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38 >Privoxy Frequently Asked Questions</TH
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73 >1. General Information</A
81 >1.1. What is this new version of <SPAN
87 > In the beginning, there was the
89 HREF="http://www.junkbusters.com/ijb.html"
93 >Internet Junkbuster</SPAN
96 by Anonymous Coders and <A
97 HREF="http://www.junkbusters.com/"
101 >. It saved many users a lot of pain in the early days of
102 web advertising and user tracking.</P
104 > But the web, its protocols and standards, and with it, the techniques for
105 forcing users to consume ads, give up autonomy over their browsing, and
106 for spying on them, kept evolving. Unfortunately, the <SPAN
110 > did not. Version 2.0.2, published in 1998, was
111 (and is) the last official
113 HREF="http://www.junkbusters.com/ijbdist.html#release"
118 HREF="http://www.junkbusters.com"
120 >Junkbusters Corporation</A
122 Fortunately, it had been released under the GNU
124 HREF="http://www.gnu.org/licenses/gpl.html"
127 >, which allowed further
128 development by others.</P
130 > So Stefan Waldherr started maintaining an
132 HREF="http://www.waldherr.org/junkbuster/"
134 >improved version of the
136 >, to which eventually a number of people contributed patches.
137 It could already replace banners with a transparent image, and had a first
138 version of pop-up killing, but it was still very closely based on the
139 original, with all its limitations, such as the lack of HTTP/1.1 support,
140 flexible per-site configuration, or content modification. The last release
141 from this effort was version 2.0.2-10, published in 2000.</P
145 HREF="http://www.privoxy.org/user-manual/copyright.html#AUTHORS"
149 picked up the thread, and started turning the software inside out, upside down,
150 and then reassembled it, adding many
152 HREF="http://www.privoxy.org/user-manual/introduction.html#FEATURES"
158 > The result of this is <SPAN
162 stable release, 3.0, is due in June 2002.</P
173 >? Why a name change at all?</A
184 >Privacy Enhancing Proxy</I
187 modification and junk suppression allow you to browse your
197 HREF="http://junkbusters.com/"
199 >Junkbusters Corporation</A
201 continues to offer their original version of the <SPAN
209 >-derived software under the same name
212 > There are also potential legal complications from the continued use of the
216 > name, which is a registered trademark of
218 HREF="http://junkbusters.com/"
220 >Junkbusters Corporation</A
222 There are, however, no objections from Junkbusters Corporation to the
226 > project itself, and they, in fact, still
227 share our ideals and goals.</P
229 > The developers also believed that there are so many changes from the original
230 code, that it was time to make a clean break from the past and make
231 a name in their own right, especially now with the pending
232 release of version 3.0.</P
257 > left off. All the old features remain.
261 > still blocks ads and banners,
262 still manages cookies, and still helps protect your privacy. But, these are
263 all enhanced, and many new features have been added, all in the same vein.
266 > The configuration has changed significantly as well. This is something that
267 users will notice right off the bat if upgrading from
281 > and much more has been
282 combined into the <SPAN
285 > files, with a completely different
287 HREF="../user-manual/upgradersnote.html"
296 >'s new features include:</P
303 > Integrated browser based configuration and control utility at <A
304 HREF="http://config.privoxy.org/"
306 >http://config.privoxy.org/</A
313 tracing of rule and filter effects. Remote toggling.
318 > Web page content filtering (removes banners based on size,
322 >, JavaScript and HTML annoyances, pop-up windows, etc.)
327 > Modularized configuration that allows for standard settings and
328 user settings to reside in separate files, so that installing updated
329 actions files won't overwrite individual user settings.
334 > HTTP/1.1 compliant (but not all optional 1.1 features are supported).
339 > Support for Perl Compatible Regular Expressions in the configuration files, and
340 generally a more sophisticated and flexible configuration syntax over
346 > Improved cookie management features (e.g. session based cookies).
356 > Bypass many click-tracking scripts (avoids script redirection).
361 > Multi-threaded (POSIX and native threads).
366 > User-customizable HTML templates for all proxy-generated pages (e.g. "blocked" page).
371 > Auto-detection and re-reading of config file changes.
376 > Improved signal handling, and a true daemon mode (Unix).
381 > Every feature now controllable on a per-site or per-location basis, configuration
382 more powerful and versatile over-all.
387 > Many smaller new features added, limitations and bugs removed, and security holes fixed.
399 >1.4. What is a <SPAN
409 > A web proxy is a service, based on a software such as <SPAN
413 that clients (i.e. browsers) can use instead of connecting directly to the web
414 servers on the Internet. The clients then ask the proxy to fetch the objects
415 they need (web pages, images, movies etc) on their behalf, and when the proxy
416 has done so, it hands the results back to the client.
419 > There are many reasons to use web proxies, such as security (firewalling),
420 efficiency (caching) and others, and there are just as many different proxies
421 to accommodate those needs.
427 > is a proxy that is solely focused on privacy
428 protection and junk elimination. Sitting between your browser(s) and the Internet,
429 it is in a perfect position to filter outbound personal information that your
430 browser is leaking, as well as inbound junk. It uses a variety of techniques to do
431 this, all of which are under your control via the various configuration
445 an ad, and what is not?</A
451 >'s approach to blocking ads is twofold:</P
453 > First, there are certain patterns in the <I
457 of banner images. This applies to both the path (you wouldn't guess how many
458 web sites serve their banners from a directory called <SPAN
462 and the host (blocking the big banner hosting services like doublecklick.net
463 already helps a lot). <SPAN
466 > takes advantage of this
468 HREF="../user-manual/actions-file.html#AF-PATTERNS"
472 > to sort out and block the requests for banners.</P
474 > Second, banners tend to come in certain <I
478 can't tell the size of an image by its URL without downloading it, and if you
479 do, it's too late to save bandwidth. Therefore, <SPAN
483 also inspects the HTML sources of web pages while they are loaded, and replaces
484 references to images with standard banner sizes by dummy references, so that
485 your browser doesn't request them anymore in the first place.</P
487 > Both of this involves a certain amount of guesswork and is, of course, freely
500 This does not sound very scientific.</A
503 > Actually, it's a black art ;-) And yes, it is always possible to have a broad
504 rule accidentally block or change something by mistake. There is a good chance
505 you may run into such a situation at some point. It is tricky writing rules to
506 cover every conceivable possibility, and not occasionally get false positives.</P
508 > But this should not be a big concern since the
512 > configuration is very flexible, and
513 includes tools to help identify these types of situations so they can be
514 addressed as needed, allowing you to customize your installation.
516 HREF="trouble.html#AEN737"
517 >See the Troubleshooting section below</A
526 >1.7. My browser does the same things as
537 > Modern browsers do indeed have <I
541 functionality as <SPAN
545 adequate for you. But <SPAN
549 versatile and powerful, and can do a number of things that browsers just can't.
552 > In addition, a proxy is good choice if you use multiple browsers, or
553 have a LAN with multiple computers. This way all the configuration
554 is in one place, and you don't have to maintain a similar configuration
555 for possibly many browsers.
564 >1.8. Is there is a license or fee? What about a
565 warranty? Registration?</A
571 > is licensed under the <A
572 HREF="http://www.gnu.org/copyleft/gpl.html"
574 >GNU General Public License (GPL)</A
576 It is free to use, copy, modify or distribute as you wish under the terms of this
577 license. Please see the <A
578 HREF="copyright.html"
581 information on the license and copyright. Or the <TT
585 that should be included.
591 > of any kind, expressed, implied or otherwise.
592 That is something that would cost real money ;-) There is no registration either.
609 >1.9. I would like to help you, what do I do?</A
616 NAME="JOINTEAM-MONEY"
617 >1.9.1. Money Money Money</A
620 > We, of course, welcome donations and could use money for domain registering,
621 buying software to test <SPAN
624 > with, and, of course,
625 for regular world-wide get-togethers (hahaha). If you enjoy the software and feel
626 like helping us with a donation, just <A
627 HREF="mailto:developers@privoxy.org"
637 NAME="JOINTEAM-SOFTWARE"
641 > If you are a vendor of a web-related software like a browser, web server
642 or proxy, and would like us to ensure that <SPAN
646 runs smoothly with your product, you might consider supplying us with a
647 copy or license. We can't, however, guarantee that we will fix all potential
648 compatibility issues as a result.</P
656 >1.9.3. You want to work with us?</A
659 > Well, helping the team is always a good idea. We welcome new developers,
660 packaging gurus or documentation writers. Simply <A
661 HREF="https://sourceforge.net/account/register.php"
663 >get an account on SourceForge.net</A
665 and mail your id to the <A
666 HREF="mailto:developers@privoxy.org"
671 HREF="../developer-manual/index.html"
673 >Developer's Manual</A
676 > Once we have added you to the team, you'll have write access to the <A
677 HREF="http://sourceforge.net/cvs/?group_id=11118"
681 together we'll find a suitable task for you.</P
716 HREF="installation.html"
725 >Privoxy Frequently Asked Questions</TD