1 Privoxy Frequently Asked Questions
5 $Id: faq.sgml,v 1.33 2002/03/29 01:31:48 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. 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 You can find the latest version of the document at http://www.privoxy.org/faq/.
23 Please see the Contact section in the user-manual if you want to contact the
26 -------------------------------------------------------------------------------
29 1. Frequently Asked Questions
31 1.1. General Information
33 1.1.1. What is this new version of Privoxy?
34 1.1.2. Why "Privoxy"? Why a name change at all?
35 1.1.3. How does Privoxy differ from the old Junkbuster?
36 1.1.4. What are some of the new features?
37 1.1.5. What is a "proxy"? How does Privoxy work?
38 1.1.6. How does Privoxy know what is an ad, and what is not?
39 1.1.7. Can Privoxy make mistakes? This does not sound very scientific.
40 1.1.8. My browser does the same things as Privoxy. Why should I use
42 1.1.9. Is there is a license or fee? What about a warranty?
44 1.1.10. I would like to help you, what do I do?
48 1.2.1. Which browsers are supported by Privoxy?
49 1.2.2. Which operating systems are supported?
50 1.2.3. Can I install Privoxy over Junkbuster?
51 1.2.4. I just installed Privoxy. Is there anything special I have to do
53 1.2.5. What is the proxy address of Privoxy?
54 1.2.6. I just installed Privoxy, and nothing is happening. All the ads
55 are there. What's wrong?
59 1.3.1. Can I use my old config files?
60 1.3.2. What is an "actions" file?
61 1.3.3. The "actions"concept confuses me. Please list some of these
63 1.3.4. How are actions files configured? What is the easiest way to do
65 1.3.5. What are the differences between intermediate.action,
67 1.3.6. Why can I change the configuration with a browser? Does that not
68 raise security issues?
69 1.3.7. What is "default.filter"?
70 1.3.8. How can I set up Privoxy to act as a proxy for my LAN?
71 1.3.9. Instead of ads, now I get a checkerboard pattern. I don't want
73 1.3.10. Why would anybody want to see a checkerboard pattern?
74 1.3.11. I see large red banners on some pages that say "Blocked". Why
75 and how do I get rid of this?
76 1.3.12. I cannot see all of the "Blocked" page banner. All I see is a
78 1.3.13. How can I make Privoxy work with other proxies like Squid?
82 1.4.1. How much does Privoxy slow my browsing down? This has to add
83 extra time to browsing.
84 1.4.2. I noticed considerable delays in page requests compared to the
85 old Junkbuster. What's wrong?
86 1.4.3. What is the "http://p.p/"?
87 1.4.4. Do you still maintain the blocklists?
88 1.4.5. How can I submit new ads?
89 1.4.6. How can I hide my IP address?
90 1.4.7. Can Privoxy guarantee I am anonymous?
91 1.4.8. Might some things break because header information is being
93 1.4.9. Can Privoxy act as a "caching" proxy to speed up web browsing?
94 1.4.10. What about as a firewall? Can Privoxy protect me?
95 1.4.11. The Privoxy logo that replaces ads is very blocky and ugly
96 looking. Can't a better font be used?
97 1.4.12. I have large empty spaces now where ads used to be. Why?
98 1.4.13. How can Privoxy filter Secure (HTTPS) URLs?
99 1.4.14. Privoxy runs as a "server". How secure is it? Do I need to take
100 any special precautions?
101 1.4.15. How can I temporarily disable Privoxy?
105 1.5.1. I just upgraded and am getting "connection refused" with every
107 1.5.2. I just added a new rule, but the steenkin ad is still getting
109 1.5.3. One of my favorite sites does not work with Privoxy. What can I
111 1.5.4. Where can I get help? Report bugs? Feature Requests? Etc?
112 1.5.5. What time is it?
114 2. Copyright and History
117 1. Frequently Asked Questions
119 1.1. General Information
121 1.1.1. What is this new version of Privoxy?
123 The original Internet Junkbuster (tm) is a copyrighted product of Junkbusters
124 Corporation. Development of this effort stopped some time ago as of version
125 2.0.2. Stefan Waldherr started the ijbswa project on Sourceforge to rekindle
126 development. Other developers subsequently joined with Stefan, and have since
127 added many new features, refinements and enhancements. The result of this
130 Privoxy started with the same Junkbuster 2.0.2 code base, but has advanced
131 significantly at this point.
133 -------------------------------------------------------------------------------
135 1.1.2. Why "Privoxy"? Why a name change at all?
137 Privoxy is the "Privacy Enhancing Proxy".
139 There are possible legal complications from the continued use of the Junkbuster
140 name, which is a trademark of Junkbusters Corporation. (There are, however, no
141 objections from Junkbusters Corporation to the Privoxy project itself, and
142 they, in fact, still share our ideals and goals.)
144 The developers also believed that there so many changes from the original code,
145 that it was time to make a clean break from the past and make a name in their
146 own right, especially now with the pending release of version 3.0.
148 -------------------------------------------------------------------------------
150 1.1.3. How does Privoxy differ from the old Junkbuster?
152 Privoxy picks up where Junkbuster left off. All the old features remain. The
153 new Privoxy still blocks ads and banners, still manages cookies, and still
154 helps protect your privacy. But, these are all enhanced, and many new features
155 have been added, all in the same vein.
157 The configuration has changed significantly as well. This is something that
158 users will notice right off the bat. The "blocklist" file does not exist any
159 more. This is replaced by "actions" files, such as default.actions. This is
160 where most of the per site configuration is now.
162 -------------------------------------------------------------------------------
164 1.1.4. What are some of the new features?
166 * Integrated browser based configuration and control utility (http://p.p).
167 Browser-based tracing of rule and filter effects.
169 * Blocking of annoying pop-up browser windows.
171 * HTTP/1.1 compliant (most, but not all 1.1 features are supported).
173 * Support for Perl Compatible Regular Expressions in the configuration files,
174 and generally a more sophisticated and flexible configuration syntax over
179 * Web page content filtering (removes banners based on size, invisible
180 "web-bugs", JavaScript, pop-ups, status bar abuse, etc.)
182 * Bypass many click-tracking scripts (avoids script redirection).
184 * Multi-threaded (POSIX and native threads).
186 * Auto-detection and re-reading of config file changes.
188 * User-customizable HTML templates (e.g. 404 error page).
190 * Improved cookie management features (e.g. session based cookies).
192 * Improved signal handling, and a true daemon mode (Unix).
194 * Builds from source on most UNIX-like systems. Packages available for: Linux
195 (RedHat, SuSE, or Debian), Windows, Sun Solaris, Mac OSX, OS/2, HP-UX 11
198 * In addition, the configuration is much more powerful and versatile
201 -------------------------------------------------------------------------------
203 1.1.5. What is a "proxy"? How does Privoxy work?
205 When you connect to a web site with Privoxy, you are really connecting to your
206 locally running version of Privoxy. Privoxy intercepts your requests for the
207 web page, and relays that to the "real" web site. The web site sends the HTTP
208 data stream back to Privoxy, where Privoxy can work its magic before it relays
209 this data back to your web browser.
211 Since Privoxy sits between you and the WWW, it is in a position to intercept
212 and completely manage all web traffic and HTTP content before it gets to your
213 browser. Privoxy uses various programming methods to do this, all of which is
214 under your control via the various configuration files and options.
216 There are many kinds of proxies. Privoxy best fits the "filtering proxy"
219 -------------------------------------------------------------------------------
221 1.1.6. How does Privoxy know what is an ad, and what is not?
223 Privoxy processes all the raw content of every web page. So it reads everything
224 on each page. It then compares this to the rules as set up in the configuration
225 files, and looks for any matches to these rules. Privoxy makes heavy use of
226 "regular expressions". (If you are not familiar with regular expressions, it is
227 explained briefly in the user manual.) Regular expressions facilitate matching
228 of one text string against another, using wildcards to build complex patterns.
229 So Privoxy will typically look for URLs and other content that match certain
230 key words and expressions as defined in the configuration files. For instance a
231 URL that contains "/banners", has a high probability of containing ad banners,
232 and thus would be a prime candidate to have a matching rule.
234 So Privoxy will look for these kinds of obvious looking culprits. And also,
235 will use lists of known organizations that specialize in ads. Again, using
236 complex patterns to match as many potential combinations as possible since
237 there tend to be many, many variations used by advertisers, and new ones are
238 being introduced all the time.
240 -------------------------------------------------------------------------------
242 1.1.7. Can Privoxy make mistakes? This does not sound very scientific.
244 Actually, it's a black art ;-) And yes, it is always possible to have a broad
245 rule accidentally block something by mistake. There is a good chance you may
246 run into such a situation at some point. It is tricky writing rules to cover
247 every conceivable possibility, and not occasionally get false positives.
249 But this should not be a big concern since the Privoxy configuration is very
250 flexible, and includes tools to help identify these types of situations so they
251 can be addressed as needed, allowing you to customize your installation. (See
254 -------------------------------------------------------------------------------
256 1.1.8. My browser does the same things as Privoxy. Why should I use Privoxy at
259 Modern browsers do indeed have some of the same functionality as Privoxy. Maybe
260 this is adequate for you. But Privoxy is much more versatile and powerful, and
261 can do a number of things that browsers just can't.
263 In addition, a proxy is good choice if you use multiple browsers, or have a LAN
264 with multiple computers. This way all the configuration is in one place, and
265 you don't have to maintain a similar configuration for possibly many browsers.
267 -------------------------------------------------------------------------------
269 1.1.9. Is there is a license or fee? What about a warranty? Registration?
271 Privoxy is licensed under the GNU General Public License (GPL). It is free to
272 use, copy, modify or distribute as you wish under the terms of this license.
273 See http://www.gnu.org/copyleft/gpl.html for specifics.
275 There is no warranty of any kind, expressed, implied or otherwise. That is
276 something that would cost real money ;-) There is no registration either.
277 Privoxy really is free in every respect!
279 -------------------------------------------------------------------------------
281 1.1.10. I would like to help you, what do I do?
283 1.1.10.1. Money Money Money
285 We, of course, welcome donations and use the money for domain registering,
286 regular world-wide get-togethers (hahaha). Anyway, we'll soon describe the
287 process how to donate money to the team.
289 -------------------------------------------------------------------------------
291 1.1.10.2. You want to work with us?
293 Well, helping the team is always a good idea. We welcome new developers, RPM
294 gurus or documentation makers. Simply get an account on sourceforge.net and
295 mail your id to the developer mailing list. Then read the section Quickstart in
296 the Developer's Manual.
298 Once we have added you to the team, you'll have write access to the CVS
299 repository, and together we'll find a suitable task for you.
301 -------------------------------------------------------------------------------
305 1.2.1. Which browsers are supported by Privoxy?
307 Any browser that can be configured to use a "proxy", which should be virtually
308 all browsers. Direct browser support is not necessary since Privoxy runs as a
309 separate application and just exchanges standard HTML data with your browser.
311 -------------------------------------------------------------------------------
313 1.2.2. Which operating systems are supported?
315 Right now Win32, Mac OSX, OS/2, AmigaOS, Linux, and many flavors of Unix.
317 Source code is available, so porting to other operating systems, is always a
320 -------------------------------------------------------------------------------
322 1.2.3. Can I install Privoxy over Junkbuster?
324 We recommend you uninstall Junkbuster first to minimize conflicts and
325 confusion. You may want to save your old configuration files for future
326 reference. The configuration is substantially changed.
328 See the user-manual for platform specific installation instructions. [FIXME:
329 This is meant for after the name change for 3.0!]
331 Note: Some installers may automatically uninstall Junkbuster, if present!
333 -------------------------------------------------------------------------------
335 1.2.4. I just installed Privoxy. Is there anything special I have to do now?
337 All browsers must be told to use Privoxy as a proxy by specifying the correct
338 proxy address and port number in the appropriate configuration area for the
339 browser. See below. Also, you should flush your browser's memory and disk cache
340 to get rid of any cached items.
342 -------------------------------------------------------------------------------
344 1.2.5. What is the proxy address of Privoxy?
346 If you set up the Privoxy to run on the computer you browse from (rather than
347 your ISP's server or some networked computer on a LAN), the proxy will be on
348 "localhost" (which is the special name used by every computer on the Internet
349 to refer to itself) and the port will be 8118 (unless you have Privoxy to run
350 on a different port with the listen-address config option).
352 When configuring your browser's proxy settings you typically enter the word
353 "localhost" in the boxes next to "HTTP" and "Secure" (HTTPS) and then the
354 number "8118" for "port". This tells your browser to send all web requests to
355 Privoxy instead of directly to the Internet.
357 Privoxy can also be used to proxy for a Local Area Network. In this case, your
358 would enter either the IP address of the LAN host where Privoxy is running, or
359 the equivalent hostname. Port assignment would be same as above.
361 Privoxy does not currently handle protocols such as FTP, SMTP, IM, IRC, ICQ, or
362 other Internet protocols.
364 -------------------------------------------------------------------------------
366 1.2.6. I just installed Privoxy, and nothing is happening. All the ads are
369 Did you configure your browser to use Privoxy as a proxy? It does not sound
370 like it. See above. You might also try flushing the browser's caches to force a
371 full re-reading of pages. You can verify that Privoxy is running, and your
372 browser is correctly configured by entering the special URL: http://p.p/. This
373 should give you a banner that says "This is Privoxy" and access to Privoxy's
374 internal configuration. If you see this, then you are good to go. If not, the
375 browser or Privoxy are not set up correctly.
377 -------------------------------------------------------------------------------
381 1.3.1. Can I use my old config files?
383 There are major changes to Junkbuster configuration from version 2.0.x to 2.9.x
384 and later. The older files will not work at all. If this is the case, you will
385 need to re-enter your old data into the new configuration structure. This is
386 probably also a good recommendation even if upgrading from 2.9.x to 3.x since
387 there were many minor changes along the way.
389 -------------------------------------------------------------------------------
391 1.3.2. What is an "actions" file?
393 "actions" files are where various actions that Privoxy might take, are
394 configured. Typically, you would define a set of default actions that apply to
395 all URLs, then add exceptions to these defaults.
397 Actions can be defined on a per site basis, or for groups of sites. Actions can
398 also be grouped together and then applied to one or more sites. There are many
399 possible actions that might apply to any given site. As an example, if we are
400 blocking cookies as one of our default actions, but need to accept cookies from
401 a given site, we would define this in our "actions" file.
403 Privoxy comes with several default actions files, with varying degrees of
404 filtering and blocking, as starting points for your own configuration (see
407 -------------------------------------------------------------------------------
409 1.3.3. The "actions"concept confuses me. Please list some of these "actions".
411 These are all explained in the user-manual. Please refer to that.
413 -------------------------------------------------------------------------------
415 1.3.4. How are actions files configured? What is the easiest way to do this?
417 The easiest way to do this, is to access Privoxy with your web browser at http:
418 //p.p/, and then select "Edit the actions list" from the selection list. You
419 can also do this by editing the appropriate file with a text editor.
421 Please see the user-manual for a detailed explanation of these and other
422 configuration files, and their various options and syntax.
424 -------------------------------------------------------------------------------
426 1.3.5. What are the differences between intermediate.action, basic.action,
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
435 +--------------------------------------------------------------------------------------+
436 |Feature |default.action|basic.action |intermediate.action|advanced.action|
437 |--------------------+--------------+--------------+-------------------+---------------|
438 |ad-filtering |? |x |x |x |
439 |--------------------+--------------+--------------+-------------------+---------------|
440 |blank image |? |x |x |x |
441 |--------------------+--------------+--------------+-------------------+---------------|
442 |de-animate GIFs |? |x |x |x |
443 |--------------------+--------------+--------------+-------------------+---------------|
444 |referer forging |? |x |x |x |
445 |--------------------+--------------+--------------+-------------------+---------------|
447 |+no-cookies-keep | | | | |
448 |(i.e. session | | | | |
449 |cookies only) | | | | |
450 |--------------------+--------------+--------------+-------------------+---------------|
451 |no-popup windows |? | |x |x |
452 |--------------------+--------------+--------------+-------------------+---------------|
453 |fast redirects |? | |x |x |
454 |--------------------+--------------+--------------+-------------------+---------------|
455 |hide-referrer |? | |x |x |
456 |--------------------+--------------+--------------+-------------------+---------------|
457 |hide-useragent |? | |x |x |
458 |--------------------+--------------+--------------+-------------------+---------------|
459 |content-modification|? | | |x |
460 |--------------------+--------------+--------------+-------------------+---------------|
461 |feature-x |? | | | |
462 |--------------------+--------------+--------------+-------------------+---------------|
463 |feature-y |? | | | |
464 |--------------------+--------------+--------------+-------------------+---------------|
465 |feature-z |? | | | |
466 +--------------------------------------------------------------------------------------+
468 -------------------------------------------------------------------------------
470 1.3.6. Why can I change the configuration with a browser? Does that not raise
473 What I don't understand, is how I can browser edit the config file as a regular
474 user, while the whole /etc/privoxy hierarchy belongs to the user "privoxy",
477 When you use the browser-based editor, Privoxy itself is writing to the config
478 files. Because Privoxy is running as the user "privoxy", it can update the
481 If you don't like this, setting "enable-edit-actions 0" in the config file will
482 disable the browser-based editor. If you're that paranoid, you should also
483 consider setting "enable-remote-toggle 0" to prevent browser-based enabling/
484 disabling of Privoxy.
486 Note that normally only local users can connect to Privoxy, so this is not
487 (normally) a security problem.
489 -------------------------------------------------------------------------------
491 1.3.7. What is "default.filter"?
493 The "default.filter" file is used to "filter" any web page content. By
494 "filtering" we mean it can modify, remove, or change anything on the page,
495 including HTML tags, and JavaScript. Regular expressions are used to accomplish
496 this, and operate on a line by line basis. This is potentially a very powerful
497 feature, but requires some expertise.
499 If you are familiar with regular expressions, and HTML, you can look at the
500 provided default.filter with a text editor and see some of things it can be
503 Presently, there is no GUI editor option for this part of the configuration,
504 but you can disable/enable various sections of the included default file with
505 the "Actions List Editor" from your browser.
507 -------------------------------------------------------------------------------
509 1.3.8. How can I set up Privoxy to act as a proxy for my LAN?
511 By default, Privoxy only responds to requests from localhost. To have it act as
512 a server for a network, this needs to be changed in the main config file where
513 the Privoxy configuration is located. In that file is a "listen-address"
514 option. It may be commented out with a "#" symbol. Make sure it is uncommented,
515 and assign it the address of the LAN gateway interface, and port number to use:
517 listen-address 192.168.1.1:8118
520 Save the file, and restart Privoxy. Configure all browsers on the network then
521 to use this address and port number.
523 -------------------------------------------------------------------------------
525 1.3.9. Instead of ads, now I get a checkerboard pattern. I don't want to see
528 This is a configuration option for images that Privoxy is stopping. You have
529 the choice of a checkerboard pattern, a transparent 1x1 GIF image (aka
530 "blank"), or a custom URL of your choice. Note that to fit this category, the
531 URL must match both the "+image" and "+block" actions.
533 If you want to see nothing, then change the "+image-blocker" action to
534 "+image-blocker{blank}". This can be done from the "Edit Actions List"
535 selection at http://p.p/. Or by hand editing the appropriate actions file. This
536 will only effect what is defined as "images" though. Also, any URLs that
537 generate the bright red "Blocked" banner, can be moved to the "+image-blocker"
538 section for the same reason.
540 -------------------------------------------------------------------------------
542 1.3.10. Why would anybody want to see a checkerboard pattern?
544 This can be helpful for troubleshooting problems. It might also be good for
545 anyone new to Privoxy so that they can see if their favorite pages are
546 displaying correctly, and Privoxy is not inadvertently removing something
549 -------------------------------------------------------------------------------
551 1.3.11. I see large red banners on some pages that say "Blocked". Why and how
552 do I get rid of this?
554 These are URLs that match something in one of Privoxy's block actions (+block).
555 It is meant to be a warning so that you know something has been blocked and an
556 easy way for you to see why. These are handled differently than what has been
557 defined explicitly as "images" (e.g. ad banners). Depending on the URL itself,
558 it is sometimes hard for Privoxy to really know whether it is indeed an ad
561 If you want them to be treated as if they were images, so that they can be made
562 invisible, then move the offending URL from the "+block" section to the
563 "+imageblock" section of your actions file. Just be forewarned, if make any URL
564 is made "invisible", you may not have any inkling that something has been
565 removed from that page.
567 Alternately, you could modify the "block" HTML template that is used by Privoxy
568 to display this, and make it something more to your liking.
570 -------------------------------------------------------------------------------
572 1.3.12. I cannot see all of the "Blocked" page banner. All I see is a bright
575 There is not enough space to fit the entire page. Try right clicking on the
576 visible, red portion, and select "Show Frame", or equivalent. This will usually
577 allow you to see the entire Privoxy "Blocked" page, and from there you can see
578 just what is being blocked, and why.
580 -------------------------------------------------------------------------------
582 1.3.13. How can I make Privoxy work with other proxies like Squid?
584 This can be done. See the user manual, which describes how to do this.
586 -------------------------------------------------------------------------------
590 1.4.1. How much does Privoxy slow my browsing down? This has to add extra time
593 It should not slow you down any in real terms, and may actually help speed
594 things up since ads, banners and other junk are not being displayed. The actual
595 processing time required by Privoxy itself for each page, is relatively small
596 in the overall scheme of things, and happens very quickly. This is typically
597 more than offset by time saved not downloading and rendering ad images.
599 "Filtering" via the filterfile mechanism may cause a perceived slowdown, since
600 the entire page is buffered before displaying. See below.
602 -------------------------------------------------------------------------------
604 1.4.2. I noticed considerable delays in page requests compared to the old
605 Junkbuster. What's wrong?
607 Using the default filtering configuration, I noticed considerable delays in
608 page requests compared to the old Junkbuster. Loading pages with large contents
609 seemed to take forever, then suddenly delivering all the content at once.
611 The whole content must be loaded in order to filter, and nothing is is sent to
612 the browser during this time. The loading time does not really change in real
613 numbers, but the feeling is different, because most browsers are able to start
614 rendering incomplete content, giving the user a feeling of "it works".
616 To modify the content of a page (i.e. make frames resizeable again, etc.) and
617 not just replace ads, Privoxy needs to download the entire page first, do its
618 content magic and then send the page to the browser.
620 -------------------------------------------------------------------------------
622 1.4.3. What is the "http://p.p/"?
624 Since Privoxy sits between your web browser and the Internet, it can be
625 programmed to handle certain pages specially.
627 With recent versions of Privoxy (version 2.9.x), you can get some information
628 about Privoxy and change some settings by going to http://p.p/ or,
629 equivalently, http://www.privoxy.org/config/ (Note that p.p is far easier to
630 type but may not work in some configurations).
632 These pages are *not* forwarded to a server on the Internet - instead they are
633 handled by a special web server which is built in to Privoxy.
635 If you are not running Privoxy, then http://p.p/ will fail, and http://
636 www.privoxy.org/config/ will return a web page telling you you're not running
639 If you have version 2.0.2, then the equivalent is http://example.com/
640 show-proxy-args (but you get far less information, and you should really
641 consider upgrading to 2.9.x).
643 -------------------------------------------------------------------------------
645 1.4.4. Do you still maintain the blocklists?
647 No. The format of the blocklists has changed significantly in the versions
648 2.9.x. Once we have released the new stable version, v3.0, there will again be
649 blocklists that you can update automatically.
651 -------------------------------------------------------------------------------
653 1.4.5. How can I submit new ads?
655 As of now, please discontinue to submit new ad blocking infos. Once we have
656 released the new version, there will again be a form on the website, which you
657 can use to contribute new ads.
659 -------------------------------------------------------------------------------
661 1.4.6. How can I hide my IP address?
663 You cannot hide your IP address with Privoxy or any other software, since the
664 server needs to know your IP address to send the answer to you.
666 Fortunately there are many publicly usable anonymous proxies out there, which
667 solve the problem by providing a further level of indirection between you and
668 the web server, shared by many people and thus letting your requests "drown" in
669 white noise of unrelated requests as far as user tracking is concerned.
671 Most of them will, however, log your IP address and make it available to the
672 authorities in case you abuse that anonymity for criminal purposes. In fact you
673 can't even rule out that some of them only exist to *collect* information on
674 (those suspicious) people with a more than average preference for privacy.
676 You can find a list of anonymous public proxies at multiproxy.org and many more
679 -------------------------------------------------------------------------------
681 1.4.7. Can Privoxy guarantee I am anonymous?
683 No. Your chances of remaining anonymous are greatly improved, but unless you
684 are an expert on Internet security it would be safest to assume that everything
685 you do on the Web can be traced back to you.
687 Privoxy can remove various information about you, and allows you more freedom
688 to decide which sites you can trust. But it's still possible that web sites can
689 find out who you are. Here's one way this can happen.
691 A few browsers disclose the user's email address in certain situations, such as
692 when transferring a file by FTP. Privoxy does not filter FTP. If you need this
693 feature, or are concerned about the mail handler of your browser disclosing
694 your email address, you might consider products such as NSClean.
696 Browsers available only as binaries could use non-standard headers to give out
697 any information they can have access to: see the manufacturer's license
698 agreement. It's impossible to anticipate and prevent every breach of privacy
699 that might occur. The professionally paranoid prefer browsers available as
700 source code, because anticipating their behavior is easier. Trust the source,
703 -------------------------------------------------------------------------------
705 1.4.8. Might some things break because header information is being altered?
707 Definitely. More and more sites use HTTP header content to decide what to
708 display and how to display it. There is many ways that this can be handled, so
709 having hard and fast rules, is tricky.
711 "USER AGENT" in particular is often used in this way to identify the browser,
712 and adjust content accordingly. Changing this now is not recommended, since so
713 many sites do look for this. You may get undesirable results by changing this.
715 For instance, different browsers use different encodings of Russian and Czech
716 characters, certain web servers convert pages on-the-fly according to the User
717 Agent header. Giving a "User Agent" with the wrong operating system or browser
718 manufacturer causes some sites in these languages to be garbled; Surfers to
719 Eastern European sites should change it to something closer. And then some page
720 access counters work by looking at the "REFERER" header; they may fail or break
721 if unavailable. The weather maps of Intellicast have been blocked by their
722 server when no "REFERER" or cookie is provided, is another example. There are
723 many, many other ways things can go wrong when trying to fool a web server.
725 If you have problems with a site, you will have to adjust your configuration
726 accordingly. Cookies are probably the most likely adjustment that may be
727 required, but by no means the only one.
729 -------------------------------------------------------------------------------
731 1.4.9. Can Privoxy act as a "caching" proxy to speed up web browsing?
733 No, it does not have this ability at all. You want something like Squid for
734 this. And, yes, before you ask, Privoxy can co-exist with other kinds of
737 -------------------------------------------------------------------------------
739 1.4.10. What about as a firewall? Can Privoxy protect me?
741 Not in the way you mean, or in the way a true firewall can, or a proxy that has
742 this specific capability. Privoxy can help protect your privacy, but not really
743 protect you from intrusion attempts.
745 -------------------------------------------------------------------------------
747 1.4.11. The Privoxy logo that replaces ads is very blocky and ugly looking.
748 Can't a better font be used?
750 This is not a font problem. The logo is an image that is created by Privoxy on
751 the fly. So as to not waste memory, the image is rather small. The blockiness
752 comes when the image is scaled to fill a largish area. There is not much to be
753 done about this, other than to use one of the other "imageblock" directives:
754 pattern, blank, or a URL of your choosing.
756 Given the above problem, we have decided to remove the logo option entirely [as
759 -------------------------------------------------------------------------------
761 1.4.12. I have large empty spaces now where ads used to be. Why?
763 It would be easy enough to just eliminate this space altogether, rather than
764 fill it with blank space. But, this would create problems with many pages that
765 use the overall size of the ad to help organize the page layout and position
766 the various components of the page where they were intended to be. It is best
769 -------------------------------------------------------------------------------
771 1.4.13. How can Privoxy filter Secure (HTTPS) URLs?
773 This is a limitation since HTTPS transactions are encrypted SSL sessions
774 between your browser and the secure site, and are meant to be reliably secure
775 and private. This means that all cookies and HTTP header information are also
776 encrypted from the time they leave your browser, to the site, and vice versa.
777 Privoxy does not try to unencrypt this information, so it just passes through
778 as is. Privoxy can still catch images and ads that are embedded in the SSL
781 -------------------------------------------------------------------------------
783 1.4.14. Privoxy runs as a "server". How secure is it? Do I need to take any
786 There are no known exploits that might effect Privoxy. On Unix-like systems,
787 Privoxy can run as a non-privileged user, which is how we recommend it be run.
788 Also, by default Privoxy only listens to requests from "localhost". The server
789 aspect of Privoxy is not itself directly exposed to the Internet in this
790 configuration. If you want to have Privoxy serve as a LAN proxy, this will have
791 to be opened up to allow for LAN requests. In this case, we'd recommend you
792 specify only the LAN gateway address, e.g. 192.168.1.1, in the main Privoxy
793 config file. All LAN hosts can then use this as their proxy address in the
794 browser proxy configuration. In this way, Privoxy will not listen on any
795 external ports. Of course, a firewall is always good too. Better safe than
798 -------------------------------------------------------------------------------
800 1.4.15. How can I temporarily disable Privoxy?
802 The easiest way is to access Privoxy with your browser by using the special
803 URL: http://p.p/ and select "Toggle Privoxy on or off" from that page.
805 -------------------------------------------------------------------------------
809 1.5.1. I just upgraded and am getting "connection refused" with every web page?
811 Either Privoxy is not running, or your browser is configured for a different
812 port than what Privoxy is using.
814 The old Privoxy (and also Junkbuster) used port 8000 by default. This has been
815 changed to port 8118 now, due to a conflict with NAS (Network Audio Service),
816 which uses port 8000. If you haven't, you need to change your browser to the
817 new port number, or alternately change Privoxy's "listen-address" setting in
818 the config file used to start Privoxy.
820 -------------------------------------------------------------------------------
822 1.5.2. I just added a new rule, but the steenkin ad is still getting through.
825 If the ad had been displayed before you added its URL, it will probably be held
826 in the browser's cache for some time, so it will be displayed without the need
827 for any request to the server, and Privoxy will not be in the picture. The best
828 thing to do is try flushing the browser's caches. And then try again.
830 If this doesn't help, you probably have an error in the rule you applied. Try
831 pasting the full URL of the offending ad into http://www.privoxy.org/config/
832 show-url-info and see if any actions match your new rule.
834 -------------------------------------------------------------------------------
836 1.5.3. One of my favorite sites does not work with Privoxy. What can I do?
838 First verify that it is indeed a Privoxy problem, by disabling Privoxy
839 filtering and blocking. Go to http://p.p/ and click on "Toggle Privoxy On or
840 Off", then disable it. Now try that page again. It's probably a good idea to
841 flush the browser cache as well.
843 If still a problem, go to "Show which actions apply to a URL and why" from
844 http://p.p/ and paste the full URL of the page in question into the prompt. See
845 which actions are being applied to the URL. Now, armed with this information,
846 go to "Edit the actions list". Here you should see various sections that have
847 various Privoxy features disabled for specific sites. Disabled "actions" will
848 have a "-" (minus sign) in front of them. Add your problem page URL to one of
849 these sections that looks like it is disabling the feature that is causing the
850 problem. Re-try the page. There might be some trial and error involved. This is
851 discussed in a little more detail in the user-manual appendix.
853 Alternately, if you are comfortable with a text editor, you can accomplish the
854 same thing by editing the appropriate "actions" file.
856 -------------------------------------------------------------------------------
858 1.5.4. Where can I get help? Report bugs? Feature Requests? Etc?
860 Feedback is encouraged, whether good, bad or ugly. Please see the contact page
861 in the user-manual for details.
863 -------------------------------------------------------------------------------
865 1.5.5. What time is it?
869 -------------------------------------------------------------------------------
871 2. Copyright and History
873 Please see the user-manual for information on Copyright and History.
875 -------------------------------------------------------------------------------
879 Please see the user-manual for others references.