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9) <a href="<page docs/documentation>">Documentation » </a>
10) <a href="<page docs/faq>">FAQ</a>
11) </div>
12) <div id="maincol">
13) <!-- PUT CONTENT AFTER THIS TAG -->
14) <h1>Tor FAQ</h1>
15) <hr />
16)
17) <p>General questions:</p>
18) <ul>
19) <li><a href="#WhatIsTor">What is Tor?</a></li>
20) <li><a href="#Torisdifferent">How is Tor different from other proxies?</a></li>
21) <li><a href="#CompatibleApplications">What programs can I use with
22) Tor?</a></li>
23) <li><a href="#WhyCalledTor">Why is it called Tor?</a></li>
24) <li><a href="#Backdoor">Is there a backdoor in Tor?</a></li>
25) <li><a href="#DistributingTor">Can I distribute Tor on my magazine's
26) CD?</a></li>
27) <li><a href="#SupportMail">How can I get an answer to my
28) Tor support mail?</a></li>
29) <li><a href="#WhySlow">Why is Tor so slow?</a></li>
30) <li><a href="#Funding">What would The Tor Project do with more
31) funding?</a></li>
32) </ul>
33)
34) <p>Compilation and Installation:</p>
35) <ul>
36) <li><a href="#HowUninstallTor">How do I uninstall Tor?</a></li>
37) <li><a href="#PGPSigs">What are these "sig" files on the download
38) page?</a></li>
39) <li><a href="#CompileTorWindows">How do I compile Tor under Windows?</a></li>
40) <li><a href="#VirusFalsePositives">Why does my Tor executable appear to
41) have a virus or spyware?</a></li>
42) <li><a href="#LiveCD">Is there a LiveCD or other bundle that includes Tor?</a></li>
43) </ul>
44)
45) <p>Running Tor:</p>
46)
47) <p>Running a Tor client:</p>
48) <ul>
49) <li><a href="#ChooseEntryExit">Can I control which nodes (or country) are used for entry/exit?</a></li>
50) </ul>
51)
52) <p>Running a Tor relay:</p>
53) <ul>
54) <li><a href="#RelayFlexible">How stable does my relay need to be?</a></li>
55) <li><a href="#ExitPolicies">I'd run a relay, but I don't want to deal
56) with abuse issues.</a></li>
57) <li><a href="#RelayOrBridge">Should I be a normal relay or bridge
58) relay?</a></li>
59) <li><a href="#RelayMemory">Why is my Tor relay using so much memory?</a></li>
60) <li><a href="#WhyNotNamed">Why is my Tor relay not named?</a></li>
61) </ul>
62)
63) <p>Running a Tor hidden service:</p>
64)
65) <p>Anonymity and Security:</p>
66) <ul>
67) <li><a href="#KeyManagement">Tell me about all the keys Tor uses.</a></li>
68) </ul>
69)
70) <p>Alternate designs that we don't do (yet):</p>
71) <ul>
72) <li><a href="#EverybodyARelay">You should make every Tor user be a
73) relay.</a></li>
74) </ul>
75)
76) <p>Abuse</p>
77) <ul>
78) <li><a href="#Criminals">Doesn't Tor enable criminals to do bad things?</a></li>
79) <li><a href="#RespondISP">How do I respond to my ISP about my exit
80) relay?</a></li>
81) </ul>
82)
83) <p>For other questions not yet on this version of the FAQ, see the <a
84) href="https://trac.torproject.org/projects/tor/wiki/TheOnionRouter/TorFAQ">wiki
85) FAQ</a> for now.</p>
86)
87) <hr />
88)
89) <a id="General"></a>
90)
91) <a id="WhatIsTor"></a>
92) <h3><a class="anchor" href="#WhatIsTor">What is Tor?</a></h3>
93)
94) <p>
95) The name "Tor" can refer to several different components.
96) </p>
97)
98) <p>
99) The Tor software is a program you can run on your computer that helps keep
100) you safe on the Internet. Tor protects you by bouncing your communications
101) around a distributed network of relays run by volunteers all around
102) the world: it prevents somebody watching your Internet connection from
103) learning what sites you visit, and it prevents the sites you visit
104) from learning your physical location. This set of volunteer relays is
105) called the Tor network. You can read more about how Tor works on the <a
106) href="<page about/overview>">overview page</a>.
107) </p>
108)
109) <p>
110) The Tor Project is a non-profit (charity) organization that maintains
111) and develops the Tor software.
112) </p>
113)
114) <hr />
115)
116) <a id="Torisdifferent"></a>
117) <h3><a class="anchor" href="#Torisdifferent">How is Tor different from other proxies?</a></h3>
118) <p>
119) A typical proxy provider sets up a server somewhere on the Internet and allows you to use it to relay your traffic. This creates a simple, easy to maintain architecture. The users all enter and leave through the same server. The provider may charge for use of the proxy, or fund their costs through advertisements on the server. In the simplest configuration, you don't have to install anything. You just have to point your browser at their proxy server. Simple proxy providers are fine solutions if you do not want protections for your privacy and anonymity online and you trust the provider from doing bad things. Some simple proxy providers use SSL to secure your connection to them. This may protect you against local eavesdroppers, such as those at a cafe with free wifi Internet.
120) </p>
121) <p>
122) Simple proxy providers also create a single point of failure. The provider knows who you are and where you browse on the Internet. They can see your traffic as it passes through their server. In some cases, they can see your encrypted traffic as they relay it to your banking site or to ecommerce stores. You have to trust the provider isn't doing any number of things, such as watching your traffic, injecting their own advertisements into your traffic stream, and isn't recording your personal details.
123) </p>
124) <p>
125) Tor passes your traffic through at least 3 different servers before sending it on to the destination. Tor does not modify, or even know, what you are sending into it. It merely relays your traffic, completely encrypted through the Tor network and has it pop out somewhere else in the world, completely intact. The Tor client is required because we assume you trust your local computer. The Tor client manages the encryption and the path chosen through the network. The relays located all over the world merely pass encrypted packets between themselves.</p>
126) <p>
127) <dl>
128) <dt>Doesn't the first server see who I am?</dt><dd>Possibly. A bad first of three servers can see encrypted Tor traffic coming from your computer. It still doesn't know who you are and what you are doing over Tor. It merely sees "This IP address is using Tor". Tor is not illegal anywhere in the world, so using Tor by itself is fine. You are still protected from this node figuring out who you are and where you are going on the Internet.</dd>
129) <dt>Can't the third server see my traffic?</dt><dd>Possibly. A bad third of three servers can see the traffic you sent into Tor. It won't know who sent this traffic. If you're using encryption, such as visiting a bank or e-commerce website, or encrypted mail connections, etc, it will only know the destination. It won't be able to see the data inside the traffic stream. You are still protected from this node figuring out who you are and if using encryption, what data you're sending to the destination.</dd>
130) </dl>
131) </p>
132)
133) <hr />
134)
135) <a id="CompatibleApplications"></a>
136) <h3><a class="anchor" href="#CompatibleApplications">What programs can
137) I use with Tor?</a></h3>
138)
139) <p>
140) There are two pieces to "Torifying" a program: connection-level anonymity
141) and application-level anonymity. Connection-level anonymity focuses on
142) making sure the application's Internet connections get sent through Tor.
143) This step is normally done by configuring
144) the program to use your Tor client as a "socks" proxy, but there are
145) other ways to do it too. For application-level anonymity, you need to
146) make sure that the information the application sends out doesn't hurt
147) your privacy. (Even if the connections are being routed through Tor, you
148) still don't want to include sensitive information like your name.) This
149) second step needs to be done on a program-by-program basis, which is
150) why we don't yet recommend very many programs for safe use with Tor.
151) </p>
152)
153) <p>
154) Most of our work so far has focused on the Firefox web browser. The
155) bundles on the <a href="<page download/download>">download page</a> automatically
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Andrew Lewman authored 13 years ago
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157) extension</a> if you have Firefox installed. As of version 1.2.0,
158) Torbutton now takes care of a lot of the connection-level and
159) application-level worries.
160) </p>
161)
162) <p>
163) There are plenty of other programs you can use with Tor,
164) but we haven't researched the application-level anonymity
165) issues on them well enough to be able to recommend a safe
166) configuration. Our wiki has a list of instructions for <a
167) href="https://trac.torproject.org/projects/tor/wiki/TheOnionRouter/TorifyHOWTO">Torifying
168) specific applications</a>. There's also a <a
169) href="https://trac.torproject.org/projects/tor/wiki/TheOnionRouter/SupportPrograms">list
170) of applications that help you direct your traffic through Tor</a>.
171) Please add to these lists and help us keep them accurate!
172) </p>
173)
174) <hr />
175)
176) <a id="WhyCalledTor"></a>
177) <h3><a class="anchor" href="#WhyCalledTor">Why is it called Tor?</a></h3>
178)
179) <p>
180) Because Tor is the onion routing network. When we were starting the
181) new next-generation design and implementation of onion routing in
182) 2001-2002, we would tell people we were working on onion routing,
183) and they would say "Neat. Which one?" Even if onion routing has
184) become a standard household term, Tor was born out of the actual <a
185) href="http://www.onion-router.net/">onion routing project</a> run by
186) the Naval Research Lab.
187) </p>
188)
189) <p>
190) (It's also got a fine translation from German and Turkish.)
191) </p>
192)
193) <p>
194) Note: even though it originally came from an acronym, Tor is not spelled
195) "TOR". Only the first letter is capitalized. In fact, we can usually
196) spot people who haven't read any of our website (and have instead learned
197) everything they know about Tor from news articles) by the fact that they
198) spell it wrong.
199) </p>
200)
201) <hr />
202)
203) <a id="Backdoor"></a>
204) <h3><a class="anchor" href="#Backdoor">Is there a backdoor in Tor?</a></h3>
205)
206) <p>
207) There is absolutely no backdoor in Tor. Nobody has asked us to put one
208) in, and we know some smart lawyers who say that it's unlikely that anybody
209) will try to make us add one in our jurisdiction (U.S.). If they do
210) ask us, we will fight them, and (the lawyers say) probably win.
211) </p>
212)
213) <p>
214) We think that putting a backdoor in Tor would be tremendously
215) irresponsible to our users, and a bad precedent for security software
216) in general. If we ever put a deliberate backdoor in our security
217) software, it would ruin our professional reputations. Nobody would
218) trust our software ever again — for excellent reason!
219) </p>
220)
221) <p>
222) But that said, there are still plenty of subtle attacks
223) people might try. Somebody might impersonate us, or break into our
224) computers, or something like that. Tor is open source, and you should
225) always check the source (or at least the diffs since the last release)
226) for suspicious things. If we (or the distributors) don't give you
227) source, that's a sure sign something funny might be going on. You
228) should also check the <a href="<page docs/verifying-signatures>">PGP
229) signatures</a> on the releases, to make sure nobody messed with the
230) distribution sites.
231) </p>
232)
233) <p>
234) Also, there might be accidental bugs in Tor that could affect your
235) anonymity. We periodically find and fix anonymity-related bugs, so make
236) sure you keep your Tor versions up-to-date.
237) </p>
238)
239) <hr />
240)
241) <a id="DistributingTor"></a>
242) <h3><a class="anchor" href="#DistributingTor">Can I distribute Tor on
243) my magazine's CD?</a></h3>
244)
245) <p>
246) Yes.
247) </p>
248)
249) <p>
250) The Tor software is <a href="https://www.fsf.org/">free software</a>. This
251) means we give you the rights to redistribute the Tor software, either
252) modified or unmodified, either for a fee or gratis. You don't have to
253) ask us for specific permission.
254) </p>
255)
256) <p>
257) However, if you want to redistribute the Tor software you must follow our
258) <a href="<gitblob>LICENSE">LICENSE</a>.
259) Essentially this means that you need to include our LICENSE file along
260) with whatever part of the Tor software you're distributing.
261) </p>
262)
263) <p>
264) Most people who ask us this question don't want to distribute just the
265) Tor software, though. They want to distribute the Tor bundles, which
266) typically include <a href="http://www.pps.jussieu.fr/~jch/software/polipo/">Polipo</a>
267) and <a href="<page projects/vidalia>">Vidalia</a>.
268) You will need to follow the licenses for those programs
269) as well. Both of them are distributed under the <a
270) href="https://www.fsf.org/licensing/licenses/gpl.html">GNU General
271) Public License</a>. The simplest way to obey their licenses is to
272) include the source code for these programs everywhere you include
273) the bundles themselves. Look for "source" packages on the <a
274) href="<page projects/vidalia>">Vidalia page</a> and the <a
275) href="http://www.pps.jussieu.fr/~jch/software/polipo/">Polipo
276) download page</a>.
277) </p>
278)
279) <p>
280) Also, you should make sure not to confuse your readers about what Tor is,
281) who makes it, and what properties it provides (and doesn't provide). See
282) our <a href="<page docs/trademark-faq>">trademark FAQ</a> for details.
283) </p>
284)
285) <p>
286) Lastly, you should realize that we release new versions of the
287) Tor software frequently, and sometimes we make backward incompatible
288) changes. So if you distribute a particular version of the Tor software, it
289) may not be supported — or even work — six months later. This
290) is a fact of life for all security software under heavy development.
291) </p>
292)
293) <hr />
294)
295) <a id="SupportMail"></a>
296) <h3><a class="anchor" href="#SupportMail">How can I get an answer to my
297) Tor support mail?</a></h3>
298)
299) <p>
300) Many people send the Tor developers mail privately, or send mail to
301) our internal <a href="<page about/contact>">lists</a>, with questions about their
302) specific setup — they can't get their firewall working right,
303) they can't configure Polipo correctly, or so on. Sometimes our
304) volunteers can answer these mails, but typically they need to spend
305) most of their time on development tasks that will benefit more people.
306) This is especially true if your question is already covered in the <a
307) href="<page docs/documentation>">documentation</a> or on this FAQ.
308) </p>
309)
310) <p>
311) So if we don't answer your mail, first check the <a href="<page
312) docs/documentation>">documentation</a> page, along with this FAQ,
313) to make sure your question isn't already answered. Then read <a
314) href="http://www.catb.org/~esr/faqs/smart-questions.html">"How to ask
315) questions the smart way"</a>. If this doesn't help you, note that we
316) have <a href="<page docs/documentation>#Support">an IRC channel</a> where you
317) can ask your questions (but if they are still open-ended, ill-formed,
318) or not about Tor, you likely won't get much help there either). Lastly,
319) people on the <a href="<page docs/documentation>#MailingLists">or-talk
320) mailing list</a> may be able to provide some hints for you, if
321) others have experienced your problems too. Be sure to look over <a
322) href="http://archives.seul.org/or/talk/">the archives</a> first.
323) </p>
324)
325) <p>
326) Another strategy is to <a href="<page docs/tor-doc-relay>">run a Tor
327) relay for a while</a>, and/or <a href="<page donate/donate>">donate money</a>
328) <a href="<page getinvolved/volunteer>">or time</a> to the effort. We're more likely
329) to pay attention to people who have demonstrated interest and commitment
330) to giving back to the Tor community.
331) </p>
332)
333) <p>
334) If you find your answer, please stick around on the IRC channel or the
335) mailing list and answer questions from others.
336) </p>
337)
338) <hr />
339)
340) <a id="WhySlow"></a>
341) <h3><a class="anchor" href="#WhySlow">Why is Tor so slow?</a></h3>
342)
343) <p>
344) There are many reasons why the Tor network is currently slow.
345) </p>
346)
347) <p>
348) Before we answer, though, you should realize that Tor is never going to
349) be blazing fast. Your traffic is bouncing through volunteers' computers
350) in various parts of the world, and some bottlenecks and network latency
351) will always be present. You shouldn't expect to see university-style
352) bandwidth through Tor.
353) </p>
354)
355) <p>
356) But that doesn't mean that it can't be improved. The current Tor network
357) is quite small compared to the number of people trying to use it, and
358) many of these users don't understand or care that Tor can't currently
359) handle file-sharing traffic load.
360) </p>
361)
362) <p>
363) For the much more in-depth answer, see <a
364) href="https://blog.torproject.org/blog/why-tor-is-slow">Roger's blog
365) post on the topic</a>, which includes both a detailed PDF and a video
366) to go with it.
367) </p>
368)
369) <p>
370) What can you do to help?
371) </p>
372)
373) <ul>
374)
375) <li>
376) <a href="<page docs/tor-doc-relay>">Configure your Tor to relay traffic
377) for others</a>. Help make the Tor network large enough that we can handle
378) all the users who want privacy and security on the Internet.
379) </li>
380)
381) <li>
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383) especially need people to help make it easier to configure your Tor
384) as a relay. Also, we need help with clear simple documentation to
385) walk people through setting it up.
386) </li>
387)
388) <li>
389) There are some bottlenecks in the current Tor network. Help us design
390) experiments to track down and demonstrate where the problems are, and
391) then we can focus better on fixing them.
392) </li>
393)
394) <li>
395) There are some steps that individuals
396) can take to improve their Tor performance. <a
397) href="https://trac.torproject.org/projects/tor/wiki/TheOnionRouter/FireFoxTorPerf">You
398) can configure your Firefox to handle Tor better</a>, <a
399) href="http://www.pps.jussieu.fr/~jch/software/polipo/tor.html">you can use
400) Polipo with Tor</a>, or you can try <a href="<page download/download>">upgrading
401) to the latest version of Tor</a>. If this works well, please help by
402) documenting what you did, and letting us know about it.
403) </li>
404)
405) <li>
406) Tor needs some architectural changes too. One important change is to
407) start providing <a href="#EverybodyARelay">better service to people who
408) relay traffic</a>. We're working on this, and we'll finish faster if we
409) get to spend more time on it.
410) </li>
411)
412) <li>
413) Help do other things so we can do the hard stuff. Please take a moment
414) to figure out what your skills and interests are, and then <a href="<page
415) getinvolved/volunteer>">look at our volunteer page</a>.
416) </li>
417)
418) <li>
419) Help find sponsors for Tor. Do you work at a company or government agency
420) that uses Tor or has a use for Internet privacy, e.g. to browse the
421) competition's websites discreetly, or to connect back to the home servers
422) when on the road without revealing affiliations? If your organization has
423) an interest in keeping the Tor network working, please contact them about
424) supporting Tor. Without sponsors, Tor is going to become even slower.
425) </li>
426)
427) <li>
428) If you can't help out with any of the above, you can still help out
429) individually by <a href="<page donate/donate>">donating a bit of money to the
430) cause</a>. It adds up!
431) </li>
432)
433) </ul>
434)
435) <hr />
436)
437) <a id="Funding"></a>
438) <h3><a class="anchor" href="#Funding">What would The Tor Project do with
439) more funding?</a></h3>
440)
441) <p>
442) We have about 1800 relays right now, pushing over 150 MB/s average
443) traffic. We have several hundred thousand active users. But the Tor
444) network is not yet self-sustaining.
445) </p>
446)
447) <p>
448) There are six main development/maintenance pushes that need attention:
449) </p>
450)
451) <ul>
452)
453) <li>
454) Scalability: We need to keep scaling and decentralizing the Tor
455) architecture so it can handle thousands of relays and millions of
456) users. The upcoming stable release is a major improvement, but there's
457) lots more to be done next in terms of keeping Tor fast and stable.
458) </li>
459)
460) <li>
461) User support: With this many users, a lot of people are asking questions
462) all the time, offering to help out with things, and so on. We need good
463) clean docs, and we need to spend some effort coordinating volunteers.
464) </li>
465)
466) <li>
467) Relay support: the Tor network is run by volunteers, but they still need
468) attention with prompt bug fixes, explanations when things go wrong,
469) reminders to upgrade, and so on. The network itself is a commons, and
470) somebody needs to spend some energy making sure the relay operators stay
471) happy. We also need to work on <a href="#RelayOS">stability</a> on some
472) platforms — e.g., Tor relays have problems on Win XP currently.
473) </li>
474)
475) <li>
476) Usability: Beyond documentation, we also need to work on usability of the
477) software itself. This includes installers, clean GUIs, easy configuration
478) to interface with other applications, and generally automating all of
479) the difficult and confusing steps inside Tor. We've got a start on this
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