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42 <h1 class="SECT1"><a name="GENERAL" id="GENERAL">1. General
46 <h3 class="SECT2"><a name="WHO-USES" id="WHO-USES">1.1. Who should give
47 <span class="APPLICATION">Privoxy</span> a try?</a></h3>
49 <p>Anyone who is interested in security, privacy, or in finer-grained
50 control over their web and Internet experience.</p>
54 <h3 class="SECT2"><a name="BESTCHOICE" id="BESTCHOICE">1.2. Is Privoxy
55 the best choice for me?</a></h3>
57 <p><span class="APPLICATION">Privoxy</span> is certainly a good choice,
58 especially for those who want more control and security. Those with the
59 willingness to read the documentation and the ability to fine-tune
60 their installation will benefit the most.</p>
62 <p>One of <span class="APPLICATION">Privoxy's</span> strengths is that
63 it is highly configurable giving you the ability to completely
64 personalize your installation. Being familiar with, or at least having
65 an interest in learning about <a href=
66 "http://en.wikipedia.org/wiki/Http" target="_top">HTTP</a> and other
67 networking protocols, <a href="http://en.wikipedia.org/wiki/Html"
68 target="_top">HTML</a>, and <a href=
69 "http://en.wikipedia.org/wiki/Regular_expressions" target=
70 "_top"><span class="QUOTE">"Regular Expressions"</span></a> will be a
71 big plus and will help you get the most out of <span class=
72 "APPLICATION">Privoxy</span>. A new installation just includes a very
73 basic configuration. The user should take this as a starting point
74 only, and enhance it as he or she sees fit. In fact, the user is
75 encouraged, and expected to, fine-tune the configuration.</p>
77 <p>Much of <span class="APPLICATION">Privoxy's</span> configuration can
78 be done with a <a href="http://en.wikipedia.org/wiki/Web_browser"
79 target="_top">Web browser</a>. But there are areas where configuration
80 is done using a <a href="http://en.wikipedia.org/wiki/Text_editors"
81 target="_top">text editor</a> to edit configuration files. Also note
82 that the web-based action editor doesn't use authentication and should
83 only be enabled in environments where all clients with access to
84 <span class="APPLICATION">Privoxy</span> listening port can be
89 <h3 class="SECT2"><a name="PROXYMORON" id="PROXYMORON">1.3. What is a
90 <span class="QUOTE">"proxy"</span>? How does Privoxy work?</a></h3>
92 <p>A <a href="http://en.wikipedia.org/wiki/Proxy_server" target=
93 "_top">web proxy</a> is a service, based on a software such as
94 <span class="APPLICATION">Privoxy</span>, that clients (i.e. browsers)
95 can use instead of connecting to web servers directly. The clients then
96 ask the proxy to request objects (web pages, images, movies etc) on
97 their behalf and to forward the data to the clients. It is a
98 <span class="QUOTE">"go-between"</span>. For details, see <a href=
99 "http://en.wikipedia.org/wiki/Proxy_server" target="_top">Wikipedia's
100 proxy definition</a>.</p>
102 <p>There are many reasons to use web proxies, such as security
103 (firewalling), efficiency (caching) and others, and there are any
104 number of proxies to accommodate those needs.</p>
106 <p><span class="APPLICATION">Privoxy</span> is a proxy that is
107 primarily focused on privacy enhancement, ad and junk elimination and
108 freeing the user from restrictions placed on his activities. Sitting
109 between your browser(s) and the Internet, it is in a perfect position
110 to filter outbound personal information that your browser is leaking,
111 as well as inbound junk. It uses a variety of techniques to do this,
112 all of which are under your complete control via the various
113 configuration files and options. Being a proxy also makes it easier to
114 share configurations among multiple browsers and/or users.</p>
118 <h3 class="SECT2"><a name="OTHERSTUFF" id="OTHERSTUFF">1.4. Does
119 Privoxy do anything more than ad blocking?</a></h3>
121 <p>Yes, ad blocking is but one possible use. There are many, many ways
122 <span class="APPLICATION">Privoxy</span> can be used to sanitize and
123 customize web browsing.</p>
127 <h3 class="SECT2"><a name="NEWJB" id="NEWJB">1.5. What is this new
128 version of <span class="QUOTE">"Junkbuster"</span>?</a></h3>
130 <p>A long time ago, there was the <a href=
131 "http://www.junkbusters.com/ijb.html" target="_top"><span class=
132 "APPLICATION">Internet Junkbuster</span></a>, by Anonymous Coders and
133 <a href="http://www.junkbusters.com/" target="_top">Junkbusters
134 Corporation</a>. This saved many users a lot of pain in the early days
135 of web advertising and user tracking.</p>
137 <p>But the web, its protocols and standards, and with it, the
138 techniques for forcing ads on users, give up autonomy over their
139 browsing, and for tracking them, keeps evolving. Unfortunately, the
140 <span class="APPLICATION">Internet Junkbuster</span> did not. Version
141 2.0.2, published in 1998, was (and is) the last official <a href=
142 "http://www.junkbusters.com/ijbdist.html#release" target=
143 "_top">release</a> available from <a href="http://www.junkbusters.com"
144 target="_top">Junkbusters Corporation</a>. Fortunately, it had been
145 released under the GNU <a href=
146 "http://www.gnu.org/licenses/old-licenses/gpl-2.0.html" target=
147 "_top">GPL</a>, which allowed further development by others.</p>
149 <p>So Stefan Waldherr started maintaining an improved version of the
150 software, to which eventually a number of people contributed patches.
151 It could already replace banners with a transparent image, and had a
152 first version of pop-up killing, but it was still very closely based on
153 the original, with all its limitations, such as the lack of HTTP/1.1
154 support, flexible per-site configuration, or content modification. The
155 last release from this effort was version 2.0.2-10, published in
158 <p>Then, some <a href=
159 "http://www.privoxy.org/user-manual/copyright.html#AUTHORS" target=
160 "_top">developers</a> picked up the thread, and started turning the
161 software inside out, upside down, and then reassembled it, adding many
162 <a href="http://www.privoxy.org/user-manual/introduction.html#FEATURES"
163 target="_top">new features</a> along the way.</p>
165 <p>The result of this is <span class="APPLICATION">Privoxy</span>,
166 whose first stable version, 3.0, was released August, 2002.</p>
170 <h3 class="SECT2"><a name="AEN85" id="AEN85">1.6. Why <span class=
171 "QUOTE">"Privoxy"</span>? Why change the name from Junkbuster at
174 <p>Though outdated, <a href="http://junkbusters.com/" target=
175 "_top">Junkbusters Corporation</a> continues to offer their original
176 version of the <span class="APPLICATION">Internet Junkbuster</span>, so
177 publishing our <span class="APPLICATION">Junkbuster</span>-derived
178 software under the same name led to confusion.</p>
180 <p>There are also potential legal complications from our use of the
181 <span class="APPLICATION">Junkbuster</span> name, which is a registered
182 trademark of <a href="http://junkbusters.com/" target=
183 "_top">Junkbusters Corporation</a>. There are, however, no objections
184 from Junkbusters Corporation to the <span class=
185 "APPLICATION">Privoxy</span> project itself, and they, in fact, still
186 share our ideals and goals.</p>
188 <p>The developers also believed that there are so many improvements
189 over the original code, that it was time to make a clean break from the
190 past and make a name in their own right.</p>
192 <p><span class="APPLICATION">Privoxy</span> is the <span class=
193 "QUOTE">"<span class="emphasis"><i class="EMPHASIS">Privacy Enhancing
194 Proxy</i></span>"</span>. Also, its content modification and junk
195 suppression gives <span class="emphasis"><i class=
196 "EMPHASIS">you</i></span>, the user, more control, more freedom, and
197 allows you to browse your personal and <span class=
198 "QUOTE">"<span class="emphasis"><i class="EMPHASIS">private</i></span>
199 edition"</span> of the web.</p>
203 <h3 class="SECT2"><a name="DIFFERS" id="DIFFERS">1.7. How does Privoxy
204 differ from the old Junkbuster?</a></h3>
206 <p><span class="APPLICATION">Privoxy</span> picks up where <span class=
207 "APPLICATION">Junkbuster</span> left off. The new <span class=
208 "APPLICATION">Privoxy</span> still blocks ads and banners, still
209 manages <a href="http://en.wikipedia.org/wiki/Browser_cookie" target=
210 "_top">cookies</a>, and still helps protect your privacy. But, most of
211 these features have been enhanced, and many new ones have been added,
212 all in the same vein.</p>
214 <p><span class="APPLICATION">Privoxy</span>'s new features include:</p>
218 <p>Supports "Connection: keep-alive". Outgoing connections can be
219 kept alive independently from the client.</p>
223 <p>Supports IPv6, provided the operating system does so too, and
224 the configure script detects it.</p>
228 <p>Supports tagging which allows to change the behaviour based on
229 client and server headers.</p>
233 <p>Can be run as an "intercepting" proxy, which obviates the need
234 to configure browsers individually.</p>
238 <p>Sophisticated actions and filters for manipulating both server
239 and client headers.</p>
243 <p>Can be chained with other proxies.</p>
247 <p>Integrated browser-based configuration and control utility at
248 <a href="http://config.privoxy.org/" target=
249 "_top">http://config.privoxy.org/</a> (shortcut: <a href=
250 "http://p.p/" target="_top">http://p.p/</a>). Browser-based tracing
251 of rule and filter effects. Remote toggling.</p>
255 <p>Web page filtering (text replacements, removes banners based on
256 size, invisible <span class="QUOTE">"web-bugs"</span> and HTML
257 annoyances, etc.)</p>
261 <p>Modularized configuration that allows for standard settings and
262 user settings to reside in separate files, so that installing
263 updated actions files won't overwrite individual user settings.</p>
267 <p>Support for Perl Compatible Regular Expressions in the
268 configuration files, and a more sophisticated and flexible
269 configuration syntax.</p>
273 <p>GIF de-animation.</p>
277 <p>Bypass many click-tracking scripts (avoids script
282 <p>User-customizable HTML templates for most proxy-generated pages
283 (e.g. "blocked" page).</p>
287 <p>Auto-detection and re-reading of config file changes.</p>
291 <p>Most features are controllable on a per-site or per-location
296 <p>Many smaller new features added, limitations and bugs
303 <h3 class="SECT2"><a name="WHATSANAD" id="WHATSANAD">1.8. How does
304 Privoxy know what is an ad, and what is not?</a></h3>
306 <p><span class="APPLICATION">Privoxy</span>'s approach to blocking ads
309 <p>First, there are certain patterns in the <span class=
310 "emphasis"><i class="EMPHASIS">locations</i></span> (URLs) of banner
311 images. This applies to both the path (you wouldn't guess how many web
312 sites serve their banners from a directory called <span class=
313 "QUOTE">"banners"</span>!) and the host (blocking the big banner
314 hosting services like doublecklick.net already helps a lot).
315 <span class="APPLICATION">Privoxy</span> takes advantage of this fact
316 by using <a href="../user-manual/actions-file.html#AF-PATTERNS" target=
317 "_top">URL patterns</a> to sort out and block the requests for things
318 that sound like they would be ads or banners.</p>
320 <p>Second, banners tend to come in certain <span class=
321 "emphasis"><i class="EMPHASIS">sizes</i></span>. But you can't tell the
322 size of an image by its URL without downloading it, and if you do, it's
323 too late to save bandwidth. Therefore, <span class=
324 "APPLICATION">Privoxy</span> also inspects the HTML sources of web
325 pages while they are loaded, and replaces references to images with
326 standard banner sizes by dummy references, so that your browser doesn't
327 request them anymore in the first place.</p>
329 <p>Both of this involves a certain amount of guesswork and is, of
330 course, freely and readily configurable.</p>
334 <h3 class="SECT2"><a name="AEN163" id="AEN163">1.9. Can Privoxy make
335 mistakes? This does not sound very scientific.</a></h3>
337 <p>Actually, it's a black art ;-) And yes, it is always possible to
338 have a broad rule accidentally block or change something by mistake.
339 You will almost surely run into such situations at some point. It is
340 tricky writing rules to cover every conceivable possibility, and not
341 occasionally get false positives.</p>
343 <p>But this should not be a big concern since the <span class=
344 "APPLICATION">Privoxy</span> configuration is very flexible, and
345 includes tools to help identify these types of situations so they can
346 be addressed as needed, allowing you to customize your installation.
347 (<a href="trouble.html#BADSITE">See the Troubleshooting section
352 <h3 class="SECT2"><a name="AEN169" id="AEN169">1.10. Will I have to
353 configure Privoxy before I can use it?</a></h3>
355 <p>That depends on your expectations. The default installation should
356 give you a good starting point, and block <span class=
357 "emphasis"><i class="EMPHASIS">most</i></span> ads and unwanted
358 content, but many of the more advanced features are off by default, and
359 require you to activate them.</p>
361 <p>You do have to set up your browser to use <span class=
362 "APPLICATION">Privoxy</span> (see the <a href=
363 "installation.html#FIRSTSTEP">Installation section below</a>).</p>
365 <p>And you will certainly run into situations where there are false
366 positives, or ads not being blocked that you may not want to see. In
367 these cases, you would certainly benefit by customizing <span class=
368 "APPLICATION">Privoxy's</span> configuration to more closely match your
369 individual situation. And we encourage you to do this. This is where
370 the real power of <span class="APPLICATION">Privoxy</span> lies!</p>
374 <h3 class="SECT2"><a name="LAN" id="LAN">1.11. Can Privoxy run as a
375 server on a network?</a></h3>
377 <p>Yes, <span class="APPLICATION">Privoxy</span> runs as a server
378 already, and can easily be configured to <span class=
379 "QUOTE">"serve"</span> more than one client. See <a href=
380 "configuration.html#LANCONFIG">How can I set up Privoxy to act as a
381 proxy for my LAN</a> below.</p>
385 <h3 class="SECT2"><a name="BROWSERS2" id="BROWSERS2">1.12. My browser
386 does the same things as Privoxy. Why should I use Privoxy at
389 <p>Modern browsers do indeed have <span class="emphasis"><i class=
390 "EMPHASIS">some</i></span> of the same functionality as <span class=
391 "APPLICATION">Privoxy</span>. Maybe this is adequate for you. But
392 <span class="APPLICATION">Privoxy</span> is very versatile and
393 powerful, and can probably do a number of things your browser just
396 <p>In addition, a proxy is good choice if you use multiple browsers, or
397 have a LAN with multiple computers since <span class=
398 "APPLICATION">Privoxy</span> can run as a server application. This way
399 all the configuration is in one place, and you don't have to maintain a
400 similar configuration for possibly many browsers or users.</p>
402 <p>Note, however, that it's recommended to leverage both your browser's
403 and <span class="APPLICATION">Privoxy's</span> privacy enhancing
404 features at the same time. While your browser probably lacks some
405 features <span class="APPLICATION">Privoxy</span> offers, it should
406 also be able to do some things more reliable, for example restricting
407 and suppressing JavaScript.</p>
411 <h3 class="SECT2"><a name="WHYTRUST" id="WHYTRUST">1.13. Why should I
412 trust Privoxy?</a></h3>
414 <p>The most important reason is because you have access to <span class=
415 "emphasis"><i class="EMPHASIS">everything</i></span>, and you can
416 control everything. You can check every line of every configuration
417 file yourself. You can check every last bit of source code should you
418 desire. And even if you can't read code, there should be some comfort
419 in knowing that other people can, and do read it. You can build the
420 software from scratch, if you want, so that you know the executable is
421 clean, and that it is <span class="emphasis"><i class=
422 "EMPHASIS">yours</i></span>. In fact, we encourage this level of
423 scrutiny. It is one reason we use <span class=
424 "APPLICATION">Privoxy</span> ourselves.</p>
428 <h3 class="SECT2"><a name="LICENSE" id="LICENSE">1.14. Is there is a
429 license or fee? What about a warranty? Registration?</a></h3>
431 <p><span class="APPLICATION">Privoxy</span> is free software and
432 licensed under the <a href=
433 "http://www.gnu.org/licenses/old-licenses/gpl-2.0.html" target=
434 "_top">GNU General Public License (GPL) version 2</a>. It is free to
435 use, copy, modify or distribute as you wish under the terms of this
436 license. Please see the <a href="copyright.html">Copyright</a> section
437 for more information on the license and copyright. Or the <tt class=
438 "FILENAME">LICENSE</tt> file that should be included.</p>
440 <p>There is <span class="emphasis"><i class="EMPHASIS">no
441 warranty</i></span> of any kind, expressed, implied or otherwise. That
442 is something that would cost real money ;-) There is no registration
447 <h3 class="SECT2"><a name="SPYWARE" id="SPYWARE">1.15. Can Privoxy
448 remove spyware? Adware? Viruses?</a></h3>
450 <p>No, at least not reliably enough to trust it. <span class=
451 "APPLICATION">Privoxy</span> is not designed to be a malware removal
452 tool and the default configuration doesn't even try to filter out any
455 <p><span class="APPLICATION">Privoxy</span> could help prevent contact
456 from (known) sites that use such tactics with appropriate configuration
457 rules, and thus could conceivably prevent contamination from such
458 sites. However, keeping such a configuration up to date would require a
459 lot of time and effort that would be better spend on keeping your
460 software itself up to date so it doesn't have known
465 <h3 class="SECT2"><a name="OTHERADS" id="OTHERADS">1.16. Can I use
466 Privoxy with other ad-blocking software?</a></h3>
468 <p><span class="APPLICATION">Privoxy</span> should work fine with other
469 proxies and other software in general.</p>
471 <p>But it is probably not necessary to use <span class=
472 "APPLICATION">Privoxy</span> in conjunction with other ad-blocking
473 products, and this could conceivably cause undesirable results. It
474 might be better to choose one software or the other and work a little
475 to tweak its configuration to your liking.</p>
477 <p>Note that this is an advice specific to ad blocking.</p>
481 <h3 class="SECT2"><a name="HELP-THE-DEVELOPERS" id=
482 "HELP-THE-DEVELOPERS">1.17. I would like to help you, what can I
486 <h4 class="SECT3"><a name="PARTICIPATE" id="PARTICIPATE">1.17.1.
487 Would you like to participate?</a></h4>
489 <p>Well, we <span class="emphasis"><i class=
490 "EMPHASIS">always</i></span> need help. There is something for
491 everybody who wants to help us. We welcome new developers, packagers,
492 testers, documentation writers or really anyone with a desire to help
493 in any way. You <span class="emphasis"><i class="EMPHASIS">DO
494 NOT</i></span> need to be a <span class="QUOTE">"programmer"</span>.
495 There are many other tasks available. In fact, the programmers often
496 can't spend as much time programming because of some of the other,
497 more mundane things that need to be done, like checking the Tracker
498 feedback sections or responding to user questions on the mailing
501 <p>So first thing, subscribe to the <a href=
502 "https://lists.sourceforge.net/lists/listinfo/ijbswa-users" target=
503 "_top">Privoxy Users</a> or the <a href=
504 "https://lists.sourceforge.net/lists/listinfo/ijbswa-developers"
505 target="_top">Privoxy Developers</a> mailing list, join the
506 discussion, help out other users, provide general feedback or report
507 problems you noticed.</p>
509 <p>If you intend to help out with the trackers, you also might want
510 to <a href="https://sourceforge.net/account/register.php" target=
511 "_top">get an account on SourceForge.net</a> so we don't confuse you
512 with the other name-less users.</p>
514 <p>We also have a <a href="../developer-manual/index.html" target=
515 "_top">Developer's Manual</a>. While it is partly out of date, it's
516 still worth reading.</p>
519 "http://ijbswa.cvs.sourceforge.net/viewvc/ijbswa/current/TODO?view=markup"
520 target="_top">TODO list</a> may be of interest to you as well. Please
521 let us know if you want to work on one of the items listed.</p>
525 <h4 class="SECT3"><a name="DONATE" id="DONATE">1.17.2. Would you like
528 <p><span class="APPLICATION">Privoxy</span> is developed by unpaid
529 volunteers and thus our current running costs are pretty low.
530 Nevertheless, we have plans that will cost money in the future. They
531 include, but aren't limited to spending money on:</p>
535 <p>Hardware to help make sure <span class=
536 "APPLICATION">Privoxy</span> keeps running on platforms the
537 developers currently can't test on and can be ported to
542 <p>Technical books to educate our developers about said platforms
543 or to improve their knowledge in general.</p>
547 <p>More reliable hosting,</p>
551 <p>We would like to get this money through donations made by our
554 <p><span class="APPLICATION">Privoxy</span> has therefore become an
555 associated project of <a href=
556 "http://www.spi-inc.org/about-spi/about-spi" target="_top">Software
557 in the Public Interest (SPI)</a>, which allows us to receive
558 donations. In the United States they are tax-deductible, in a few
559 other western countries they might be tax-deductible in the
562 <p>If you read this section before you may notice that paying for the
563 project domain privoxy.org is no longer on the list. It has been
564 transferred to SPI is sponsored by Mythic Beasts Ltd.</p>
566 <p>If you enjoy our software and feel like helping out with a
567 donation, please have a look at <a href=
568 "http://www.spi-inc.org/donations" target="_top">SPI's donation
569 page</a> to see what the options are. If you have any questions
570 regarding donations please mail to either the public user mailing
571 list or, if it's a private matter, to <a href=
572 "mailto:fk@fabiankeil.de" target="_top">Fabian Keil</a> (Privoxy's
573 SPI liason) directly.</p>
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