1 Privoxy Frequently Asked Questions
5 $Id: faq.sgml,v 1.44 2002/04/07 21:24:29 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 the code of the Internet Junkbuster (tm). Junkbuster was
18 originally written by Junkbusters Corporation, and was released as free
19 open-source software under the GNU GPL. Stefan Waldherr made many improvements,
20 and started the SourceForge project to continue development.
22 Privoxy continues the Junkbuster tradition, but adds many refinements,
23 enhancements and new features.
25 You can find the latest version of the document at http://www.privoxy.org/faq/.
26 Please see the Contact section if you want to contact the developers.
28 -------------------------------------------------------------------------------
32 1. General Information
34 1.1. What is this new version of Privoxy?
35 1.2. Why "Privoxy"? Why a name change at all?
36 1.3. How does Privoxy differ from the old Junkbuster?
37 1.4. What are some of the new features?
38 1.5. What is a "proxy"? How does Privoxy work?
39 1.6. How does Privoxy know what is an ad, and what is not?
40 1.7. Can Privoxy make mistakes? This does not sound very scientific.
41 1.8. My browser does the same things as Privoxy. Why should I use Privoxy
43 1.9. Is there is a license or fee? What about a warranty? Registration?
44 1.10. I would like to help you, what do I do?
46 1.10.1. Money Money Money
47 1.10.2. You want to work with us?
51 2.1. Which browsers are supported by Privoxy?
52 2.2. Which operating systems are supported?
53 2.3. Can I install Privoxy over Junkbuster?
54 2.4. I just installed Privoxy. Is there anything special I have to do now?
55 2.5. What is the proxy address of Privoxy?
56 2.6. I just installed Privoxy, and nothing is happening. All the ads are
61 3.1. Can I use my old config files?
62 3.2. What is an "actions" file?
63 3.3. The "actions" concept confuses me. Please list some of these
65 3.4. How are actions files configured? What is the easiest way to do this?
66 3.5. What are the differences between intermediate.action, basic.action,
68 3.6. Why can I change the configuration with a browser? Does that not raise
70 3.7. What is "default.filter"?
71 3.8. How can I set up Privoxy to act as a proxy for my LAN?
72 3.9. Instead of ads, now I get a checkerboard pattern. I don't want to see
74 3.10. Why would anybody want to see a checkerboard pattern?
75 3.11. I see large red banners on some pages that say "Blocked". Why and how
77 3.12. I cannot see all of the "Blocked" page banner. All I see is a bright
79 3.13. Can Privoxy run as a service on Win2K/NT?
80 3.14. How can I make Privoxy work with other proxies like Squid?
84 4.1. How much does Privoxy slow my browsing down? This has to add extra
86 4.2. I noticed considerable delays in page requests compared to the old
87 Junkbuster. What's wrong?
88 4.3. What is the "http://p.p/"?
89 4.4. Do you still maintain the blocklists?
90 4.5. How can I submit new ads?
91 4.6. How can I hide my IP address?
92 4.7. Can Privoxy guarantee I am anonymous?
93 4.8. Might some things break because header information is being altered?
94 4.9. Can Privoxy act as a "caching" proxy to speed up web browsing?
95 4.10. What about as a firewall? Can Privoxy protect me?
96 4.11. The Privoxy logo that replaces ads is very blocky and ugly looking.
97 Can't a better font be used?
98 4.12. I have large empty spaces now where ads used to be. Why?
99 4.13. How can Privoxy filter Secure (HTTPS) URLs?
100 4.14. Privoxy runs as a "server". How secure is it? Do I need to take any
102 4.15. How can I temporarily disable Privoxy?
103 4.16. Where can I find more information about Privoxy and related issues?
107 5.1. I just upgraded and am getting "connection refused" with every web
109 5.2. I just added a new rule, but the steenkin ad is still getting through.
111 5.3. One of my favorite sites does not work with Privoxy. What can I do?
112 5.4. Where can I get help? Report bugs? Feature Requests? Etc?
113 5.5. What time is it?
115 7. Contacting the developers, Bug Reporting and Feature Requests
116 8. Copyright and History
121 -------------------------------------------------------------------------------
123 1. General Information
125 1.1. What is this new version of Privoxy?
127 The original Internet JunkbusterTM (tm) is a copyrighted product of Junkbusters
128 Corporation. Development of this effort stopped some time ago as of version
129 2.0.2. Stefan Waldherr started the ijbswa project on Sourceforge to rekindle
130 development. Other developers subsequently joined with Stefan, and have since
131 added many new features, refinements and enhancements. The result of this
134 Privoxy has evolved from the Junkbuster 2.0.2 code base, and has advanced
135 significantly at this point.
137 Please see the History section for more information on the history of
138 Junkbuster and Privoxy.
140 -------------------------------------------------------------------------------
142 1.2. Why "Privoxy"? Why a name change at all?
144 Privoxy is the "Privacy Enhancing Proxy".
146 There are potential legal complications from the continued use of the
147 Junkbuster name, which is a registered trademark of Junkbusters Corporation.
148 And thus they "own" the rights to the name. (There are, however, no objections
149 from Junkbusters Corporation to the Privoxy project itself, and they, in fact,
150 still share our ideals and goals.)
152 The developers also believed that there are so many changes from the original
153 code, that it was time to make a clean break from the past and make a name in
154 their own right, especially now with the pending release of version 3.0.
156 -------------------------------------------------------------------------------
158 1.3. How does Privoxy differ from the old Junkbuster?
160 Privoxy picks up where Junkbuster left off. All the old features remain. The
161 new Privoxy still blocks ads and banners, still manages cookies, and still
162 helps protect your privacy. But, these are all enhanced, and many new features
163 have been added, all in the same vein.
165 The configuration has changed significantly as well. This is something that
166 users will notice right off the bat if you are upgrading from Junkbuster 2.0.x.
167 The "blocklist" file does not exist any more. This is replaced by "actions"
168 files, such as default.actions. This is where most of the per site
169 configuration is now.
171 -------------------------------------------------------------------------------
173 1.4. What are some of the new features?
175 * Integrated browser based configuration and control utility (http://p.p).
176 Browser-based tracing of rule and filter effects.
178 * Blocking of annoying pop-up browser windows.
180 * HTTP/1.1 compliant (most, but not all 1.1 features are supported).
182 * Support for Perl Compatible Regular Expressions in the configuration files,
183 and generally a more sophisticated and flexible configuration syntax over
188 * Web page content filtering (removes banners based on size, invisible
189 "web-bugs", JavaScript, pop-ups, status bar abuse, etc.)
191 * Bypass many click-tracking scripts (avoids script redirection).
193 * Multi-threaded (POSIX and native threads).
195 * Auto-detection and re-reading of config file changes.
197 * User-customizable HTML templates (e.g. 404 error page).
199 * Improved cookie management features (e.g. session based cookies).
201 * Improved signal handling, and a true daemon mode (Unix).
203 * Builds from source on most UNIX-like systems. Packages available for: Linux
204 (RedHat, SuSE, or Debian), Windows, Sun Solaris, Mac OSX, OS/2, HP-UX 11
207 * In addition, the configuration is much more powerful and versatile
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 Win32, Mac OSX, OS/2, AmigaOS, Linux
327 (RedHat, Suse, Debian), FreeBSD, and many flavors of Unix. There are source and
328 binary releases for these available for download at http://sourceforge.net/
329 project/showfiles.php?group_id=11118.
331 But any operating system that runs TCP/IP, can conceivably take advantage of
332 Privoxy in a networked situation where Privoxy would run as a server on a LAN
333 gateway. Then only the "gateway" needs to be running one of the above operating
336 Source code is freely available, so porting to other operating systems, is
337 always a possibility.
339 -------------------------------------------------------------------------------
341 2.3. Can I install Privoxy over Junkbuster?
343 We recommend you uninstall Junkbuster first to minimize conflicts and
344 confusion. You may want to save your old configuration files for future
345 reference. The configuration is substantially changed.
347 See the user-manual for platform specific installation instructions.
349 Note: Some installers may automatically uninstall Junkbuster, if present!
351 -------------------------------------------------------------------------------
353 2.4. I just installed Privoxy. Is there anything special I have to do now?
355 All browsers must be told to use Privoxy as a proxy by specifying the correct
356 proxy address and port number in the appropriate configuration area for the
357 browser. See below. Also, you should flush your browser's memory and disk cache
358 to get rid of any cached items.
360 -------------------------------------------------------------------------------
362 2.5. What is the proxy address of Privoxy?
364 If you set up the Privoxy to run on the computer you browse from (rather than
365 your ISP's server or some networked computer on a LAN), the proxy will be on
366 "localhost" (which is the special name used by every computer on the Internet
367 to refer to itself) and the port will be 8118 (unless you have Privoxy to run
368 on a different port with the listen-address config option).
370 When configuring your browser's proxy settings you typically enter the word
371 "localhost" in the boxes next to "HTTP" and "Secure" (HTTPS) and then the
372 number "8118" for "port". This tells your browser to send all web requests to
373 Privoxy instead of directly to the Internet.
375 Privoxy can also be used to proxy for a Local Area Network. In this case, your
376 would enter either the IP address of the LAN host where Privoxy is running, or
377 the equivalent hostname. Port assignment would be same as above.
379 Privoxy does not currently handle protocols such as FTP, SMTP, IM, IRC, ICQ, or
380 other Internet protocols.
382 -------------------------------------------------------------------------------
384 2.6. I just installed Privoxy, and nothing is happening. All the ads are there.
387 Did you configure your browser to use Privoxy as a proxy? It does not sound
388 like it. See above. You might also try flushing the browser's caches to force a
389 full re-reading of pages. You can verify that Privoxy is running, and your
390 browser is correctly configured by entering the special URL: http://p.p/. This
391 should give you a banner that says "This is Privoxy" and access to Privoxy's
392 internal configuration. If you see this, then you are good to go. If not, the
393 browser or Privoxy are not set up correctly.
395 -------------------------------------------------------------------------------
399 3.1. Can I use my old config files?
401 There are major changes to Junkbuster/ Privoxy configuration from version 2.0.x
402 to 2.9.x and later. Most of the older files will not work at all. This is
403 especially true of blocklist. If this is the case, you will need to re-enter
404 your old data into the new configuration structure. This is probably also a
405 good recommendation even if upgrading from 2.9.x to 3.x since there were many
406 minor changes along the way.
408 -------------------------------------------------------------------------------
410 3.2. What is an "actions" file?
412 "actions" files are where various actions that Privoxy might take, are
413 configured. Typically, you would define a set of default actions that apply to
414 all URLs, then add exceptions to these defaults.
416 Actions can be defined on a per site basis, or for groups of sites. Actions can
417 also be grouped together and then applied to one or more sites. There are many
418 possible actions that might apply to any given site. As an example, if we are
419 blocking cookies as one of our default actions, but need to accept cookies from
420 a given site, we would define this in our "actions" file.
422 Privoxy comes with several default actions files, with varying degrees of
423 filtering and blocking, as starting points for your own configuration (see
426 -------------------------------------------------------------------------------
428 3.3. The "actions" concept confuses me. Please list some of these "actions".
430 These are all explained in the user-manual. Please refer to that.
432 -------------------------------------------------------------------------------
434 3.4. How are actions files configured? What is the easiest way to do this?
436 The easiest way to do this, is to access Privoxy with your web browser at http:
437 //p.p/, and then select "Edit the actions list" from the selection list. You
438 can also do this by editing the appropriate file with a text editor.
440 Please see the user-manual for a detailed explanation of these and other
441 configuration files, and their various options and syntax.
443 -------------------------------------------------------------------------------
445 3.5. What are the differences between intermediate.action, basic.action, etc.?
447 Configuring Privoxy is not easy. To help you get started, we provide you with
448 three different default configurations. The following table shows you, which
449 features are enabled in each configuration.
451 Table 1. Default Configurations
453 +--------------------------------------------------------------------------------------+
454 |Feature |default.action|basic.action |intermediate.action|advanced.action|
455 |--------------------+--------------+--------------+-------------------+---------------|
456 |ad-filtering |? |x |x |x |
457 |--------------------+--------------+--------------+-------------------+---------------|
458 |blank image |? |x |x |x |
459 |--------------------+--------------+--------------+-------------------+---------------|
460 |de-animate GIFs |? |x |x |x |
461 |--------------------+--------------+--------------+-------------------+---------------|
462 |referer forging |? |x |x |x |
463 |--------------------+--------------+--------------+-------------------+---------------|
465 |+no-cookies-keep | | | | |
466 |(i.e. session | | | | |
467 |cookies only) | | | | |
468 |--------------------+--------------+--------------+-------------------+---------------|
469 |no-popup windows |? | |x |x |
470 |--------------------+--------------+--------------+-------------------+---------------|
471 |fast redirects |? | |x |x |
472 |--------------------+--------------+--------------+-------------------+---------------|
473 |hide-referrer |? | |x |x |
474 |--------------------+--------------+--------------+-------------------+---------------|
475 |hide-useragent |? | |x |x |
476 |--------------------+--------------+--------------+-------------------+---------------|
477 |content-modification|? | | |x |
478 |--------------------+--------------+--------------+-------------------+---------------|
479 |feature-x |? | | | |
480 |--------------------+--------------+--------------+-------------------+---------------|
481 |feature-y |? | | | |
482 |--------------------+--------------+--------------+-------------------+---------------|
483 |feature-z |? | | | |
484 +--------------------------------------------------------------------------------------+
486 -------------------------------------------------------------------------------
488 3.6. Why can I change the configuration with a browser? Does that not raise
491 What I don't understand, is how I can browser edit the config file as a regular
492 user, while the whole /etc/privoxy hierarchy belongs to the user "privoxy",
493 with only 644 permissions.
495 When you use the browser-based editor, Privoxy itself is writing to the config
496 files. Because Privoxy is running as the user "privoxy", it can update the
499 If you don't like this, setting "enable-edit-actions 0" in the config file will
500 disable the browser-based editor. If you're that paranoid, you should also
501 consider setting "enable-remote-toggle 0" to prevent browser-based enabling/
502 disabling of Privoxy.
504 Note that normally only local users can connect to Privoxy, so this is not
505 (normally) a security problem.
507 -------------------------------------------------------------------------------
509 3.7. What is "default.filter"?
511 The "default.filter" file is used to "filter" any web page content. By
512 "filtering" we mean it can modify, remove, or change anything on the page,
513 including HTML tags, and JavaScript. Regular expressions are used to accomplish
514 this, and operate on a line by line basis. This is potentially a very powerful
515 feature, but requires some expertise.
517 If you are familiar with regular expressions, and HTML, you can look at the
518 provided default.filter with a text editor and see some of things it can be
521 Presently, there is no GUI editor option for this part of the configuration,
522 but you can disable/enable various sections of the included default file with
523 the "Actions List Editor" from your browser.
525 -------------------------------------------------------------------------------
527 3.8. How can I set up Privoxy to act as a proxy for my LAN?
529 By default, Privoxy only responds to requests from localhost. To have it act as
530 a server for a network, this needs to be changed in the main config file where
531 the Privoxy configuration is located. In that file is a "listen-address"
532 option. It may be commented out with a "#" symbol. Make sure it is uncommented,
533 and assign it the address of the LAN gateway interface, and port number to use:
535 listen-address 192.168.1.1:8118
538 Save the file, and restart Privoxy. Configure all browsers on the network then
539 to use this address and port number.
541 -------------------------------------------------------------------------------
543 3.9. Instead of ads, now I get a checkerboard pattern. I don't want to see
546 This is a configuration option for images that Privoxy is stopping. You have
547 the choice of a checkerboard pattern, a transparent 1x1 GIF image (aka
548 "blank"), or a custom URL of your choice. Note that to fit this category, the
549 URL must match both the "+image" and "+block" actions.
551 If you want to see nothing, then change the "+image-blocker" action to
552 "+image-blocker{blank}". This can be done from the "Edit Actions List"
553 selection at http://p.p/. Or by hand editing the appropriate actions file. This
554 will only effect what is defined as "images" though. Also, some URLs that
555 generate the bright red "Blocked" banner, can be moved to the "+image-blocker"
556 section for the same reason, but there are some limits and risks to this (see
559 -------------------------------------------------------------------------------
561 3.10. Why would anybody want to see a checkerboard pattern?
563 This can be helpful for troubleshooting problems. It might also be good for
564 anyone new to Privoxy so that they can see if their favorite pages are
565 displaying correctly, and Privoxy is not inadvertently removing something
568 -------------------------------------------------------------------------------
570 3.11. I see large red banners on some pages that say "Blocked". Why and how do
573 These are URLs that match something in one of Privoxy's block actions (+block).
574 It is meant to be a warning so that you know something has been blocked and an
575 easy way for you to see why. These are handled differently than what has been
576 defined explicitly as "images" (e.g. ad banners). Depending on the URL itself,
577 it is sometimes hard for Privoxy to really know whether there is indeed an ad
578 image there or not. And there are limitations as to what Privoxy can do to
581 For instance, if the ad is in a frame, then it is embedded in the separate HTML
582 page used for the frame. In this case, you cannot just substitute an aribitray
583 image (like we would for a "blank" image), for an HTML page. The browser is
584 expecting an HTML page, and that is what it must have for frames. So this
585 situation can be a little trickier to deal with, and Privoxy will use the
588 If you want these to be treated as if they were images, so that they can be
589 made invisible, you can try moving the offending URL from the "+block" section
590 to the "+imageblock" section of your actions file. Just be forewarned, if any
591 URL is made "invisible", you may not have any inkling that something has been
592 removed from that page, or why. If this approach does not work, then you are
593 probably dealing with a frame (or "ilayer"), and the only thing that can go
594 there is an HTML page of some sort.
596 To deal with this situation, you could modify the "block" HTML template that is
597 used by Privoxy to display this, and make it something more to your liking.
598 Currently, there is no configuration option for this. You will have to modify,
599 or create your own page, and use this to replace templates/blocked, which is
600 what Privoxy uses to display the "Blocked" page.
602 Another way to deal with this is find why and where Privoxy is blocking the
603 frame, and diable this. Then let the "+image-blocker" action handle the ad that
604 is embedded in the frame's HTML page.
606 -------------------------------------------------------------------------------
608 3.12. I cannot see all of the "Blocked" page banner. All I see is a bright red
611 There is not enough space to fit the entire page. Try right clicking on the
612 visible, red portion, and select "Show Frame", or equivalent. This will usually
613 allow you to see the entire Privoxy "Blocked" page, and from there you can see
614 just what is being blocked, and why.
616 -------------------------------------------------------------------------------
618 3.13. Can Privoxy run as a service on Win2K/NT?
620 Yes, it can run as a system service using srvany.exe. The only catch is that
621 this will effectively disable the Privoxy icon in the taskbar. You can have one
622 or the other, but not both at this time :(
624 There is a pending feature request for this functionality. See thread: http://
625 sourceforge.net/tracker/?func=detail&atid=361118&aid=485617&group_id=11118, for
626 details, and a sample configuration.
628 -------------------------------------------------------------------------------
630 3.14. How can I make Privoxy work with other proxies like Squid?
632 This can be done. See the user manual, which describes how to do this.
634 -------------------------------------------------------------------------------
638 4.1. How much does Privoxy slow my browsing down? This has to add extra time to
641 It should not slow you down any in real terms, and may actually help speed
642 things up since ads, banners and other junk are not being displayed. The actual
643 processing time required by Privoxy itself for each page, is relatively small
644 in the overall scheme of things, and happens very quickly. This is typically
645 more than offset by time saved not downloading and rendering ad images.
647 "Filtering" via the filterfile mechanism may cause a perceived slowdown, since
648 the entire page is buffered before displaying. See below.
650 -------------------------------------------------------------------------------
652 4.2. I noticed considerable delays in page requests compared to the old
653 Junkbuster. What's wrong?
655 Using the default filtering configuration, I noticed considerable delays in
656 page requests compared to the old Junkbuster. Loading pages with large contents
657 seemed to take forever, then suddenly delivering all the content at once.
659 The whole content must be loaded in order to filter, and nothing is is sent to
660 the browser during this time. The loading time does not really change in real
661 numbers, but the feeling is different, because most browsers are able to start
662 rendering incomplete content, giving the user a feeling of "it works".
664 To modify the content of a page (i.e. make frames resizeable again, etc.) and
665 not just replace ads, Privoxy needs to download the entire page first, do its
666 content magic and then send the page to the browser.
668 -------------------------------------------------------------------------------
670 4.3. What is the "http://p.p/"?
672 Since Privoxy sits between your web browser and the Internet, it can be
673 programmed to handle certain pages specially.
675 With recent versions of Privoxy (version 2.9.x), you can get some information
676 about Privoxy and change some settings by going to http://p.p/ or,
677 equivalently, http://config.privoxy.org/ (Note that p.p is far easier to type
678 but may not work in some configurations. With the name change to Privoxy, this
679 is changed from the previous http://i.j.b/ or earlier 2.9.x versions).
681 These pages are not forwarded to a server on the Internet - instead they are
682 handled by a special web server which is built in to Privoxy.
684 If you are not running Privoxy, then http://p.p/ will fail, and http://
685 config.privoxy.org/ will return a web page telling you you're not running
688 If you have version 2.0.2, then the equivalent is http://example.com/
689 show-proxy-args (but you get far less information, and you should really
690 consider upgrading to 2.9.14).
692 -------------------------------------------------------------------------------
694 4.4. Do you still maintain the blocklists?
696 No. The format of the blocklists has changed significantly in versions 2.9.x
697 and later. Once we have released the new stable version, v3.0, there will again
698 be blocklists that you can update automatically.
700 -------------------------------------------------------------------------------
702 4.5. How can I submit new ads?
704 As of now, please discontinue to submit new ad blocking infos. Once we have
705 released the new version, there will again be a form on the website, which you
706 can use to contribute new ads.
708 -------------------------------------------------------------------------------
710 4.6. How can I hide my IP address?
712 You cannot hide your IP address with Privoxy or any other software, since the
713 server needs to know your IP address to send the answer to you.
715 Fortunately there are many publicly usable anonymous proxies out there, which
716 solve the problem by providing a further level of indirection between you and
717 the web server, shared by many people and thus letting your requests "drown" in
718 white noise of unrelated requests as far as user tracking is concerned.
720 Most of them will, however, log your IP address and make it available to the
721 authorities in case you abuse that anonymity for criminal purposes. In fact you
722 can't even rule out that some of them only exist to *collect* information on
723 (those suspicious) people with a more than average preference for privacy.
725 You can find a list of anonymous public proxies at multiproxy.org and many more
728 -------------------------------------------------------------------------------
730 4.7. Can Privoxy guarantee I am anonymous?
732 No. Your chances of remaining anonymous are greatly improved, but unless you
733 are an expert on Internet security it would be safest to assume that everything
734 you do on the Web can be traced back to you.
736 Privoxy can remove various information about you, and allows you more freedom
737 to decide which sites you can trust, and what details you want to reveal. But
738 it's still possible that web sites can find out who you are. Here's one way
741 A few browsers disclose the user's email address in certain situations, such as
742 when transferring a file by FTP. Privoxy does not filter FTP. If you need this
743 feature, or are concerned about the mail handler of your browser disclosing
744 your email address, you might consider products such as NSClean.
746 Browsers available only as binaries could use non-standard headers to give out
747 any information they can have access to: see the manufacturer's license
748 agreement. It's impossible to anticipate and prevent every breach of privacy
749 that might occur. The professionally paranoid prefer browsers available as
750 source code, because anticipating their behavior is easier. Trust the source,
753 -------------------------------------------------------------------------------
755 4.8. Might some things break because header information is being altered?
757 Definitely. More and more sites use HTTP header content to decide what to
758 display and how to display it. There is many ways that this can be handled, so
759 having hard and fast rules, is tricky.
761 "USER AGENT" in particular is often used in this way to identify the browser,
762 and adjust content accordingly. Changing this now is not recommended, since so
763 many sites do look for this. You may get undesirable results by changing this.
765 For instance, different browsers use different encodings of Russian and Czech
766 characters, certain web servers convert pages on-the-fly according to the User
767 Agent header. Giving a "User Agent" with the wrong operating system or browser
768 manufacturer causes some sites in these languages to be garbled; Surfers to
769 Eastern European sites should change it to something closer. And then some page
770 access counters work by looking at the "REFERER" header; they may fail or break
771 if unavailable. The weather maps of Intellicast have been blocked by their
772 server when no "REFERER" or cookie is provided, is another example. There are
773 many, many other ways things can go wrong when trying to fool a web server.
775 If you have problems with a site, you will have to adjust your configuration
776 accordingly. Cookies are probably the most likely adjustment that may be
777 required, but by no means the only one.
779 -------------------------------------------------------------------------------
781 4.9. Can Privoxy act as a "caching" proxy to speed up web browsing?
783 No, it does not have this ability at all. You want something like Squid for
784 this. And, yes, before you ask, Privoxy can co-exist with other kinds of
787 -------------------------------------------------------------------------------
789 4.10. What about as a firewall? Can Privoxy protect me?
791 Not in the way you mean, or in the way a true firewall can, or a proxy that has
792 this specific capability. Privoxy can help protect your privacy, but not really
793 protect you from intrusion attempts.
795 -------------------------------------------------------------------------------
797 4.11. The Privoxy logo that replaces ads is very blocky and ugly looking. Can't
798 a better font be used?
800 This is not a font problem. The logo is an image that is created by Privoxy on
801 the fly. So as to not waste memory, the image is rather small. The blockiness
802 comes when the image is scaled to fill a largish area. There is not much to be
803 done about this, other than to use one of the other "imageblock" directives:
804 pattern, blank, or a URL of your choosing.
806 Given the above problem, we have decided to remove the logo option entirely [as
809 -------------------------------------------------------------------------------
811 4.12. I have large empty spaces now where ads used to be. Why?
813 It would be easy enough to just eliminate this space altogether, rather than
814 fill it with blank space. But, this would create problems with many pages that
815 use the overall size of the ad to help organize the page layout and position
816 the various components of the page where they were intended to be. It is best
819 -------------------------------------------------------------------------------
821 4.13. How can Privoxy filter Secure (HTTPS) URLs?
823 This is a limitation since HTTPS transactions are encrypted SSL sessions
824 between your browser and the secure site, and are meant to be reliably secure
825 and private. This means that all cookies and HTTP header information are also
826 encrypted from the time they leave your browser, to the site, and vice versa.
827 Privoxy does not try to unencrypt this information, so it just passes through
828 as is. Privoxy can still catch images and ads that are embedded in the SSL
831 -------------------------------------------------------------------------------
833 4.14. Privoxy runs as a "server". How secure is it? Do I need to take any
836 There are no known exploits that might effect Privoxy. On Unix-like systems,
837 Privoxy can run as a non-privileged user, which is how we recommend it be run.
838 Also, by default Privoxy only listens to requests from "localhost". The server
839 aspect of Privoxy is not itself directly exposed to the Internet in this
840 configuration. If you want to have Privoxy serve as a LAN proxy, this will have
841 to be opened up to allow for LAN requests. In this case, we'd recommend you
842 specify only the LAN gateway address, e.g. 192.168.1.1, in the main Privoxy
843 config file. All LAN hosts can then use this as their proxy address in the
844 browser proxy configuration. In this way, Privoxy will not listen on any
845 external ports. Of course, a firewall is always good too. Better safe than
848 -------------------------------------------------------------------------------
850 4.15. How can I temporarily disable Privoxy?
852 The easiest way is to access Privoxy with your browser by using the special
853 URL: http://p.p/ and select "Toggle Privoxy on or off" from that page.
855 -------------------------------------------------------------------------------
857 4.16. Where can I find more information about Privoxy and related issues?
859 Other references and sites of interest to Privoxy users:
861 http://www.privoxy.org/, The Privoxy Home page.
863 http://sourceforge.net/projects/ijbswa, the Project Page for Privoxy on
866 http://p.p/, access Privoxy from your browser. Alternately, http://
867 config.privoxy.org may work in some situations where the first does not.
869 http://www.junkbusters.com/ht/en/cookies.html
871 http://www.waldherr.org/junkbuster/
873 http://privacy.net/analyze/
875 http://www.squid-cache.org/
879 -------------------------------------------------------------------------------
883 5.1. I just upgraded and am getting "connection refused" with every web page?
885 Either Privoxy is not running, or your browser is configured for a different
886 port than what Privoxy is using.
888 The old Privoxy (and also Junkbuster) used port 8000 by default. This has been
889 changed to port 8118 now, due to a conflict with NAS (Network Audio Service),
890 which uses port 8000. If you haven't, you need to change your browser to the
891 new port number, or alternately change Privoxy's "listen-address" setting in
892 the config file used to start Privoxy.
894 -------------------------------------------------------------------------------
896 5.2. I just added a new rule, but the steenkin ad is still getting through.
899 If the ad had been displayed before you added its URL, it will probably be held
900 in the browser's cache for some time, so it will be displayed without the need
901 for any request to the server, and Privoxy will not be in the picture. The best
902 thing to do is try flushing the browser's caches. And then try again.
904 If this doesn't help, you probably have an error in the rule you applied. Try
905 pasting the full URL of the offending ad into http://config.privoxy.org/
906 show-url-info and see if any actions match your new rule.
908 -------------------------------------------------------------------------------
910 5.3. One of my favorite sites does not work with Privoxy. What can I do?
912 First verify that it is indeed a Privoxy problem, by disabling Privoxy
913 filtering and blocking. Go to http://p.p/ and click on "Toggle Privoxy On or
914 Off", then disable it. Now try that page again. It's probably a good idea to
915 flush the browser cache as well.
917 If still a problem, go to "Show which actions apply to a URL and why" from
918 http://p.p/ and paste the full URL of the page in question into the prompt. See
919 which actions are being applied to the URL. Now, armed with this information,
920 go to "Edit the actions list". Here you should see various sections that have
921 various Privoxy features disabled for specific sites. Most disabled "actions"
922 will have a "-" (minus sign) in front of them. Some aliases are used just to
923 disable other actions, e.g. "shop" and "fragile", and won't necessarily use a
924 "+" or "-" sign. Add your problem page URL to one of these sections that looks
925 like it is disabling the feature that is causing the problem. Rember to flush
926 your browser's caches when making such changes! As a last resort, try "fragile"
927 which disables most actions. Now re-try the page. There might be some trial and
928 error involved. This is discussed in a little more detail in the user-manual
931 Alternately, if you are comfortable with a text editor, you can accomplish the
932 same thing by editing the appropriate "actions" file.
934 -------------------------------------------------------------------------------
936 5.4. Where can I get help? Report bugs? Feature Requests? Etc?
938 Feedback is encouraged, whether good, bad or ugly. Please see the contact page
939 in the user-manual for details.
941 -------------------------------------------------------------------------------
943 5.5. What time is it?
947 -------------------------------------------------------------------------------
949 7. Contacting the developers, Bug Reporting and Feature Requests
951 We value your feedback. However, to provide you with the best support, please
954 * Use the Sourceforge Support Forum to get help:
956 http://sourceforge.net/tracker/?group_id=11118&atid=211118
959 * Submit bugs only through our Sourceforge Bug Forum:
961 http://sourceforge.net/tracker/?group_id=11118&atid=111118.
964 Make sure that the bug has not already been submitted. Please try to verify
965 that it is a Privoxy bug, and not a browser or site bug first. If you are
966 using your own custom configuration, please try the stock configs to see if
967 the problem is a configuration related bug. And if not using the latest
968 development snapshot, please try the latest one. Or even better, CVS
969 sources. Please be sure to include the Privoxy/Junkbuster version,
970 platform, browser, any pertinent log data, any other relevant details
971 (please be specific) and, if possible, some way to reproduce the bug.
973 * Submit feature requests only through our Sourceforge feature request
976 http://sourceforge.net/tracker/?atid=361118&group_id=11118&func=browse.
979 * We will soon have an automated way to submit advertisements, incorrectly
980 blocked images, popups and the like. Check back.
983 * For any other issues, feel free to use the mailing lists:
985 http://sourceforge.net/mail/?group_id=11118.
988 Anyone interested in actively participating in development and related
989 discussions can also join the appropriate mailing list. Archives are
992 -------------------------------------------------------------------------------
994 8. Copyright and History
998 Privoxy is free software; you can redistribute it and/or modify it under the
999 terms of the GNU General Public License as published by the Free Software
1000 Foundation; either version 2 of the License, or (at your option) any later
1003 This program is distributed in the hope that it will be useful, but WITHOUT ANY
1004 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
1005 PARTICULAR PURPOSE. See the GNU General Public License for more details, which
1006 is available from the Free Software Foundation, Inc, 59 Temple Place - Suite
1007 330, Boston, MA 02111-1307, USA.
1009 You should have received a copy of the GNU General Public License along with
1010 this program; if not, write to the Free Software Foundation, Inc., 59 Temple
1011 Place, Suite 330, Boston, MA 02111-1307 USA.
1013 -------------------------------------------------------------------------------
1017 Privoxy is evolved, and derived from, the Internet Junkbuster, with many
1018 improvments and enhancements over the original.
1020 Junkbuster was originally written by Anonymous Coders and Junkbuster's
1021 Corporation, and was released as free open-source software under the GNU GPL.
1022 Stefan Waldherr made many improvements, and started the SourceForge project
1023 Privoxy to rekindle development. There are now several active developers
1024 contributing. The last stable release of Junkbuster was v2.0.2, which has now