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5) #include "head.wmi" TITLE="Tor Project: FAQ" CHARSET="UTF-8"
6) <div id="content" class="clearfix">
7)   <div id="breadcrumbs">

8)     <a href="<page index>">Home &raquo; </a>

9)     <a href="<page docs/documentation>">Documentation &raquo; </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
21) proxies?</a></li>

22)     <li><a href="#CompatibleApplications">What programs can I use with
23)     Tor?</a></li>
24)     <li><a href="#WhyCalledTor">Why is it called Tor?</a></li>
25)     <li><a href="#Backdoor">Is there a backdoor in Tor?</a></li>

26)     <li><a href="#DistributingTor">Can I distribute Tor?</a></li>

27)     <li><a href="#SupportMail">How can I get support?</a></li>

28)     <li><a href="#Forum">Is there a Tor forum?</a></li>

29)     <li><a href="#WhySlow">Why is Tor so slow?</a></li>

30)     <li><a href="#FileSharing">How can I share files anonymously through Tor?
31)     </a></li>
32)     <li><a href="#OutboundPorts">Do I have to open all these outbound ports 
33)     on my firewall?</a></li>

34)     <li><a href="#Funding">What would The Tor Project do with more
35)     funding?</a></li>

36)     <li><a href="#IsItWorking">How can I tell if Tor is working, and that my 
37)     connections really are anonymized?</a></li>

38)     <li><a href="#FTP">How do I use my browser for ftp with Tor?</a></li>

39)     <li><a href="#Metrics">How many people use Tor? How many relays or
40)     exit nodes are there?</a></li>

41)     <li><a href="#SSLcertfingerprint">What are your SSL certificate

42)     fingerprints?</a></li>

43)     </ul>

44) 

45)     <p>Compilation and Installation:</p>
46)     <ul>
47)     <li><a href="#HowUninstallTor">How do I uninstall Tor?</a></li>
48)     <li><a href="#PGPSigs">What are these "sig" files on the download
49)     page?</a></li>

50)     <li><a href="#GetTor">Your website is blocked in my country. How
51)     do I download Tor?</a></li>

52)     <li><a href="#CompileTorWindows">How do I compile Tor under
53) Windows?</a></li>
54)     <li><a href="#VirusFalsePositives">Why does my Tor executable appear
55) to

56)     have a virus or spyware?</a></li>

57)     <li><a href="#LiveCD">Is there a LiveCD or other bundle that
58) includes Tor?</a></li>

59)     </ul>

60) 

61)     <p>Tor Browser Bundle:</p>
62)     <ul>

63) 

64)     <li><a href="#TBBFlash">Why can't I view videos on YouTube and other
65)     Flash-based sites?</a></li>

66)     <li><a href="#Ubuntu">I'm using Ubuntu and I can't start Tor Browser
67)     </a></li>

68)     <li><a href="#TBBSocksPort">I want to

69)     run another application through the Tor launched by Tor Browser

70)     Bundle.</a></li>

71)     <li><a href="#TBBPolipo">I need an HTTP proxy. Where did Polipo
72)     go?</a></li>

73)     <li><a href="#TBBOtherExtensions">Can I install other Firefox

74)     extensions? Which extensions should I avoid using?</a></li>

75)     <li><a href="#TBBJavaScriptEnabled">Why is NoScript configured to
76) allow JavaScript by default in the Tor Browser Bundle?  Isn't that
77) unsafe?</a></li>

78)     <li><a href="#TBBOtherBrowser">I want to use Chrome/IE/Opera/etc
79)     with Tor.</a></li>

80)     <li><a href="#TorbuttonOtherBrowser">Will ​Torbutton be available for other browsers?</a></li>

81)     <li><a href="#TBBCloseBrowser">I want to leave Tor Browser Bundle
82)     running but close the browser.</a></li>
83) 

84)     <li><a href="#GoogleCAPTCHA">Google makes me solve a CAPTCHA or

85) tells

86)     me I have spyware installed.</a></li>

87)     <li><a href="#ForeignLanguages">Why does Google show up in foreign 
88)     languages?</li></a>

89)     <li><a href="#GmailWarning">Gmail warns me that my account may have
90)     been compromised.</a></li>
91)     </ul>
92) 
93)     <p>Advanced Tor usage:</p>

94)     <ul>
95)     <li><a href="#torrc">I'm supposed to "edit my torrc". What does
96)     that mean?</a></li>

97)     <li><a href="#Logs">How do I set up logging, or see Tor's

98)     logs?</a></li>

99)     <li><a href="#LogLevel">What log level should I use?</a></li>

100)     <li><a href="#DoesntWork">Tor is running, but it's not working
101)     correctly.</a></li>

102)     <li><a href="#TorCrash">My Tor keeps crashing.</a></li>

103)     <li><a href="#VidaliaPassword">Tor/Vidalia prompts for a password at
104)     start.</a></li>

105)     <li><a href="#ChooseEntryExit">Can I control which nodes (or
106) country)

107)     are used for entry/exit?</a></li>

108)     <li><a href="#FirewallPorts">My firewall only allows a few outgoing
109)     ports.</a></li>

110)     <li><a href="#ExitPorts">Is there a list of default exit ports?</a></li>

111)     <li><a href="#SocksAndDNS">How do I check if my application that uses 
112)     SOCKS is leaking DNS requests?</a></li>
113)     <li><a href="#DifferentComputer">I want to run my Tor client on a 
114)     different computer than my applications.</a></li>
115)     <li><a href="#ServerClient">Can I install Tor on a central server, and 
116)     have my clients connect to it?</a></li>
117)     <li><a href="#JoinTheNetwork">So I can just configure a nickname and 
118)     ORPort and join the network?</a></li>

119)     </ul>

120) 

121)     <p>Running a Tor relay:</p>
122)     <ul>

123) 
124)     <li><a href="#HowDoIDecide">How do I decide if I should run a relay?
125)     </a></li>

126)     <li><a href="#WhyIsntMyRelayBeingUsedMore">Why isn't my relay being 
127)     used more?</a></li>
128)     <li><a href="#HighCapacityConnection">How can I get Tor to fully 
129)     make use of my high capacity connection?</a></li>

130)     <li><a href="#RelayFlexible">How stable does my relay need to
131) be?</a></li>
132)     <li><a href="#ExitPolicies">I'd run a relay, but I don't want to
133) deal

134)     with abuse issues.</a></li>
135)     <li><a href="#RelayOrBridge">Should I be a normal relay or bridge
136)     relay?</a></li>

137)     <li><a href="#UpgradeOrMove">I want to upgrade/move my relay. How do I 
138)     keep the same key?</a></li>

139)     <li><a href="#MultipleRelays">I want to run more than one
140) relay.</a></li>

141)     <li><a href="#NTService">How do I run my Tor relay as an NT service?
142)     </a></li>
143)     <li><a href="#VirtualServer">Can I run a Tor relay from my virtual server 
144)     account?</a></li>

145)     <li><a href="#WrongIP">My relay is picking the wrong IP address.</a></li>
146)     <li><a href="#BehindANAT">I'm behind a NAT/Firewall</a></li>

147)     <li><a href="#RelayMemory">Why is my Tor relay using so much memory?
148)     </a></li>
149)     <li><a href="#BetterAnonymity">Do I get better anonymity if I run a relay?
150)     </a></li>

151)     <li><a href="#RelayDonations">Can I donate for a relay rather than
152)     run my own?</a></li>

153)     </ul>

154) 

155)     <p>Tor hidden services:</p>
156)     <ul>
157)     <li><a href="#AccessHiddenServices">How do I access hidden services?</a></li>
158)     <li><a href="#ProvideAHiddenService">How do I provide a hidden service</a></li>
159)     </ul>

160) 

161)     <p>Anonymity and Security:</p>
162)     <ul>

163)     <li><a href="#WhatProtectionsDoesTorProvide">What protections does Tor 
164)     provide?</a></li>
165)     <li><a href="#CanExitNodesEavesdrop">Can exit nodes eavesdrop on 
166)     communications? Isn't that bad? </a></li>
167)     <li><a href="#ExitEnclaving">What is Exit Enclaving?</a></li>

168)     <li><a href="#KeyManagement">Tell me about all the keys Tor
169) uses.</a></li>

170)     <li><a href="#EntryGuards">What are Entry Guards?</a></li>

171)     <li><a href="#ChangePaths">How often does Tor change its paths?</a></li>

172)     <li><a href="#CellSize">Tor uses hundreds of bytes for every IRC line. I 
173)     can't afford that!</a></li>
174)     <li><a href="#OutboundConnections">Why does netstat show these outbound 
175)     connections?</a></li>
176)     <li><a href="#PowerfulBlockers">What about powerful blocking mechanisms
177)     </a></li>
178)     <li><a href="#RemotePhysicalDeviceFingerprinting">Does Tor resist 
179)     "remote physical device fingerprinting"?</a></li>
180)     <li><a href="#AttacksOnOnionRouting">What attacks remain against onion 
181)     routing?</a></li>

182)     </ul>

183) 

184)     <p>Alternate designs that we don't do (yet):</p>
185)     <ul>
186)     <li><a href="#EverybodyARelay">You should make every Tor user be a
187)     relay.</a></li>

188)     <li><a href="#TransportIPnotTCP">You should transport all IP
189) packets,

190)     not just TCP packets.</a></li>

191)     <li><a href="#HideExits">You should hide the list of Tor relays,
192)     so people can't block the exits.</a></li>

193)     <li><a href="#ChoosePathLength">You should let people choose their path 
194)     length.</a></li>
195)     <li><a href="#SplitEachConnection">You should split each connection over 
196)     many paths.</a></li>
197)     <li><a href="#UnallocatedNetBlocks">Your default exit policy should block 
198)     unallocated net blocks too.</a></li>
199)     <li><a href="#BlockWebsites">Exit policies should be able to block 
200)     websites, not just IP addresses.</a></li>
201)     <li><a href="#BlockContent">You should change Tor to prevent users from 
202)     posting certain content.</a></li>

203)     <li><a href="#SendPadding">You should send padding so it's more secure.
204)     </a></li>
205)     <li><a href="#Steganography">You should use steganography to hide Tor 
206)     traffic.</a></li>

207)     <li><a href="#IPv6">Tor should support IPv6.</a></li>

208)     </ul>

209) 

210)     <p>Abuse:</p>

211)     <ul>

212)     <li><a href="#Criminals">Doesn't Tor enable criminals to do bad
213) things?</a></li>

214)     <li><a href="#RespondISP">How do I respond to my ISP about my exit
215)     relay?</a></li>
216)     </ul>

217) 

218)     <p>For other questions not yet on this version of the FAQ, see the
219) <a

220)     href="<wikifaq>">wiki FAQ</a> for now.</p>

221) 

222)     <hr>

223) 

224)     <a id="General"></a>

225) 

226)     <a id="WhatIsTor"></a>
227)     <h3><a class="anchor" href="#WhatIsTor">What is Tor?</a></h3>

228) 

229)     <p>
230)     The name "Tor" can refer to several different components.
231)     </p>

232) 

233)     <p>

234)     The Tor software is a program you can run on your computer that
235) helps keep
236)     you safe on the Internet. Tor protects you by bouncing your
237) communications

238)     around a distributed network of relays run by volunteers all around

239)     the world: it prevents somebody watching your Internet connection
240) from

241)     learning what sites you visit, and it prevents the sites you visit

242)     from learning your physical location. This set of volunteer relays
243) is
244)     called the Tor network. You can read more about how Tor works on the
245) <a

246)     href="<page about/overview>">overview page</a>.
247)     </p>

248) 

249)     <p>

250)     The Tor Project is a non-profit (charity) organization that
251) maintains

252)     and develops the Tor software.
253)     </p>

254) 

255)     <hr>

256) 

257)     <a id="Torisdifferent"></a>

258)     <h3><a class="anchor" href="#Torisdifferent">How is Tor different
259) from other proxies?</a></h3>
260)     <p>
261)     A typical proxy provider sets up a server somewhere on the Internet
262) and
263) allows you to use it to relay your traffic.  This creates a simple, easy
264) to
265) maintain architecture.  The users all enter and leave through the same
266) server.
267) The provider may charge for use of the proxy, or fund their costs
268) through
269) advertisements on the server.  In the simplest configuration, you don't
270) have to
271) install anything.  You just have to point your browser at their proxy
272) server.
273) Simple proxy providers are fine solutions if you do not want protections
274) for
275) your privacy and anonymity online and you trust the provider from doing
276) bad
277) things.  Some simple proxy providers use SSL to secure your connection
278) to them.
279) This may protect you against local eavesdroppers, such as those at a
280) cafe with

281) free wifi Internet.
282)     </p>
283)     <p>

284)     Simple proxy providers also create a single point of failure.  The
285) provider
286) knows who you are and where you browse on the Internet.  They can see
287) your
288) traffic as it passes through their server.  In some cases, they can even
289) see

290) inside your

291) encrypted traffic as they relay it to your banking site or to ecommerce
292) stores.

293) You have to trust the provider isn't doing any number of things, such as

294) watching your traffic, injecting their own advertisements into your
295) traffic

296) stream, and recording your personal details.

297)     </p>
298)     <p>

299)     Tor passes your traffic through at least 3 different servers before
300) sending
301) it on to the destination. Because there's a separate layer of encryption
302) for
303) each of the three relays, Tor does not modify, or even know, what you
304) are
305) sending into it.  It merely relays your traffic, completely encrypted
306) through
307) the Tor network and has it pop out somewhere else in the world,
308) completely
309) intact.  The Tor client is required because we assume you trust your
310) local
311) computer.  The Tor client manages the encryption and the path chosen
312) through
313) the network.  The relays located all over the world merely pass
314) encrypted

315) packets between themselves.</p>

316)     <p>
317)     <dl>

318)     <dt>Doesn't the first server see who I am?</dt><dd>Possibly. A bad
319) first of
320) three servers can see encrypted Tor traffic coming from your computer.
321) It
322) still doesn't know who you are and what you are doing over Tor.  It
323) merely sees
324) "This IP address is using Tor".  Tor is not illegal anywhere in the
325) world, so
326) using Tor by itself is fine.  You are still protected from this node
327) figuring

328) out who you are and where you are going on the Internet.</dd>

329)     <dt>Can't the third server see my traffic?</dt><dd>Possibly.  A bad
330) third
331) of three servers can see the traffic you sent into Tor.  It won't know
332) who sent

333) this traffic.  If you're using encryption, such as visiting a bank or

334) e-commerce website, or encrypted mail connections, etc, it will only
335) know the
336) destination.  It won't be able to see the data inside the traffic
337) stream.  You

338) are still protected from this node figuring out who you are and if using
339) encryption, what data you're sending to the destination.</dd>

340)     </dl>
341)     </p>

342) 

343)     <hr>

344) 

345)     <a id="CompatibleApplications"></a>

346)     <h3><a class="anchor" href="#CompatibleApplications">What programs
347) can I use with Tor?</a></h3>

348) 

349)     <p>

350)     If you want to use Tor with a web browser, we provide the Tor Browser 
351)     Bundle, which includes everything you need to browse the web safely using 
352)     Tor. If you want to use another web browser with Tor, see <a 
353)     href="#TBBOtherBrowser">Other web browsers</a>. 

354)     </p>
355)     <p>
356)     There are plenty of other programs you can use with Tor,
357)     but we haven't researched the application-level anonymity

358)     issues on all of them well enough to be able to recommend a safe

359)     configuration. Our wiki has a list of instructions for <a

360)     href="<wiki>doc/TorifyHOWTO">Torifying

361)     specific applications</a>.

362)     Please add to these lists and help us keep them accurate!
363)     </p>

364) 

365)     <hr>

366) 

367)     <a id="WhyCalledTor"></a>

368)     <h3><a class="anchor" href="#WhyCalledTor">Why is it called
369) Tor?</a></h3>

370) 

371)     <p>
372)     Because Tor is the onion routing network. When we were starting the
373)     new next-generation design and implementation of onion routing in
374)     2001-2002, we would tell people we were working on onion routing,
375)     and they would say "Neat. Which one?" Even if onion routing has
376)     become a standard household term, Tor was born out of the actual <a
377)     href="http://www.onion-router.net/">onion routing project</a> run by
378)     the Naval Research Lab.
379)     </p>

380) 

381)     <p>
382)     (It's also got a fine translation from German and Turkish.)
383)     </p>

384) 

385)     <p>

386)     Note: even though it originally came from an acronym, Tor is not
387) spelled

388)     "TOR". Only the first letter is capitalized. In fact, we can usually

389)     spot people who haven't read any of our website (and have instead
390) learned
391)     everything they know about Tor from news articles) by the fact that
392) they

393)     spell it wrong.
394)     </p>

395) 

396)     <hr>

397) 

398)     <a id="Backdoor"></a>

399)     <h3><a class="anchor" href="#Backdoor">Is there a backdoor in
400) Tor?</a></h3>

401) 

402)     <p>

403)     There is absolutely no backdoor in Tor. Nobody has asked us to put
404) one
405)     in, and we know some smart lawyers who say that it's unlikely that
406) anybody

407)     will try to make us add one in our jurisdiction (U.S.). If they do
408)     ask us, we will fight them, and (the lawyers say) probably win.
409)     </p>

410) 

411)     <p>
412)     We think that putting a backdoor in Tor would be tremendously

413)     irresponsible to our users, and a bad precedent for security
414) software

415)     in general. If we ever put a deliberate backdoor in our security
416)     software, it would ruin our professional reputations. Nobody would
417)     trust our software ever again — for excellent reason!
418)     </p>

419) 

420)     <p>
421)     But that said, there are still plenty of subtle attacks
422)     people might try. Somebody might impersonate us, or break into our

423)     computers, or something like that. Tor is open source, and you
424) should
425)     always check the source (or at least the diffs since the last
426) release)

427)     for suspicious things. If we (or the distributors) don't give you
428)     source, that's a sure sign something funny might be going on. You
429)     should also check the <a href="<page docs/verifying-signatures>">PGP
430)     signatures</a> on the releases, to make sure nobody messed with the
431)     distribution sites.
432)     </p>

433) 

434)     <p>
435)     Also, there might be accidental bugs in Tor that could affect your

436)     anonymity. We periodically find and fix anonymity-related bugs, so
437) make

438)     sure you keep your Tor versions up-to-date.
439)     </p>

440) 

441)     <hr>

442) 

443)     <a id="DistributingTor"></a>

444)     <h3><a class="anchor" href="#DistributingTor">Can I distribute
445) Tor?</a></h3>

446) 

447)     <p>
448)     Yes.
449)     </p>

450) 

451)     <p>

452)     The Tor software is <a href="https://www.fsf.org/">free
453) software</a>. This
454)     means we give you the rights to redistribute the Tor software,
455) either
456)     modified or unmodified, either for a fee or gratis. You don't have
457) to

458)     ask us for specific permission.
459)     </p>

460) 

461)     <p>

462)     However, if you want to redistribute the Tor software you must
463) follow our

464)     <a href="<gitblob>LICENSE">LICENSE</a>.

465)     Essentially this means that you need to include our LICENSE file
466) along

467)     with whatever part of the Tor software you're distributing.
468)     </p>

469) 

470)     <p>

471)     Most people who ask us this question don't want to distribute just
472) the

473)     Tor software, though. They want to distribute the <a

474)     href="<page projects/torbrowser>">Tor Browser</a>. This includes <a

475)     href="https://www.mozilla.org/en-US/firefox/all-aurora.html">Mozilla
476)     Aurora</a> and <a href="<page projects/vidalia>">Vidalia</a>.

477)     You will need to follow the licenses for those programs
478)     as well. Both of them are distributed under the <a
479)     href="https://www.fsf.org/licensing/licenses/gpl.html">GNU General

480)     Public License</a>. The simplest way to obey their licenses is
481)     to include the source code for these programs everywhere you
482)     include the bundles themselves. Look for "source" packages on
483)     the <a href="<page projects/vidalia>">Vidalia page</a> and <a
484)     href="https://www.mozilla.org/en-US/firefox/all-aurora.html">Mozilla
485)     Aurora</a> pages.

486)     </p>

487) 

488)     <p>

489)     Also, you should make sure not to confuse your readers about what
490) Tor is,
491)     who makes it, and what properties it provides (and doesn't provide).
492) See
493)     our <a href="<page docs/trademark-faq>">trademark FAQ</a> for
494) details.

495)     </p>

496) 

497)     <p>
498)     Lastly, you should realize that we release new versions of the
499)     Tor software frequently, and sometimes we make backward incompatible

500)     changes. So if you distribute a particular version of the Tor
501) software, it
502)     may not be supported — or even work — six months later.
503) This

504)     is a fact of life for all security software under heavy development.
505)     </p>

506) 

507)     <hr>

508) 

509)     <a id="SupportMail"></a>

510)     <h3><a class="anchor" href="#SupportMail">How can I get
511) support?</a></h3>

512) 

513)     <p>Your best bet is to first try the following:</p>

514)     <ol>
515)     <li>Read through this <a href="<page docs/faq>">FAQ</a>.</li>

516)     <li>Read through the <a href="<page
517) docs/documentation>">documentation</a>.</li>

518)     <li>Read through the <a

519) 
520) href="https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-talk">
521) tor-talk

522)     archives</a> and see if your question is already answered.</li>

523)     <li>Join our <a href="ircs://irc.torproject.org#tor">irc channel</a>
524) and

525)     state the issue and wait for help.</li>

526)     <li>Send an email to <a

527) 
528) href="mailto:help@rt.torproject.org">help@rt.torproject.org</a>.</li>
529)     <li>If all else fails, try <a href="<page about/contact>">contacting
530) us</a> directly.</li>

531)     </ol>

532) 

533)     <p>If you find your answer, please stick around on the IRC channel
534) or the

535)     mailing list to help others who were once in your position.</p>

536) 

537)     <hr>

538) 

539)     <a id="Forum"></a>
540)     <h3><a class="anchor" href="#Forum">Is there a Tor forum?</a></h3>
541) 
542)     <p>Not yet, but we're working on it. Most forum software is
543)     a disaster to maintain and keep secure, and at the same time
544)     too many of the Tor developers are spread too thin to be able

545)     to contribute enough to a forum.

546)     </p>
547) 
548)     <hr>
549) 

550)     <a id="WhySlow"></a>
551)     <h3><a class="anchor" href="#WhySlow">Why is Tor so slow?</a></h3>

552) 

553)     <p>
554)     There are many reasons why the Tor network is currently slow.
555)     </p>

556) 

557)     <p>

558)     Before we answer, though, you should realize that Tor is never going
559) to
560)     be blazing fast. Your traffic is bouncing through volunteers'
561) computers
562)     in various parts of the world, and some bottlenecks and network
563) latency

564)     will always be present. You shouldn't expect to see university-style
565)     bandwidth through Tor.
566)     </p>

567) 

568)     <p>

569)     But that doesn't mean that it can't be improved. The current Tor
570) network
571)     is quite small compared to the number of people trying to use it,
572) and
573)     many of these users don't understand or care that Tor can't
574) currently

575)     handle file-sharing traffic load.
576)     </p>

577) 

578)     <p>
579)     For the much more in-depth answer, see <a

580)     href="<blog>why-tor-is-slow">Roger's blog

581)     post on the topic</a>, which includes both a detailed PDF and a
582) video

583)     to go with it.
584)     </p>

585) 

586)     <p>
587)     What can you do to help?
588)     </p>

589) 

590)     <ul>

591) 

592)     <li>

593)     <a href="<page docs/tor-doc-relay>">Configure your Tor to relay
594) traffic
595)     for others</a>. Help make the Tor network large enough that we can
596) handle

597)     all the users who want privacy and security on the Internet.
598)     </li>

599) 

600)     <li>

601)     <a href="<page projects/vidalia>">Help us make Tor more usable</a>.
602) We

603)     especially need people to help make it easier to configure your Tor
604)     as a relay. Also, we need help with clear simple documentation to
605)     walk people through setting it up.
606)     </li>

607) 

608)     <li>

609)     There are some bottlenecks in the current Tor network. Help us
610) design
611)     experiments to track down and demonstrate where the problems are,
612) and

613)     then we can focus better on fixing them.
614)     </li>

615) 

616)     <li>
617)     Tor needs some architectural changes too. One important change is to

618)     start providing <a href="#EverybodyARelay">better service to people
619) who
620)     relay traffic</a>. We're working on this, and we'll finish faster if
621) we

622)     get to spend more time on it.
623)     </li>

624) 

625)     <li>

626)     Help do other things so we can do the hard stuff. Please take a
627) moment
628)     to figure out what your skills and interests are, and then <a
629) href="<page

630)     getinvolved/volunteer>">look at our volunteer page</a>.
631)     </li>

632) 

633)     <li>

634)     Help find sponsors for Tor. Do you work at a company or government
635) agency

636)     that uses Tor or has a use for Internet privacy, e.g. to browse the

637)     competition's websites discreetly, or to connect back to the home
638) servers
639)     when on the road without revealing affiliations? If your
640) organization has
641)     an interest in keeping the Tor network working, please contact them
642) about
643)     supporting Tor. Without sponsors, Tor is going to become even
644) slower.

645)     </li>

646) 

647)     <li>
648)     If you can't help out with any of the above, you can still help out

649)     individually by <a href="<page donate/donate>">donating a bit of
650) money to the

651)     cause</a>. It adds up!
652)     </li>

653) 

654)     </ul>

655) 

656)     <hr>

657) 

658)     <a id="FileSharing"></a>

659)     <h3><a class="anchor" href="#FileSharing">How can I share files 
660)     anonymously through Tor?</a></h3>

661) 
662)     <p>

663)     File sharing (peer-to-peer/P2P) is widely unwanted in the Tor network, 
664)     and exit nodes are configured to block file sharing traffic by default. 
665)     Tor is not really designed for it, and file sharing through Tor slows 
666)     down everyone's browsing. Also, Bittorrent over Tor <a 
667)     href="https://blog.torproject.org/blog/bittorrent-over-tor-isnt-good-idea">
668)     is not anonymous</a>!

669)     </p>
670) 
671)     <hr>
672) 

673)     <a id="Funding"></a>

674)     <h3><a class="anchor" href="#Funding">What would The Tor Project do
675) with more funding?</a></h3>

676) 

677)     <p>

678)     The Tor network's <a

679) 
680) href="https://metrics.torproject.org/network.html#networksize">several

681)     thousand</a> relays push <a
682)     href="https://metrics.torproject.org/network.html#bandwidth">over
683)     1GB per second on average</a>. We have <a

684) 
685) href="https://metrics.torproject.org/users.html#direct-users">several

686)     hundred thousand daily users</a>. But the Tor network is not yet
687)     self-sustaining.

688)     </p>

689) 

690)     <p>

691)     There are six main development/maintenance pushes that need
692) attention:

693)     </p>

694) 

695)     <ul>

696) 

697)     <li>
698)     Scalability: We need to keep scaling and decentralizing the Tor
699)     architecture so it can handle thousands of relays and millions of

700)     users. The upcoming stable release is a major improvement, but
701) there's

702)     lots more to be done next in terms of keeping Tor fast and stable.
703)     </li>

704) 

705)     <li>

706)     User support: With this many users, a lot of people are asking
707) questions
708)     all the time, offering to help out with things, and so on. We need
709) good
710)     clean docs, and we need to spend some effort coordinating
711) volunteers.

712)     </li>

713) 

714)     <li>

715)     Relay support: the Tor network is run by volunteers, but they still
716) need

717)     attention with prompt bug fixes, explanations when things go wrong,

718)     reminders to upgrade, and so on. The network itself is a commons,
719) and
720)     somebody needs to spend some energy making sure the relay operators
721) stay
722)     happy. We also need to work on stability on some platforms —
723) e.g.,

724)     Tor relays have problems on Win XP currently.

725)     </li>

726) 

727)     <li>

728)     Usability: Beyond documentation, we also need to work on usability
729) of the
730)     software itself. This includes installers, clean GUIs, easy
731) configuration
732)     to interface with other applications, and generally automating all
733) of
734)     the difficult and confusing steps inside Tor. We've got a start on
735) this
736)     with the <a href="<page projects/vidalia>">Vidalia GUI</a>, but much
737) more work

738)     remains — usability for privacy software has never been easy.
739)     </li>

740) 

741)     <li>
742)     Incentives: We need to work on ways to encourage people to configure
743)     their Tors as relays and exit nodes rather than just clients.

744)     <a href="#EverybodyARelay">We need to make it easy to become a
745) relay,

746)     and we need to give people incentives to do it.</a>
747)     </li>

748) 

749)     <li>
750)     Research: The anonymous communications field is full
751)     of surprises and gotchas. In our copious free time, we
752)     also help run top anonymity and privacy conferences like <a
753)     href="http://petsymposium.org/">PETS</a>. We've identified a set of

754)     critical <a href="<page getinvolved/volunteer>#Research">Tor
755) research questions</a>
756)     that will help us figure out how to make Tor secure against the
757) variety of
758)     attacks out there. Of course, there are more research questions
759) waiting

760)     behind these.
761)     </li>

762) 

763)     </ul>

764) 

765)     <p>
766)     We're continuing to move forward on all of these, but at this rate

767)     <a href="#WhySlow">the Tor network is growing faster than the
768) developers

769)     can keep up</a>.

770)     Now would be an excellent time to add a few more developers to the
771) effort

772)     so we can continue to grow the network.
773)     </p>

774) 

775)     <p>
776)     We are also excited about tackling related problems, such as
777)     censorship-resistance.
778)     </p>

779) 

780)     <p>

781)     We are proud to have <a href="<page about/sponsors>">sponsorship and
782) support</a>
783)     from the Omidyar Network, the International Broadcasting Bureau,
784) Bell
785)     Security Solutions, the Electronic Frontier Foundation, several
786) government

787)     agencies and research groups, and hundreds of private contributors.
788)     </p>

789) 

790)     <p>

791)     However, this support is not enough to keep Tor abreast of changes
792) in the
793)     Internet privacy landscape. Please <a href="<page
794) donate/donate>">donate</a>
795)     to the project, or <a href="<page about/contact>">contact</a> our
796) executive

797)     director for information on making grants or major donations.
798)     </p>

799) 

800)     <hr>
801) 

802)      <a id="OutboundPorts"></a>

803)     <h3><a class="anchor" href="#OutboundPorts">Do I have to open all these 
804)     outbound ports on my firewall?</a></h3>

805) 
806)     <p>

807)     Tor may attempt to connect to any port that is advertised in the 
808)     directory as an ORPort (for making Tor connections) or a DirPort (for 
809)     fetching updates to the directory). There are a variety of these ports, 
810)     but many of them are running on 80, 443, 9001, and 9030.

811)     </p>
812)     <p>

813)     So as a client, you could probably get away with opening only those four 
814)     ports. Since Tor does all its connections in the background, it will retry 
815)     ones that fail, and hopefully you'll never have to know that it failed, as 
816)     long as it finds a working one often enough. However, to get the most 
817)     diversity in your entry nodes -- and thus the most security -- as well as 
818)     the most robustness in your connectivity, you'll want to let it connect 
819)     to all of them.

820)     </p>
821)     <p>

822)     If you really need to connect to only a small set of ports, see the FAQ 
823)     entry on firewalled ports.

824)     </p>
825)     <p>

826)     Note that if you're running Tor as a relay, you must allow outgoing 
827)     connections to every other relay and to anywhere your exit policy 
828)     advertises that you allow. The cleanest way to do that is simply to allow 
829)     all outgoing connections at your firewall. If you don't, clients will try 
830)     to use these connections and things won't work. 

831)     </p>
832)     
833)     <hr>
834)     
835)     <a id="IsItWorking"></a>

836)     <h3><a class="anchor" href="#IsItWorking">How can I tell if Tor is 
837)     working, and that my connections really are anonymized?</a></h3>

838) 
839)     <p>

840)     There are sites you can visit that will tell you if you appear to be 
841)     coming through the Tor network. Try the <a href="https://check.torproject.org">
842)     Tor Check</a> site and see whether it thinks you are using Tor or not.

843)     </p>
844)     <p>

845)     If that site is down, you can still test, but it will involve more effort. 
846)     Sites like <a href="http://ipid.shat.net">http://ipid.shat.net</a> and 
847)     <a href="http://www.showmyip.com/">http://www.showmyip.com/</a> will tell 
848)     you what your IP address appears to be, but you'll need to know your 
849)     current IP address so you can compare and decide whether you're using Tor 
850)     correctly.

851)     </p>
852)     <p>

853)     To learn your IP address on OS X, Linux, BSD, etc, run "ifconfig". On 
854)     Windows, go to the Start menu, click Run and enter "cmd". At the command 
855)     prompt, enter "ipconfig /a".

856)     </p>
857)     <p>

858)     If you are behind a NAT or firewall, though, your IP address will be 
859)     within the range of 10.XXX.XXX.XXX, 192.168.XXX.XXX, or 172.16.XXX.XXX - 
860)     172.31.XXX.XXX, which is not your public IP address. In this case, you 
861)     should check your IP address with one of the sites above without using 
862)     Tor, and then check again using Tor to see whether your IP address has 
863)     changed. 

864)     </p>
865)     
866)     <hr>
867)     
868)     <a id="FTP"></a>
869)     <h3><a class="anchor" href="#FTP">How do I use my browser for ftp with Tor?
870)     </a></h3>
871) 

872)     <p>
873)     Use the Tor Browser Bundle. If you want a separate application for an 
874)     ftp client, we've heard good things about  FileZilla for Windows. You can 
875)     configure it to point to Tor as a "socks4a" proxy on "localhost" port 
876)     "9050". 
877)     </p>

878)     <hr>
879)     

880)     <a id="Metrics"></a>

881)     <h3><a class="anchor" href="#Metrics">How many people use Tor? How

882)     many relays or exit nodes are there?</a></h3>

883) 

884)     <p>
885)     All this and more about measuring Tor can be found at the <a

886)     href="https://metrics.torproject.org/">Tor Metrics Portal</a>.</p>

887)     <hr>

888) 

889)     <a id="SSLcertfingerprint"></a>

890)     <h3><a class="anchor" href="#SSLcertfingerprint">What are the SSL 
891)     certificate fingerprints for Tor's various websites?</a></h3>

892)     <p>

893)     <pre>

894)     *.torproject.org SSL certificate from Digicert:

895)     The serial number is:

896) 06:DE:97:E5:1D:C3:9D:C2:64:8D:AC:72:DD:41:01:FC
897)     The SHA-1 fingerprint is: 1f9d306e8bfccfcb03981a71a27a9f5d1e0876ce

898)     The SHA-256 fingerprint is:

899) 3613d2b22a750094760c41ad19db52a4f05bdea80172e2578761ad967f7ed9aa

900) 

901)     blog.torproject.org SSL certificate from RapidSSL:

902)     The serial number is: 00:EF:A3
903)     The SHA-1 fingerprint is: 50af43db8438e67f305a3257d8ef198e8c42f13f

904)     </pre>

905)     </p>
906)     <hr>
907) 

908)     <a id="HowUninstallTor"></a>

909)     <h3><a class="anchor" href="#HowUninstallTor">How do I uninstall
910) Tor?</a></h3>
911) 
912)     <p>
913)     Tor Browser does not install itself in the classic sense of
914) applications. You just simply delete the folder or directory named "Tor
915) Browser" and it is removed from your system.
916)     </p>

917) 

918)     <p>

919)     If this is not related to Tor Browser, uninstallation depends
920) entirely on how you installed it and which operating system you
921)     have. If you installed a package, then hopefully your package has a
922) way to

923)     uninstall itself. The Windows packages include uninstallers. 

924)     </p>

925) 

926)     <p>
927)     For Mac OS X, follow the <a
928)     href="<page docs/tor-doc-osx>#uninstall">uninstall directions</a>.
929)     </p>

930) 

931)     <p>

932)     If you installed by source, I'm afraid there is no easy uninstall
933) method. But
934)     on the bright side, by default it only installs into /usr/local/ and
935) it should

936)     be pretty easy to notice things there.
937)     </p>

938) 

939)     <hr>

940) 

941)     <a id="PGPSigs"></a>

942)     <h3><a class="anchor" href="#PGPSigs">What are these "sig" files on
943) the download page?</a></h3>

944) 

945)     <p>

946)     These are PGP signatures, so you can verify that the file you've
947) downloaded is

948)     exactly the one that we intended you to get.
949)     </p>

950) 

951)     <p>
952)     Please read the <a

953)     href="<page docs/verifying-signatures>">verifying signatures</a>
954) page for details.

955)     </p>

956) 

957) <hr>
958) 
959) <a id="GetTor"></a>
960) <h3><a class="anchor" href="#GetTor">Your website is blocked in my
961) country. How do I download Tor?</a></h3>
962) 
963) <p>
964) Some government or corporate firewalls censor connections to Tor's
965) website. In those cases, you have three options. First, get it from

966) a friend &mdash; the <a href="<page projects/torbrowser>">Tor Browser

967) Bundle</a> fits nicely on a USB key. Second, find the <a

968) href="https://encrypted.google.com/search?q=tor+mirrors">google
969) cache</a>

970) for the <a href="<page getinvolved/mirrors>">Tor mirrors</a> page
971) and see if any of those copies of our website work for you. Third,
972) you can download Tor via email: log in to your Gmail account and mail

973) '<tt>gettor@gettor.torproject.org</tt>'. If you include the word 'help'

974) in the body of the email, it will reply with instructions. Note that
975) only a few webmail providers are supported, since they need to be able
976) to receive very large attachments.
977) </p>
978) 
979) <p>

980) Be sure to <a href="<page docs/verifying-signatures>">verify the
981) signature</a>

982) of any package you download, especially when you get it from somewhere
983) other than our official HTTPS website.

984) </p>
985) 
986) <hr>

987) 

988)     <a id="CompileTorWindows"></a>

989)     <h3><a class="anchor" href="#CompileTorWindows">How do I compile Tor
990) under Windows?</a></h3>

991) 

992)     <p>

993)     Try following the steps at <a
994) href="<gitblob>doc/tor-win32-mingw-creation.txt">

995)     tor-win32-mingw-creation.txt</a>.
996)     </p>

997) 

998)     <p>
999)     (Note that you don't need to compile Tor yourself in order to use

1000)     it. Most people just use the packages available on the <a
1001) href="<page

1002)     download/download>">download page</a>.)
1003)     </p>

1004) 

1005)     <hr>

1006) 

1007)     <a id="VirusFalsePositives"></a>

1008)     <h3><a class="anchor" href="#VirusFalsePositives">Why does my Tor
1009) executable appear to have a virus or spyware?</a></h3>

1010) 

1011)     <p>

1012)     Sometimes, overzealous Windows virus and spyware detectors trigger
1013) on some
1014)     parts of the Tor Windows binary. Our best guess is that these are
1015) false
1016)     positives — after all, the anti-virus and anti-spyware
1017) business is just a
1018)     guessing game anyway. You should contact your vendor and explain
1019) that you have
1020)     a program that seems to be triggering false positives. Or pick a
1021) better vendor.

1022)     </p>

1023) 

1024)     <p>
1025)     In the meantime, we encourage you to not just take our word for

1026)     it. Our job is to provide the source; if you're concerned, please do
1027) <a

1028)     href="#CompileTorWindows">recompile it yourself</a>.
1029)     </p>

1030) 

1031)     <hr>

1032) 

1033)     <a id="LiveCD"></a>

1034)     <h3><a class="anchor" href="#LiveCD">Is there a LiveCD or other
1035) bundle that includes Tor?</a></h3>

1036) 

1037)     <p>

1038)     Yes.  Use <a href="https://tails.boum.org/">The Amnesic Incognito

1039)     Live System</a> or <a href="<page projects/torbrowser>">the Tor
1040) Browser

1041)     Bundle</a>.

1042)     </p>

1043) 
1044) <hr>
1045) 

1046) <a id="TBBFlash"></a>

1047) <h3><a class="anchor" href="#TBBFlash">Why can't I view videos on
1048) YouTube

1049) and other Flash-based sites?</a></h3>

1050) 
1051) <p>

1052) YouTube and similar sites require third party browser plugins such as Flash.
1053) Plugins operate independently from Firefox and can perform
1054) activity on your computer that ruins your anonymity. This includes
1055) but is not limited to: <a href="http://decloak.net">completely disregarding
1056) proxy settings</a>, querying your <a

1057) href="http://forums.sun.com/thread.jspa?threadID=5162138&messageID=9618376">
1058) local IP address</a>, and <a

1059) href="http://epic.org/privacy/cookies/flash.html">storing their own
1060) cookies</a>. It is possible to use a LiveCD solution such as

1061) or <a href="https://tails.boum.org/">The Amnesic Incognito Live System</a> 
1062) that creates a secure, transparent proxy to protect you from proxy bypass, 
1063) however issues with local IP address discovery and Flash cookies still remain. 
1064) </p>

1065) 
1066) <p>

1067) <a href="https://www.youtube.com/html5">YouTube offers experimental HTML5 video
1068) support</a> for many of their videos. You can use their Advanced Search to

1069) find HTML5 videos.
1070) </p>
1071) 

1072) <hr>
1073) 

1074) <a id="Ubuntu"></a>
1075) <h3><a class="anchor" href="#Ubuntu">
1076) I'm using Ubuntu and I can't start Tor Browser</a></h3>
1077) <p>

1078) Ubuntu prevents its users from executing shell scripts by clicking them, 
1079) even when the file permissions are set correctly. For now you need to 
1080) start the Tor Browser from the command line by running </p>

1081) <pre>
1082) ./start-tor-browser
1083) </pre>
1084) <p>
1085) from inside the Tor Browser directory.
1086) </p>
1087) 
1088) <hr>
1089) 

1090) <a id="TBBSocksPort"></a>

1091) <h3><a class="anchor" href="#TBBSocksPort">

1092) I want to run another application through the Tor launched by Tor

1093) Browser Bundle.</a></h3>

1094) 
1095) <p>

1096) Typically Tor listens for Socks connections on port 9050. TBB listens

1097) on port 9150.

1098) The goal is to avoid conflicting with a "system" Tor install,

1099) so you can run a system Tor and TBB at the same time. We're <a
1100) href="https://trac.torproject.org/projects/tor/ticket/3948">working on
1101) a feature</a> where Tor will try the usual ports first and then back

1102) off to a random choice if they're already in use.

1103) </p>
1104) 
1105) <hr>
1106) 
1107) <a id="TBBPolipo"></a>
1108) <h3><a class="anchor" href="#TBBPolipo">I need an HTTP proxy. Where did
1109) Polipo go?</a></h3>
1110) 
1111) <p>
1112) In the past, Tor bundles included an HTTP proxy like Privoxy or Polipo,
1113) solely to work around a bug in Firefox that was finally fixed in Firefox
1114) 6. Now you don't need a separate HTTP proxy to use Tor, and in fact
1115) leaving it out makes you safer because Torbutton has better control over
1116) Firefox's interaction with websites.
1117) </p>
1118) 
1119) <p>
1120) If you are trying to use some external application with Tor, step zero

1121) should be to <a href="<page download/download>#warning">reread the set

1122) of warnings</a> for ways you can screw up. Step one should be to try

1123) to use a Socks proxy rather than an http proxy — Tor runs a Socks

1124) proxy on port 9050 on Windows, or <a href="#TBBSocksPort">see above</a>
1125) for OSX and Linux.
1126) </p>
1127) 
1128) <p>

1129) If that fails, feel free to install <a

1130) href="http://www.privoxy.org/">privoxy</a>.
1131) However, please realize that this approach is not recommended for novice
1132) users. Privoxy has an <a
1133) href="http://www.privoxy.org/faq/misc.html#TOR">example
1134) configuration</a> of Tor and Privoxy.

1135) </p>
1136) 
1137) <hr>
1138) 

1139) <a id="TBBOtherExtensions"></a>
1140) <h3><a class="anchor" href="#TBBOtherExtensions">Can I install other
1141) Firefox extensions?</a></h3>
1142) 
1143) <p>

1144) The Tor Browser is free software, so there is nothing preventing you from 
1145) modifying it any way you like. However, we do not recommend installing any 
1146) additional Firefox add-ons with the Tor Browser Bundle. Add-ons can break 
1147) your anonymity in a number of ways, including browser fingerprinting and 
1148) bypassing proxy settings.

1149) </p>

1150) <p>

1151) Some people have suggested we include ad-blocking software or 
1152) anti-tracking software with the Tor Browser Bundle. Right now, we do not 
1153) think that's such a good idea. The Tor Browser Bundle aims to provide 
1154) sufficient privacy that additional add-ons to stop ads and trackers are 
1155) not necessary. Using add-ons like these may cause some sites to break, which 
1156) <a href="https://www.torproject.org/projects/torbrowser/design/#philosophy">
1157) we don't want to do</a>. Additionally, maintaining a list of "bad" sites that 
1158) should be black-listed provides another opportunity to uniquely fingerprint 
1159) users. 

1160) </p>

1161) 

1162) <hr>
1163) 

1164) <a id="TBBJavaScriptEnabled"></a>

1165) <a id="TBBCanIBlockJS"></a>

1166) <h3><a class="anchor" href="#TBBJavaScriptEnabled">Why is NoScript
1167) configured to allow JavaScript by default in the Tor Browser Bundle?
1168) Isn't that unsafe?</a></h3>

1169) 
1170) <p>
1171) We configure NoScript to allow JavaScript by default in the Tor
1172) Browser Bundle because many websites will not work with JavaScript
1173) disabled.  Most users would give up on Tor entirely if a website
1174) they want to use requires JavaScript, because they would not know
1175) how to allow a website to use JavaScript (or that enabling
1176) JavaScript might make a website work).
1177) </p>
1178) 

1179) <p>
1180) There's a tradeoff here. On the one hand, we should leave
1181) JavaScript enabled by default so websites work the way
1182) users expect. On the other hand, we should disable JavaScript
1183) by default to better protect against browser vulnerabilities (<a

1184) href="https://blog.torproject.org/blog/tor-security-advisory-old-tor-browser-bundles-vulnerable">
1185) not just a theoretical concern!</a>). But there's a third issue: websites

1186) can easily determine whether you have allowed JavaScript for them,
1187) and if you disable JavaScript by default but then allow a few websites
1188) to run scripts (the way most people use NoScript), then your choice of
1189) whitelisted websites acts as a sort of cookie that makes you recognizable
1190) (and distinguishable), thus harming your anonymity.
1191) </p>

1192) 
1193) <p>

1194) Ultimately, we want the default Tor bundles to use
1195) a combination of firewalls (like the iptables rules
1196) in <a href="https://tails.boum.org/">Tails</a>) and <a
1197) href="https://trac.torproject.org/projects/tor/ticket/7680">sandboxes</a>
1198) to make JavaScript not so scary. In
1199) the shorter term, TBB 3.0 will hopefully <a
1200) href="https://trac.torproject.org/projects/tor/ticket/9387">allow users
1201) to choose their JavaScript settings more easily</a> &mdash; but the
1202) partitioning concern will remain.

1203) </p>
1204) 
1205) <p>

1206) Until we get there, feel free to leave JavaScript on or off depending
1207) on your security, anonymity, and usability priorities.

1208) </p>
1209) 
1210) <hr>
1211) 

1212) <a id="TBBOtherBrowser"></a>
1213) <h3><a class="anchor" href="#TBBOtherBrowser">I want to use
1214) Chrome/IE/Opera/etc with Tor.</a></h3>
1215) 
1216) <p>
1217) Unfortunately, Torbutton only works with Firefox right now, and without
1218) <a href="https://www.torproject.org/torbutton/en/design/">Torbutton's
1219) extensive privacy fixes</a> there are many ways for websites or other

1220) attackers to recognize you, track you back to your IP address, and so
1221) on.

1222) In short, using any browser besides Tor Browser Bundle with Tor is a
1223) really bad idea.
1224) </p>
1225) 
1226) <p>
1227) We're working with the Chrome team to <a

1228) href="https://blog.torproject.org/blog/google-chrome-incognito-mode-tor-
1229) and-fingerprinting">fix
1230) some bugs and missing APIs in Chrome</a> so it will be possible to write
1231) a
1232) Torbutton for Chrome. No support for any other browser is on the
1233) horizon.

1234) </p>
1235) 
1236) <hr>
1237) 

1238) <a id="TorbuttonOtherBrowser"></a>

1239) <h3><a class="anchor" href="TorbuttonOtherBrowser">
1240) Will ​Torbutton be available for other browsers?</a></h3>

1241) 
1242) <p>

1243)  We don't support IE, Opera or Safari and never plan to. There are too many ways that your privacy can go wrong with those browsers, and because of their closed design it is really hard for us to do anything to change these privacy problems.

1244) </p>
1245) <p>

1246) We are working with the Chrome people to modify Chrome's internals so that we can eventually support it. But for now, Firefox is the only safe choice. 

1247) </p>
1248) 

1249) <hr>

1250) 

1251) <a id="TBBCloseBrowser"></a>

1252) <h3><a class="anchor" href="#TBBCloseBrowser">I want to leave Tor
1253) Browser

1254) Bundle running but close the browser.</a></h3>
1255) 
1256) <p>
1257) We're working on a way to make this possible on all platforms. Please
1258) be patient.
1259) </p>
1260) 
1261) <hr>
1262) 

1263) <a id="GoogleCAPTCHA"></a>
1264) <h3><a class="anchor" href="#GoogleCAPTCHA">Google makes me solve a
1265) CAPTCHA or tells me I have spyware installed.</a></h3>

1266) 
1267) <p>
1268) This is a known and intermittent problem; it does not mean that Google
1269) considers Tor to be spyware.
1270) </p>
1271) 
1272) <p>

1273) When you use Tor, you are sending queries through exit relays that are
1274) also

1275) shared by thousands of other users. Tor users typically see this message

1276) when many Tor users are querying Google in a short period of time.
1277) Google

1278) interprets the high volume of traffic from a single IP address (the exit
1279) relay you happened to pick) as somebody trying to "crawl" their website,
1280) so it slows down traffic from that IP address for a short time.
1281) </p>
1282) <p>
1283) An alternate explanation is that Google tries to detect certain
1284) kinds of spyware or viruses that send distinctive queries to Google
1285) Search. It notes the IP addresses from which those queries are received
1286) (not realizing that they are Tor exit relays), and tries to warn any
1287) connections coming from those IP addresses that recent queries indicate
1288) an infection.
1289) </p>
1290) 
1291) <p>

1292) To our knowledge, Google is not doing anything intentionally
1293) specifically

1294) to deter or block Tor use. The error message about an infected machine
1295) should clear up again after a short time.
1296) </p>
1297) 
1298) <p>
1299) Torbutton 1.2.5 (released in mid 2010) detects Google captchas and can
1300) automatically redirect you to a more Tor-friendly search engine such as

1301) DuckDuckGo, ixquick, or Bing.

1302) </p>
1303) 
1304) <hr />
1305) 

1306) <a id="ForeignLanguages"></a>
1307) <h3><a class="anchor" href="#ForeignLanguages">
1308) Why does Google show up in foreign languages?</a></h3>
1309) 
1310) <p>

1311)  Google uses "geolocation" to determine where in the world you are, so it 
1312)  can give you a personalized experience. This includes using the language 
1313)  it thinks you prefer, and it also includes giving you different results 
1314)  on your queries.

1315) </p>
1316) <p>

1317) If you really want to see Google in English you can click the link that 
1318) provides that. But we consider this a feature with Tor, not a bug --- the 
1319) Internet is not flat, and it in fact does look different depending on 
1320) where you are. This feature reminds people of this fact. The easy way to 
1321) avoid this "feature" is to use 
1322) <a href="https://google.com/ncr">https://google.com/ncr</a>.

1323) </p>
1324) <p>

1325) Note that Google search URLs take name/value pairs as arguments and one 
1326) of those names is "hl". If you set "hl" to "en" then Google will return 
1327) search results in English regardless of what Google server you have been 
1328) sent to. On a query this looks like: 
1329) </p>
1330) <pre>https://encrypted.google.com/search?q=online%20anonymity&hl=en

1331) </pre>

1332) <p>

1333) Another method is to simply use your country code for accessing Google. 
1334) This can be google.be, google.de, google.us and so on. 

1335) </p>
1336) <hr />

1337) <a id="GmailWarning"></a>

1338) <h3><a class="anchor" href="#GmailWarning">Gmail warns me that my

1339) account may have been compromised.</a></h3>

1340) 
1341) <p>
1342) Sometimes, after you've used Gmail over Tor, Google presents a
1343) pop-up notification that your account may have been compromised.
1344) The notification window lists a series of IP addresses and locations
1345) throughout the world recently used to access your account.
1346) </p>
1347) 
1348) <p>
1349) In general this is a false alarm: Google saw a bunch of logins from

1350) different places, as a result of running the service via Tor, and
1351) decided

1352) it was a good idea to confirm the account was being accessed by it's
1353) rightful owner.
1354) </p>
1355) 
1356) <p>
1357) Even though this may be a biproduct of using the service via tor,
1358) that doesn't mean you can entirely ignore the warning. It is
1359) <i>probably</i> a false positive, but it might not be since it is
1360) possible for someone to hijack your Google cookie.
1361) </p>
1362) 
1363) <p>
1364) Cookie hijacking is possible by either physical access to your computer
1365) or by watching your network traffic.  In theory only physical access
1366) should compromise your system because Gmail and similar services
1367) should only send the cookie over an SSL link. In practice, alas, it's <a

1368) href="http://fscked.org/blog/fully-automated-active-https-cookie-
1369) hijacking">

1370) way more complex than that</a>.
1371) </p>
1372) 
1373) <p>
1374) And if somebody <i>did</i> steal your google cookie, they might end
1375) up logging in from unusual places (though of course they also might
1376) not). So the summary is that since you're using Tor, this security
1377) measure that Google uses isn't so useful for you, because it's full of
1378) false positives. You'll have to use other approaches, like seeing if
1379) anything looks weird on the account, or looking at the timestamps for
1380) recent logins and wondering if you actually logged in at those times.
1381) </p>
1382) 
1383) <hr>
1384) 

1385) <a id="torrc"></a>

1386) <h3><a class="anchor" href="#torrc">I'm supposed to "edit my torrc".
1387) What does that mean?</a></h3>

1388) 
1389) <p>
1390) Tor installs a text file called torrc that contains configuration
1391) instructions for how your Tor program should behave. The default
1392) configuration should work fine for most Tor users. Users of Vidalia can
1393) make common changes through the Vidalia interface &mdash; only advanced
1394) users should need to modify their torrc file directly.
1395) </p>

1396) <p>

1397) Tor Browser Bundle users should edit your torrc through Vidalia. Open
1398) the
1399) Vidalia Control Panel. Choose Settings. Choose Advanced. Click the
1400) button

1401) labelled "Edit current torrc". Remember to make sure the checkbox for
1402) "Save Settings." is checked. Hit the Ok button and you are done.
1403) </p>

1404) <p>

1405) Otherwise, you will need to edit the file manually.

1406) The location of your torrc file depends on the way you installed Tor:
1407) </p>
1408) <ul>

1409) <li>If you installed Tor Browser Bundle, look for
1410) <code>Data/Tor/torrc</code> inside your Tor Browser Bundle directory.
1411) </li>

1412) <li>On Windows, if you installed a Tor bundle with Vidalia, you can
1413) find your torrc file in the Start menu under Programs -&gt; Vidalia
1414) Bundle -&gt; Tor, or you can find it by hand in <code>\Documents and
1415) Settings\<i>username</i>\Application Data\Vidalia\torrc</code>. If you
1416) installed Tor without Vidalia, you can find your torrc in the Start
1417) menu under Programs -&gt; Tor, or manually in either <code>\Documents
1418) and Settings\Application Data\tor\torrc</code> or <code>\Documents and
1419) Settings\<i>username</i>\Application Data\tor\torrc</code>.
1420) </li>
1421) <li>On OS X, if you use Vidalia, edit
1422) <code>~/.vidalia/torrc</code>. Otherwise, open your favorite text editor
1423) and load <code>/Library/Tor/torrc</code>.
1424) </li>
1425) <li>On Unix, if you installed a pre-built package, look for
1426) <code>/etc/tor/torrc</code> or <code>/etc/torrc</code> or consult your
1427) package's documentation.
1428) </li>
1429) <li>Finally, if you installed from source, you may not have a torrc
1430) installed yet: look in <code>/usr/local/etc/</code> and note that you

1431) may need to manually copy <code>torrc.sample</code> to
1432) <code>torrc</code>.

1433) </li>
1434) </ul>
1435) 
1436) <p>
1437) If you use Vidalia, be sure to exit both Tor and Vidalia before you edit

1438) your torrc file manually. Otherwise Vidalia might overwrite your
1439) changes.

1440) </p>
1441) 
1442) <p>
1443) Once you've changed your torrc, you will need to restart Tor for the
1444) changes to take effect. (For advanced users on OS X and Unix, note that

1445) you actually only need to send Tor a HUP signal, not actually restart
1446) it.)

1447) </p>
1448) 
1449) <p>
1450) For other configuration options you can use, look at the <a href="<page
1451) docs/tor-manual>">Tor manual page</a>. Remember, all lines beginning
1452) with # in torrc are treated as comments and have no effect on Tor's
1453) configuration.
1454) </p>
1455) 
1456) <hr>
1457) 

1458) <a id="Logs"></a>

1459) <h3><a class="anchor" href="#Logs">How do I set up logging, or see Tor's
1460) logs?</a></h3>

1461) 
1462) <p>

1463) If you installed a Tor bundle that includes Vidalia, then Vidalia has a

1464) window called "Message Log" that will show you Tor's log messages. Click
1465) on "Advanced" to see more details. You can click on "Settings" to change
1466) your log verbosity or save the messages to a file. You're all set.

1467) </p>
1468) 
1469) <p>
1470) If you're not using Vidalia, you'll have to go find the log files by

1471) hand. Here are some likely places for your logs to be:

1472) </p>
1473) 
1474) <ul>
1475) <li>On OS X, Debian, Red Hat, etc, the logs are in /var/log/tor/
1476) </li>

1477) <li>On Windows, there are no default log files currently. If you enable
1478) logs in your torrc file, they default to <code>\username\Application
1479) Data\tor\log\</code> or <code>\Application Data\tor\log\</code>
1480) </li>
1481) <li>If you compiled Tor from source, by default your Tor logs to <a
1482) href="http://en.wikipedia.org/wiki/Standard_streams">"stdout"</a>
1483) at log-level notice. If you enable logs in your torrc file, they
1484) default to <code>/usr/local/var/log/tor/</code>.

1485) </li>
1486) </ul>
1487) 
1488) <p>

1489) To change your logging setup by hand, <a href="#torrc">edit your
1490) torrc</a>

1491) and find the section (near the top of the file) which contains the
1492) following line:

1493) </p>
1494) 
1495) <pre>

1496) \## Logs go to stdout at level "notice" unless redirected by something
1497) \## else, like one of the below lines.

1498) </pre>

1499) 
1500) <p>

1501) For example, if you want Tor to send complete debug, info, notice, warn,

1502) and err level messages to a file, append the following line to the end
1503) of the section:
1504) </p>
1505) 
1506) <pre>
1507) Log debug file c:/program files/tor/debug.log
1508) </pre>
1509) 
1510) <p>

1511) Replace <code>c:/program files/tor/debug.log</code> with a directory
1512) and filename for your Tor log.

1513) </p>
1514) 
1515) <hr>
1516) 

1517) 
1518) <a id="LogLevel"></a>
1519) <h3><a class="anchor" href="#LogLevel">What log level should I use?</a></h3>
1520) 
1521) <p>

1522) There are five log levels (also called "log severities") you might see in 
1523) Tor's logs:

1524) </p>
1525) 
1526) <ul>

1527)     <li>"err": something bad just happened, and we can't recover. Tor will 
1528)     exit.</li>
1529)     <li>"warn": something bad happened, but we're still running. The bad 
1530)     thing might be a bug in the code, some other Tor process doing something 
1531)     unexpected, etc. The operator should examine the message and try to 
1532)     correct the problem.</li>

1533)     <li>"notice": something the operator will want to know about.</li>

1534)     <li>"info": something happened (maybe bad, maybe ok), but there's 
1535)     nothing you need to (or can) do about it.</li>

1536)     <li>"debug": for everything louder than info. It is quite loud indeed.</li> 
1537) </ul>
1538) 
1539) <p>

1540) Alas, some of the warn messages are hard for ordinary users to correct -- the 
1541) developers are slowly making progress at making Tor automatically react 
1542) correctly for each situation.

1543) </p>
1544) 
1545) <p>

1546) We recommend running at the default, which is "notice". You will hear about 
1547) important things, and you won't hear about unimportant things.

1548) </p>
1549) 
1550) <p>

1551) Tor relays in particular should avoid logging at info or debug in normal 
1552) operation, since they might end up recording sensitive information in 
1553) their logs. 

1554) </p>
1555) 

1556) <hr>
1557) 

1558) <a id="DoesntWork"></a>

1559) <h3><a class="anchor" href="#DoesntWork">I installed Tor but it's not
1560) working.</a></h3>

1561) 
1562) <p>

1563) Once you've got the Tor bundle up and running, the first question to
1564) ask is whether your Tor client is able to establish a circuit.

1565) </p>
1566) 
1567) <p>If Tor can establish a circuit, the onion icon in

1568) Vidalia will turn green (and if you're running Tor Browser Bundle, it
1569) will
1570) automatically launch a browser for you). You can also check in the
1571) Vidalia

1572) Control Panel to make sure it says "Connected to the Tor
1573) network!" under Status. For those not using Vidalia, check your <a

1574) href="#Logs">Tor logs</a> for

1575) a line saying that Tor "has successfully opened a circuit. Looks like
1576) client functionality is working."
1577) </p>
1578) 
1579) <p>
1580) If Tor can't establish a circuit, here are some hints:
1581) </p>
1582) 
1583) <ol>
1584) <li>Are you sure Tor is running? If you're using Vidalia, you may have
1585) to click on the onion and select "Start" to launch Tor.</li>
1586) <li>Check your system clock. If it's more than a few hours off, Tor will

1587) refuse to build circuits. For Microsoft Windows users, synchronize your
1588) clock under the clock -> Internet time tab. In addition, correct the

1589) day and date under the 'Date & Time' Tab. Also make sure your time
1590) zone is correct.</li>

1591) <li>Is your Internet connection <a href="#FirewallPorts">firewalled
1592) by port</a>, or do you normally need to use a <a

1593) href="<wikifaq>#MyInternetconnectionrequiresanHTTPorSOCKSproxy.">proxy</a>?

1594) </li>

1595) <li>Are you running programs like Norton Internet Security or SELinux
1596) that

1597) block certain connections, even though you don't realize they do? They
1598) could be preventing Tor from making network connections.</li>
1599) <li>Are you in China, or behind a restrictive corporate network firewall
1600) that blocks the public Tor relays? If so, you should learn about <a

1601) href="<page docs/bridges>">Tor bridges</a>.</li>

1602) <li>Check your <a href="#Logs">Tor logs</a>. Do they give you any hints
1603) about what's going wrong?</li>

1604) </ol>
1605) 
1606) <hr />
1607) 

1608) <a id="TorCrash"></a>
1609) <h3><a class="anchor" href="#TorCrash">My Tor keeps crashing.</a></h3>
1610) <p>
1611)  We want to hear from you! There are supposed to be zero crash bugs in Tor. 
1612)  This FAQ entry describes the best way for you to be helpful to us. But even 
1613)  if you can't work out all the details, we still want to hear about it, so 
1614)  we can help you track it down. 
1615) </p>
1616) <p>
1617) First, make sure you're using the latest version of Tor (either the latest 
1618) stable or the latest development version). 
1619) </p>
1620) <p>
1621) Second, make sure your version of libevent is new enough. We recommend at 
1622) least libevent 1.3a. 
1623) </p>
1624) <p>
1625) Third, see if there's already an entry for your bug in the <a 
1626) href="https://bugs.torproject.org/">Tor bugtracker</a>. If so, 
1627) check if there are any new details that you can add. 
1628) </p>
1629) <p>
1630) Fourth, is the crash repeatable? Can you cause the crash? Can 
1631) you isolate some of the circumstances or config options that 
1632) make it happen? How quickly or often does the bug show up? 
1633) Can you check if it happens with other versions of Tor, for 
1634) example the latest stable release? 
1635) </p>
1636) <p>
1637) Fifth, what sort of crash do you get? 
1638) </p>
1639) <ul>
1640) <li>
1641) Does your Tor log include an "assert failure"? If so, please 
1642) tell us that line, since it helps us figure out what's going on. 
1643) Tell us the previous couple of log messages as well, especially 
1644) if they seem important. 
1645) </li>
1646) <li>
1647) If it says "Segmentation fault - core dumped" then you need to 
1648) do a bit more to track it down. Look for a file like "core" or 
1649) "tor.core" or "core.12345" in your current directory, or in your 
1650) Data Directory. If it's there, run "gdb tor core" and then "bt", 
1651) and include the output. If you can't find a core, run "ulimit -c 
1652) unlimited", restart Tor, and try to make it crash again. (This core 
1653) thing will only work on Unix -- alas, tracking down bugs on Windows 
1654) is harder. If you're on Windows, can you get somebody to duplicate 
1655) your bug on Unix?)
1656) </li>
1657) <li>
1658) If Tor simply vanishes mysteriously, it probably is a segmentation 
1659) fault but you're running Tor in the background (as a daemon) so you 
1660) won't notice. Go look at the end of your log file, and look for a 
1661) core file as above. If you don't find any good hints, you should 
1662) consider running Tor in the foreground (from a shell) so you can 
1663) see how it dies. Warning: if you switch to running Tor in the foreground, 
1664) you might start using a different torrc file, with a different default 
1665) Data Directory; see the <a href="#UpgradeOrMove">relay-upgrade FAQ entry</a> 
1666) for details. 
1667) </li>
1668) <li>
1669) If it's still vanishing mysteriously, perhaps something else is killing it? 
1670) Do you have resource limits (ulimits) configured that kill off processes 
1671) sometimes? (This is especially common on OpenBSD.) On Linux, try running 
1672) "dmesg" to see if the out-of-memory killer removed your process. (Tor will 
1673) exit cleanly if it notices that it's run out of memory, but in some cases 
1674) it might not have time to notice.) In very rare circumstances, hardware 
1675) problems could also be the culprit. 
1676) </li>
1677) </ul>
1678) <p>
1679) Sixth, if the above ideas don't point out the bug, consider increasing your 
1680) log level to "loglevel debug". You can look at the log-configuration FAQ 
1681) entry for instructions on what to put in your torrc file. If it usually 
1682) takes a long time for the crash to show up, you will want to reserve a whole 
1683) lot of disk space for the debug log. Alternatively, you could just send 
1684) debug-level logs to the screen (it's called "stdout" in the torrc), and then 
1685) when it crashes you'll see the last couple of log lines it had printed. 
1686) (Note that running with verbose logging like this will slow Tor down 
1687) considerably, and note also that it's generally not a good idea security-wise 
1688) to keep logs like this sitting around.) 
1689) </p>
1690) 
1691) <hr />
1692) 

1693) <a id="VidaliaPassword"></a>

1694) <h3><a class="anchor" href="#VidaliaPassword">Tor/Vidalia prompts for a
1695) password at start.</a></h3>

1696) 
1697) <p>
1698) Vidalia interacts with the Tor software via Tor's "control port". The
1699) control port lets Vidalia receive status updates from Tor, request a new
1700) identity, configure Tor's settings, etc. Each time Vidalia starts Tor,
1701) Vidalia sets a random password for Tor's control port to prevent other
1702) applications from also connecting to the control port and potentially
1703) compromising your anonymity.
1704) </p>
1705) 
1706) <p>
1707) Usually this process of generating and setting a random control password
1708) happens in the background. There are three common situations, though,
1709) where Vidalia may prompt you for a password:
1710) </p>
1711) 
1712) <ol>
1713) <li>You're already running Vidalia and Tor. For example, this situation
1714) can happen if you installed the Vidalia bundle and now you're trying to
1715) run the Tor Browser Bundle. In that case, you'll need to close the old
1716) Vidalia and Tor before you can run this one.
1717) </li>
1718) <li>Vidalia crashed, but left Tor running with the last known random
1719) password. After you restart Vidalia, it generates a new random password,

1720) but Vidalia can't talk to Tor, because the random passwords are
1721) different.

1722) <br />

1723) If the dialog that prompts you for a control password has a Reset
1724) button,

1725) you can click the button and Vidalia will restart Tor with a new random
1726) control password.
1727) <br />
1728) If you do not see a Reset button, or if Vidalia is unable to restart
1729) Tor for you, you can still fix the problem manually. Simply go into your
1730) process or task manager, and terminate the Tor process. Then use Vidalia
1731) to restart Tor and all will work again.
1732) </li>
1733) <li>You had previously set Tor to run as a Windows NT service. When Tor
1734) is set to
1735) run as a service, it starts up when the system boots. If you configured
1736) Tor to start as a service through Vidalia, a random password was set
1737) and saved in Tor. When you reboot, Tor starts up and uses the random
1738) password it saved. You login and start up Vidalia. Vidalia attempts to
1739) talk to the already running Tor. Vidalia generates a random password,
1740) but it is different than the saved password in the Tor service.
1741) <br />
1742) You need to reconfigure Tor to not be a service. See the FAQ entry on

1743) <a href="#NTservice">running Tor as a

1744) Windows NT service</a>

1745) for more information on how to remove the Tor service.
1746) </li>
1747) </ol>
1748) 

1749)     <hr>

1750) 

1751)     <a id="ChooseEntryExit"></a>

1752)     <h3><a class="anchor" href="#ChooseEntryExit">Can I control which
1753) nodes (or country) are used for entry/exit?</a></h3>

1754) 

1755)     <p>

1756)     Yes. You can set preferred entry and exit nodes as well as
1757)     inform Tor which nodes you do not want to use.

1758)     The following options can be added to your config file <a
1759)     href="#torrc">"torrc"</a> or specified on the command line:

1760)     </p>
1761)     <dl>
1762)       <dt><tt>EntryNodes $fingerprint,$fingerprint,...</tt></dt>

1763)         <dd>A list of preferred nodes to use for the first hop in the
1764) circuit, if possible.

1765)         </dd>
1766)       <dt><tt>ExitNodes $fingerprint,$fingerprint,...</tt></dt>

1767)         <dd>A list of preferred nodes to use for the last hop in the
1768) circuit, if possible.

1769)         </dd>
1770)       <dt><tt>ExcludeNodes $fingerprint,$fingerprint,...</tt></dt>

1771)         <dd>A list of nodes to never use when building a circuit.

1772)         </dd>
1773)       <dt><tt>ExcludeExitNodes $fingerprint,$fingerprint,...</tt></dt>

1774)         <dd>A list of nodes to never use when picking an exit.

1775)             Nodes listed in <tt>ExcludeNodes</tt> are automatically in
1776) this list.

1777)         </dd>
1778)     </dl>
1779)     <p>

1780)     <em>We recommend you do not use these</em>

1781)     — they are intended for testing and may disappear in future
1782) versions.

1783)     You get the best security that Tor can provide when you leave the
1784)     route selection to Tor; overriding the entry / exit nodes can mess
1785)     up your anonymity in ways we don't understand.

1786)     </p>
1787)     <p>

1788)     Note also that not every circuit is used to deliver traffic outside of 
1789)     the Tor network. It is normal to see non-exit circuits (such as those 
1790)     used to connect to hidden services, those that do directory fetches, 
1791)     those used for relay reachability self-tests, and so on) that end at 
1792)     a non-exit node. To keep a node from being used entirely, see 
1793)     <tt>ExcludeNodes</tt> and <tt>StrictNodes</tt> in the 
1794)     <a href="<page docs/tor-manual>">manual</a>.

1795)     </p>
1796)     <p>

1797)     Instead of <tt>$fingerprint</tt> you can also specify a <a

1798) 
1799) href="https://secure.wikimedia.org/wikipedia/en/wiki/ISO_3166-1_alpha-2"
1800) >2

1801)     letter ISO3166 country code</a> in curly braces (for example <tt>{de}</tt>),

1802)     or an ip address pattern (for example 255.254.0.0/8), or a node
1803)     nickname. Make sure there are no spaces between the commas and the
1804)     list items.

1805)     </p>
1806)     <p>

1807)     If you want to access a service directly through Tor's Socks
1808) interface

1809)     (eg. using ssh via connect.c), another option is to set up an

1810)     internal mapping in your configuration file using
1811) <tt>MapAddress</tt>.

1812)     See the manual page for details.
1813)     </p>

1814) 

1815)     <hr>

1816) 

1817) <a id="FirewallPorts"></a>

1818) <h3><a class="anchor" href="#FirewallPorts">My firewall only allows a
1819) few outgoing ports.</a></h3>

1820) 
1821) <p>
1822) If your firewall works by blocking ports, then you can tell Tor to only

1823) use the ports that your firewall permits by adding "FascistFirewall 1"
1824) to

1825) your <a href="<page docs/faq>#torrc">torrc

1826) configuration file</a>, or by clicking "My firewall only lets me connect
1827) to certain ports" in Vidalia's Network Settings window.
1828) </p>
1829) 
1830) <p>
1831) By default, when you set this Tor assumes that your firewall allows only
1832) port 80 and port 443 (HTTP and HTTPS respectively). You can select a
1833) different set of ports with the FirewallPorts torrc option.
1834) </p>
1835) 
1836) <p>
1837) If you want to be more fine-grained with your controls, you can also
1838) use the ReachableAddresses config options, e.g.:
1839) </p>
1840) 
1841) <pre>
1842)   ReachableDirAddresses *:80
1843)   ReachableORAddresses *:443
1844) </pre>
1845) 
1846) <hr>

1847) 

1848)     <a id="ExitPorts"></a>

1849)     <h3><a class="anchor" href="#ExitPorts">Is there a list of default exit 
1850)     ports?</a></h3>

1851)     <p>

1852) The default open ports are listed below but keep in mind that, any port or 
1853) ports can be opened by the relay operator by configuring it in torrc or 
1854) modifying the source code. But the default according to src/or/policies.c 
1855) from the source code release tor-0.2.4.16-rc is: 

1856)     </p>
1857)     <pre>
1858)   reject 0.0.0.0/8
1859)   reject 169.254.0.0/16
1860)   reject 127.0.0.0/8
1861)   reject 192.168.0.0/16
1862)   reject 10.0.0.0/8
1863)   reject 172.16.0.0/12
1864)   reject *:25
1865)   reject *:119
1866)   reject *:135-139
1867)   reject *:445
1868)   reject *:563
1869)   reject *:1214
1870)   reject *:4661-4666
1871)   reject *:6346-6429
1872)   reject *:6699
1873)   reject *:6881-6999
1874)   accept *:*
1875)     </pre>
1876)     <p>

1877)     A relay will block access to its own IP address, as well local network 
1878)     IP addresses. A relay always blocks itself by default. This prevents 
1879)     Tor users from accidentally accessing any of the exit operator's local 
1880)     services. 
1881)     </p>
1882) 
1883)     <hr>
1884) 
1885)     <a id="SocksAndDNS"></a>
1886)     <h3><a class="anchor" href="#SocksAndDNS">How do I check if my application that uses 
1887)     SOCKS is leaking DNS requests?</a></h3>
1888) 
1889)     <p>
1890)     These are two steps you need to take here. The first is to make sure 
1891)     that it's using the correct variant of the SOCKS protocol, and the 
1892)     second is to make sure that there aren't other leaks. 
1893)     </p>
1894) 
1895)     <p>
1896)     Step one: add "TestSocks 1" to your torrc file, and then watch your 
1897)     logs as you use your application. Tor will then log, for each SOCKS 
1898)     connection, whether it was using a 'good' variant or a 'bad' one. 
1899)     (If you want to automatically disable all 'bad' variants, set 
1900)     "SafeSocks 1" in your <a href="#torrc">torrc</a> file.) 
1901)     </p>
1902) 
1903)     <p>
1904)     Step two: even if your application is using the correct variant of 
1905)     the SOCKS protocol, there is still a risk that it could be leaking 
1906)     DNS queries. This problem happens in Firefox extensions that resolve 
1907)     the destination hostname themselves, for example to show you its IP 
1908)     address, what country it's in, etc. These applications may use a safe 
1909)     SOCKS variant when actually making connections, but they still do DNS 
1910)     resolves locally. If you suspect your application might behave like 
1911)     this, you should use a network sniffer like <a 
1912)     href="https://www.wireshark.org/">Wireshark</a> and look for 
1913)     suspicious outbound DNS requests. I'm afraid the details of how to look 
1914)     for these problems are beyond the scope of a FAQ entry though -- find 
1915)     a friend to help if you have problems. 

1916)     </p>
1917) 
1918)     <hr>
1919) 

1920)     <a id="HowDoIDecide"></a>
1921)     <h3><a class="anchor" href="#HowDoIDecide">How do I decide if I should 
1922)     run a relay?</a></h3>
1923)     <p>
1924)     We're looking for people with reasonably reliable Internet connections, 
1925)     that have at least 20 kilobytes/second each way. If that's you, please 
1926)     consider <a href="https://www.torproject.org/docs/tor-relay-debian">helping 
1927)     out</a>. 
1928)     </p>
1929)     
1930)     <hr>
1931)     
1932)     <a id="WhyIsntMyRelayBeingUsedMore"></a>
1933)     <h3><a class="anchor" href="#WhyIsntMyRelayBeingUsedMore">Why isn't my 
1934)     relay being used more?</a></h3>
1935)     <p>
1936)     If your relay is relatively new then give it time. Tor decides which 
1937)     relays it uses heuristically based on reports from Bandwidth 
1938)     Authorities. These authorities take measurements of your relay's 
1939)     capacity and, over time, directs more traffic there until it reaches 
1940)     an optimal load. The lifecycle of a new relay is explained in more 
1941)     depth in <a href="https://blog.torproject.org/blog/lifecycle-of-a-new-relay">
1942)     this blog post</a>.
1943)     </p>
1944)     <p>
1945)     If you've been running a relay for a while and still having issues 
1946)     then try asking on the <a href=
1947)     "https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-relays/">
1948)     tor-relays list</a>. 
1949)     </p>
1950)     
1951)     <hr>
1952) 

1953)     <a id="HighCapacityConnection"></a>    
1954)     <h3><a class="anchor" href="#HighCapacityConnection">How can I get Tor to fully 
1955)     make use of my high capacity connection?</a></h3>
1956)     
1957)     <p>
1958)     See <a href="http://archives.seul.org/or/relays/Aug-2010/msg00034.html">this 
1959)     tor-relays thread</a>.
1960)     </p>
1961)     
1962)     <hr>    
1963)     

1964)     <a id="RelayFlexible"></a>

1965)     <h3><a class="anchor" href="#RelayFlexible">How stable does my relay
1966) need to be?</a></h3>

1967) 

1968)     <p>
1969)     We aim to make setting up a Tor relay easy and convenient:
1970)     </p>

1971) 

1972)     <ul>
1973)     <li>Tor has built-in support for <a

1974)     href="<wikifaq>#WhatbandwidthshapingoptionsareavailabletoTorrelays">

1975)     rate limiting</a>. Further, if you have a fast
1976)     link but want to limit the number of bytes per
1977)     day (or week or month) that you donate, check out the <a

1978) 
1979) href="<wikifaq>#HowcanIlimitthetotalamountofbandwidthusedbymyTorrelay">
1980) hibernation

1981)     feature</a>.
1982)     </li>

1983)     <li>Each Tor relay has an <a href="#ExitPolicies">exit policy</a>
1984) that
1985)     specifies what sort of outbound connections are allowed or refused
1986) from
1987)     that relay. If you are uncomfortable allowing people to exit from
1988) your
1989)     relay, you can set it up to only allow connections to other Tor
1990) relays.

1991)     </li>
1992)     <li>It's fine if the relay goes offline sometimes. The directories
1993)     notice this quickly and stop advertising the relay. Just try to make
1994)     sure it's not too often, since connections using the relay when it
1995)     disconnects will break.
1996)     </li>
1997)     <li>We can handle relays with dynamic IPs just fine &mdash; simply
1998)     leave the Address config option blank, and Tor will try to guess.
1999)     </li>
2000)     <li>If your relay is behind a NAT and it doesn't know its public
2001)     IP (e.g. it has an IP of 192.168.x.y), you'll need to set up port

2002)     forwarding. Forwarding TCP connections is system dependent but

2003)     <a href="<wikifaq>#ImbehindaNATFirewall">this FAQ entry</a>

2004)     offers some examples on how to do this.
2005)     </li>
2006)     <li>Your relay will passively estimate and advertise its recent

2007)     bandwidth capacity, so high-bandwidth relays will attract more users
2008) than
2009)     low-bandwidth ones. Therefore having low-bandwidth relays is useful
2010) too.

2011)     </li>
2012)     </ul>

2013) 

2014)     <hr>

2015) 

2016)     <a id="ExitPolicies"></a>

2017)     <h3><a class="anchor" href="#ExitPolicies">I'd run a relay, but I
2018) don't want to deal with abuse issues.</a></h3>

2019) 

2020)     <p>
2021)     Great. That's exactly why we implemented exit policies.
2022)     </p>

2023) 

2024)     <p>
2025)     Each Tor relay has an exit policy that specifies what sort of

2026)     outbound connections are allowed or refused from that relay. The
2027) exit

2028)     policies are propagated to Tor clients via the directory, so clients
2029)     will automatically avoid picking exit relays that would refuse to
2030)     exit to their intended destination. This way each relay can decide
2031)     the services, hosts, and networks he wants to allow connections to,

2032)     based on abuse potential and his own situation. Read the FAQ entry
2033) on
2034)     <a href="<page docs/faq-abuse>#TypicalAbuses">issues you might
2035) encounter</a>

2036)     if you use the default exit policy, and then read Mike Perry's

2037)     <a href="<blog>tips-running-exit-node-minimal-harassment">tips

2038)     for running an exit node with minimal harassment</a>.
2039)     </p>

2040) 

2041)     <p>

2042)     The default exit policy allows access to many popular services

2043)     (e.g. web browsing), but <a
2044) href="<wikifaq>#Istherealistofdefaultexitports">restricts</a>

2045)     some due to abuse potential (e.g. mail) and some since
2046)     the Tor network can't handle the load (e.g. default
2047)     file-sharing ports). You can change your exit policy

2048)     using Vidalia's "Sharing" tab, or by manually editing your

2049)     <a href="<page docs/faq>#torrc">torrc</a>

2050)     file. If you want to avoid most if not all abuse potential, set it
2051) to
2052)     "reject *:*" (or un-check all the boxes in Vidalia). This setting
2053) means
2054)     that your relay will be used for relaying traffic inside the Tor
2055) network,

2056)     but not for connections to external websites or other services.
2057)     </p>

2058) 

2059)     <p>

2060)     If you do allow any exit connections, make sure name resolution
2061) works

2062)     (that is, your computer can resolve Internet addresses correctly).

2063)     If there are any resources that your computer can't reach (for
2064) example,

2065)     you are behind a restrictive firewall or content filter), please

2066)     explicitly reject them in your exit policy — otherwise Tor
2067) users

2068)     will be impacted too.
2069)     </p>

2070) 

2071)     <hr>

2072) 

2073)     <a id="DifferentComputer"></a>

2074)     <h3><a class="anchor" href="#DifferentComputer">I want to run my 
2075)     Tor client on a different computer than my applications.</a></h3>

2076)     <p>

2077)     By default, your Tor client only listens for applications that 
2078)     connect from localhost. Connections from other computers are 
2079)     refused. If you want to torify applications on different computers 
2080)     than the Tor client, you should edit your torrc to define 
2081)     SocksListenAddress 0.0.0.0 g and then restart (or hup) Tor. If you 
2082)     want to get more advanced, you can configure your Tor client on a 
2083)     firewall to bind to your internal IP but not your external IP.  

2084)     </p>
2085) 
2086)     <hr>
2087) 
2088)     <a id="ServerClient"></a>

2089)     <h3><a class="anchor" href="#ServerClient">Can I install Tor on a 
2090)     central server, and have my clients connect to it?</a></h3>
2091)     <p>
2092)      Yes. Tor can be configured as a client or a relay on another 
2093)      machine, and allow other machines to be able to connect to it 
2094)      for anonymity. This is most useful in an environment where many 
2095)      computers want a gateway of anonymity to the rest of the world. 
2096)      However, be forwarned that with this configuration, anyone within 
2097)      your private network (existing between you and the Tor 
2098)      client/relay) can see what traffic you are sending in clear text. 
2099)      The anonymity doesn't start until you get to the Tor relay. 
2100)      Because of this, if you are the controller of your domain and you 
2101)      know everything's locked down, you will be OK, but this configuration 
2102)      may not be suitable for large private networks where security is 
2103)      key all around.
2104)     </p>
2105)     <p>
2106) Configuration is simple, editing your torrc file's SocksListenAddress 
2107) according to the following examples:

2108)     </p>
2109)     <pre>

2110) 
2111)   #This provides local interface access only, 
2112)   #needs SocksPort to be greater than 0
2113)   SocksListenAddress 127.0.0.1 
2114) 
2115)   #This provides access to Tor on a specified interface
2116)   SocksListenAddress 192.168.x.x:9100 
2117) 
2118)   #Accept from all interfaces
2119)   SocksListenAddress 0.0.0.0:9100
2120)    </pre>

2121)     <p>

2122) You can state multiple listen addresses, in the case that you are 
2123) part of several networks or subnets.

2124)     </p>
2125)     <pre>
2126)   SocksListenAddress 192.168.x.x:9100 #eth0
2127)   SocksListenAddress 10.x.x.x:9100 #eth1
2128)     </pre>
2129)     <p>

2130) After this, your clients on their respective networks/subnets would specify 
2131) a socks proxy with the address and port you specified SocksListenAddress 
2132) to be. 

2133)     </p>
2134)     <p>

2135) Please note that the SocksPort configuration option gives the port ONLY for 
2136) localhost (127.0.0.1). When setting up your SocksListenAddress(es), you need 
2137) to give the port with the address, as shown above.

2138)     <p>

2139) If you are interested in forcing all outgoing data through the central Tor 
2140) client/relay, instead of the server only being an optional proxy, you may find 
2141) the program iptables (for *nix) useful. 

2142)     </p>
2143) 
2144)     <hr>
2145) 

2146)     <a id="JoinTheNetwork"></a>

2147)     <h3><a class="anchor" href="#JoinTheNetwork">So I can just configure a 
2148)     nickname and ORPort and join the network?</a></h3>

2149) 
2150)     <p>

2151)      Yes. You can join the network and be a useful relay just by configuring 
2152)      your Tor to be a relay and making sure it's reachable from the outside.

2153)     </p>
2154)     <p>
2155) 30 Seconds to a Tor Relay:
2156)     </p>
2157)     <ul><li>
2158)     Configure a Nickname: 
2159)     </li></ul>
2160)     <pre>
2161) Nickname ididnteditheconfig
2162)     </pre>

2163)     <ul><li>

2164)     Configure ORPort: 

2165)     </li></ul>

2166)     <pre>
2167) ORPort 9001
2168)     </pre>

2169)     <ul><li>

2170)     Configure Contact Info: 

2171)     </li></ul>

2172) 
2173)     <pre>
2174) ContactInfo human@…

2175)     </pre>
2176)     <ul><li>

2177)     Start Tor. Watch the log file for a log entry that states: "Self-testing 
2178)     indicates your ORPort is reachable from the outside. Excellent. Publishing 
2179)     server descriptor."

2180)     </li></ul>

2181) 
2182)     <hr />

2183) 

2184)     <a id="RelayOrBridge"></a>

2185)     <h3><a class="anchor" href="#RelayOrBridge">Should I be a normal
2186) relay or bridge relay?</a></h3>

2187) 

2188)     <p><a href="<page docs/bridges>">Bridge relays</a> (or "bridges" for
2189) short)
2190)     are <a href="<page docs/tor-doc-relay>">Tor relays</a> that aren't

2191)     listed in the public Tor directory.

2192)     That means that ISPs or governments trying to block access to the

2193)     Tor network can't simply block all bridges.

2194)     </p>

2195) 

2196)     <p>Being a normal relay vs being a bridge relay is almost the same
2197)     configuration: it's just a matter of whether your relay is listed

2198)     publicly or not.

2199)     </p>

2200) 

2201)     <p>

2202)     So bridges are useful a) for Tor users in oppressive regimes,

2203)     and b) for people who want an extra layer of security

2204)     because they're worried somebody will recognize that it's a public
2205)     Tor relay IP address they're contacting.

2206)     </p>

2207) 

2208)     <p>
2209)     Several countries, including China and Iran, have found ways to

2210)     detect and block connections to Tor bridges.

2211)     <a href="<page projects/obfsproxy>">Obfsproxy</a> bridges address

2212)     this by adding another layer of obfuscation.

2213)     </p>
2214) 

2215)     <p>So should you run a normal relay or bridge relay? If you have
2216) lots

2217)     of bandwidth, you should definitely run a normal relay.
2218)     If you're willing

2219)     to <a href="#ExitPolicies">be an exit</a>, you should definitely
2220)     run a normal relay, since we need more exits. If you can't be an
2221)     exit and only have a little bit of bandwidth, be a bridge. Thanks
2222)     for volunteering!

2223)     </p>

2224) 

2225)     <hr>

2226) 

2227) <a id="UpgradeOrMove"></a>

2228) <h3><a class="anchor" href="#UpgradeOrMove">I want to upgrade/move my relay. 
2229) How do I keep the same key?</a></h3>

2230) 
2231) <p>

2232)  When upgrading your Tor relay, or running it on a different computer, 
2233)  the important part is to keep the same nickname (defined in your torrc 
2234)  file) and the same identity key (stored in "keys/secret_id_key" in 
2235)  your DataDirectory).

2236) </p>
2237) <p>

2238) This means that if you're upgrading your Tor relay and you keep the same 
2239) torrc and the same DataDirectory, then the upgrade should just work and 
2240) your relay will keep using the same key. If you need to pick a new 
2241) DataDirectory, be sure to copy your old keys/secret_id_key over. 

2242) </p>
2243) 
2244)     <hr>
2245) 
2246) <a id="NTService"></a>

2247) <h3><a class="anchor" href="#NTService">How do I run my Tor relay as an NT 
2248) service?</a></h3>

2249) 
2250) <p>

2251)  You can run Tor as a service on all versions of Windows except Windows 
2252)  95/98/ME. This way you can run a Tor relay without needing to always have 
2253)  Vidalia running.

2254) </p>
2255) <p>

2256) If you've already configured your Tor to be a relay, please note that when 
2257) you enable Tor as a service, it will use a different DatagDirectory, and 
2258) thus will generate a different key. If you want to keep using the old key, 
2259) see the Upgrading your Tor relay FAQ entry for how to restore the old 
2260) identity key.

2261) </p>
2262) <p>
2263) To install Tor as a service, you can simply run:
2264) </p>
2265) <pre>
2266) tor --service install
2267) </pre>
2268) <p>

2269) A service called Tor Win32 Service will be installed and started. This 
2270) service will also automatically start every time Windows boots, unless 
2271) you change the Start-up type. An easy way to check the status of Tor, 
2272) start or stop the service, and change the start-up type is by running 
2273) services.msc and finding the Tor service in the list of currently 
2274) installed services.

2275) </p>
2276) <p>

2277) Optionally, you can specify additional options for the Tor service using 
2278) the -options argument. For example, if you want Tor to use C:\tor\torrc, 
2279) instead of the default torrc, and open a control port on port 9151, you 
2280) would run:

2281) </p>
2282) <pre>
2283) tor --service install -options -f C:\tor\torrc ControlPort 9151
2284) </pre>
2285) <p>
2286) You can also start or stop the Tor service from the command line by typing:
2287) </p>
2288) <pre>
2289)  tor --service start
2290) </pre>
2291) <p>
2292) or
2293) </p>
2294) <pre>
2295)  tor --service stop
2296) </pre>
2297) <p>
2298) To remove the Tor service, you can run the following command:
2299) </p>
2300) <pre>
2301) tor --service remove
2302) </pre>
2303) <p>

2304) If you are running Tor as a service and you want to uninstall Tor entirely, 
2305) be sure to run the service removal command (shown above) first before 
2306) running the uninstaller from "Add/Remove Programs". The uninstaller is 
2307) currently not capable of removing the active service.

2308) </p>
2309) 
2310) <hr>
2311) 
2312) <a id="VirtualServer"></a>

2313) <h3><a class="anchor" href="#VirtualServer">Can I run a Tor relay from my 
2314) virtual server account?</a></h3>

2315) 
2316) <p>

2317) Some ISPs are selling "vserver" accounts that provide what they call a 
2318) virtual server -- you can't actually interact with the hardware, and 
2319) they can artificially limit certain resources such as the number of file 
2320) descriptors you can open at once. Competent vserver admins are able to 
2321) configure your server to not hit these limits. For example, in SWSoft's 
2322) Virtuozzo, investigate /proc/user_beancounters. Look for "failcnt" in 
2323) tcpsndbuf, tcprecvbuf, numothersock, and othersockbuf. Ask for these to 
2324) be increased accordingly. Some users have seen settings work well as follows: 

2325) <p>

2326) <table border="1">

2327) <tr>
2328) <td>
2329) <i>resource</i>
2330) </td>
2331) <td>
2332) <i>held</i>
2333) </td>
2334) <td>
2335) <i>maxheld</i>
2336) </td>
2337) <td>
2338) <i>barrier</i>
2339) </td>
2340) <td>
2341) <i>limit</i>
2342) </td>
2343) <td>
2344) <i>failcnt</i>
2345) </td>
2346) </tr>
2347) <tr>
2348) <td>
2349) tcpsndbuf
2350) </td>
2351) <td>
2352) 46620
2353) </td>
2354) <td>
2355) 48840
2356) </td>
2357) <td>
2358) 3440640
2359) </td>
2360) <td>
2361) 5406720
2362) </td>
2363) <td>
2364) 0
2365) </td>
2366) </tr>
2367) <tr>
2368) <td>
2369) tcprcvbuf
2370) </td>
2371) <td>
2372) 0
2373) </td>
2374) <td>
2375) 2220
2376) </td>
2377) <td>
2378) 3440640
2379) </td>
2380) <td>
2381) 5406720
2382) </td>
2383) <td>
2384) 0
2385) </td>
2386) </tr>
2387) <tr>
2388) <td>
2389) othersockbuf
2390) </td>
2391) <td>
2392) 243516
2393) </td>
2394) <td>
2395) 260072
2396) </td>
2397) <td>
2398) 2252160
2399) </td>
2400) <td>
2401) 4194304
2402) </td>
2403) <td>
2404) 0
2405) </td>
2406) </tr>
2407) <tr>
2408) <td>
2409) numothersock
2410) </td>
2411) <td>
2412) 151
2413) </td>
2414) <td>
2415) 153
2416) </td>
2417) <td>
2418) 720
2419) </td>
2420) <td>
2421) 720
2422) </td>
2423) <td>
2424) 0
2425) </td>
2426) </tr>
2427) </table>
2428) <p>
2429)  Xen, Virtual Box and VMware virtual servers have no such limits normally.
2430) </p>
2431) <p>

2432) If the vserver admin will not increase system limits another option is 
2433) to reduce the memory allocated to the send and receive buffers on TCP 
2434) connections Tor uses. An experimental feature to constrain socket buffers 
2435) has recently been added. If your version of Tor supports it, set 
2436) "ConstrainedSockets 1" in your configuration. See the tor man page for 
2437) additional details about this option.

2438) </p>
2439) <p>

2440) Unfortunately, since Tor currently requires you to be able to connect to 
2441) all the other Tor relays, we need you to be able to use at least 1024 file 
2442) descriptors. This means we can't make use of Tor relays that are crippled 
2443) in this way.

2444) </p>
2445) <p>

2446) We hope to fix this in the future, once we know how to build a Tor network 
2447) with restricted topologies -- that is, where each node connects to only a 
2448) few other nodes. But this is still a long way off.

2449) </p>
2450) 

2451) <hr>
2452) 

2453) <a id="MultipleRelays"></a>

2454) <h3><a class="anchor" href="#MultipleRelays">I want to run more than one
2455) relay.</a></h3>

2456) 
2457) <p>
2458) Great. If you want to run several relays to donate more to the network,
2459) we're happy with that. But please don't run more than a few dozen on
2460) the same network, since part of the goal of the Tor network is dispersal
2461) and diversity.
2462) </p>
2463) 
2464) <p>
2465) If you do decide to run more than one relay, please set the "MyFamily"

2466) config option in the <a href="#torrc">torrc</a> of each relay, listing
2467) all the relays (comma-separated) that are under your control:

2468) </p>
2469) 
2470) <pre>
2471)     MyFamily $fingerprint1,$fingerprint2,$fingerprint3
2472) </pre>
2473) 
2474) <p>
2475) where each fingerprint is the 40 character identity fingerprint (without

2476) spaces). You can also list them by nickname, but fingerprint is safer.
2477) Be

2478) sure to prefix the digest strings with a dollar sign ('$') so that the
2479) digest is not confused with a nickname in the config file.
2480) </p>
2481) 
2482) <p>
2483) That way clients will know to avoid using more than one of your relays
2484) in a single circuit. You should set MyFamily if you have administrative
2485) control of the computers or of their network, even if they're not all in
2486) the same geographic location.
2487) </p>
2488) 
2489)     <hr>
2490) 

2491)     <a id="WrongIP"></a>

2492)     <h3><a class="anchor" href="#WrongIP">My relay is picking the wrong 
2493)     IP address.</a></h3>

2494)     <p>

2495)  Tor guesses its IP address by asking the computer for its hostname, and 
2496)  then resolving that hostname. Often people have old entries in their 
2497)  /etc/hosts file that point to old IP addresses.

2498)     </p>
2499)     <p>

2500) If that doesn't fix it, you should use the "Address" config option to 
2501) specify the IP you want it to pick. If your computer is behind a NAT and 
2502) it only has an internal IP address, see the following FAQ entry on <a 
2503) href="https://www.torproject.org/docs/faq.html.en#RelayFlexible">dynamic 
2504) IP addresses</a>.

2505)     </p>
2506)     <p>

2507) Also, if you have many addresses, you might also want to set 
2508) "OutboundBindAddress" so external connections come from the IP you intend 
2509) to present to the world. 

2510)     </p>
2511) 
2512)     <hr>
2513) 
2514)     <a id="BehindANAT"></a>
2515)     <h3><a class="anchor" href="#BehindANAT">I'm behind a NAT/Firewall.</a></h3>
2516) 
2517)     <p>

2518) See <a>​http://portforward.com/</a> for directions on how to port forward with 
2519) your NAT/router device.

2520) </p>
2521) <p>

2522) If your relay is running on a internal net you need to setup port forwarding. 
2523) Forwarding TCP connections is system dependent but the firewalled-clients FAQ 
2524) entry offers some examples on how to do this.

2525) </p>
2526) <p>

2527) Also, here's an example of how you would do this on GNU/Linux if you're using 
2528) iptables:

2529) </p>
2530) <pre>
2531) /sbin/iptables -A INPUT -i eth0 -p tcp --destination-port 9001 -j ACCEPT
2532) </pre>
2533) <p>

2534) You may have to change "eth0" if you have a different external interface 
2535) (the one connected to the Internet). Chances are you have only one (except 
2536) the loopback) so it shouldn't be too hard to figure out. 

2537)     </p>
2538)     <hr>
2539) 

2540)     <a id="RelayMemory"></a>

2541)     <h3><a class="anchor" href="#RelayMemory">Why is my Tor relay using
2542) so much memory?</a></h3>

2543) 

2544)     <p>If your Tor relay is using more memory than you'd like, here are
2545) some

2546)     tips for reducing its footprint:
2547)     </p>

2548) 

2549)     <ol>
2550)     <li>If you're on Linux, you may be encountering memory fragmentation

2551)     bugs in glibc's malloc implementation. That is, when Tor releases
2552) memory
2553)     back to the system, the pieces of memory are fragmented so they're
2554) hard
2555)     to reuse. The Tor tarball ships with OpenBSD's malloc
2556) implementation,
2557)     which doesn't have as many fragmentation bugs (but the tradeoff is
2558) higher
2559)     CPU load). You can tell Tor to use this malloc implementation
2560) instead:

2561)     <tt>./configure --enable-openbsd-malloc</tt></li>

2562) 

2563)     <li>If you're running a fast relay, meaning you have many TLS
2564) connections

2565)     open, you are probably losing a lot of memory to OpenSSL's internal
2566)     buffers (38KB+ per socket). We've patched OpenSSL to <a

2567) 
2568) href="https://lists.torproject.org/pipermail/tor-dev/2008-June/001519.
2569) html">release

2570)     unused buffer memory more aggressively</a>. If you update to OpenSSL

2571)     1.0.0 or newer, Tor's build process will automatically recognize and
2572) use

2573)     this feature.</li>

2574) 

2575)     <li>If you're running on Solaris, OpenBSD, NetBSD, or
2576)     old FreeBSD, Tor is probably forking separate processes
2577)     rather than using threads. Consider switching to a <a
2578)     href="<wikifaq>#WhydoesntmyWindowsorotherOSTorrelayrunwell">better
2579)     operating system</a>.</li>

2580) 

2581)     <li>If you still can't handle the memory load, consider reducing the

2582)     amount of bandwidth your relay advertises. Advertising less
2583) bandwidth

2584)     means you will attract fewer users, so your relay shouldn't grow
2585)     as large. See the <tt>MaxAdvertisedBandwidth</tt> option in the man
2586)     page.</li>

2587) 

2588)     </ol>

2589) 

2590)     <p>

2591)     All of this said, fast Tor relays do use a lot of ram. It is not
2592) unusual

2593)     for a fast exit relay to use 500-1000 MB of memory.
2594)     </p>

2595) 

2596)     <hr>

2597) 

2598)     <a id="BetterAnonymity"></a>

2599)     <h3><a class="anchor" href="#BetterAnonymity">Do I get better anonymity 
2600)     if I run a relay?</a></h3>

2601) 

2602)     <p>

2603) Yes, you do get better anonymity against some attacks.
2604)     </p>
2605)     <p>

2606) The simplest example is an attacker who owns a small number of Tor relays. 
2607) He will see a connection from you, but he won't be able to know whether 
2608) the connection originated at your computer or was relayed from somebody else.

2609)     </p>
2610)     <p>

2611) There are some cases where it doesn't seem to help: if an attacker can 
2612) watch all of your incoming and outgoing traffic, then it's easy for him 
2613) to learn which connections were relayed and which started at you. (In 
2614) this case he still doesn't know your destinations unless he is watching 
2615) them too, but you're no better off than if you were an ordinary client.)

2616)     </p>
2617)     <p>

2618) There are also some downsides to running a Tor relay. First, while we 
2619) only have a few hundred relays, the fact that you're running one might 
2620) signal to an attacker that you place a high value on your anonymity. 
2621) Second, there are some more esoteric attacks that are not as 
2622) well-understood or well-tested that involve making use of the knowledge 
2623) that you're running a relay -- for example, an attacker may be able to 
2624) "observe" whether you're sending traffic even if he can't actually watch 
2625) your network, by relaying traffic through your Tor relay and noticing 
2626) changes in traffic timing.

2627)     </p>
2628)     <p>

2629) It is an open research question whether the benefits outweigh the risks. 
2630) A lot of that depends on the attacks you are most worried about. For 
2631) most users, we think it's a smart move. 

2632)     </p>

2633) 

2634)     <hr>

2635) 

2636)     <a id="RelayDonations"></a>

2637)     <h3><a class="anchor" href="#RelayDonations">Can I donate for a
2638)     relay rather than run my own?</a></h3>

2639) 
2640)     <p>

2641)     Sure! We recommend these non-profit charities that are happy to turn

2642)     your donations into better speed and anonymity for the Tor network:
2643)     </p>
2644)     <ul>
2645)     <li><a href="https://www.torservers.net/">torservers.net</a>
2646)     is a German charitable non-profit that runs a wide variety of

2647)     exit relays worldwide. They also like donations of bandwidth from
2648)     ISPs.</li>

2649)     <li><a

2650) href="https://www.noisebridge.net/wiki/Noisebridge_Tor">Noisebridge</a>

2651)     is a US-based 501(c)(3) non-profit that collects donations and turns

2652)     them into more US-based exit relay capacity.</li>
2653)     <li><a href="https://nos-oignons.net/">Nos Oignons</a> is a French
2654)     charitable non-profit that runs fast exit relays in France.</li>

2655)     </ul>
2656) 
2657)     <p>
2658)     These organizations are not the same as <a href="<page
2659)     donate/donate>">The Tor Project, Inc</a>, but we consider that a

2660)     good thing. They're both run by nice people who are part of the
2661)     Tor community.

2662)     </p>
2663) 
2664)     <p>
2665)     Note that there can be a tradeoff here between anonymity and

2666)     performance. The Tor network's anonymity comes in part from
2667) diversity,

2668)     so if you are in a position to run your own relay, you will be

2669)     improving Tor's anonymity more than by donating. At the same time
2670)     though, economies

2671)     of scale for bandwidth mean that combining many small donations into

2672)     several larger relays is more efficient at improving network

2673)     performance. Improving anonymity and improving performance are both
2674)     worthwhile goals, so however you can help is great!
2675)     </p>
2676) 
2677)     <hr>
2678) 

2679)     <a id="AccessHiddenServices"></a>
2680)     <h3><a class="anchor" href="#AccessHiddenServices">How do I access 
2681)     hidden services?</a></h3>
2682)     
2683)     <p>
2684)     Tor hidden services are named with a special top-level domain (TLD) 
2685)     name in DNS: .onion. Since the .onion TLD is not recognized by the 
2686)     official root DNS servers on the Internet, your application will not 
2687)     get the response it needs to locate the service. Currently, the Tor 
2688)     directory server provides this look-up service; and thus the look-up 
2689)     request must get to the Tor network. 
2690)     </p>
2691) 
2692) <p>
2693)  Therefore, your application <b>needs</b> to pass the .onion hostname to 
2694)  Tor directly. You can't try to resolve it to an IP address, since there 
2695)  <i>is</i> no corresponding IP address: the server is hidden, after all! 
2696) </p>
2697)     
2698)     <p>
2699)     So, how do you make your application pass the hostname directly to Tor? 
2700)     You can't use SOCKS 4, since SOCKS 4 proxies require an IP from the 
2701)     client (a web browser is an example of a SOCKS client). Even though 
2702)     SOCKS 5 can accept either an IP or a hostname, most applications 
2703)     supporting SOCKS 5 try to resolve the name before passing it to the 
2704)     SOCKS proxy. SOCKS 4a, however, always accepts a hostname: You'll need 
2705)     to use SOCKS 4a. 
2706)     </p>
2707)     
2708)     <p>
2709)     Some applications, such as the browsers Mozilla Firefox and Apple's 
2710)     Safari, support sending DNS queries to Tor's SOCKS 5 proxy. Most web 
2711)     browsers don't support SOCKS 4a very well, though. The workaround is 
2712)     to point your web browser at an HTTP proxy, and tell the HTTP proxy 
2713)     to speak to Tor with SOCKS 4a. We recommend Polipo as your HTTP proxy.
2714)     </p>
2715)     
2716)     <p>
2717)     For applications that do not support HTTP proxy, and so cannot use 
2718)     Polipo, <a href="http://www.freecap.ru/eng/">FreeCap</a> is an 
2719)     alternative. When using FreeCap set proxy protocol  to SOCKS 5 and under 
2720)     settings set DNS name resolving to remote. This 
2721)     will allow you to use almost any program with Tor without leaking DNS 
2722)     lookups and allow those same programs to access hidden services. 
2723)     </p>
2724)     
2725)     <p>
2726)     See also the <a href="#SocksAndDNS">question on DNS</a>. 
2727)     </p>    
2728)     
2729)     <hr>
2730) 
2731)     <a id="ProvideAHiddenService"></a>
2732)     <h3><a class="anchor" href="#ProvideAHiddenService">How do I provide a 
2733)     hidden service?</a></h3>
2734)     
2735)     <p>

2736)     See the <a href="https://www.torproject.org/docs/tor-hidden-service.html.en">

2737)     official hidden service configuration instructions</a>.
2738)     </p>
2739) 
2740)     <hr>
2741)     

2742)     <a id="WhatProtectionsDoesTorProvide"></a>
2743)     <h3><a class="anchor" href="#WhatProtectionsDoesTorProvide">What 
2744)     protections does Tor provide?</a></h3>
2745)     
2746)     <p>
2747)      Internet communication is based on a store-and-forward model that 
2748)      can be understood in analogy to postal mail: Data is transmitted in 
2749)      blocks called IP datagrams or packets. Every packet includes a source 
2750)      IP address (of the sender) and a destination IP address (of the 
2751)      receiver), just as ordinary letters contain postal addresses of sender 
2752)      and receiver. The way from sender to receiver involves multiple hops of 
2753)      routers, where each router inspects the destination IP address and 
2754)      forwards the packet closer to its destination. Thus, every router 
2755)      between sender and receiver learns that the sender is communicating 
2756)      with the receiver. In particular, your local ISP is in the position to 
2757)      build a complete profile of your Internet usage. In addition, every 
2758)      server in the Internet that can see any of the packets can profile your 
2759)      behaviour. 
2760)     </p>
2761)     
2762)     <p>
2763)     The aim of Tor is to improve your privacy by sending your traffic through 
2764)     a series of proxies. Your communication is encrypted in multiple layers 
2765)     and routed via multiple hops through the Tor network to the final 
2766)     receiver. More details on this process can be found in the <a 
2767)     href="https://www.torproject.org/about/overview">Tor overview</a>. 
2768)     Note that all your local ISP can observe now is that you are 
2769)     communicating with Tor nodes. Similarly, servers in the Internet just 
2770)     see that they are being contacted by Tor nodes.
2771)     </p>
2772)     
2773)     <p>
2774)     Generally speaking, Tor aims to solve three privacy problems: 
2775)     </p>
2776)     
2777)     <p>
2778)     First, Tor prevents websites and other services from learning 
2779)     your location, which they can use to build databases about your 
2780)     habits and interests. With Tor, your Internet connections don't 
2781)     give you away by default -- now you can have the ability to choose, 
2782)     for each connection, how much information to reveal. 
2783)     </p>
2784)     
2785)     <p>
2786)     Second, Tor prevents people watching your traffic locally (such as 
2787)     your ISP) from learning what information you're fetching and where 
2788)     you're fetching it from. It also stops them from deciding what you're 
2789)     allowed to learn and publish -- if you can get to any part of the Tor 
2790)     network, you can reach any site on the Internet.     
2791)     </p>
2792) 
2793)     <p>
2794)     Third, Tor routes your connection through more than one Tor relay 
2795)     so no single relay can learn what you're up to. Because these relays 
2796)     are run by different individuals or organizations, distributing trust 
2797)     provides more security than the old <a href="#Torisdifferent">one hop proxy
2798)     </a> approach. 
2799)     </p>
2800)     
2801)     <p>
2802)     Note, however, that there are situations where Tor fails to solve these 
2803)     privacy problems entirely: see the entry below on <a 
2804)     href="#AttacksOnOnionRouting">remaining attacks</a>.    
2805)     </p>
2806)     
2807)     <hr>
2808)     
2809)     <a id="CanExitNodesEavesdrop"></a>
2810)     <h3><a class="anchor" href="#CanExitNodesEavesdrop">Can exit nodes eavesdrop 
2811)     on communications? Isn't that bad?</a></h3>
2812)     
2813)     <p>
2814)     Yes, the guy running the exit node can read the bytes that come in and 
2815)     out there. Tor anonymizes the origin of your traffic, and it makes sure 
2816)     to encrypt everything inside the Tor network, but it does not magically 
2817)     encrypt all traffic throughout the Internet. 
2818)     </p>
2819)     
2820)     <p>
2821)     This is why you should always use end-to-end encryption such as SSL for 
2822)     sensitive Internet connections. (The corollary to this answer is that if 
2823)     you are worried about somebody intercepting your traffic and you're 
2824)     *not* using end-to-end encryption at the application layer, then something 
2825)     has already gone wrong and you shouldn't be thinking that Tor is the problem.) 
2826)     </p>
2827)     
2828)     <p>
2829)     Tor does provide a partial solution in a very specific situation, though. 
2830)     When you make a connection to a destination that also runs a Tor relay, 
2831)     Tor will automatically extend your circuit so you exit from that circuit. 
2832)     So for example if Indymedia ran a Tor relay on the same IP address as 
2833)     their website, people using Tor to get to the Indymedia website would 
2834)     automatically exit from their Tor relay, thus getting *better* encryption 
2835)     and authentication properties than just browsing there the normal way. 
2836)     </p>
2837) 
2838)     <p>
2839)     We'd like to make it still work even if the service is nearby the Tor 
2840)     relay but not on the same IP address. But there are a variety of 
2841)     technical problems we need to overcome first (the main one being "how 
2842)     does the Tor client learn which relays are associated with which 
2843)     websites in a decentralized yet non-gamable way?"). 
2844)     </p>
2845)             
2846)     <hr>
2847)     
2848)     <a id="ExitEnclaving"></a>
2849)     <h3><a class="anchor" href="#ExitEnclaving">What is Exit Enclaving?</a></h3>
2850) 
2851)     <p>
2852)     When a machine that runs a Tor relay also runs a public service, such as 
2853)     a webserver, you can configure Tor to offer Exit Enclaving to that 
2854)     service. Running an Exit Enclave for all of your services you wish to 
2855)     be accessible via Tor provides your users the assurance that they will 
2856)     exit through your server, rather than exiting from a randomly selected 
2857)     exit node that could be watched. Normally, a tor circuit would end at 
2858)     an exit node and then that node would make a connection to your service. 
2859)     Anyone watching that exit node could see the connection to your service, 
2860)     and be able to snoop on the contents if it were an unencrypted 
2861)     connection. If you run an Exit Enclave for your service, then the exit 
2862)     from the Tor network happens on the machine that runs your service, 
2863)     rather than on an untrusted random node. This works when Tor clients 
2864)     wishing to connect to this public service extend their their circuit 
2865)     to exit from the Tor relay running on that same host. For example, if 
2866)     the server at 1.2.3.4 runs a web server on port 80 and also acts as a 
2867)     Tor relay configured for Exit Enclaving, then Tor clients wishing to 
2868)     connect to the webserver will extend their circuit a fourth hop to exit 
2869)     to port 80 on the Tor relay running on 1.2.3.4. 
2870)     </p>
2871)     <p>
2872)     Exit Enclaving is disabled by default to prevent attackers from 
2873)     exploiting trust relationships with locally bound services. For 
2874)     example, often 127.0.0.1 will run services that are not designed to 
2875)     be shared with the entire world. Sometimes these services will also 
2876)     be bound to the public IP address, but will only allow connections if 
2877)     the source address is something trusted, such as 127.0.0.1. 
2878)     </p>
2879)     <p>
2880)     As a result of possible trust issues, relay operators must configure 
2881)     their exit policy to allow connections to themselves, but they should 
2882)     do so only when they are certain that this is a feature that they would 
2883)     like. Once certain, turning off the ExitPolicyRejectPrivate option will 
2884)     enable Exit Enclaving. An example configuration would be as follows: 
2885)     </p>
2886)     <pre>
2887)     ExitPolicy accept 1.2.3.4:80
2888)     ExitPolicy reject 127.0.0.1/8
2889)     ExitPolicyRejectPrivate 0
2890)     </pre>
2891)     <p>
2892)     This option should be used with care as it may expose internal network 
2893)     blocks that are not meant to be accessible from the outside world or 
2894)     the Tor network. Please tailor your ExitPolicy to reflect all netblocks 
2895)     that you want to prohibit access. 
2896)     </p>
2897)     <p>
2898)     This option should be used with care as it may expose internal network 
2899)     blocks that are not meant to be accessible from the outside world or 
2900)     the Tor network. Please tailor your ExitPolicy to reflect all netblocks 
2901)     that you want to prohibit access. 
2902)     </p>
2903)     <p>
2904)     While useful, this behavior may go away in the future because it is 
2905)     imperfect. A great idea but not such a great implementation. 
2906)     </p>
2907) 
2908)     <hr>
2909)     

2910)     <a id="KeyManagement"></a>

2911)     <h3><a class="anchor" href="#KeyManagement">Tell me about all the
2912) keys Tor uses.</a></h3>

2913) 

2914)     <p>
2915)     Tor uses a variety of different keys, with three goals in mind: 1)
2916)     encryption to ensure privacy of data within the Tor network, 2)
2917)     authentication so clients know they're

2918)     talking to the relays they meant to talk to, and 3) signatures to
2919) make

2920)     sure all clients know the same set of relays.
2921)     </p>

2922) 

2923)     <p>

2924)     <b>Encryption</b>: first, all connections in Tor use TLS link
2925) encryption,

2926)     so observers can't look inside to see which circuit a given cell is

2927)     intended for. Further, the Tor client establishes an ephemeral
2928) encryption

2929)     key with each relay in the circuit; these extra layers of encryption
2930)     mean that only the exit relay can read

2931)     the cells. Both sides discard the circuit key when the circuit ends,

2932)     so logging traffic and then breaking into the relay to discover the

2933)     key won't work.

2934)     </p>

2935) 

2936)     <p>
2937)     <b>Authentication</b>:
2938)     Every Tor relay has a public decryption key called the "onion key".

2939)     Each relay rotates its onion key once a week.

2940)     When the Tor client establishes circuits, at each step it <a

2941) 
2942) href="<svnprojects>design-paper/tor-design.html#subsec:circuits">demands