1 Privoxy Frequently Asked Questions
5 $Id: faq.sgml,v 1.52 2002/04/29 03:08:43 hal9 Exp $
7 This FAQ gives users and developers alike answers to frequently asked questions
10 Privoxy is a web proxy with advanced filtering capabilities for protecting
11 privacy, filtering web page content, managing cookies, controlling access, and
12 removing ads, banners, pop-ups and other obnoxious Internet junk. Privoxy has a
13 very flexible configuration and can be customized to suit individual needs and
14 tastes. Privoxy has application for both stand-alone systems and multi-user
17 Privoxy is based on Internet Junkbuster (tm).
19 You can find the latest version of the document at http://www.privoxy.org/faq/.
20 Please see the Contact section if you want to contact the developers.
22 -------------------------------------------------------------------------------
26 1. General Information
28 1.1. What is this new version of Privoxy?
29 1.2. Why "Privoxy"? Why a name change at all?
30 1.3. How does Privoxy differ from the old Junkbuster?
31 1.4. What are some of the new features?
32 1.5. What is a "proxy"? How does Privoxy work?
33 1.6. How does Privoxy know what is an ad, and what is not?
34 1.7. Can Privoxy make mistakes? This does not sound very scientific.
35 1.8. My browser does the same things as Privoxy. Why should I use Privoxy
37 1.9. Is there is a license or fee? What about a warranty? Registration?
38 1.10. I would like to help you, what do I do?
40 1.10.1. Money Money Money
41 1.10.2. You want to work with us?
45 2.1. Which browsers are supported by Privoxy?
46 2.2. Which operating systems are supported?
47 2.3. Can I install Privoxy over Junkbuster?
48 2.4. I just installed Privoxy. Is there anything special I have to do now?
49 2.5. What is the proxy address of Privoxy?
50 2.6. I just installed Privoxy, and nothing is happening. All the ads are
55 3.1. Can I use my old config files?
56 3.2. What is an "actions" file?
57 3.3. The "actions" concept confuses me. Please list some of these
59 3.4. How are actions files configured? What is the easiest way to do this?
60 3.5. There are several different "actions" files. What are the differences?
61 3.6. Why can I change the configuration with a browser? Does that not raise
63 3.7. What is "default.filter"?
64 3.8. How can I set up Privoxy to act as a proxy for my LAN?
65 3.9. Instead of ads, now I get a checkerboard pattern. I don't want to see
67 3.10. Why would anybody want to see a checkerboard pattern?
68 3.11. I see large red banners on some pages that say "Blocked". Why and how
70 3.12. I cannot see all of the "Blocked" page banner. Help.
71 3.13. Can Privoxy run as a service on Win2K/NT?
72 3.14. How can I make Privoxy work with other proxies like Squid?
76 4.1. How much does Privoxy slow my browsing down? This has to add extra
78 4.2. I noticed considerable delays in page requests compared to the old
79 Junkbuster. What's wrong?
80 4.3. What is the "http://p.p/"?
81 4.4. Do you still maintain the blocklists?
82 4.5. How can I submit new ads?
83 4.6. How can I hide my IP address?
84 4.7. Can Privoxy guarantee I am anonymous?
85 4.8. Might some things break because header information is being altered?
86 4.9. Can Privoxy act as a "caching" proxy to speed up web browsing?
87 4.10. What about as a firewall? Can Privoxy protect me?
88 4.11. The Privoxy logo that replaces ads is very blocky and ugly looking.
89 Can't a better font be used?
90 4.12. I have large empty spaces now where ads used to be. Why?
91 4.13. How can Privoxy filter Secure (HTTPS) URLs?
92 4.14. Privoxy runs as a "server". How secure is it? Do I need to take any
94 4.15. How can I temporarily disable Privoxy?
95 4.16. Where can I find more information about Privoxy and related issues?
99 5.1. I just upgraded and am getting "connection refused" with every web
101 5.2. I just added a new rule, but the steenkin ad is still getting through.
103 5.3. One of my favorite sites does not work with Privoxy. What can I do?
105 7. Contacting the developers, Bug Reporting and Feature Requests
109 7.3. Request new features
110 7.4. Report ads or other filter problems
113 8. Copyright and History
118 -------------------------------------------------------------------------------
120 1. General Information
122 1.1. What is this new version of Privoxy?
124 The original Internet Junkbuster™ (tm) is a copyrighted product of
125 Junkbusters Corporation. Development of this effort stopped some time ago as of
126 version 2.0.2. Stefan Waldherr started the ijbswa project on Sourceforge to
127 rekindle development. Other developers subsequently joined with Stefan, and
128 have since added many new features, refinements and enhancements. The result of
129 this effort is Privoxy.
131 Privoxy has evolved from the Junkbuster 2.0.2 code base, and has advanced
132 significantly at this point.
134 Please see the History section for more information on the history of
135 Junkbuster and Privoxy.
137 -------------------------------------------------------------------------------
139 1.2. Why "Privoxy"? Why a name change at all?
141 Privoxy is the "Privacy Enhancing Proxy".
143 There are potential legal complications from the continued use of the
144 Junkbuster name, which is a registered trademark of Junkbusters Corporation.
145 And thus they "own" the rights to the name. (There are, however, no objections
146 from Junkbusters Corporation to the Privoxy project itself, and they, in fact,
147 still share our ideals and goals.)
149 The developers also believed that there are so many changes from the original
150 code, that it was time to make a clean break from the past and make a name in
151 their own right, especially now with the pending release of version 3.0.
153 -------------------------------------------------------------------------------
155 1.3. How does Privoxy differ from the old Junkbuster?
157 Privoxy picks up where Junkbuster left off. All the old features remain. The
158 new Privoxy still blocks ads and banners, still manages cookies, and still
159 helps protect your privacy. But, these are all enhanced, and many new features
160 have been added, all in the same vein.
162 The configuration has changed significantly as well. This is something that
163 users will notice right off the bat if you are upgrading from Junkbuster 2.0.x.
164 The "blocklist" file does not exist any more. This is replaced by "actions"
165 files, such as default.actions. This is where most of the per site
166 configuration is now.
168 -------------------------------------------------------------------------------
170 1.4. What are some of the new features?
172 * FIXME: complete the list of features. change the order: most important
173 features to the top of the list. prefix new features with "NEW".
175 * Integrated browser based configuration and control utility at http://
176 config.privoxy.org/ (shortcut: http://p.p/). Browser-based tracing of rule
177 and filter effects. Remote toggling.
179 * Blocking of annoying pop-up browser windows.
181 * HTTP/1.1 compliant (but not all optional 1.1 features are supported).
183 * Support for Perl Compatible Regular Expressions in the configuration files,
184 and generally a more sophisticated and flexible configuration syntax over
189 * Web page content filtering (removes banners based on size, invisible
190 "web-bugs", JavaScript and HTML annoyances, pop-ups, etc.)
192 * Bypass many click-tracking scripts (avoids script redirection).
194 * Multi-threaded (POSIX and native threads).
196 * Auto-detection and re-reading of config file changes.
198 * User-customizable HTML templates (e.g. 404 error page).
200 * Improved cookie management features (e.g. session based cookies).
202 * Improved signal handling, and a true daemon mode (Unix).
204 * Every feature now controllable on a per-site or per-location basis,
205 configuration more powerful and versatile over-all.
207 * Many smaller new features added, limitations and bugs removed, and security
210 -------------------------------------------------------------------------------
212 1.5. What is a "proxy"? How does Privoxy work?
214 When you connect to a web site with Privoxy, you are really connecting to your
215 locally running version of Privoxy. Privoxy intercepts your requests for the
216 web page, and relays that to the "real" web site. The web site sends the HTTP
217 data stream back to Privoxy, where Privoxy can work its magic before it relays
218 this data back to your web browser.
220 Since Privoxy sits between you and the WWW, it is in a position to intercept
221 and completely manage all web traffic and HTTP content before it gets to your
222 browser. Privoxy uses various programming methods to do this, all of which is
223 under your control via the various configuration files and options.
225 There are many kinds of proxies. Privoxy best fits the "filtering proxy"
228 -------------------------------------------------------------------------------
230 1.6. How does Privoxy know what is an ad, and what is not?
232 Privoxy processes all the raw content of every web page. So it reads everything
233 on each page. It then compares this to the rules as set up in the configuration
234 files, and looks for any matches to these rules. Privoxy makes heavy use of
235 "regular expressions". (If you are not familiar with regular expressions, it is
236 explained briefly in the user manual.) Regular expressions facilitate matching
237 of one text string against another, using wildcards to build complex patterns.
238 So Privoxy will typically look for URLs and other content that match certain
239 key words and expressions as defined in the configuration files. For instance a
240 URL that contains "/banners", has a high probability of containing ad banners,
241 and thus would be a prime candidate to have a matching rule.
243 So Privoxy will look for these kinds of obvious looking culprits. And also,
244 will use lists of known organizations that specialize in ads. Again, using
245 complex patterns to match as many potential combinations as possible since
246 there tend to be many, many variations used by advertisers, and new ones are
247 being introduced all the time.
249 -------------------------------------------------------------------------------
251 1.7. Can Privoxy make mistakes? This does not sound very scientific.
253 Actually, it's a black art ;-) And yes, it is always possible to have a broad
254 rule accidentally block something by mistake. There is a good chance you may
255 run into such a situation at some point. It is tricky writing rules to cover
256 every conceivable possibility, and not occasionally get false positives.
258 But this should not be a big concern since the Privoxy configuration is very
259 flexible, and includes tools to help identify these types of situations so they
260 can be addressed as needed, allowing you to customize your installation. (See
261 the Troubleshooting section below.)
263 -------------------------------------------------------------------------------
265 1.8. My browser does the same things as Privoxy. Why should I use Privoxy at
268 Modern browsers do indeed have some of the same functionality as Privoxy. Maybe
269 this is adequate for you. But Privoxy is much more versatile and powerful, and
270 can do a number of things that browsers just can't.
272 In addition, a proxy is good choice if you use multiple browsers, or have a LAN
273 with multiple computers. This way all the configuration is in one place, and
274 you don't have to maintain a similar configuration for possibly many browsers.
276 -------------------------------------------------------------------------------
278 1.9. Is there is a license or fee? What about a warranty? Registration?
280 Privoxy is licensed under the GNU General Public License (GPL). It is free to
281 use, copy, modify or distribute as you wish under the terms of this license.
282 Please see the Copyright section for more information on the license and
285 There is no warranty of any kind, expressed, implied or otherwise. That is
286 something that would cost real money ;-) There is no registration either.
287 Privoxy really is free in every respect!
289 -------------------------------------------------------------------------------
291 1.10. I would like to help you, what do I do?
293 1.10.1. Money Money Money
295 We, of course, welcome donations and use the money for domain registering,
296 regular world-wide get-togethers (hahaha). Anyway, we'll soon describe the
297 process how to donate money to the team.
299 -------------------------------------------------------------------------------
301 1.10.2. You want to work with us?
303 Well, helping the team is always a good idea. We welcome new developers, RPM
304 gurus or documentation makers. Simply get an account on sourceforge.net and
305 mail your id to the developer mailing list. Then read the section Quickstart in
306 the Developer's Manual.
308 Once we have added you to the team, you'll have write access to the CVS
309 repository, and together we'll find a suitable task for you.
311 -------------------------------------------------------------------------------
315 2.1. Which browsers are supported by Privoxy?
317 Any browser that can be configured to use a "proxy", which should be virtually
318 all browsers. Direct browser support is not necessary since Privoxy runs as a
319 separate application and just exchanges standard HTML data with your browser,
320 just like a web server does.
322 -------------------------------------------------------------------------------
324 2.2. Which operating systems are supported?
326 At present, Privoxy is known to run on Windows(95, 98, ME, 2000, XP), Linux
327 (RedHat, Suse, Debian), Mac OSX, OS/2, AmigaOS, FreeBSD, NetBSD, BeOS, and many
328 more flavors of Unix.
330 But any operating system that runs TCP/IP, can conceivably take advantage of
331 Privoxy in a networked situation where Privoxy would run as a server on a LAN
332 gateway. Then only the "gateway" needs to be running one of the above operating
335 Source code is freely available, so porting to other operating systems, is
336 always a possibility.
338 -------------------------------------------------------------------------------
340 2.3. Can I install Privoxy over Junkbuster?
342 We recommend you uninstall Junkbuster first to minimize conflicts and
343 confusion. You may want to save your old configuration files for future
344 reference. The configuration is substantially changed.
346 See the user-manual for platform specific installation instructions.
348 Note: Some installers may automatically uninstall Junkbuster, if present!
350 -------------------------------------------------------------------------------
352 2.4. I just installed Privoxy. Is there anything special I have to do now?
354 All browsers must be told to use Privoxy as a proxy by specifying the correct
355 proxy address and port number in the appropriate configuration area for the
356 browser. See below. Also, you should flush your browser's memory and disk cache
357 to get rid of any cached items.
359 -------------------------------------------------------------------------------
361 2.5. What is the proxy address of Privoxy?
363 If you set up the Privoxy to run on the computer you browse from (rather than
364 your ISP's server or some networked computer on a LAN), the proxy will be on
365 "localhost" (which is the special name used by every computer on the Internet
366 to refer to itself) and the port will be 8118 (unless you have Privoxy to run
367 on a different port with the listen-address config option).
369 When configuring your browser's proxy settings you typically enter the word
370 "localhost" in the boxes next to "HTTP" and "Secure" (HTTPS) and then the
371 number "8118" for "port". This tells your browser to send all web requests to
372 Privoxy instead of directly to the Internet.
374 Privoxy can also be used to proxy for a Local Area Network. In this case, your
375 would enter either the IP address of the LAN host where Privoxy is running, or
376 the equivalent hostname. Port assignment would be same as above.
378 Privoxy does not currently handle protocols such as FTP, SMTP, IM, IRC, ICQ, or
379 other Internet protocols.
381 -------------------------------------------------------------------------------
383 2.6. I just installed Privoxy, and nothing is happening. All the ads are there.
386 Did you configure your browser to use Privoxy as a proxy? It does not sound
387 like it. See above. You might also try flushing the browser's caches to force a
388 full re-reading of pages. You can verify that Privoxy is running, and your
389 browser is correctly configured by entering the special URL: http://p.p/. This
390 should give you a banner that says "This is Privoxy" and access to Privoxy's
391 internal configuration. If you see this, then you are good to go. If not, the
392 browser or Privoxy are not set up correctly.
394 -------------------------------------------------------------------------------
398 3.1. Can I use my old config files?
400 There are major changes to Junkbuster/ Privoxy configuration from version 2.0.x
401 to 2.9.x and later. Most of the older files will not work at all. This is
402 especially true of blocklist. If this is the case, you will need to re-enter
403 your old data into the new configuration structure. This is probably also a
404 good recommendation even if upgrading from 2.9.x to 3.x since there were many
405 minor changes along the way.
407 -------------------------------------------------------------------------------
409 3.2. What is an "actions" file?
411 "actions" files are where various actions that Privoxy might take, are
412 configured. Typically, you would define a set of default actions that apply to
413 all URLs, then add exceptions to these defaults where needed.
415 Actions can be defined on a per site basis, or for groups of sites. Actions can
416 also be grouped together and then applied to one or more sites. There are many
417 possible actions that might apply to any given site. As an example, if we are
418 blocking cookies as one of our default actions, but need to accept cookies from
419 a given site, we would define this in our "actions" file.
421 -------------------------------------------------------------------------------
423 3.3. The "actions" concept confuses me. Please list some of these "actions".
425 These are all explained in the user-manual. Please refer to that.
427 -------------------------------------------------------------------------------
429 3.4. How are actions files configured? What is the easiest way to do this?
431 The easiest way to do this, is to access Privoxy with your web browser at http:
432 //p.p/, and then select "View & change the current configuration" from the
433 selection list. You can also do this by editing the appropriate file with a
436 Please see the user-manual for a detailed explanation of these and other
437 configuration files, and their various options and syntax.
439 -------------------------------------------------------------------------------
441 3.5. There are several different "actions" files. What are the differences?
443 As of Privoxy v2.9.15, three actions files are being included, to be used for
444 different purposes. These are default.action, standard.action, and user.action.
445 Please see the User Manual for an explanation of each.
447 Earlier versions included three different versions default.action files. The
448 new scheme allows for greater flexibility of local configuration, and for
449 browser based configuration.
451 -------------------------------------------------------------------------------
453 3.6. Why can I change the configuration with a browser? Does that not raise
456 What I don't understand, is how I can browser edit the config file as a regular
457 user, while the whole /etc/privoxy hierarchy belongs to the user "privoxy",
458 with only 644 permissions.
460 When you use the browser-based editor, Privoxy itself is writing to the config
461 files. Because Privoxy is running as the user "privoxy", it can update the
464 If you don't like this, setting "enable-edit-actions 0" in the config file will
465 disable the browser-based editor. If you're that paranoid, you should also
466 consider setting "enable-remote-toggle 0" to prevent browser-based enabling/
467 disabling of Privoxy.
469 Note that normally only local users can connect to Privoxy, so this is not
470 (normally) a security problem.
472 -------------------------------------------------------------------------------
474 3.7. What is "default.filter"?
476 The "default.filter" file is where "filters" are defined, which are used to
477 "filter" any web page content. By "filtering" we mean it can modify, remove, or
478 change anything on the page, including HTML tags, and JavaScript. Regular
479 expressions are used to accomplish this, and operate on a line by line basis.
480 This is potentially a very powerful feature, but requires some expertise.
482 If you are familiar with regular expressions, and HTML, you can look at the
483 provided default.filter with a text editor and see some of things it can be
486 Presently, there is no GUI editor option for this part of the configuration,
487 but you can disable/enable various sections of the included default file with
488 the "View & change the current configuration" from your browser.
490 -------------------------------------------------------------------------------
492 3.8. How can I set up Privoxy to act as a proxy for my LAN?
494 By default, Privoxy only responds to requests from localhost. To have it act as
495 a server for a network, this needs to be changed in the main config file where
496 the Privoxy configuration is located. In that file is a "listen-address"
497 option. It may be commented out with a "#" symbol. Make sure it is uncommented,
498 and assign it the address of the LAN gateway interface, and port number to use:
500 listen-address 192.168.1.1:8118
502 Save the file, and restart Privoxy. Configure all browsers on the network then
503 to use this address and port number.
505 -------------------------------------------------------------------------------
507 3.9. Instead of ads, now I get a checkerboard pattern. I don't want to see
510 This is a configuration option for images that Privoxy is stopping. You have
511 the choice of a checkerboard pattern, a transparent 1x1 GIF image (aka
512 "blank"), or a custom URL of your choice. Note that to fit this category, the
513 URL must match both the "+handle-as-image" and "+block" actions.
515 If you want to see nothing, then change the "+set-image-blocker" action to
516 "+image-blocker{blank}". This can be done from the "View & change the current
517 configuration" selection at http://p.p/. Or by hand editing the appropriate
518 actions file. This will only effect what is defined as "images" though. Also,
519 some URLs that generate the bright red "Blocked" banner, can be moved to the
520 "+set-image-blocker" section for the same reason, but there are some limits and
521 risks to this (see below).
523 -------------------------------------------------------------------------------
525 3.10. Why would anybody want to see a checkerboard pattern?
527 This can be helpful for troubleshooting problems. It might also be good for
528 anyone new to Privoxy so that they can see if their favorite pages are
529 displaying correctly, and Privoxy is not inadvertently removing something
532 -------------------------------------------------------------------------------
534 3.11. I see large red banners on some pages that say "Blocked". Why and how do
537 These are URLs that match something in one of Privoxy's block actions ("+block"
538 ). It is meant to be a warning so that you know something has been blocked and
539 an easy way for you to see why. These are handled differently than what has
540 been defined explicitly as "images" (e.g. ads that are GIF image files).
541 Depending on the URL itself, it is sometimes hard for Privoxy to really know
542 whether there is indeed an ad image there or not. And there are limitations as
543 to what Privoxy can do to "fool" the browser.
545 For instance, if the ad is in a frame, then it is embedded in the separate HTML
546 page used for the frame. In this case, you cannot just substitute an aribitrary
547 image (like we would for a "blank" image), for an HTML page. The browser is
548 expecting an HTML page, and that is what it must have for frames. Such
549 situations can be a little trickier to deal with, and Privoxy may show the
550 "Blocked" page, despite your best efforts.
552 If you want these to be treated as if they were images, so that they can be
553 made invisible, you can try moving the offending URL from the "+block" section
554 to the "+imageblock" section of your actions file. Just be forewarned, if any
555 URL is made "invisible", you may not have any inkling that something has been
556 removed from that page, or why. If this approach does not work, then you are
557 probably dealing with a frame (or "ilayer"), and the only thing that can go
558 there is an HTML page of some sort.
560 To deal with this situation, you could modify the "block" HTML template that is
561 used by Privoxy to display this, and make it something more to your liking.
562 Currently, there is no configuration option for this. You will have to modify,
563 or create your own page, and use this to replace templates/blocked, which is
564 what Privoxy uses to display the "Blocked" page.
566 Another way to deal with this is find why and where Privoxy is blocking the
567 frame, and diable this. Then let the "+set-image-blocker" action handle the ad
568 that is embedded in the frame's HTML page.
570 -------------------------------------------------------------------------------
572 3.12. I cannot see all of the "Blocked" page banner. Help.
574 There is not enough available space to fit the entire Blocked page. Try right
575 clicking on the visible portion, and select "Show Frame", or equivalent. This
576 will usually allow you to see the entire Privoxy "Blocked" page, and from there
577 you can see just what is being blocked, and why.
579 As of Privoxy 2.9.14, the Blocked banner page is re-sizeable, and tries to
580 adjust to the allotted space. There may be occassions where there just isn't
581 enough room to display much of anything useful though.
583 -------------------------------------------------------------------------------
585 3.13. Can Privoxy run as a service on Win2K/NT?
587 Yes, it can run as a system service using srvany.exe. The only catch is that
588 this will effectively disable the Privoxy icon in the taskbar. You can have one
589 or the other, but not both at this time :(
591 There is a pending feature request for this functionality. See thread: http://
592 sourceforge.net/tracker/?func=detail&atid=361118&aid=485617&group_id=11118, for
593 details, and a sample configuration.
595 -------------------------------------------------------------------------------
597 3.14. How can I make Privoxy work with other proxies like Squid?
599 This can be done. See the user manual, which describes how to do this.
601 -------------------------------------------------------------------------------
605 4.1. How much does Privoxy slow my browsing down? This has to add extra time to
608 It should not slow you down any in real terms, and may actually help speed
609 things up since ads, banners and other junk are not being displayed. The actual
610 processing time required by Privoxy itself for each page, is relatively small
611 in the overall scheme of things, and happens very quickly. This is typically
612 more than offset by time saved not downloading and rendering ad images.
614 "Filtering" via the filterfile mechanism may cause a perceived slowdown, since
615 the entire page is buffered before displaying. See below.
617 -------------------------------------------------------------------------------
619 4.2. I noticed considerable delays in page requests compared to the old
620 Junkbuster. What's wrong?
622 The entire page content must be loaded into memory in order for the filtering
623 mechanism to work, and nothing is sent to the browser during this time. The
624 loading time does not really change in real numbers, but the feeling is
625 different, because most browsers are able to start rendering incomplete
626 content, giving the user a feeling of "it works".
628 To modify the content of a page (i.e. make frames resizeable again, etc.) and
629 not just replace ads, Privoxy needs to download the entire page first, do its
630 content magic and then send the page to the browser.
632 -------------------------------------------------------------------------------
634 4.3. What is the "http://p.p/"?
636 Since Privoxy sits between your web browser and the Internet, it can be
637 programmed to handle certain pages specially.
639 With recent versions of Privoxy (version 2.9.x and greater), you can get some
640 information about Privoxy and change some settings by going to http://p.p/ or,
641 equivalently, http://config.privoxy.org/ (Note that p.p is far easier to type
642 but may not work in some configurations. With the name change to Privoxy, this
643 is changed from the previous http://i.j.b/ and earlier 2.9.x versions).
645 These pages are not forwarded to a server on the Internet - instead they are
646 handled by a special web server which is built in to Privoxy.
648 If you are not running Privoxy, then http://p.p/ will fail, and http://
649 config.privoxy.org/ will return a web page telling you you're not running
652 If you have version 2.0.2, then the equivalent is http://example.com/
653 show-proxy-args (but you get far less information, and you should really
654 consider upgrading to 2.9.14).
656 -------------------------------------------------------------------------------
658 4.4. Do you still maintain the blocklists?
660 No, not by this name. The format of the blocklists has changed significantly in
661 versions 2.9.x and later. This functionality is done by the "actions" file now.
662 See next question ...
664 -------------------------------------------------------------------------------
666 4.5. How can I submit new ads?
668 Please see the Contact section.
670 This process does not work with earlier versions of Privoxy or Junkbuster.
672 -------------------------------------------------------------------------------
674 4.6. How can I hide my IP address?
676 You cannot hide your IP address with Privoxy or any other software, since the
677 server needs to know your IP address to send the answers back to you.
679 Fortunately there are many publicly usable anonymous proxies out there, which
680 solve the problem by providing a further level of indirection between you and
681 the web server, shared by many people and thus letting your requests "drown" in
682 white noise of unrelated requests as far as user tracking is concerned.
684 Most of them will, however, log your IP address and make it available to the
685 authorities in case you abuse that anonymity for criminal purposes. In fact you
686 can't even rule out that some of them only exist to *collect* information on
687 (those suspicious) people with a more than average preference for privacy.
689 You can find a list of anonymous public proxies at multiproxy.org and many more
692 -------------------------------------------------------------------------------
694 4.7. Can Privoxy guarantee I am anonymous?
696 No. Your chances of remaining anonymous are greatly improved, but unless you
697 are an expert on Internet security it would be safest to assume that everything
698 you do on the Web can be traced back to you.
700 Privoxy can remove various information about you, and allows you more freedom
701 to decide which sites you can trust, and what details you want to reveal. But
702 it's still possible that web sites can find out who you are. Here's one way
705 A few browsers disclose the user's email address in certain situations, such as
706 when transferring a file by FTP. Privoxy does not filter FTP. If you need this
707 feature, or are concerned about the mail handler of your browser disclosing
708 your email address, you might consider products such as NSClean.
710 Browsers available only as binaries could use non-standard headers to give out
711 any information they can have access to: see the manufacturer's license
712 agreement. It's impossible to anticipate and prevent every breach of privacy
713 that might occur. The professionally paranoid prefer browsers available as
714 source code, because anticipating their behavior is easier. Trust the source,
717 -------------------------------------------------------------------------------
719 4.8. Might some things break because header information is being altered?
721 Definitely. More and more sites use HTTP header content to decide what to
722 display and how to display it. There is many ways that this can be handled, so
723 having hard and fast rules, is tricky.
725 "USER AGENT" in particular is often used in this way to identify the browser,
726 and adjust content accordingly. Changing this now is not recommended, since so
727 many sites do look for this. You may get undesirable results by changing this.
729 For instance, different browsers use different encodings of Russian and Czech
730 characters, certain web servers convert pages on-the-fly according to the User
731 Agent header. Giving a "User Agent" with the wrong operating system or browser
732 manufacturer causes some sites in these languages to be garbled; Surfers to
733 Eastern European sites should change it to something closer. And then some page
734 access counters work by looking at the "REFERER" header; they may fail or break
735 if unavailable. The weather maps of Intellicast have been blocked by their
736 server when no "REFERER" or cookie is provided, is another example. There are
737 many, many other ways things can go wrong when trying to fool a web server.
739 If you have problems with a site, you will have to adjust your configuration
740 accordingly. Cookies are probably the most likely adjustment that may be
741 required, but by no means the only one.
743 -------------------------------------------------------------------------------
745 4.9. Can Privoxy act as a "caching" proxy to speed up web browsing?
747 No, it does not have this ability at all. You want something like Squid for
748 this. And, yes, before you ask, Privoxy can co-exist with other kinds of
751 -------------------------------------------------------------------------------
753 4.10. What about as a firewall? Can Privoxy protect me?
755 Not in the way you mean, or in the way a true firewall can, or a proxy that has
756 this specific capability. Privoxy can help protect your privacy, but not really
757 protect you from intrusion attempts.
759 -------------------------------------------------------------------------------
761 4.11. The Privoxy logo that replaces ads is very blocky and ugly looking. Can't
762 a better font be used?
764 This is not a font problem. The logo is an image that is created by Privoxy on
765 the fly. So as to not waste memory, the image is rather small. The blockiness
766 comes when the image is scaled to fill a largish area. There is not much to be
767 done about this, other than to use one of the other "imageblock" directives:
768 pattern, blank, or a URL of your choosing.
770 Given the above problem, we have decided to remove the logo option entirely [as
773 -------------------------------------------------------------------------------
775 4.12. I have large empty spaces now where ads used to be. Why?
777 It would be easy enough to just eliminate this space altogether, rather than
778 fill it with blank space. But, this would create problems with many pages that
779 use the overall size of the ad to help organize the page layout and position
780 the various components of the page where they were intended to be. It is best
783 -------------------------------------------------------------------------------
785 4.13. How can Privoxy filter Secure (HTTPS) URLs?
787 This is a limitation since HTTPS transactions are encrypted SSL sessions
788 between your browser and the secure site, and are meant to be reliably secure
789 and private. This means that all cookies and HTTP header information are also
790 encrypted from the time they leave your browser, to the site, and vice versa.
791 Privoxy does not try to unencrypt this information, so it just passes through
792 as is. Privoxy can still catch images and ads that are embedded in the SSL
795 -------------------------------------------------------------------------------
797 4.14. Privoxy runs as a "server". How secure is it? Do I need to take any
800 There are no known exploits that might effect Privoxy. On Unix-like systems,
801 Privoxy can run as a non-privileged user, which is how we recommend it be run.
802 Also, by default Privoxy only listens to requests from "localhost". The server
803 aspect of Privoxy is not itself directly exposed to the Internet in this
804 configuration. If you want to have Privoxy serve as a LAN proxy, this will have
805 to be opened up to allow for LAN requests. In this case, we'd recommend you
806 specify only the LAN gateway address, e.g. 192.168.1.1, in the main Privoxy
807 config file. All LAN hosts can then use this as their proxy address in the
808 browser proxy configuration. In this way, Privoxy will not listen on any
809 external ports. Of course, a firewall is always good too. Better safe than
812 -------------------------------------------------------------------------------
814 4.15. How can I temporarily disable Privoxy?
816 The easiest way is to access Privoxy with your browser by using the special
817 URL: http://p.p/ and select "Toggle Privoxy on or off" from that page.
819 -------------------------------------------------------------------------------
821 4.16. Where can I find more information about Privoxy and related issues?
823 Other references and sites of interest to Privoxy users:
825 http://www.privoxy.org/, The Privoxy Home page.
827 http://sourceforge.net/projects/ijbswa, the Project Page for Privoxy on
830 http://p.p/, access Privoxy from your browser. Alternately, http://
831 config.privoxy.org may work in some situations where the first does not.
833 http://p.p/, and select "Privoxy - Submit Filter Feedback" to submit "misses"
836 http://www.junkbusters.com/ht/en/cookies.html
838 http://www.waldherr.org/junkbuster/
840 http://privacy.net/analyze/
842 http://www.squid-cache.org/
846 -------------------------------------------------------------------------------
850 5.1. I just upgraded and am getting "connection refused" with every web page?
852 Either Privoxy is not running, or your browser is configured for a different
853 port than what Privoxy is using.
855 The old Privoxy (and also Junkbuster) used port 8000 by default. This has been
856 changed to port 8118 now, due to a conflict with NAS (Network Audio Service),
857 which uses port 8000. If you haven't, you need to change your browser to the
858 new port number, or alternately change Privoxy's "listen-address" setting in
859 the config file used to start Privoxy.
861 -------------------------------------------------------------------------------
863 5.2. I just added a new rule, but the steenkin ad is still getting through.
866 If the ad had been displayed before you added its URL, it will probably be held
867 in the browser's cache for some time, so it will be displayed without the need
868 for any request to the server, and Privoxy will not be in the picture. The best
869 thing to do is try flushing the browser's caches. And then try again.
871 If this doesn't help, you probably have an error in the rule you applied. Try
872 pasting the full URL of the offending ad into http://config.privoxy.org/
873 show-url-info and see if any actions match your new rule.
875 -------------------------------------------------------------------------------
877 5.3. One of my favorite sites does not work with Privoxy. What can I do?
879 First verify that it is indeed a Privoxy problem, by disabling Privoxy
880 filtering and blocking. Go to http://p.p/ and click on "Toggle Privoxy On or
881 Off", then disable it. Now try that page again. It's probably a good idea to
882 flush the browser cache as well with Shift+Reload to flush caches.
884 If still a problem, go to "Show which actions apply to a URL and why" from
885 http://p.p/ and paste the full URL of the page in question into the prompt. See
886 which actions are being applied to the URL. Now, armed with this information,
887 go to "View & change the current configuration". Here you should see various
888 sections that have various Privoxy features disabled for specific sites. Most
889 disabled "actions" will have a "-" (minus sign) in front of them. Some aliases
890 are used just to disable other actions, e.g. "shop" and "fragile", and won't
891 necessarily use a "+" or "-" sign. Add your problem page URL to one of these
892 sections that looks like it is disabling the feature that is causing the
893 problem. Rember to flush your browser's caches when making such changes! As a
894 last resort, try "fragile" which disables most actions. Now re-try the page.
895 There might be some trial and error involved. This is discussed in more detail
896 in the user-manual appendix.
898 Alternately, if you are comfortable with a text editor, you can accomplish the
899 same thing by editing the appropriate "actions" file.
901 -------------------------------------------------------------------------------
903 7. Contacting the developers, Bug Reporting and Feature Requests
905 We value your feedback. However, to provide you with the best support, please
906 note the following sections.
908 -------------------------------------------------------------------------------
912 To get support, use the Sourceforge Support Forum:
914 http://sourceforge.net/tracker/?group_id=11118&atid=211118
916 -------------------------------------------------------------------------------
920 To submit bugs, use the Sourceforge Bug Forum:
922 http://sourceforge.net/tracker/?group_id=11118&atid=111118.
924 Make sure that the bug has not already been submitted. Please try to verify
925 that it is a Privoxy bug, and not a browser or site bug first. If you are using
926 your own custom configuration, please try the stock configs to see if the
927 problem is a configuration related bug. And if not using the latest development
928 snapshot, please try the latest one. Or even better, CVS sources. Please be
929 sure to include the Privoxy version, platform, browser, any pertinent log data,
930 any other relevant details (please be specific) and, if possible, some way to
933 -------------------------------------------------------------------------------
935 7.3. Request new features
937 To submit ideas on new features, use the Sourceforge feature request forum:
939 http://sourceforge.net/tracker/?atid=361118&group_id=11118&func=browse.
941 -------------------------------------------------------------------------------
943 7.4. Report ads or other filter problems
945 You can also send feedback on websites that Privoxy has problems with. Please
946 bookmark the following link: "Privoxy - Submit Filter Feedback". Once you surf
947 to a page with problems, use the bookmark to send us feedback. We will look
948 into the issue as soon as possible.
950 New, improved default.action files will occasionally be made available based on
951 your feedback. These will be announced on the ijbswa-announce list.
953 -------------------------------------------------------------------------------
957 For any other issues, feel free to use the mailing lists:
959 http://sourceforge.net/mail/?group_id=11118.
961 Anyone interested in actively participating in development and related
962 discussions can also join the appropriate mailing list. Archives are available,
963 too. See the page on Sourceforge.
965 -------------------------------------------------------------------------------
967 8. Copyright and History
971 Privoxy is free software; you can redistribute it and/or modify it under the
972 terms of the GNU General Public License as published by the Free Software
973 Foundation; either version 2 of the License, or (at your option) any later
976 This program is distributed in the hope that it will be useful, but WITHOUT ANY
977 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
978 PARTICULAR PURPOSE. See the GNU General Public License for more details, which
979 is available from the Free Software Foundation, Inc, 59 Temple Place - Suite
980 330, Boston, MA 02111-1307, USA.
982 You should have received a copy of the GNU General Public License along with
983 this program; if not, write to the Free Software Foundation, Inc., 59 Temple
984 Place, Suite 330, Boston, MA 02111-1307 USA.
986 -------------------------------------------------------------------------------
990 Privoxy is evolved, and derived from, the Internet Junkbuster, with many
991 improvments and enhancements over the original.
993 Junkbuster was originally written by Anonymous Coders and Junkbusters
994 Corporation, and was released as free open-source software under the GNU GPL.
995 Stefan Waldherr made many improvements, and started the SourceForge project
996 Privoxy to rekindle development. There are now several active developers
997 contributing. The last stable release of Junkbuster was v2.0.2, which has now