1 Privoxy Frequently Asked Questions
6 $Id: faq.sgml,v 1.43 2002/04/04 21:59:53 hal9 Exp $
9 This FAQ gives users and developers alike answers to frequently asked questions
12 Privoxy is a web proxy with advanced filtering capabilities for protecting
13 privacy, filtering web page content, managing cookies, controlling access, and
14 removing ads, banners, pop-ups and other obnoxious Internet junk. Privoxy has a
15 very flexible configuration and can be customized to suit individual needs and
16 tastes. Privoxy has application for both stand-alone systems and multi-user
19 Privoxy is based on the code of the Internet Junkbuster (tm). Junkbuster was
20 originally written by JunkBusters Corporation, and was released as free
21 open-source software under the GNU GPL. Stefan Waldherr made many improvements,
22 and started the SourceForge project to continue development.
24 Privoxy continues the Junkbuster tradition, but adds many refinements,
25 enhancements and new features.
27 You can find the latest version of the document at http://www.privoxy.org/faq/.
28 Please see the Contact section if you want to contact the developers.
30 -------------------------------------------------------------------------------
33 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?
45 1.10.1. Money Money Money
46 1.10.2. You want to work with us?
52 2.1. Which browsers are supported by Privoxy?
53 2.2. Which operating systems are supported?
54 2.3. Can I install Privoxy over Junkbuster?
55 2.4. I just installed Privoxy. Is there anything special I have to do now?
56 2.5. What is the proxy address of Privoxy?
57 2.6. I just installed Privoxy, and nothing is happening. All the ads are
62 3.1. Can I use my old config files?
63 3.2. What is an "actions" file?
64 3.3. The "actions" concept confuses me. Please list some of these "actions"
66 3.4. How are actions files configured? What is the easiest way to do this?
67 3.5. What are the differences between intermediate.action, basic.action,
69 3.6. Why can I change the configuration with a browser? Does that not raise
71 3.7. What is "default.filter"?
72 3.8. How can I set up Privoxy to act as a proxy for my LAN?
73 3.9. Instead of ads, now I get a checkerboard pattern. I don't want to see
75 3.10. Why would anybody want to see a checkerboard pattern?
76 3.11. I see large red banners on some pages that say "Blocked". Why and how
78 3.12. I cannot see all of the "Blocked" page banner. All I see is a bright
80 3.13. Can Privoxy run as a service on Win2K/NT?
81 3.14. How can I make Privoxy work with other proxies like Squid?
85 4.1. How much does Privoxy slow my browsing down? This has to add extra
87 4.2. I noticed considerable delays in page requests compared to the old
88 Junkbuster. What's wrong?
89 4.3. What is the "http://p.p/"?
90 4.4. Do you still maintain the blocklists?
91 4.5. How can I submit new ads?
92 4.6. How can I hide my IP address?
93 4.7. Can Privoxy guarantee I am anonymous?
94 4.8. Might some things break because header information is being altered?
95 4.9. Can Privoxy act as a "caching" proxy to speed up web browsing?
96 4.10. What about as a firewall? Can Privoxy protect me?
97 4.11. The Privoxy logo that replaces ads is very blocky and ugly looking.
98 Can't a better font be used?
99 4.12. I have large empty spaces now where ads used to be. Why?
100 4.13. How can Privoxy filter Secure (HTTPS) URLs?
101 4.14. Privoxy runs as a "server". How secure is it? Do I need to take any
103 4.15. How can I temporarily disable Privoxy?
104 4.16. Where can I find more information about Privoxy and related issues?
108 5.1. I just upgraded and am getting "connection refused" with every web
110 5.2. I just added a new rule, but the steenkin ad is still getting through.
112 5.3. One of my favorite sites does not work with Privoxy. What can I do?
113 5.4. Where can I get help? Report bugs? Feature Requests? Etc?
114 5.5. What time is it?
117 7. Contacting the developers, Bug Reporting and Feature Requests
118 8. Copyright and History
125 -------------------------------------------------------------------------------
126 1. General Information
128 1.1. What is this new version of Privoxy?
130 The original Internet Junkbuster™ (tm) is a copyrighted product of
131 Junkbusters Corporation. Development of this effort stopped some time ago as of
132 version 2.0.2. Stefan Waldherr started the ijbswa project on Sourceforge to
133 rekindle development. Other developers subsequently joined with Stefan, and
134 have since added many new features, refinements and enhancements. The result of
135 this effort is Privoxy.
137 Privoxy has evolved from the Junkbuster 2.0.2 code base, and has advanced
138 significantly at this point.
140 Please see the History section for more information on the history of
141 Junkbuster and Privoxy.
142 -------------------------------------------------------------------------------
144 1.2. Why "Privoxy"? Why a name change at all?
146 Privoxy is the "Privacy Enhancing Proxy".
148 There are potential legal complications from the continued use of the
149 Junkbuster name, which is a trademark of Junkbusters Corporation. (There are,
150 however, no objections from Junkbusters Corporation to the Privoxy project
151 itself, and they, in fact, still share our ideals and goals.)
153 The developers also believed that there are so many changes from the original
154 code, that it was time to make a clean break from the past and make a name in
155 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.
170 -------------------------------------------------------------------------------
172 1.4. What are some of the new features?
174 * Integrated browser based configuration and control utility (http://p.p).
175 Browser-based tracing of rule and filter effects.
177 * Blocking of annoying pop-up browser windows.
179 * HTTP/1.1 compliant (most, but not all 1.1 features are supported).
181 * Support for Perl Compatible Regular Expressions in the configuration files,
182 and generally a more sophisticated and flexible configuration syntax over
187 * Web page content filtering (removes banners based on size, invisible
188 "web-bugs", JavaScript, pop-ups, status bar abuse, etc.)
190 * Bypass many click-tracking scripts (avoids script redirection).
192 * Multi-threaded (POSIX and native threads).
194 * Auto-detection and re-reading of config file changes.
196 * User-customizable HTML templates (e.g. 404 error page).
198 * Improved cookie management features (e.g. session based cookies).
200 * Improved signal handling, and a true daemon mode (Unix).
202 * Builds from source on most UNIX-like systems. Packages available for: Linux
203 (RedHat, SuSE, or Debian), Windows, Sun Solaris, Mac OSX, OS/2, HP-UX 11
206 * In addition, the configuration is much more powerful and versatile
210 -------------------------------------------------------------------------------
211 1.5. What is a "proxy"? How does Privoxy work?
213 When you connect to a web site with Privoxy, you are really connecting to your
214 locally running version of Privoxy. Privoxy intercepts your requests for the
215 web page, and relays that to the "real" web site. The web site sends the HTTP
216 data stream back to Privoxy, where Privoxy can work its magic before it relays
217 this data back to your web browser.
219 Since Privoxy sits between you and the WWW, it is in a position to intercept
220 and completely manage all web traffic and HTTP content before it gets to your
221 browser. Privoxy uses various programming methods to do this, all of which is
222 under your control via the various configuration files and options.
224 There are many kinds of proxies. Privoxy best fits the "filtering proxy"
226 -------------------------------------------------------------------------------
228 1.6. How does Privoxy know what is an ad, and what is not?
230 Privoxy processes all the raw content of every web page. So it reads everything
231 on each page. It then compares this to the rules as set up in the configuration
232 files, and looks for any matches to these rules. Privoxy makes heavy use of
233 "regular expressions". (If you are not familiar with regular expressions, it is
234 explained briefly in the user manual.) Regular expressions facilitate matching
235 of one text string against another, using wildcards to build complex patterns.
236 So Privoxy will typically look for URLs and other content that match certain
237 key words and expressions as defined in the configuration files. For instance a
238 URL that contains "/banners", has a high probability of containing ad banners,
239 and thus would be a prime candidate to have a matching rule.
241 So Privoxy will look for these kinds of obvious looking culprits. And also,
242 will use lists of known organizations that specialize in ads. Again, using
243 complex patterns to match as many potential combinations as possible since
244 there tend to be many, many variations used by advertisers, and new ones are
245 being introduced all the time.
246 -------------------------------------------------------------------------------
248 1.7. Can Privoxy make mistakes? This does not sound very scientific.
250 Actually, it's a black art ;-) And yes, it is always possible to have a broad
251 rule accidentally block something by mistake. There is a good chance you may
252 run into such a situation at some point. It is tricky writing rules to cover
253 every conceivable possibility, and not occasionally get false positives.
255 But this should not be a big concern since the Privoxy configuration is very
256 flexible, and includes tools to help identify these types of situations so they
257 can be addressed as needed, allowing you to customize your installation. (See
258 the Troubleshooting section below.)
259 -------------------------------------------------------------------------------
261 1.8. My browser does the same things as Privoxy. Why should I use Privoxy at
264 Modern browsers do indeed have some of the same functionality as Privoxy. Maybe
265 this is adequate for you. But Privoxy is much more versatile and powerful, and
266 can do a number of things that browsers just can't.
268 In addition, a proxy is good choice if you use multiple browsers, or have a LAN
269 with multiple computers. This way all the configuration is in one place, and
270 you don't have to maintain a similar configuration for possibly many browsers.
271 -------------------------------------------------------------------------------
273 1.9. Is there is a license or fee? What about a warranty? Registration?
275 Privoxy is licensed under the GNU General Public License (GPL). It is free to
276 use, copy, modify or distribute as you wish under the terms of this license.
277 Please see the Copyright section for more information on the license and
280 There is no warranty of any kind, expressed, implied or otherwise. That is
281 something that would cost real money ;-) There is no registration either.
282 Privoxy really is free in every respect!
283 -------------------------------------------------------------------------------
285 1.10. I would like to help you, what do I do?
287 1.10.1. Money Money Money
289 We, of course, welcome donations and use the money for domain registering,
290 regular world-wide get-togethers (hahaha). Anyway, we'll soon describe the
291 process how to donate money to the team.
292 -------------------------------------------------------------------------------
294 1.10.2. You want to work with us?
296 Well, helping the team is always a good idea. We welcome new developers, RPM
297 gurus or documentation makers. Simply get an account on sourceforge.net and
298 mail your id to the developer mailing list. Then read the section Quickstart in
299 the Developer's Manual.
301 Once we have added you to the team, you'll have write access to the CVS
302 repository, and together we'll find a suitable task for you.
303 -------------------------------------------------------------------------------
307 2.1. Which browsers are supported by Privoxy?
309 Any browser that can be configured to use a "proxy", which should be virtually
310 all browsers. Direct browser support is not necessary since Privoxy runs as a
311 separate application and just exchanges standard HTML data with your browser,
312 just like a web server does.
313 -------------------------------------------------------------------------------
315 2.2. Which operating systems are supported?
317 At present, Privoxy is known to run on Win32, Mac OSX, OS/2, AmigaOS, Linux
318 (RedHat, Suse, Debian), FreeBSD, and many flavors of Unix. There are source and
319 binary releases for these available for download at http://sourceforge.net/
320 project/showfiles.php?group_id=11118.
322 But any operating system that runs TCP/IP, can conceivably take advantage of
323 Privoxy in a networked situation where Privoxy would run as a server on a LAN
324 gateway. Then only the "gateway" needs to be running one of the above operating
327 Source code is freely available, so porting to other operating systems, is
328 always a possibility.
329 -------------------------------------------------------------------------------
331 2.3. Can I install Privoxy over Junkbuster?
333 We recommend you uninstall Junkbuster first to minimize conflicts and
334 confusion. You may want to save your old configuration files for future
335 reference. The configuration is substantially changed.
337 See the user-manual for platform specific installation instructions.
339 Note: Some installers may automatically uninstall Junkbuster, if present!
340 -------------------------------------------------------------------------------
342 2.4. I just installed Privoxy. Is there anything special I have to do now?
344 All browsers must be told to use Privoxy as a proxy by specifying the correct
345 proxy address and port number in the appropriate configuration area for the
346 browser. See below. Also, you should flush your browser's memory and disk cache
347 to get rid of any cached items.
348 -------------------------------------------------------------------------------
350 2.5. What is the proxy address of Privoxy?
352 If you set up the Privoxy to run on the computer you browse from (rather than
353 your ISP's server or some networked computer on a LAN), the proxy will be on
354 "localhost" (which is the special name used by every computer on the Internet
355 to refer to itself) and the port will be 8118 (unless you have Privoxy to run
356 on a different port with the listen-address config option).
358 When configuring your browser's proxy settings you typically enter the word
359 "localhost" in the boxes next to "HTTP" and "Secure" (HTTPS) and then the
360 number "8118" for "port". This tells your browser to send all web requests to
361 Privoxy instead of directly to the Internet.
363 Privoxy can also be used to proxy for a Local Area Network. In this case, your
364 would enter either the IP address of the LAN host where Privoxy is running, or
365 the equivalent hostname. Port assignment would be same as above.
367 Privoxy does not currently handle protocols such as FTP, SMTP, IM, IRC, ICQ, or
368 other Internet protocols.
369 -------------------------------------------------------------------------------
371 2.6. I just installed Privoxy, and nothing is happening. All the ads are there.
374 Did you configure your browser to use Privoxy as a proxy? It does not sound
375 like it. See above. You might also try flushing the browser's caches to force a
376 full re-reading of pages. You can verify that Privoxy is running, and your
377 browser is correctly configured by entering the special URL: http://p.p/. This
378 should give you a banner that says "This is Privoxy" and access to Privoxy's
379 internal configuration. If you see this, then you are good to go. If not, the
380 browser or Privoxy are not set up correctly.
381 -------------------------------------------------------------------------------
385 3.1. Can I use my old config files?
387 There are major changes to Junkbuster/ Privoxy configuration from version 2.0.x
388 to 2.9.x and later. Most of the older files will not work at all. This is
389 especially true of blocklist. If this is the case, you will need to re-enter
390 your old data into the new configuration structure. This is probably also a
391 good recommendation even if upgrading from 2.9.x to 3.x since there were many
392 minor changes along the way.
393 -------------------------------------------------------------------------------
395 3.2. What is an "actions" file?
397 "actions" files are where various actions that Privoxy might take, are
398 configured. Typically, you would define a set of default actions that apply to
399 all URLs, then add exceptions to these defaults.
401 Actions can be defined on a per site basis, or for groups of sites. Actions can
402 also be grouped together and then applied to one or more sites. There are many
403 possible actions that might apply to any given site. As an example, if we are
404 blocking cookies as one of our default actions, but need to accept cookies from
405 a given site, we would define this in our "actions" file.
407 Privoxy comes with several default actions files, with varying degrees of
408 filtering and blocking, as starting points for your own configuration (see
410 -------------------------------------------------------------------------------
412 3.3. The "actions" concept confuses me. Please list some of these "actions".
414 These are all explained in the user-manual. Please refer to that.
415 -------------------------------------------------------------------------------
417 3.4. How are actions files configured? What is the easiest way to do this?
419 The easiest way to do this, is to access Privoxy with your web browser at http:
420 //p.p/, and then select "Edit the actions list" from the selection list. You
421 can also do this by editing the appropriate file with a text editor.
423 Please see the user-manual for a detailed explanation of these and other
424 configuration files, and their various options and syntax.
425 -------------------------------------------------------------------------------
427 3.5. What are the differences between intermediate.action, basic.action, etc.?
429 Configuring Privoxy is not easy. To help you get started, we provide you with
430 three different default configurations. The following table shows you, which
431 features are enabled in each configuration.
433 Table 1. Default Configurations
434 +--------------------+--------------+--------------+-------------------+---------------+
435 |Feature |default.action|basic.action |intermediate.action|advanced.action|
436 +--------------------+--------------+--------------+-------------------+---------------+
437 |ad-filtering |? |x |x |x |
438 +--------------------+--------------+--------------+-------------------+---------------+
439 |blank image |? |x |x |x |
440 +--------------------+--------------+--------------+-------------------+---------------+
441 |de-animate GIFs |? |x |x |x |
442 +--------------------+--------------+--------------+-------------------+---------------+
443 |referer forging |? |x |x |x |
444 +--------------------+--------------+--------------+-------------------+---------------+
446 |+no-cookies-keep | | | | |
447 |(i.e. session | | | | |
448 |cookies only) | | | | |
449 +--------------------+--------------+--------------+-------------------+---------------+
450 |no-popup windows |? | |x |x |
451 +--------------------+--------------+--------------+-------------------+---------------+
452 |fast redirects |? | |x |x |
453 +--------------------+--------------+--------------+-------------------+---------------+
454 |hide-referrer |? | |x |x |
455 +--------------------+--------------+--------------+-------------------+---------------+
456 |hide-useragent |? | |x |x |
457 +--------------------+--------------+--------------+-------------------+---------------+
458 |content-modification|? | | |x |
459 +--------------------+--------------+--------------+-------------------+---------------+
460 |feature-x |? | | | |
461 +--------------------+--------------+--------------+-------------------+---------------+
462 |feature-y |? | | | |
463 +--------------------+--------------+--------------+-------------------+---------------+
464 |feature-z |? | | | |
465 +--------------------+--------------+--------------+-------------------+---------------+
466 -------------------------------------------------------------------------------
468 3.6. Why can I change the configuration with a browser? Does that not raise
471 What I don't understand, is how I can browser edit the config file as a regular
472 user, while the whole /etc/privoxy hierarchy belongs to the user "privoxy",
473 with only 644 permissions.
475 When you use the browser-based editor, Privoxy itself is writing to the config
476 files. Because Privoxy is running as the user "privoxy", it can update the
479 If you don't like this, setting "enable-edit-actions 0" in the config file will
480 disable the browser-based editor. If you're that paranoid, you should also
481 consider setting "enable-remote-toggle 0" to prevent browser-based enabling/
482 disabling of Privoxy.
484 Note that normally only local users can connect to Privoxy, so this is not
485 (normally) a security problem.
486 -------------------------------------------------------------------------------
488 3.7. What is "default.filter"?
490 The "default.filter" file is used to "filter" any web page content. By
491 "filtering" we mean it can modify, remove, or change anything on the page,
492 including HTML tags, and JavaScript. Regular expressions are used to accomplish
493 this, and operate on a line by line basis. This is potentially a very powerful
494 feature, but requires some expertise.
496 If you are familiar with regular expressions, and HTML, you can look at the
497 provided default.filter with a text editor and see some of things it can be
500 Presently, there is no GUI editor option for this part of the configuration,
501 but you can disable/enable various sections of the included default file with
502 the "Actions List Editor" from your browser.
503 -------------------------------------------------------------------------------
505 3.8. How can I set up Privoxy to act as a proxy for my LAN?
507 By default, Privoxy only responds to requests from localhost. To have it act as
508 a server for a network, this needs to be changed in the main config file where
509 the Privoxy configuration is located. In that file is a "listen-address"
510 option. It may be commented out with a "#" symbol. Make sure it is uncommented,
511 and assign it the address of the LAN gateway interface, and port number to use:
513 listen-address 192.168.1.1:8118
516 Save the file, and restart Privoxy. Configure all browsers on the network then
517 to use this address and port number.
518 -------------------------------------------------------------------------------
520 3.9. Instead of ads, now I get a checkerboard pattern. I don't want to see
523 This is a configuration option for images that Privoxy is stopping. You have
524 the choice of a checkerboard pattern, a transparent 1x1 GIF image (aka "blank"
525 ), or a custom URL of your choice. Note that to fit this category, the URL must
526 match both the "+image" and "+block" actions.
528 If you want to see nothing, then change the "+image-blocker" action to
529 "+image-blocker{blank}". This can be done from the "Edit Actions List"
530 selection at http://p.p/. Or by hand editing the appropriate actions file. This
531 will only effect what is defined as "images" though. Also, some URLs that
532 generate the bright red "Blocked" banner, can be moved to the "+image-blocker"
533 section for the same reason, but there are some limits and risks to this (see
535 -------------------------------------------------------------------------------
537 3.10. Why would anybody want to see a checkerboard pattern?
539 This can be helpful for troubleshooting problems. It might also be good for
540 anyone new to Privoxy so that they can see if their favorite pages are
541 displaying correctly, and Privoxy is not inadvertently removing something
543 -------------------------------------------------------------------------------
545 3.11. I see large red banners on some pages that say "Blocked". Why and how do
548 These are URLs that match something in one of Privoxy's block actions (+block).
549 It is meant to be a warning so that you know something has been blocked and an
550 easy way for you to see why. These are handled differently than what has been
551 defined explicitly as "images" (e.g. ad banners). Depending on the URL itself,
552 it is sometimes hard for Privoxy to really know whether there is indeed an ad
553 image there or not. And there are limitations as to what Privoxy can do to
556 For instance, if the ad is in a frame, then it is embedded in the separate HTML
557 page used for the frame. In this case, you cannot just substitute an aribitray
558 image (like we would for a "blank" image), for an HTML page. The browser is
559 expecting an HTML page, and that is what it must have for frames. So this
560 situation can be a little trickier to deal with, and Privoxy will use the
563 If you want these to be treated as if they were images, so that they can be
564 made invisible, you can try moving the offending URL from the "+block" section
565 to the "+imageblock" section of your actions file. Just be forewarned, if any
566 URL is made "invisible", you may not have any inkling that something has been
567 removed from that page, or why. If this approach does not work, then you are
568 probably dealing with a frame (or "ilayer"), and the only thing that can go
569 there is an HTML page of some sort.
571 To deal with this situation, you could modify the "block" HTML template that is
572 used by Privoxy to display this, and make it something more to your liking.
573 Currently, there is no configuration option for this. You will have to modify,
574 or create your own page, and use this to replace templates/blocked, which is
575 what Privoxy uses to display the "Blocked" page.
577 Another way to deal with this is find why and where Privoxy is blocking the
578 frame, and diable this. Then let the "+image-blocker" action handle the ad that
579 is embedded in the frame's HTML page.
580 -------------------------------------------------------------------------------
582 3.12. I cannot see all of the "Blocked" page banner. All I see is a bright red
585 There is not enough space to fit the entire page. Try right clicking on the
586 visible, red portion, and select "Show Frame", or equivalent. This will usually
587 allow you to see the entire Privoxy "Blocked" page, and from there you can see
588 just what is being blocked, and why.
589 -------------------------------------------------------------------------------
591 3.13. Can Privoxy run as a service on Win2K/NT?
593 Yes, it can run as a system service using srvany.exe. The only catch is that
594 this will effectively disable the Privoxy icon in the taskbar. You can have one
595 or the other, but not both at this time :(
597 There is a pending feature request for this functionality. See thread: http://
598 sourceforge.net/tracker/?func=detail&atid=361118&aid=485617&group_id=11118, for
599 details, and a sample configuration.
600 -------------------------------------------------------------------------------
602 3.14. How can I make Privoxy work with other proxies like Squid?
604 This can be done. See the user manual, which describes how to do this.
605 -------------------------------------------------------------------------------
609 4.1. How much does Privoxy slow my browsing down? This has to add extra time to
612 It should not slow you down any in real terms, and may actually help speed
613 things up since ads, banners and other junk are not being displayed. The actual
614 processing time required by Privoxy itself for each page, is relatively small
615 in the overall scheme of things, and happens very quickly. This is typically
616 more than offset by time saved not downloading and rendering ad images.
618 "Filtering" via the filterfile mechanism may cause a perceived slowdown, since
619 the entire page is buffered before displaying. See below.
620 -------------------------------------------------------------------------------
622 4.2. I noticed considerable delays in page requests compared to the old
623 Junkbuster. What's wrong?
625 Using the default filtering configuration, I noticed considerable delays in
626 page requests compared to the old Junkbuster. Loading pages with large contents
627 seemed to take forever, then suddenly delivering all the content at once.
629 The whole content must be loaded in order to filter, and nothing is is sent to
630 the browser during this time. The loading time does not really change in real
631 numbers, but the feeling is different, because most browsers are able to start
632 rendering incomplete content, giving the user a feeling of "it works".
634 To modify the content of a page (i.e. make frames resizeable again, etc.) and
635 not just replace ads, Privoxy needs to download the entire page first, do its
636 content magic and then send the page to the browser.
637 -------------------------------------------------------------------------------
639 4.3. What is the "http://p.p/"?
641 Since Privoxy sits between your web browser and the Internet, it can be
642 programmed to handle certain pages specially.
644 With recent versions of Privoxy (version 2.9.x), you can get some information
645 about Privoxy and change some settings by going to http://p.p/ or,
646 equivalently, http://config.privoxy.org/ (Note that p.p is far easier to type
647 but may not work in some configurations. With the name change to Privoxy, this
648 is changed from the previous http://i.j.b/ or earlier 2.9.x versions).
650 These pages are not forwarded to a server on the Internet - instead they are
651 handled by a special web server which is built in to Privoxy.
653 If you are not running Privoxy, then http://p.p/ will fail, and http://
654 config.privoxy.org/ will return a web page telling you you're not running
657 If you have version 2.0.2, then the equivalent is http://example.com/
658 show-proxy-args (but you get far less information, and you should really
659 consider upgrading to 2.9.13).
660 -------------------------------------------------------------------------------
662 4.4. Do you still maintain the blocklists?
664 No. The format of the blocklists has changed significantly in versions 2.9.x
665 and later. Once we have released the new stable version, v3.0, there will again
666 be blocklists that you can update automatically.
667 -------------------------------------------------------------------------------
669 4.5. How can I submit new ads?
671 As of now, please discontinue to submit new ad blocking infos. Once we have
672 released the new version, there will again be a form on the website, which you
673 can use to contribute new ads.
674 -------------------------------------------------------------------------------
676 4.6. How can I hide my IP address?
678 You cannot hide your IP address with Privoxy or any other software, since the
679 server needs to know your IP address to send the answer to you.
681 Fortunately there are many publicly usable anonymous proxies out there, which
682 solve the problem by providing a further level of indirection between you and
683 the web server, shared by many people and thus letting your requests "drown" in
684 white noise of unrelated requests as far as user tracking is concerned.
686 Most of them will, however, log your IP address and make it available to the
687 authorities in case you abuse that anonymity for criminal purposes. In fact you
688 can't even rule out that some of them only exist to *collect* information on
689 (those suspicious) people with a more than average preference for privacy.
691 You can find a list of anonymous public proxies at multiproxy.org and many more
693 -------------------------------------------------------------------------------
695 4.7. Can Privoxy guarantee I am anonymous?
697 No. Your chances of remaining anonymous are greatly improved, but unless you
698 are an expert on Internet security it would be safest to assume that everything
699 you do on the Web can be traced back to you.
701 Privoxy can remove various information about you, and allows you more freedom
702 to decide which sites you can trust, and what details you want to reveal. But
703 it's still possible that web sites can find out who you are. Here's one way
706 A few browsers disclose the user's email address in certain situations, such as
707 when transferring a file by FTP. Privoxy does not filter FTP. If you need this
708 feature, or are concerned about the mail handler of your browser disclosing
709 your email address, you might consider products such as NSClean.
711 Browsers available only as binaries could use non-standard headers to give out
712 any information they can have access to: see the manufacturer's license
713 agreement. It's impossible to anticipate and prevent every breach of privacy
714 that might occur. The professionally paranoid prefer browsers available as
715 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.
742 -------------------------------------------------------------------------------
744 4.9. Can Privoxy act as a "caching" proxy to speed up web browsing?
746 No, it does not have this ability at all. You want something like Squid for
747 this. And, yes, before you ask, Privoxy can co-exist with other kinds of
749 -------------------------------------------------------------------------------
751 4.10. What about as a firewall? Can Privoxy protect me?
753 Not in the way you mean, or in the way a true firewall can, or a proxy that has
754 this specific capability. Privoxy can help protect your privacy, but not really
755 protect you from intrusion attempts.
756 -------------------------------------------------------------------------------
758 4.11. The Privoxy logo that replaces ads is very blocky and ugly looking. Can't
759 a better font be used?
761 This is not a font problem. The logo is an image that is created by Privoxy on
762 the fly. So as to not waste memory, the image is rather small. The blockiness
763 comes when the image is scaled to fill a largish area. There is not much to be
764 done about this, other than to use one of the other "imageblock" directives:
765 pattern, blank, or a URL of your choosing.
767 Given the above problem, we have decided to remove the logo option entirely [as
769 -------------------------------------------------------------------------------
771 4.12. I have large empty spaces now where ads used to be. Why?
773 It would be easy enough to just eliminate this space altogether, rather than
774 fill it with blank space. But, this would create problems with many pages that
775 use the overall size of the ad to help organize the page layout and position
776 the various components of the page where they were intended to be. It is best
778 -------------------------------------------------------------------------------
780 4.13. How can Privoxy filter Secure (HTTPS) URLs?
782 This is a limitation since HTTPS transactions are encrypted SSL sessions
783 between your browser and the secure site, and are meant to be reliably secure
784 and private. This means that all cookies and HTTP header information are also
785 encrypted from the time they leave your browser, to the site, and vice versa.
786 Privoxy does not try to unencrypt this information, so it just passes through
787 as is. Privoxy can still catch images and ads that are embedded in the SSL
789 -------------------------------------------------------------------------------
791 4.14. Privoxy runs as a "server". How secure is it? Do I need to take any
794 There are no known exploits that might effect Privoxy. On Unix-like systems,
795 Privoxy can run as a non-privileged user, which is how we recommend it be run.
796 Also, by default Privoxy only listens to requests from "localhost". The server
797 aspect of Privoxy is not itself directly exposed to the Internet in this
798 configuration. If you want to have Privoxy serve as a LAN proxy, this will have
799 to be opened up to allow for LAN requests. In this case, we'd recommend you
800 specify only the LAN gateway address, e.g. 192.168.1.1, in the main Privoxy
801 config file. All LAN hosts can then use this as their proxy address in the
802 browser proxy configuration. In this way, Privoxy will not listen on any
803 external ports. Of course, a firewall is always good too. Better safe than
805 -------------------------------------------------------------------------------
807 4.15. How can I temporarily disable Privoxy?
809 The easiest way is to access Privoxy with your browser by using the special
810 URL: http://p.p/ and select "Toggle Privoxy on or off" from that page.
811 -------------------------------------------------------------------------------
813 4.16. Where can I find more information about Privoxy and related issues?
815 Other references and sites of interest to Privoxy users:
817 http://www.privoxy.org/, The Privoxy Home page.
819 http://sourceforge.net/projects/ijbswa, the Project Page for Privoxy on
822 http://p.p/, access Privoxy from your browser. Alternately, http://
823 config.privoxy.org may work in some situations where the first does not.
825 http://www.junkbusters.com/ht/en/cookies.html
827 http://www.waldherr.org/junkbuster/
829 http://privacy.net/analyze/
831 http://www.squid-cache.org/
834 -------------------------------------------------------------------------------
838 5.1. I just upgraded and am getting "connection refused" with every web page?
840 Either Privoxy is not running, or your browser is configured for a different
841 port than what Privoxy is using.
843 The old Privoxy (and also Junkbuster) used port 8000 by default. This has been
844 changed to port 8118 now, due to a conflict with NAS (Network Audio Service),
845 which uses port 8000. If you haven't, you need to change your browser to the
846 new port number, or alternately change Privoxy's "listen-address" setting in
847 the config file used to start Privoxy.
848 -------------------------------------------------------------------------------
850 5.2. I just added a new rule, but the steenkin ad is still getting through.
853 If the ad had been displayed before you added its URL, it will probably be held
854 in the browser's cache for some time, so it will be displayed without the need
855 for any request to the server, and Privoxy will not be in the picture. The best
856 thing to do is try flushing the browser's caches. And then try again.
858 If this doesn't help, you probably have an error in the rule you applied. Try
859 pasting the full URL of the offending ad into http://config.privoxy.org/
860 show-url-info and see if any actions match your new rule.
861 -------------------------------------------------------------------------------
863 5.3. One of my favorite sites does not work with Privoxy. What can I do?
865 First verify that it is indeed a Privoxy problem, by disabling Privoxy
866 filtering and blocking. Go to http://p.p/ and click on "Toggle Privoxy On or
867 Off", then disable it. Now try that page again. It's probably a good idea to
868 flush the browser cache as well.
870 If still a problem, go to "Show which actions apply to a URL and why" from
871 http://p.p/ and paste the full URL of the page in question into the prompt. See
872 which actions are being applied to the URL. Now, armed with this information,
873 go to "Edit the actions list". Here you should see various sections that have
874 various Privoxy features disabled for specific sites. Most disabled "actions"
875 will have a "-" (minus sign) in front of them. Some aliases are used just to
876 disable other actions, e.g. "shop" and "fragile", and won't necessarily use a
877 "+" or "-" sign. Add your problem page URL to one of these sections that looks
878 like it is disabling the feature that is causing the problem. Rember to flush
879 your browser's caches when making such changes! As a last resort, try "fragile"
880 which disables most actions. Now re-try the page. There might be some trial and
881 error involved. This is discussed in a little more detail in the user-manual
884 Alternately, if you are comfortable with a text editor, you can accomplish the
885 same thing by editing the appropriate "actions" file.
886 -------------------------------------------------------------------------------
888 5.4. Where can I get help? Report bugs? Feature Requests? Etc?
890 Feedback is encouraged, whether good, bad or ugly. Please see the contact page
891 in the user-manual for details.
892 -------------------------------------------------------------------------------
894 5.5. What time is it?
897 -------------------------------------------------------------------------------
899 7. Contacting the developers, Bug Reporting and Feature Requests
901 We value your feedback. However, to provide you with the best support, please
904 * Use the Sourceforge Support Forum to get help:
906 http://sourceforge.net/tracker/?group_id=11118&atid=211118
909 * Submit bugs only through our Sourceforge Bug Forum:
911 http://sourceforge.net/tracker/?group_id=11118&atid=111118.
914 Make sure that the bug has not already been submitted. Please try to verify
915 that it is a Privoxy bug, and not a browser or site bug first. If you are
916 using your own custom configuration, please try the stock configs to see if
917 the problem is a configuration related bug. And if not using the latest
918 development snapshot, please try the latest one. Or even better, CVS
919 sources. Please be sure to include the Privoxy/Junkbuster version,
920 platform, browser, any pertinent log data, any other relevant details
921 (please be specific) and, if possible, some way to reproduce the bug.
923 * Submit feature requests only through our Sourceforge feature request
926 http://sourceforge.net/tracker/?atid=361118&group_id=11118&func=browse.
929 * We will soon have an automated way to submit advertisements, incorrectly
930 blocked images, popups and the like. Check back.
933 * For any other issues, feel free to use the mailing lists:
935 http://sourceforge.net/mail/?group_id=11118.
938 Anyone interested in actively participating in development and related
939 discussions can also join the appropriate mailing list. Archives are
943 -------------------------------------------------------------------------------
944 8. Copyright and History
948 Privoxy is free software; you can redistribute it and/or modify it under the
949 terms of the GNU General Public License as published by the Free Software
950 Foundation; either version 2 of the License, or (at your option) any later
953 This program is distributed in the hope that it will be useful, but WITHOUT ANY
954 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
955 PARTICULAR PURPOSE. See the GNU General Public License for more details, which
956 is available from the Free Software Foundation, Inc, 59 Temple Place - Suite
957 330, Boston, MA 02111-1307, USA.
959 You should have received a copy of the GNU General Public License along with
960 this program; if not, write to the Free Software Foundation, Inc., 59 Temple
961 Place, Suite 330, Boston, MA 02111-1307 USA.
962 -------------------------------------------------------------------------------
966 Privoxy is evolved, and derived from, the Internet Junkbuster, with many
967 improvments and enhancements over the original.
969 Junkbuster was originally written by Anonymous Coders and Junkbuster's
970 Corporation, and was released as free open-source software under the GNU GPL.
971 Stefan Waldherr made many improvements, and started the SourceForge project
972 Privoxy to rekindle development. There are now several active developers
973 contributing. The last stable release of Junkbuster was v2.0.2, which has now