app; + is blocking the requests. Privoxy's error messages are delivered + unencrypted and while it's obvious for the browser that the HTTPS + request is already blocked by the proxy, some warn about unauthenticated + content anyway. + + + To work around the problem you can redirect those requests to an invalid + local address instead of blocking them. While the redirects aren't + encrypted either, many browsers don't care. They simply follow the + redirect, fail to reach a server and display an error message instead + of the ad. + + + To do that, enable logging to figure out which requests get blocked by + &my-app; and add the hosts (no path patterns) to a section like this: + + + + + + + + Additionally you have to configure your browser to contact + 127.0.0.1:0 directly (instead of through &my-app;). + + + To add a proxy exception in Mozilla Firefox + open the Preferences, click the Settings + button located on the Network tab in the Advanced + section, and add 127.0.0.1:0 in the No Proxy for: + field. + + + + + +I get selinux error messages. How can I fix this? + + Please report the problem to the creator of your selinux policies. + + + The problem is that some selinux policy writers aren't familiar + with the application they are trying to secure and + thus create policies that make no sense. + + + In Privoxy's case the problem usually + is that the policy only allows outgoing connections for certain + destination ports (e.g. 80 and 443). While this may cover the + standard ports, websites occasionally use other ports as well. + This isn't a security problem and therefore Privoxy's + default configuration doesn't block these requests. + + + If you really want to block these ports (and don't be able + to load websites that don't use standard ports), you should + configure Privoxy to block these ports as well, so it doesn't + trigger the selinux warnings. + + + + + +I compiled &my-app; with Gentoo's portage and it appears to be very slow. Why? + + Probably you unintentionally compiled &my-app; without threading support + in which case requests have to be serialized and only one can be served + at the same time. + + + Check your USE flags and make sure they include + threads. If they don't, add the flag and rebuild &my-app;. + + + If you compiled &my-app; with threading support (on POSIX-based systems), + the Conditional #defines section on http://config.privoxy.org/show-status + will list FEATURE_PTHREAD as enabled. + + + + +What are tainted sockets and how do I prevent them? + + &my-app; marks sockets as tainted when it can't use them to + serve additional requests. + This does not necessarily mean that something went wrong and + information about tainted sockets is only logged if connection + debugging is enabled (debug 2). + + + For example server sockets that were used for CONNECT requests + (which are used to tunnel https:// requests) are considered tainted + once the client closed its connection to &my-app;. + Technically &my-app; could keep the connection to the server open, + but the server would not accept requests that do not belong to the + previous TLS/SSL session (and the client may even have terminated + the session). + + + Server sockets are also marked tainted when a client requests a + resource, but closes the connection before &my-app; has completely + received (and forwarded) the resource to the client. + In this case the server would (probably) accept additional requests, + but &my-app; could not get the response without completely reading + the leftovers from the previous response. + + + These are just two examples, there are currently a bit more than + 25 scenarios in which a socket is considered tainted. + + + While sockets can also be marked tainted as a result of a technical + problem that may be worth fixing, the problem will be explicitly + logged as error. + + + + + + + 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; + + + + + + + + + + + + + + +