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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><a href="#General">General questions:</a><br />
18)     <a href="#CompilationAndInstallation">Compilation and Installation:</a><br />

19)     <a href="#TBBGeneral">Tor Browser (general):</a><br />
20)     <a href="#TBB3.x">Tor Browser (3.x and later):</a><br />

21)     <a href="#AdvancedTorUsage">Advanced Tor usage:</a><br />
22)     <a href="#RunningATorRelay">Running a Tor relay:</a><br />
23)     <a href="#TorHiddenServices">Tor hidden services:</a><br />
24)     <a href="#Development">Development:</a><br />
25)     <a href="#AnonymityAndSecurity">Anonymity and Security:</a><br />
26)     <a href="#AlternateDesigns">Alternate designs that we don't do (yet):</a><br />
27)     <a href="#Abuse">Abuse:</a></p>

28) 

29) <hr>
30) 
31)     <p>General questions:</p>

32)     <ul>
33)     <li><a href="#WhatIsTor">What is Tor?</a></li>

34)     <li><a href="#Torisdifferent">How is Tor different from other
35) proxies?</a></li>

36)     <li><a href="#CompatibleApplications">What programs can I use with
37)     Tor?</a></li>
38)     <li><a href="#WhyCalledTor">Why is it called Tor?</a></li>
39)     <li><a href="#Backdoor">Is there a backdoor in Tor?</a></li>

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

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

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

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

44)     <li><a href="#FileSharing">How can I share files anonymously through Tor?
45)     </a></li>

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

48)     <li><a href="#IsItWorking">How can I tell if Tor is working, and that my

49)     connections really are anonymized?</a></li>

50)     <li><a href="#Mobile">Can I use Tor on my phone or mobile device?</a></li>

51)     <li><a href="#OutboundPorts">Which outbound ports must be open when
52)     using Tor as a client?</a></li>

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

54)     <li><a href="#NoDataScrubbing">Does Tor remove personal information

55)     from the data my application sends?</a></li>

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

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

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

60)     </ul>

61) 

62)     <p>Compilation and Installation:</p>

63) 

64)     <ul>
65)     <li><a href="#HowUninstallTor">How do I uninstall Tor?</a></li>
66)     <li><a href="#PGPSigs">What are these "sig" files on the download
67)     page?</a></li>

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

70)     <li><a href="#VirusFalsePositives">Why does my Tor executable appear to

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

72)     <li><a href="#tarballs">How do I open a .tar.gz or .tar.xz file?</a></li>

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

75)     </ul>

76) 

77)     <p>Tor Browser (general):</p>

78)     <ul>

79) 

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

82)     <li><a href="#Ubuntu">I'm using Ubuntu, and I can't start Tor Browser.

83)     </a></li>

84)     <li><a href="#SophosOnMac">I'm using the Sophos anti-virus

85)     software on my Mac, and Tor starts but I can't browse anywhere.</a></li>

86)     <li><a href="#XPCOMError">When I start Tor Browser I get an 
87) error message: "Cannot load XPCOM".</a></li>

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

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

90)     <li><a href="#TBBJavaScriptEnabled">Why is NoScript configured to

91) allow JavaScript by default in Tor Browser?  Isn't that

92) unsafe?</a></li>

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

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

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

97)     <li><a href="#ForeignLanguages">Why does Google show up in foreign

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

99)     <li><a href="#GmailWarning">Gmail warns me that my account may have
100)     been compromised.</a></li>

101)     <li><a href="#NeedToUseAProxy">My internet connection requires an HTTP

102)     or SOCKS Proxy</a></li>

103)     <li><a href="#TBBSocksPort">I want to
104)     run another application through Tor.</a></li>

105)     <li><a href="#CantSetProxy">What should I do if I can't set a proxy

106)     with my application?</a></li>

107)     </ul>
108) 

109)     <p>Tor Browser (3.x and later):</p>

110) 
111)     <ul>

112)     <li><a href="#DisableJS">How do I disable JavaScript?</a></li>

113)     <li><a href="#VerifyDownload">How do I verify the download

114)     (sha256sums.txt)?</a></li>

115)     <li><a href="#NewIdentityClosingTabs">Why does "New Identity" close

116)     all my open tabs?</a></li>

117)     <li><a href="#ConfigureRelayOrBridge">How do I configure Tor as a relay

118)     or bridge?</a></li>
119)     <li><a href="#Timestamps">Why are the file timestamps from 2000?</a></li>

120)     <li><a href="#TBBSourceCode">Where is the source code for Tor Browser?

121)     How do I verify a build?</a></li>

122)     </ul>
123) 

124)     <p>Advanced Tor usage:</p>

125) 

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

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

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

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

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

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

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

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

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

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

141)     <li><a href="#WarningsAboutSOCKSandDNSInformationLeaks">I keep seeing
142)     these warnings about SOCKS and DNS information leaks. Should I

143)     worry?</a></li>

144)     <li><a href="#SocksAndDNS">How do I check if my application that uses

145)     SOCKS is leaking DNS requests?</a></li>

146)     </ul>

147) 

148)     <p>Running a Tor relay:</p>

149)     <ul>

150) 
151)     <li><a href="#HowDoIDecide">How do I decide if I should run a relay?
152)     </a></li>

153)     <li><a href="#WhyIsntMyRelayBeingUsedMore">Why isn't my relay being

154)     used more?</a></li>

155)     <li><a href="#IDontHaveAStaticIP">I don't have a static IP.</a></li>

156)     <li><a href="#PortscannedMore">Why do I get portscanned more often

157)     when I run a Tor relay?</a></li>

158)     <li><a href="#HighCapacityConnection">How can I get Tor to fully

159)     make use of my high capacity connection?</a></li>

160)     <li><a href="#RelayFlexible">How stable does my relay need to
161) be?</a></li>

162)     <li><a href="#BandwidthShaping">What bandwidth shaping options are

163)     available to Tor relays?</a></li>

164)     <li><a href="#LimitTotalBandwidth">How can I limit the total amount

165)     of bandwidth used by my Tor relay?</a></li>

166)     <li><a href="#RelayWritesMoreThanItReads">Why does my relay write

167)     more bytes onto the network than it reads?</a></li>

168)     <li><a href="#Hibernation">Why can I not browse anymore after

169)     limiting bandwidth on my Tor relay?</a></li>

170)     <li><a href="#ExitPolicies">I'd run a relay, but I don't want to deal

171)     with abuse issues.</a></li>

172)     <li><a href="#BestOSForRelay">Why doesn't my Windows (or other OS) Tor

173)     relay run well?</a></li>

174)     <li><a href="#PackagedTor">Should I install Tor from my package manager,

175)     or build from source?</a></li>

176)     <li><a href="#WhatIsTheBadExitFlag">What is the BadExit flag?</a></li>

177)     <li><a href="#IGotTheBadExitFlagWhyDidThatHappen">I got the BadExit flag.

178)     Why did that happen?</a></li>

179)     <li><a href="#MyRelayRecentlyGotTheGuardFlagAndTrafficDroppedByHalf">My

180)     relay recently got the Guard flag and traffic dropped by half.</a></li>

181)     <li><a href="#TorClientOnADifferentComputerThanMyApplications">I want to run my Tor client on a

182)     different computer than my applications.</a></li>

183)     <li><a href="#ServerClient">Can I install Tor on a central server, and

184)     have my clients connect to it?</a></li>

185)     <li><a href="#JoinTheNetwork">So I can just configure a nickname and

186)     ORPort and join the network?</a></li>

187)     <li><a href="#RelayOrBridge">Should I be a normal relay or bridge
188)     relay?</a></li>

189)     <li><a href="#UpgradeOrMove">I want to upgrade/move my relay. How do I

190)     keep the same key?</a></li>

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

193)     <li><a href="#NTService">How do I run my Tor relay as an NT service?
194)     </a></li>

195)     <li><a href="#VirtualServer">Can I run a Tor relay from my virtual server

196)     account?</a></li>

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

199)     <li><a href="#OutgoingFirewall">How should I configure the outgoing filters on my relay?</a></li>

200)     <li><a href="#RelayMemory">Why is my Tor relay using so much memory?
201)     </a></li>
202)     <li><a href="#BetterAnonymity">Do I get better anonymity if I run a relay?
203)     </a></li>

204)     <li><a href="#FacingLegalTrouble">I'm facing legal trouble. How do I

205)     prove that my server was a Tor relay at a given time?</a></li>

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

208)     </ul>

209) 

210)     <p>Tor hidden services:</p>

211) 

212)     <ul>
213)     <li><a href="#AccessHiddenServices">How do I access hidden services?</a></li>

214)     <li><a href="#ProvideAHiddenService">How do I provide a hidden service?</a></li>

215)     </ul>

216) 

217)     <p>Development:</p>

218) 

219)     <ul>

220)     <li><a href="#VersionNumbers">What do these weird version numbers

221)     mean?</a></li>
222)     <li><a href="#PrivateTorNetwork">How do I set up my own private
223)     Tor network?</a></li>

224)     <li><a href="#UseTorWithJava">How can I make my Java program use the

225)     Tor network?</a></li>
226)     <li><a href="#WhatIsLibevent">What is Libevent?</a></li>

227)     <li><a href="#MyNewFeature">What do I need to do to get a new feature

228)     into Tor?</a></li>
229)     </ul>
230) 

231)     <p>Anonymity and Security:</p>

232)     <ul>

233)     <li><a href="#WhatProtectionsDoesTorProvide">What protections does Tor

234)     provide?</a></li>

235)     <li><a href="#CanExitNodesEavesdrop">Can exit nodes eavesdrop on

236)     communications? Isn't that bad? </a></li>

237)     <li><a href="#AmITotallyAnonymous">So I'm totally anonymous if I use

238)     Tor?</a></li>

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

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

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

243)     <li><a href="#CellSize">Tor uses hundreds of bytes for every IRC line. I

244)     can't afford that!</a></li>

245)     <li><a href="#OutboundConnections">Why does netstat show these outbound

246)     connections?</a></li>
247)     <li><a href="#PowerfulBlockers">What about powerful blocking mechanisms
248)     </a></li>

249)     <li><a href="#RemotePhysicalDeviceFingerprinting">Does Tor resist

250)     "remote physical device fingerprinting"?</a></li>

251)     <li><a href="#IsTorLikeAVPN">Is Tor like a VPN?</a></li>

252)     <li><a href="#Proxychains">Aren't 10 proxies (proxychains) better than

253)     Tor with only 3 hops?</a></li>

254)     <li><a href="#AttacksOnOnionRouting">What attacks remain against onion

255)     routing?</a></li>

256)     <li><a href="#LearnMoreAboutAnonymity">Where can I learn more about anonymity?</a></li>

257)     </ul>

258) 

259)     <p>Alternate designs that we don't do (yet):</p>

260) 

261)     <ul>
262)     <li><a href="#EverybodyARelay">You should make every Tor user be a
263)     relay.</a></li>

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

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

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

269)     <li><a href="#ChoosePathLength">You should let people choose their path

270)     length.</a></li>

271)     <li><a href="#SplitEachConnection">You should split each connection over

272)     many paths.</a></li>

273)     <li><a href="#MigrateApplicationStreamsAcrossCircuits">You should migrate

274)     application streams across circuits.</a></li>

275)     <li><a href="#LetTheNetworkPickThePath">You should let the network pick

276)     the path, not the client.</a></li>

277)     <li><a href="#UnallocatedNetBlocks">Your default exit policy should block

278)     unallocated net blocks too.</a></li>

279)     <li><a href="#BlockWebsites">Exit policies should be able to block

280)     websites, not just IP addresses.</a></li>

281)     <li><a href="#BlockContent">You should change Tor to prevent users from

282)     posting certain content.</a></li>

283)     <li><a href="#SendPadding">You should send padding so it's more secure.
284)     </a></li>

285)     <li><a href="#Steganography">You should use steganography to hide Tor

286)     traffic.</a></li>

287)     </ul>

288) 

289)     <p>Abuse:</p>

290)     <ul>

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

293)     <li><a href="#RespondISP">How do I respond to my ISP about my exit
294)     relay?</a></li>

295)     <li><a href="#HelpPoliceOrLawyers">I have questions about
296)    a Tor IP address for a legal case.</a></li>

297)     </ul>

298) 

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

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

302) 

303)     <hr>

304) 

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

306)     <h2><a class="anchor">General:</a></h2>

307) 

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

310) 

311)     <p>
312)     The name "Tor" can refer to several different components.
313)     </p>

314) 

315)     <p>

316)     The Tor software is a program you can run on your computer that
317) helps keep
318)     you safe on the Internet. Tor protects you by bouncing your
319) communications

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

321)     the world: it prevents somebody watching your Internet connection
322) from

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

324)     from learning your physical location. This set of volunteer relays
325) is
326)     called the Tor network. You can read more about how Tor works on the
327) <a

328)     href="<page about/overview>">overview page</a>.
329)     </p>

330) 

331)     <p>

332)     The Tor Project is a non-profit (charity) organization that
333) maintains

334)     and develops the Tor software.
335)     </p>

336) 

337)     <hr>

338) 

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

340)     <h3><a class="anchor" href="#Torisdifferent">How is Tor different
341) from other proxies?</a></h3>
342)     <p>
343)     A typical proxy provider sets up a server somewhere on the Internet
344) and
345) allows you to use it to relay your traffic.  This creates a simple, easy
346) to
347) maintain architecture.  The users all enter and leave through the same
348) server.
349) The provider may charge for use of the proxy, or fund their costs
350) through
351) advertisements on the server.  In the simplest configuration, you don't
352) have to
353) install anything.  You just have to point your browser at their proxy
354) server.
355) Simple proxy providers are fine solutions if you do not want protections
356) for
357) your privacy and anonymity online and you trust the provider from doing
358) bad
359) things.  Some simple proxy providers use SSL to secure your connection
360) to them.
361) This may protect you against local eavesdroppers, such as those at a
362) cafe with

363) free wifi Internet.
364)     </p>
365)     <p>

366)     Simple proxy providers also create a single point of failure.  The
367) provider
368) knows who you are and where you browse on the Internet.  They can see
369) your
370) traffic as it passes through their server.  In some cases, they can even
371) see

372) inside your

373) encrypted traffic as they relay it to your banking site or to ecommerce
374) stores.

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

376) watching your traffic, injecting their own advertisements into your
377) traffic

378) stream, and recording your personal details.

379)     </p>
380)     <p>

381)     Tor passes your traffic through at least 3 different servers before
382) sending
383) it on to the destination. Because there's a separate layer of encryption
384) for
385) each of the three relays, Tor does not modify, or even know, what you
386) are
387) sending into it.  It merely relays your traffic, completely encrypted
388) through
389) the Tor network and has it pop out somewhere else in the world,
390) completely
391) intact.  The Tor client is required because we assume you trust your
392) local
393) computer.  The Tor client manages the encryption and the path chosen
394) through
395) the network.  The relays located all over the world merely pass
396) encrypted

397) packets between themselves.</p>

398)     <p>
399)     <dl>

400)     <dt>Doesn't the first server see who I am?</dt><dd>Possibly. A bad
401) first of
402) three servers can see encrypted Tor traffic coming from your computer.
403) It
404) still doesn't know who you are and what you are doing over Tor.  It
405) merely sees
406) "This IP address is using Tor".  Tor is not illegal anywhere in the
407) world, so
408) using Tor by itself is fine.  You are still protected from this node
409) figuring

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

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

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

416) e-commerce website, or encrypted mail connections, etc, it will only
417) know the
418) destination.  It won't be able to see the data inside the traffic
419) stream.  You

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

422)     </dl>
423)     </p>

424) 

425)     <hr>

426) 

427) 

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

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

431) 

432)     <p>

433)     If you want to use Tor with a web browser, we provide the Tor Browser,
434)     which includes everything you need to browse the web safely using

435)     Tor. If you want to use another web browser with Tor, see <a
436)     href="#TBBOtherBrowser">Other web browsers</a>.

437)     </p>
438)     <p>
439)     There are plenty of other programs you can use with Tor,
440)     but we haven't researched the application-level anonymity

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

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

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

444)     specific applications</a>.

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

447) 

448)     <hr>

449) 

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

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

453) 

454)     <p>
455)     Because Tor is the onion routing network. When we were starting the
456)     new next-generation design and implementation of onion routing in
457)     2001-2002, we would tell people we were working on onion routing,
458)     and they would say "Neat. Which one?" Even if onion routing has
459)     become a standard household term, Tor was born out of the actual <a
460)     href="http://www.onion-router.net/">onion routing project</a> run by
461)     the Naval Research Lab.
462)     </p>

463) 

464)     <p>
465)     (It's also got a fine translation from German and Turkish.)
466)     </p>

467) 

468)     <p>

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

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

472)     spot people who haven't read any of our website (and have instead
473) learned
474)     everything they know about Tor from news articles) by the fact that
475) they

476)     spell it wrong.
477)     </p>

478) 

479)     <hr>

480) 

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

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

484) 

485)     <p>

486)     There is absolutely no backdoor in Tor.  We know some smart lawyers
487)     who say that it's unlikely that anybody will try to make us add one
488)     in our jurisdiction (U.S.). If they do ask us, we will fight them,
489)     and (the lawyers say) probably win.

490)     </p>

491) 

492)     <p>
493)     We think that putting a backdoor in Tor would be tremendously

494)     irresponsible to our users, and a bad precedent for security

495)     software in general. If we ever put a deliberate backdoor in our
496)     security software, it would ruin our professional reputations.
497)     Nobody would trust our software ever again — for excellent
498)     reason!

499)     </p>

500) 

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

504)     computers, or something like that. Tor is open source, and you

505)     should always check the source (or at least the diffs since the last
506)     release) for suspicious things. If we (or the distributors) don't
507)     give you source, that's a sure sign something funny might be going
508)     on. You should also check the <a href="<page
509)     docs/verifying-signatures>">PGP signatures</a> on the releases, to
510)     make sure nobody messed with the distribution sites.

511)     </p>

512) 

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

515)     anonymity. We periodically find and fix anonymity-related bugs, so

516)     make sure you keep your Tor versions up-to-date.

517)     </p>

518) 

519)     <hr>

520) 

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

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

524) 

525)     <p>
526)     Yes.
527)     </p>

528) 

529)     <p>

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

533)     ask us for specific permission.
534)     </p>

535) 

536)     <p>

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

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

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

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

542) 

543)     <p>

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

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

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

547)     href="https://www.mozilla.org/en-US/firefox/organizations/">Firefox

548)     Extended Support Release</a>, and the NoScript and HTTPS-Everywhere
549)     extensions. You will need to follow the license for those programs as
550)     well. Both of those Firefox extensions are distributed under

551)     the <a href="https://www.fsf.org/licensing/licenses/gpl.html">GNU General

552)     Public License</a>, while Firefox ESR is released under the Mozilla Public
553)     License. The simplest way to obey their licenses is to include the source
554)     code for these programs everywhere you include the bundles themselves.

555)     </p>

556) 

557)     <p>

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

561)     </p>

562) 

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

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

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

570) 

571)     <hr>

572) 

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

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

576) 

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

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

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

582)     <li>Read through the <a

583) 
584) href="https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-talk">
585) tor-talk

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

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

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

590)     <li>Send an email to <a

591) 
592) href="mailto:help@rt.torproject.org">help@rt.torproject.org</a>.</li>
593)     <li>If all else fails, try <a href="<page about/contact>">contacting
594) us</a> directly.</li>

595)     </ol>

596) 

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

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

600) 

601)     <hr>

602) 

603)     <a id="Forum"></a>
604)     <h3><a class="anchor" href="#Forum">Is there a Tor forum?</a></h3>
605) 

606)     <p>We have a <a href="https://tor.stackexchange.com/">StackExchange

607)     page</a> that is currently in public beta.

608)     </p>
609) 
610)     <hr>
611) 

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

614) 

615)     <p>
616)     There are many reasons why the Tor network is currently slow.
617)     </p>

618) 

619)     <p>

620)     Before we answer, though, you should realize that Tor is never going
621) to
622)     be blazing fast. Your traffic is bouncing through volunteers'
623) computers
624)     in various parts of the world, and some bottlenecks and network
625) latency

626)     will always be present. You shouldn't expect to see university-style
627)     bandwidth through Tor.
628)     </p>

629) 

630)     <p>

631)     But that doesn't mean that it can't be improved. The current Tor
632) network
633)     is quite small compared to the number of people trying to use it,
634) and
635)     many of these users don't understand or care that Tor can't
636) currently

637)     handle file-sharing traffic load.
638)     </p>

639) 

640)     <p>
641)     For the much more in-depth answer, see <a

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

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

645)     to go with it.
646)     </p>

647) 

648)     <p>
649)     What can you do to help?
650)     </p>

651) 

652)     <ul>

653) 

654)     <li>

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

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

661) 

662)     <li>

663)     Help us make Tor more usable. We

664)     especially need people to help make it easier to configure your Tor
665)     as a relay. Also, we need help with clear simple documentation to
666)     walk people through setting it up.
667)     </li>

668) 

669)     <li>

670)     There are some bottlenecks in the current Tor network. Help us
671) design
672)     experiments to track down and demonstrate where the problems are,
673) and

674)     then we can focus better on fixing them.
675)     </li>

676) 

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

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

683)     get to spend more time on it.
684)     </li>

685) 

686)     <li>

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

691)     getinvolved/volunteer>">look at our volunteer page</a>.
692)     </li>

693) 

694)     <li>

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

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

698)     competition's websites discreetly, or to connect back to the home
699) servers
700)     when on the road without revealing affiliations? If your
701) organization has
702)     an interest in keeping the Tor network working, please contact them
703) about
704)     supporting Tor. Without sponsors, Tor is going to become even
705) slower.

706)     </li>

707) 

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

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

712)     cause</a>. It adds up!
713)     </li>

714) 

715)     </ul>

716) 

717)     <hr>

718) 

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

720)     <h3><a class="anchor" href="#FileSharing">How can I share files

721)     anonymously through Tor?</a></h3>

722) 
723)     <p>

724)     File sharing (peer-to-peer/P2P) is widely unwanted in the Tor network,
725)     and exit nodes are configured to block file sharing traffic by default.
726)     Tor is not really designed for it, and file sharing through Tor slows
727)     down everyone's browsing. Also, Bittorrent over Tor <a

728)     href="https://blog.torproject.org/blog/bittorrent-over-tor-isnt-good-idea">
729)     is not anonymous</a>!

730)     </p>
731) 
732)     <hr>
733) 

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

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

737) 

738)     <p>

739)     The Tor network's <a

740) 
741) href="https://metrics.torproject.org/network.html#networksize">several

742)     thousand</a> relays push <a
743)     href="https://metrics.torproject.org/network.html#bandwidth">over
744)     1GB per second on average</a>. We have <a

745) 
746) href="https://metrics.torproject.org/users.html#direct-users">several

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

749)     </p>

750) 

751)     <p>

752)     There are six main development/maintenance pushes that need
753) attention:

754)     </p>

755) 

756)     <ul>

757) 

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

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

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

765) 

766)     <li>

767)     User support: With this many users, a lot of people are asking
768) questions
769)     all the time, offering to help out with things, and so on. We need
770) good
771)     clean docs, and we need to spend some effort coordinating
772) volunteers.

773)     </li>

774) 

775)     <li>

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

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

779)     reminders to upgrade, and so on. The network itself is a commons,
780) and
781)     somebody needs to spend some energy making sure the relay operators
782) stay
783)     happy. We also need to work on stability on some platforms —
784) e.g.,

785)     Tor relays have problems on Win XP currently.

786)     </li>

787) 

788)     <li>

789)     Usability: Beyond documentation, we also need to work on usability
790) of the
791)     software itself. This includes installers, clean GUIs, easy
792) configuration
793)     to interface with other applications, and generally automating all
794) of

795)     the difficult and confusing steps inside Tor.
796)     Usability for privacy software has never been easy.

797)     </li>

798) 

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

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

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

806) 

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

812)     critical <a href="<page getinvolved/volunteer>#Research">Tor
813) research questions</a>
814)     that will help us figure out how to make Tor secure against the
815) variety of
816)     attacks out there. Of course, there are more research questions
817) waiting

818)     behind these.
819)     </li>

820) 

821)     </ul>

822) 

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

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

827)     can keep up</a>.

828)     Now would be an excellent time to add a few more developers to the
829) effort

830)     so we can continue to grow the network.
831)     </p>

832) 

833)     <p>
834)     We are also excited about tackling related problems, such as
835)     censorship-resistance.
836)     </p>

837) 

838)     <p>

839)     We are proud to have <a href="<page about/sponsors>">sponsorship and
840) support</a>
841)     from the Omidyar Network, the International Broadcasting Bureau,
842) Bell
843)     Security Solutions, the Electronic Frontier Foundation, several
844) government

845)     agencies and research groups, and hundreds of private contributors.
846)     </p>

847) 

848)     <p>

849)     However, this support is not enough to keep Tor abreast of changes
850) in the
851)     Internet privacy landscape. Please <a href="<page
852) donate/donate>">donate</a>
853)     to the project, or <a href="<page about/contact>">contact</a> our
854) executive

855)     director for information on making grants or major donations.
856)     </p>

857) 

858)     <hr>
859) 
860) 
861)     <a id="Mobile"></a>

862)     <h3><a class="anchor" href="#Mobile">Can I use Tor on my phone or mobile

863)     device?</a></h3>
864) 
865)     <p>

866)     Tor on Android devices is maintained by the <a
867)     href="https://guardianproject.info">Guardian Project</a>. Currently, there
868)     is no supported way of using Tor on iOS; the Guardian Project is

869)     working to make this a reality in the future.
870)     </p>
871) 

872)     <hr>
873) 

874)     <a id="OutboundPorts"></a>
875)     <h3><a class="anchor" href="#OutboundPorts">Which outbound ports must be open when
876)     using Tor as a client?</a></h3>

877)     <p>

878)     Tor may attempt to connect to any port that is advertised in the
879)     directory as an ORPort (for making Tor connections) or a DirPort (for

880)     fetching updates to the directory). There are a variety of these ports:
881)     many of them are running on 80, 443, 9001, and 9030, but many use other
882)     ports too.

883)     </p>
884)     <p>

885)     When using Tor as a client, you could probably get away with opening only those four

886)     ports. Since Tor does all its connections in the background, it will retry
887)     ones that fail, and hopefully you'll never have to know that it failed, as
888)     long as it finds a working one often enough. However, to get the most

889)     diversity in your entry nodes — and thus the most security
890)     — as well as the most robustness in your connectivity, you'll
891)     want to let it connect to all of them.
892)     See the FAQ entry on <a href="#FirewallPorts">firewalled ports</a> if
893)     you want to explicitly tell your Tor client which ports are reachable
894)     for you.
895)     </p>

896) 

897)     <hr>

898) 

899)     <a id="IsItWorking"></a>

900)     <h3><a class="anchor" href="#IsItWorking">How can I tell if Tor is

901)     working, and that my connections really are anonymized?</a></h3>

902) 
903)     <p>

904)     There are sites you can visit that will tell you if you appear to be

905)     coming through the Tor network. Try the <a href="https://check.torproject.org">
906)     Tor Check</a> site and see whether it thinks you are using Tor or not.

907)     </p>

908) 

909)     <hr>

910) 

911)     <a id="FTP"></a>
912)     <h3><a class="anchor" href="#FTP">How do I use my browser for ftp with Tor?
913)     </a></h3>
914) 

915)     <p>

916)     Use <a href="https://torproject.org/projects/torbrowser.html">Tor
917)     Browser</a>. If you want a separate application for an

918)     ftp client, we've heard good things about  FileZilla for Windows. You can
919)     configure it to point to Tor as a "socks4a" proxy on "localhost" port
920)     "9050".

921)     </p>

922) 

923)     <hr>

924) 

925)     <a id="NoDataScrubbing"></a>

926)     <h3><a class="anchor" href="#NoDataScrubbing">Does Tor remove personal

927)     information from the data my application sends?</a></h3>
928) 

929)     <p>No, it doesn't. You need to use a separate program that understands
930)     your application and protocol and knows how to clean or "scrub" the data

931)     it sends. The Tor Browser tries to keep application-level data,

932)     like the user-agent string, uniform for all users. The Tor Browser can't
933)     do anything about text that you type into forms, though. <a

934)     href="<page download/download-easy>#warning">Be

935)     careful and be smart.</a>
936)     </p>
937) 
938)     <hr>
939) 

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

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

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

943) 

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

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

947)     <hr>

948) 

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

950)     <h3><a class="anchor" href="#SSLcertfingerprint">What are the SSL

951)     certificate fingerprints for Tor's various websites?</a></h3>

952)     <p>

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

954)     </p>
955)     <pre>
956) Issued Certificate
957) Version: 3
958) Serial Number: 09 48 B1 A9 3B 25 1D 0D B1 05 10 59 E2 C2 68 0A
959) Not Valid Before: 2013-10-22
960) Not Valid After: 2016-05-03
961) Certificate Fingerprints
962) SHA1: 84 24 56 56 8E D7 90 43 47 AA 89 AB 77 7D A4 94 3B A1 A7 D5
963) MD5: A4 16 66 80 AE B9 A4 EC AA 88 01 1B 6F B9 EB CB

964)     </pre>

965) <br>
966)     <p>
967) blog.torproject.org SSL certificate from RapidSSL:

968)     </p>

969)     <pre>
970) Issued Certificate
971) Version: 3
972) Serial Number: 05 CA 2A A9 A5 D6 ED 44 C7 2D 88 1A 18 B0 E7 DC
973) Not Valid Before: 2014-04-09
974) Not Valid After: 2017-06-14
975) Certificate Fingerprints
976) SHA1: DE 20 3D 46 FD C3 68 EB BA 40 56 39 F5 FA FD F5 4E 3A 1F 83
977) MD5: 8A 8A A2 5E D9 7F 84 4C 8F 00 3B 43 E0 2D E6 4D
978)     </pre>

979)     <hr>
980) 

981)     <a id="CompilationAndInstallation"></a>
982)     <h2><a class="anchor">Compilation And Installation:</a></h2>
983) 

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

985)     <h3><a class="anchor" href="#HowUninstallTor">How do I uninstall
986) Tor?</a></h3>
987) 
988)     <p>
989)     Tor Browser does not install itself in the classic sense of
990) applications. You just simply delete the folder or directory named "Tor
991) Browser" and it is removed from your system.
992)     </p>

993) 

994)     <p>

995)     If this is not related to Tor Browser, uninstallation depends
996) entirely on how you installed it and which operating system you
997)     have. If you installed a package, then hopefully your package has a
998) way to

999)     uninstall itself. The Windows packages include uninstallers.

1000)     </p>

1001) 

1002)     <p>
1003)     For Mac OS X, follow the <a
1004)     href="<page docs/tor-doc-osx>#uninstall">uninstall directions</a>.
1005)     </p>

1006) 

1007)     <p>

1008)     If you installed by source, I'm afraid there is no easy uninstall
1009) method. But
1010)     on the bright side, by default it only installs into /usr/local/ and
1011) it should

1012)     be pretty easy to notice things there.
1013)     </p>

1014) 

1015)     <hr>

1016) 

1017)     <a id="PGPSigs"></a>

1018)     <h3><a class="anchor" href="#PGPSigs">What are these "sig" files on
1019) the download page?</a></h3>

1020) 

1021)     <p>

1022)     These are PGP signatures, so you can verify that the file you've
1023) downloaded is

1024)     exactly the one that we intended you to get.
1025)     </p>

1026) 

1027)     <p>
1028)     Please read the <a

1029)     href="<page docs/verifying-signatures>">verifying signatures</a>
1030) page for details.

1031)     </p>

1032) 

1033) <hr>
1034) 
1035) <a id="GetTor"></a>
1036) <h3><a class="anchor" href="#GetTor">Your website is blocked in my
1037) country. How do I download Tor?</a></h3>
1038) 
1039) <p>
1040) Some government or corporate firewalls censor connections to Tor's
1041) website. In those cases, you have three options. First, get it from

1042) a friend &mdash; <a href="<page projects/torbrowser>">Tor Browser</a>

1043) fits nicely on a USB key. Second, find the <a

1044) href="https://encrypted.google.com/search?q=tor+mirrors">google
1045) cache</a>

1046) for the <a href="<page getinvolved/mirrors>">Tor mirrors</a> page
1047) and see if any of those copies of our website work for you. Third,

1048) you can download Tor Browser via email: log in to your email account
1049) and send an email to '<tt>gettor@torproject.org</tt>' with one of the
1050) following words in the body of the message: <tt>windows</tt>,
1051) <tt>osx</tt> or <tt>linux</tt> (case insensitive).
1052) You will receive a reply with links from popular cloud services to

1053) download Tor Browser for Windows, Mac OS X or Linux, depending on the

1054) option you chose. Currently, the only cloud service supported is

1055) Dropbox. If you send a blank message or anything different from the
1056) options mentioned, you will receive a help message with detailed

1057) instructions to ask for Tor Browser via email. Please note that you
1058) can use this service from any email address: gmail, yahoo, hotmail,
1059) riseup, etc. The only restriction is that you can do a maximum of
1060) three requests in a row, after that you'll have to wait 20 minutes to
1061) use it again. See the <a href="../projects/gettor.html">GetTor</a>
1062) section for more information.

1063) </p>
1064) 
1065) <p>

1066) Be sure to <a href="<page docs/verifying-signatures>">verify the
1067) signature</a>

1068) of any package you download, especially when you get it from somewhere
1069) other than our official HTTPS website.

1070) </p>
1071) 

1072)     <hr>

1073) 

1074)     <a id="VirusFalsePositives"></a>

1075)     <h3><a class="anchor" href="#VirusFalsePositives">Why does my
1076)     Tor executable appear to have a virus or spyware?</a></h3>

1077)     <p>

1078)     Sometimes, overzealous Windows virus and spyware detectors trigger on
1079)     some parts of the Tor Windows binary. Our best guess is that these are
1080)     false positives — after all, the anti-virus and anti-spyware business is
1081)     just a guessing game anyway. You should contact your vendor and explain
1082)     that you have a program that seems to be triggering false positives. Or

1083)     pick a better vendor.
1084)     </p>

1085)     <p>In the meantime, we encourage you to not just take our word for it.
1086)     Our job is to provide the source; if you're concerned, please do

1087)     recompile it yourself.</p>
1088) 
1089)     <hr>
1090) 

1091)     <a id="tarballs"></a>

1092)     <h3><a class="anchor" href="#tarballs">How do I open a .tar.gz

1093)     or .tar.xz file?</a></h3>

1094) 
1095)     <p>
1096)     Tar is a common archive utility for Unix and Linux systems. If your

1097)     system has a mouse, you can usually open them by double clicking.
1098)     Otherwise open a command prompt and execute</p>

1099)     <pre>tar xzf &lt;FILENAME&gt;.tar.gz</pre> or <pre>tar xJf &lt;FILENAME&gt;.tar.xz</pre>

1100)     <p>

1101)     as documented on tar's man page.

1102)     </p>
1103) 
1104)     <hr>
1105) 

1106)     <a id="LiveCD"></a>

1107)     <h3><a class="anchor" href="#LiveCD">Is there a LiveCD or other
1108) bundle that includes Tor?</a></h3>

1109) 

1110)     <p>

1111)     Yes.  Use <a href="https://tails.boum.org/">The Amnesic Incognito

1112)     Live System</a> or <a href="<page projects/torbrowser>">Tor Browser</a>.

1113)     </p>

1114) 
1115) <hr>
1116) 

1117) <a id="TBBGeneral"></a>

1118) <h2><a class="anchor">Tor Browser (general):</a></h2>

1119) 

1120) <a id="TBBFlash"></a>

1121) <h3><a class="anchor" href="#TBBFlash">Why can't I view videos on
1122) YouTube

1123) and other Flash-based sites?</a></h3>

1124) 
1125) <p>

1126) YouTube and similar sites require third party browser plugins such as Flash.
1127) Plugins operate independently from Firefox and can perform
1128) activity on your computer that ruins your anonymity. This includes
1129) but is not limited to: <a href="http://decloak.net">completely disregarding
1130) proxy settings</a>, querying your <a

1131) href="http://forums.sun.com/thread.jspa?threadID=5162138&messageID=9618376">
1132) local IP address</a>, and <a

1133) href="http://epic.org/privacy/cookies/flash.html">storing their own
1134) cookies</a>. It is possible to use a LiveCD solution such as

1135) or <a href="https://tails.boum.org/">The Amnesic Incognito Live System</a>
1136) that creates a secure, transparent proxy to protect you from proxy bypass,
1137) however issues with local IP address discovery and Flash cookies still remain.

1138) </p>

1139) 
1140) <p>

1141) <a href="https://www.youtube.com/html5">YouTube offers experimental HTML5 video

1142) support</a> for many of their videos. Often you can get the HTML5 version of
1143) videos that don't want to play by grabbing the YouTube URL from the "Embed"

1144) code under a video's "Share" option. The link switches out a URL that looks</p>
1145) <pre>https://www.youtube.com/watch?v=CJNxbpbHA-I</pre>
1146) <p>to something that looks like</p>
1147) <pre>https://www.youtube.com/embed/CJNxbpbHA-I</pre>

1148) 

1149) <hr>
1150) 

1151) <a id="Ubuntu"></a>
1152) <h3><a class="anchor" href="#Ubuntu">

1153) I'm using Ubuntu and I can't start Tor Browser.</a></h3>

1154) <p>

1155) You'll need to tell Ubuntu that you want the ability to execute shell scripts
1156) from the graphical interface. Open "Files" (Unity's explorer), open
1157) Preferences-> Behavior Tab -> Set "Run executable text files when they are

1158) opened" to "Ask every time", then OK.

1159) </p>
1160) <p>You can also start the Tor Browser from the command line by running </p>

1161) <pre>./start-tor-browser</pre>

1162) <p>
1163) from inside the Tor Browser directory.
1164) </p>
1165) 

1166) <hr>
1167) 

1168) <a id="SophosOnMac"></a>
1169) <h3><a class="anchor" href="#SophosOnMac">I'm using the Sophos anti-virus

1170)     software on my Mac, and Tor starts but I can't browse anywhere.</a></h3>

1171) <p>

1172) You'll need to modify Sophos anti-virus so that Tor can connect to the
1173) internet. Go to Preferences -> Web Protection -> General, and turn off

1174) the protections for "Malicious websites" and "Malicious downloads".
1175) </p>

1176) <p>

1177) We encourage affected Sophos users to contact Sophos support about

1178) this issue.
1179) </p>

1180) 

1181) <hr>
1182) 

1183) <a id="XPCOMError"></a>

1184) <h3><a class="anchor" href="#XPCOMError">When I start Tor Browser I get an 
1185) error message: "Cannot load XPCOM".</a></h3>

1186) 
1187) <p>

1188) This <a 
1189) href="https://trac.torproject.org/projects/tor/ticket/10789">problem</a> is 
1190) specifically caused by the Webroot SecureAnywhere Antivirus software. 
1191) From the Webroot control panel, go to Identity Protection &rarr; Application 
1192) Protection, and set all the files in your Tor Browser folder to 'Allow'. 
1193) We encourage affected Webroot users to contact Webroot support about this 
1194) issue.

1195) </p>

1196) 
1197) <hr>
1198) 

1199) <a id="TBBOtherExtensions"></a>
1200) <h3><a class="anchor" href="#TBBOtherExtensions">Can I install other
1201) Firefox extensions?</a></h3>
1202) 
1203) <p>

1204) The Tor Browser is free software, so there is nothing preventing you from
1205) modifying it any way you like. However, we do not recommend installing any

1206) additional Firefox add-ons with Tor Browser. Add-ons can break

1207) your anonymity in a number of ways, including browser fingerprinting and

1208) bypassing proxy settings.

1209) </p>

1210) <p>

1211) Some people have suggested we include ad-blocking software or

1212) anti-tracking software with the Tor Browser. Right now, we do not
1213) think that's such a good idea. Tor Browser aims to provide

1214) sufficient privacy that additional add-ons to stop ads and trackers are
1215) not necessary. Using add-ons like these may cause some sites to break, which

1216) <a href="https://www.torproject.org/projects/torbrowser/design/#philosophy">

1217) we don't want to do</a>. Additionally, maintaining a list of "bad" sites that
1218) should be black-listed provides another opportunity to uniquely fingerprint
1219) users.

1220) </p>

1221) 

1222) <hr>
1223) 

1224) <a id="TBBJavaScriptEnabled"></a>

1225) <a id="TBBCanIBlockJS"></a>

1226) <h3><a class="anchor" href="#TBBJavaScriptEnabled">Why is NoScript

1227) configured to allow JavaScript by default in Tor Browser?

1228) Isn't that unsafe?</a></h3>

1229) 
1230) <p>

1231) We configure NoScript to allow JavaScript by default in Tor
1232) Browser because many websites will not work with JavaScript

1233) disabled.  Most users would give up on Tor entirely if a website
1234) they want to use requires JavaScript, because they would not know
1235) how to allow a website to use JavaScript (or that enabling
1236) JavaScript might make a website work).
1237) </p>
1238) 

1239) <p>
1240) There's a tradeoff here. On the one hand, we should leave
1241) JavaScript enabled by default so websites work the way
1242) users expect. On the other hand, we should disable JavaScript
1243) by default to better protect against browser vulnerabilities (<a

1244) href="https://blog.torproject.org/blog/tor-security-advisory-old-tor-browser-bundles-vulnerable">
1245) not just a theoretical concern!</a>). But there's a third issue: websites

1246) can easily determine whether you have allowed JavaScript for them,
1247) and if you disable JavaScript by default but then allow a few websites
1248) to run scripts (the way most people use NoScript), then your choice of
1249) whitelisted websites acts as a sort of cookie that makes you recognizable
1250) (and distinguishable), thus harming your anonymity.
1251) </p>

1252) 
1253) <p>

1254) Ultimately, we want the default Tor bundles to use
1255) a combination of firewalls (like the iptables rules
1256) in <a href="https://tails.boum.org/">Tails</a>) and <a
1257) href="https://trac.torproject.org/projects/tor/ticket/7680">sandboxes</a>
1258) to make JavaScript not so scary. In
1259) the shorter term, TBB 3.0 will hopefully <a
1260) href="https://trac.torproject.org/projects/tor/ticket/9387">allow users
1261) to choose their JavaScript settings more easily</a> &mdash; but the
1262) partitioning concern will remain.

1263) </p>
1264) 
1265) <p>

1266) Until we get there, feel free to leave JavaScript on or off depending
1267) on your security, anonymity, and usability priorities.

1268) </p>
1269) 
1270) <hr>
1271) 

1272) <a id="TBBOtherBrowser"></a>
1273) <h3><a class="anchor" href="#TBBOtherBrowser">I want to use
1274) Chrome/IE/Opera/etc with Tor.</a></h3>
1275) 
1276) <p>

1277) In short, using any browser besides Tor Browser with Tor is a

1278) really bad idea.
1279) </p>
1280) 
1281) <p>

1282) Our efforts to work with the Chrome team to <a
1283) href="https://blog.torproject.org/blog/google-chrome-incognito-mode-tor-and-fingerprinting">add
1284) missing APIs</a> were unsuccessful, unfortunately. Currently, it is impossible
1285) to use other browsers and get the same level of protections as when using the
1286) Tor Browser.

1287) </p>
1288) 
1289) <hr>
1290) 

1291) <a id="GoogleCAPTCHA"></a>
1292) <h3><a class="anchor" href="#GoogleCAPTCHA">Google makes me solve a
1293) CAPTCHA or tells me I have spyware installed.</a></h3>

1294) 
1295) <p>
1296) This is a known and intermittent problem; it does not mean that Google
1297) considers Tor to be spyware.
1298) </p>
1299) 
1300) <p>

1301) When you use Tor, you are sending queries through exit relays that are

1302) also shared by thousands of other users. Tor users typically see this
1303) message when many Tor users are querying Google in a short period of time.
1304) Google interprets the high volume of traffic from a single IP address
1305) (the exit relay you happened to pick) as somebody trying to "crawl" their
1306) website, so it slows down traffic from that IP address for a short time.

1307) </p>
1308) <p>
1309) An alternate explanation is that Google tries to detect certain
1310) kinds of spyware or viruses that send distinctive queries to Google
1311) Search. It notes the IP addresses from which those queries are received
1312) (not realizing that they are Tor exit relays), and tries to warn any
1313) connections coming from those IP addresses that recent queries indicate
1314) an infection.
1315) </p>
1316) 
1317) <p>

1318) To our knowledge, Google is not doing anything intentionally specifically

1319) to deter or block Tor use. The error message about an infected machine
1320) should clear up again after a short time.
1321) </p>
1322) 
1323) <hr />
1324) 

1325) <a id="ForeignLanguages"></a>
1326) <h3><a class="anchor" href="#ForeignLanguages">
1327) Why does Google show up in foreign languages?</a></h3>
1328) 
1329) <p>

1330)  Google uses "geolocation" to determine where in the world you are, so it
1331)  can give you a personalized experience. This includes using the language
1332)  it thinks you prefer, and it also includes giving you different results

1333)  on your queries.

1334) </p>
1335) <p>

1336) If you really want to see Google in English you can click the link that
1337) provides that. But we consider this a feature with Tor, not a bug --- the
1338) Internet is not flat, and it in fact does look different depending on

1339) where you are. This feature reminds people of this fact.

1340) </p>
1341) <p>

1342) Note that Google search URLs take name/value pairs as arguments and one
1343) of those names is "hl". If you set "hl" to "en" then Google will return
1344) search results in English regardless of what Google server you have been
1345) sent to. On a query this looks like:

1346) </p>

1347) <pre>https://encrypted.google.com/search?q=online%20anonymity&hl=en</pre>

1348) <p>

1349) Another method is to simply use your country code for accessing Google.
1350) This can be google.be, google.de, google.us and so on.

1351) </p>
1352) <hr />

1353) <a id="GmailWarning"></a>

1354) <h3><a class="anchor" href="#GmailWarning">Gmail warns me that my

1355) account may have been compromised.</a></h3>

1356) 
1357) <p>
1358) Sometimes, after you've used Gmail over Tor, Google presents a
1359) pop-up notification that your account may have been compromised.
1360) The notification window lists a series of IP addresses and locations
1361) throughout the world recently used to access your account.
1362) </p>
1363) 
1364) <p>
1365) In general this is a false alarm: Google saw a bunch of logins from

1366) different places, as a result of running the service via Tor, and
1367) decided

1368) it was a good idea to confirm the account was being accessed by it's
1369) rightful owner.
1370) </p>
1371) 
1372) <p>
1373) Even though this may be a biproduct of using the service via tor,
1374) that doesn't mean you can entirely ignore the warning. It is
1375) <i>probably</i> a false positive, but it might not be since it is
1376) possible for someone to hijack your Google cookie.
1377) </p>
1378) 
1379) <p>
1380) Cookie hijacking is possible by either physical access to your computer
1381) or by watching your network traffic.  In theory only physical access
1382) should compromise your system because Gmail and similar services
1383) should only send the cookie over an SSL link. In practice, alas, it's <a

1384) href="http://fscked.org/blog/fully-automated-active-https-cookie-
1385) hijacking">

1386) way more complex than that</a>.
1387) </p>
1388) 
1389) <p>
1390) And if somebody <i>did</i> steal your google cookie, they might end
1391) up logging in from unusual places (though of course they also might
1392) not). So the summary is that since you're using Tor, this security
1393) measure that Google uses isn't so useful for you, because it's full of
1394) false positives. You'll have to use other approaches, like seeing if
1395) anything looks weird on the account, or looking at the timestamps for
1396) recent logins and wondering if you actually logged in at those times.
1397) </p>
1398) 
1399) <hr>
1400) 

1401) <a id="NeedToUseAProxy"></a>

1402) <h3><a class="anchor" href="#NeedToUseAProxy">My internet connection

1403) requires an HTTP or SOCKS Proxy</a></h3>

1404) 
1405) <p>

1406) You can set Proxy IP address, port, and authentication information in
1407) Tor Browser's Network Settings. If you're using Tor another way, check
1408) out the HTTPProxy and HTTPSProxy config options in the <a

1409) href="<page docs/tor-manual>">man page</a>,

1410) and modify your torrc file accordingly. You will need an HTTP proxy for
1411) doing GET requests to fetch the Tor directory, and you will need an
1412) HTTPS proxy for doing CONNECT requests to get to Tor relays. (It's fine
1413) if they're the same proxy.) Tor also recognizes the torrc options
1414) Socks4Proxy and Socks5Proxy.

1415) </p>
1416) <p>

1417) Also read up on the HTTPProxyAuthenticator and HTTPSProxyAuthenticator
1418) options if your proxy requires auth. We only support basic auth currently,
1419) but if you need NTLM authentication, you may find <a
1420) href="http://archives.seul.org/or/talk/Jun-2005/msg00223.html">this post
1421) in the archives</a> useful.

1422) </p>
1423) <p>

1424) If your proxies only allow you to connect to certain ports, look at the
1425) entry on <a href="#FirewallPorts">Firewalled clients</a> for how
1426) to restrict what ports your Tor will try to access.

1427) </p>
1428) 
1429) <hr>
1430) 

1431) 
1432) <a id="TBBSocksPort"></a>
1433) <h3><a class="anchor" href="#TBBSocksPort">
1434) I want to run another application through Tor.</a></h3>
1435) 
1436) <p>
1437) If you are trying to use some external application with Tor, step zero
1438) should be to <a href="<page download/download>#warning">reread the set
1439) of warnings</a> for ways you can screw up. Step one should be to try
1440) to use a SOCKS proxy rather than an HTTP proxy.
1441) Typically Tor listens for SOCKS connections on port 9050. Tor Browser listens
1442) on port 9150.
1443) </p>
1444) 
1445) <p>
1446) If your application doesn't support SOCKS proxies, feel free to install <a
1447) href="http://www.privoxy.org/">privoxy</a>.
1448) However, please realize that this approach is not recommended for novice
1449) users. Privoxy has an <a
1450) href="http://www.privoxy.org/faq/misc.html#TOR">example
1451) configuration</a> of Tor and Privoxy.
1452) </p>
1453) 
1454) <p>

1455) If you're unable to use the application's native proxy settings, all hope is

1456) not lost. See <a href="#CantSetProxy">below</a>.
1457) </p>
1458) 
1459) <hr>
1460) 

1461) <a id="CantSetProxy"></a>

1462) <h3><a class="anchor" href="#CantSetProxy">What should I do if I can't

1463) set a proxy with my application?</a></h3>
1464) 
1465) <p>

1466) On Unix, we recommend you give <a
1467) href="https://github.com/dgoulet/torsocks/">torsocks</a> a try.
1468) Alternative proxifying tools like <a
1469) href="http://www.dest-unreach.org/socat/">socat</a> and <a
1470) href="http://proxychains.sourceforge.net/">proxychains</a> are also

1471) available.</p>

1472) <p>
1473) The Windows way to force applications through Tor is less clear. <a
1474) href="http://freecap.ru/eng/">Some</a> <a
1475) href="http://www.freehaven.net/~aphex/torcap/">tools</a> have been <a

1476) href="http://www.crowdstrike.com/community-tools/index.html#tool-79">proposed

1477) </a>, but we'd also like to see further testing done here.

1478) </p>
1479) 
1480) <hr>
1481) 

1482) <a id="TBB3.x"></a>

1483) <h2><a class="anchor">Tor Browser (3.x and later):</a></h2>

1484)     <a id="WhereDidVidaliaGo"></a>

1485)     <h3><a class="anchor" href="#WhereDidVidaliaGo">Where did the world map

1486)     (Vidalia) go?</a></h3>
1487) 

1488)     <p>Vidalia has been replaced with Tor Launcher, which is a Firefox
1489)     extension that provides similar functionality. Unfortunately, circuit
1490)     status reporting is still missing, but we are <a
1491)     href="https://trac.torproject.org/projects/tor/ticket/8641">working

1492)     on providing it</a>. </p>
1493) 
1494)     <hr>
1495) 
1496)     <a id="DisableJS"></a>
1497)     <h3><a class="anchor" href="#DisableJS">How do I disable JavaScript?</a>
1498)     </h3>
1499) 

1500)     <p>Alas, Mozilla decided to get rid of the config checkbox for JavaScript
1501)     from earlier Firefox versions. And since TBB 3.5 is based on Firefox 24
1502)     (FF17 is unmaintained), that means TBB 3.5 doesn't have the config

1503)     checkbox anymore either, which is unfortunate.</p>
1504) 

1505)     <p>The simplest way to disable JavaScript in TBB 3.5 is to click on the
1506)     Noscript "S" (between the green onion and the address bar), and select
1507)     "Forbid scripts globally". Note that vanilla NoScript actually whitelists
1508)     several domains even when you try to disable scripts globally, whereas

1509)     Tor Browser's NoScript configuration disables all of them. </p>
1510) 

1511)     <p>The more klunky way to disable JavaScript is to go to about:config,

1512)     find javascript.enabled, and set it to false.</p>
1513) 
1514)     <p>There is also a very simple addon available at addons.mozilla.org
1515)     called QuickJS, which provides a toolbar toggle for the javascript.enabled

1516)     about:config control. There are no configuration options for the addon,
1517)     it just switches the javascript.enabled entry between true and false and

1518)     provides a button for it. </p>
1519) 

1520)     <p>If you want to be extra safe, use both the about:config setting and

1521)     NoScript. </p>
1522) 

1523)     <p>As for whether you should disable it or leave it enabled, that's <a

1524)     href="#TBBJavaScriptEnabled">a tradeoff we leave to you</a>.</p>

1525) 
1526)     <hr>
1527) 
1528)     <a id="VerifyDownload"></a>
1529)     <h3><a class="anchor" href="#VerifyDownload">How do I verify the download
1530)     (sha256sums.txt)?</a></h3>
1531) 

1532)     <p>Instructions are on the <a
1533)     href="<page docs/verifying-signatures>#BuildVerification">verifying

1534)     signatures</a> page.</p>

1535) 
1536)     <hr>

1537) 

1538)     <a id="NewIdentityClosingTabs"></a>

1539)     <h3><a class="anchor" href="#NewIdentityClosingTabs">Why does "New

1540)     Identity" close all my open tabs?</a></h3>
1541) 
1542)     <p>

1543)     That's actually a feature, since it's discarding your application-level

1544)     browser data too.

1545)     </p>
1546) 
1547)     <p>

1548)     We're working on ways to make the behavior less surprising, e.g. a popup
1549)     warning or auto restoring tabs. See ticket <a
1550)     href="https://trac.torproject.org/projects/tor/ticket/9906">#9906</a> and
1551)     ticket <a
1552)     href="https://trac.torproject.org/projects/tor/ticket/10400">#10400</a>
1553)     to follow progress there.

1554)     </p>
1555) 
1556)     <hr>
1557) 
1558)     <a id="ConfigureRelayOrBridge"></a>
1559)     <h3><a class="anchor" href="#ConfigureRelayOrBridge">How do I configure Tor as a relay or bridge?</a></h3>
1560) 
1561)     <p>

1562)     You've got three options.

1563)     </p>
1564) 
1565)     <p>

1566)     First (best option), if you're on Linux, you can install the system
1567)     Tor package (e.g. apt-get install tor) and then set it up to be a relay
1568)     (<a href="https://www.torproject.org/docs/tor-relay-debian">instructions</a>).

1569)     You can then use TBB independent of that.
1570)     </p>
1571) 
1572) 
1573)     <p>

1574)     Second (complex option), you can edit your torrc file (in Data/Tor/torrc)

1575)     directly to add the following lines:

1576)     </p>
1577)     <pre>
1578)     ORPort 443
1579)     Exitpolicy reject *:*
1580)     BridgeRelay 1  # only add this line if you want to be a bridge
1581)     </pre>
1582)     <p>

1583)     If you've installed <a

1584)     href="<page projects/obfsproxy-debian-instructions>#instructions">Obfsproxy</a>,

1585)     you'll need to add one more line:
1586)     </p>
1587)     <pre>
1588)     ServerTransportPlugin obfs3 exec /usr/bin/obfsproxy managed
1589)     </pre>
1590) 
1591)     <hr>
1592) 
1593)     <a id="Timestamps"></a>

1594)     <h3><a class="anchor" href="#Timestamps">Why are the file timestamps

1595)     from 2000?</a></h3>
1596) 

1597)     <p>One of the huge new features in TBB 3.x is the "deterministic build"

1598)     process, which allows many people to build Tor Browser and

1599)     verify that they all make exactly the same package. See Mike's <a
1600)     href="https://blog.torproject.org/blog/deterministic-builds-part-one-cyberwar-and-global-compromise">first
1601)     blog</a> post for the motivation, and his <a

1602)     href="https://blog.torproject.org/blog/deterministic-builds-part-two-technical-details">second

1603)     blog post</a> for the technical details of how we do it.

1604)     </p>
1605) 

1606)     <p>Part of creating identical builds is having everybody use the same
1607)     timestamp. Mike picked the beginning of 2000 for that time. The reason

1608)     you might see 7pm in 1999 is because of time zones. </p>
1609) 
1610)     <hr>
1611) 

1612)     <a id="TBBSourceCode"></a>

1613)     <h3><a class="anchor" href="#TBBSourceCode">Where is the source code for

1614)     Tor Browser? How do I verify a build?</a></h3>

1615) 
1616)     <p>

1617)     Start with <a href="https://gitweb.torproject.org/builders/tor-browser-bundle.git">https://gitweb.torproject.org/builders/tor-browser-bundle.git</a> and <a href="https://gitweb.torproject.org/builders/tor-browser-bundle.git/tree/gitian/README.build">https://gitweb.torproject.org/builders/tor-browser-bundle.git/tree/gitian/README.build</a>.

1618)     </p>
1619) 
1620) 

1621) <hr>
1622) 

1623) <a id="AdvancedTorUsage"></a>
1624) <h2><a class="anchor">Advanced Tor usage:</a></h2>
1625) 

1626) <a id="torrc"></a>

1627) <h3><a class="anchor" href="#torrc">I'm supposed to "edit my torrc".
1628) What does that mean?</a></h3>

1629) 
1630) <p>
1631) Tor installs a text file called torrc that contains configuration
1632) instructions for how your Tor program should behave. The default

1633) configuration should work fine for most Tor users.

1634) </p>

1635) <p>

1636) If you installed Tor Browser, look for

1637) <code>Browser/TorBrowser/Data/Tor/torrc</code> inside your Tor Browser
1638) directory.

1639) On OS X, you must right-click or command-click on the Tor Browser icon,

1640) and select "Show Package Contents" before the Tor Browser directories become
1641) visible.

1642) </p>
1643) <p>

1644) Tor puts the torrc file in <code>/usr/local/etc/tor/torrc</code> if you compiled tor from source, and <code>/etc/tor/torrc</code> or <code>/etc/torrc</code> if you installed a pre-built package.</p>

1645) 
1646) <p>

1647) Once you've changed your torrc, you will need to restart tor for the
1648) changes to take effect. (For advanced users, note that

1649) you actually only need to send Tor a HUP signal, not actually restart
1650) it.)

1651) </p>
1652) 
1653) <p>

1654) For other configuration options you can use, see the <a href="<page

1655) docs/tor-manual>">Tor manual page</a>. Have a look at <a

1656) href="https://gitweb.torproject.org/tor.git/tree/src/config/torrc.sample.in">

1657) the sample torrc file</a> for hints on common configurations. Remember, all
1658) lines beginning with # in torrc are treated as comments and have no effect

1659) on Tor's configuration.

1660) </p>
1661) 
1662) <hr>
1663) 

1664) <a id="Logs"></a>

1665) <h3><a class="anchor" href="#Logs">How do I set up logging, or see Tor's
1666) logs?</a></h3>

1667) 
1668) <p>

1669) You'll have to go find the log files by

1670) hand. Here are some likely places for your logs to be:

1671) </p>
1672) 
1673) <ul>
1674) <li>On OS X, Debian, Red Hat, etc, the logs are in /var/log/tor/
1675) </li>

1676) <li>On Windows, there are no default log files currently. If you enable
1677) logs in your torrc file, they default to <code>\username\Application
1678) Data\tor\log\</code> or <code>\Application Data\tor\log\</code>
1679) </li>
1680) <li>If you compiled Tor from source, by default your Tor logs to <a
1681) href="http://en.wikipedia.org/wiki/Standard_streams">"stdout"</a>
1682) at log-level notice. If you enable logs in your torrc file, they
1683) default to <code>/usr/local/var/log/tor/</code>.

1684) </li>
1685) </ul>
1686) 
1687) <p>

1688) To change your logging setup by hand, <a href="#torrc">edit your
1689) torrc</a>

1690) and find the section (near the top of the file) which contains the
1691) following line:

1692) </p>
1693) 
1694) <pre>

1695) \## Logs go to stdout at level "notice" unless redirected by something
1696) \## else, like one of the below lines.

1697) </pre>

1698) 
1699) <p>

1700) For example, if you want Tor to send complete debug, info, notice, warn,

1701) and err level messages to a file, append the following line to the end
1702) of the section:
1703) </p>
1704) 
1705) <pre>
1706) Log debug file c:/program files/tor/debug.log
1707) </pre>
1708) 
1709) <p>

1710) Replace <code>c:/program files/tor/debug.log</code> with a directory
1711) and filename for your Tor log.

1712) </p>
1713) 
1714) <hr>
1715) 

1716) 
1717) <a id="LogLevel"></a>
1718) <h3><a class="anchor" href="#LogLevel">What log level should I use?</a></h3>
1719) 
1720) <p>

1721) There are five log levels (also called "log severities") you might see in

1722) Tor's logs:

1723) </p>
1724) 
1725) <ul>

1726)     <li>"err": something bad just happened, and we can't recover. Tor will

1727)     exit.</li>

1728)     <li>"warn": something bad happened, but we're still running. The bad
1729)     thing might be a bug in the code, some other Tor process doing something
1730)     unexpected, etc. The operator should examine the message and try to

1731)     correct the problem.</li>

1732)     <li>"notice": something the operator will want to know about.</li>

1733)     <li>"info": something happened (maybe bad, maybe ok), but there's

1734)     nothing you need to (or can) do about it.</li>

1735)     <li>"debug": for everything louder than info. It is quite loud indeed.</li>

1736) </ul>
1737) 
1738) <p>

1739) Alas, some of the warn messages are hard for ordinary users to correct -- the
1740) developers are slowly making progress at making Tor automatically react

1741) correctly for each situation.

1742) </p>
1743) 
1744) <p>

1745) We recommend running at the default, which is "notice". You will hear about

1746) important things, and you won't hear about unimportant things.

1747) </p>
1748) 
1749) <p>

1750) Tor relays in particular should avoid logging at info or debug in normal
1751) operation, since they might end up recording sensitive information in
1752) their logs.

1753) </p>
1754) 

1755) <hr>
1756) 

1757) <a id="DoesntWork"></a>

1758) <h3><a class="anchor" href="#DoesntWork">I installed Tor but it's not
1759) working.</a></h3>

1760) 
1761) <p>

1762) Once you've got Tor Browser up and running, the first question to

1763) ask is whether your Tor client is able to establish a circuit.

1764) </p>
1765) 

1766) <p>If Tor can establish a circuit, Tor Browser will
1767) automatically launch the browser for you. You can also check in the
1768) <a href="#Logs">Tor logs</a> for

1769) a line saying that Tor "has successfully opened a circuit. Looks like
1770) client functionality is working."
1771) </p>
1772) 
1773) <p>
1774) If Tor can't establish a circuit, here are some hints:
1775) </p>
1776) 
1777) <ol>
1778) <li>Check your system clock. If it's more than a few hours off, Tor will

1779) refuse to build circuits. For Microsoft Windows users, synchronize your
1780) clock under the clock -> Internet time tab. In addition, correct the

1781) day and date under the 'Date & Time' Tab. Also make sure your time
1782) zone is correct.</li>

1783) <li>Is your Internet connection <a href="#FirewallPorts">firewalled
1784) by port</a>, or do you normally need to use a <a

1785) href="<#NeedToUseAProxy">proxy</a>?

1786) </li>

1787) <li>Are you running programs like Norton Internet Security or SELinux
1788) that

1789) block certain connections, even though you don't realize they do? They
1790) could be preventing Tor from making network connections.</li>
1791) <li>Are you in China, or behind a restrictive corporate network firewall
1792) that blocks the public Tor relays? If so, you should learn about <a

1793) href="<page docs/bridges>">Tor bridges</a>.</li>

1794) <li>Check your <a href="#Logs">Tor logs</a>. Do they give you any hints
1795) about what's going wrong?</li>

1796) </ol>
1797) 
1798) <hr />
1799) 

1800) <a id="TorCrash"></a>
1801) <h3><a class="anchor" href="#TorCrash">My Tor keeps crashing.</a></h3>
1802) <p>

1803)  We want to hear from you! There are supposed to be zero crash bugs in Tor.
1804)  This FAQ entry describes the best way for you to be helpful to us. But even
1805)  if you can't work out all the details, we still want to hear about it, so
1806)  we can help you track it down.

1807) </p>
1808) <p>

1809) First, make sure you're using the latest version of Tor (either the latest
1810) stable or the latest development version).

1811) </p>
1812) <p>

1813) Second, make sure your version of libevent is new enough. We recommend at
1814) least libevent 1.3a.

1815) </p>
1816) <p>

1817) Third, see if there's already an entry for your bug in the <a
1818) href="https://bugs.torproject.org/">Tor bugtracker</a>. If so,
1819) check if there are any new details that you can add.

1820) </p>
1821) <p>

1822) Fourth, is the crash repeatable? Can you cause the crash? Can
1823) you isolate some of the circumstances or config options that
1824) make it happen? How quickly or often does the bug show up?
1825) Can you check if it happens with other versions of Tor, for
1826) example the latest stable release?

1827) </p>
1828) <p>

1829) Fifth, what sort of crash do you get?

1830) </p>
1831) <ul>
1832) <li>

1833) Does your Tor log include an "assert failure"? If so, please
1834) tell us that line, since it helps us figure out what's going on.
1835) Tell us the previous couple of log messages as well, especially
1836) if they seem important.

1837) </li>
1838) <li>

1839) If it says "Segmentation fault - core dumped" then you need to
1840) do a bit more to track it down. Look for a file like "core" or
1841) "tor.core" or "core.12345" in your current directory, or in your
1842) Data Directory. If it's there, run "gdb tor core" and then "bt",
1843) and include the output. If you can't find a core, run "ulimit -c
1844) unlimited", restart Tor, and try to make it crash again. (This core
1845) thing will only work on Unix -- alas, tracking down bugs on Windows
1846) is harder. If you're on Windows, can you get somebody to duplicate

1847) your bug on Unix?)
1848) </li>
1849) <li>

1850) If Tor simply vanishes mysteriously, it probably is a segmentation
1851) fault but you're running Tor in the background (as a daemon) so you
1852) won't notice. Go look at the end of your log file, and look for a
1853) core file as above. If you don't find any good hints, you should
1854) consider running Tor in the foreground (from a shell) so you can
1855) see how it dies. Warning: if you switch to running Tor in the foreground,
1856) you might start using a different torrc file, with a different default
1857) Data Directory; see the <a href="#UpgradeOrMove">relay-upgrade FAQ entry</a>
1858) for details.

1859) </li>
1860) <li>

1861) If it's still vanishing mysteriously, perhaps something else is killing it?
1862) Do you have resource limits (ulimits) configured that kill off processes
1863) sometimes? (This is especially common on OpenBSD.) On Linux, try running
1864) "dmesg" to see if the out-of-memory killer removed your process. (Tor will
1865) exit cleanly if it notices that it's run out of memory, but in some cases
1866) it might not have time to notice.) In very rare circumstances, hardware
1867) problems could also be the culprit.

1868) </li>
1869) </ul>
1870) <p>

1871) Sixth, if the above ideas don't point out the bug, consider increasing your
1872) log level to "loglevel debug". You can look at the log-configuration FAQ
1873) entry for instructions on what to put in your torrc file. If it usually
1874) takes a long time for the crash to show up, you will want to reserve a whole
1875) lot of disk space for the debug log. Alternatively, you could just send
1876) debug-level logs to the screen (it's called "stdout" in the torrc), and then
1877) when it crashes you'll see the last couple of log lines it had printed.
1878) (Note that running with verbose logging like this will slow Tor down
1879) considerably, and note also that it's generally not a good idea security-wise
1880) to keep logs like this sitting around.)

1881) </p>
1882) 
1883) <hr />
1884) 

1885)     <a id="ChooseEntryExit"></a>

1886)     <h3><a class="anchor" href="#ChooseEntryExit">Can I control which
1887) nodes (or country) are used for entry/exit?</a></h3>

1888) 

1889)     <p>

1890)     Yes. You can set preferred entry and exit nodes as well as
1891)     inform Tor which nodes you do not want to use.

1892)     The following options can be added to your config file <a
1893)     href="#torrc">"torrc"</a> or specified on the command line:

1894)     </p>
1895)     <dl>
1896)       <dt><tt>EntryNodes $fingerprint,$fingerprint,...</tt></dt>

1897)         <dd>A list of preferred nodes to use for the first hop in the
1898) circuit, if possible.

1899)         </dd>
1900)       <dt><tt>ExitNodes $fingerprint,$fingerprint,...</tt></dt>

1901)         <dd>A list of preferred nodes to use for the last hop in the
1902) circuit, if possible.

1903)         </dd>
1904)       <dt><tt>ExcludeNodes $fingerprint,$fingerprint,...</tt></dt>

1905)         <dd>A list of nodes to never use when building a circuit.

1906)         </dd>
1907)       <dt><tt>ExcludeExitNodes $fingerprint,$fingerprint,...</tt></dt>

1908)         <dd>A list of nodes to never use when picking an exit.

1909)             Nodes listed in <tt>ExcludeNodes</tt> are automatically in
1910) this list.

1911)         </dd>
1912)     </dl>
1913)     <p>

1914)     <em>We recommend you do not use these</em>

1915)     — they are intended for testing and may disappear in future
1916) versions.

1917)     You get the best security that Tor can provide when you leave the
1918)     route selection to Tor; overriding the entry / exit nodes can mess
1919)     up your anonymity in ways we don't understand.

1920)     </p>
1921)     <p>

1922)     Note also that not every circuit is used to deliver traffic outside of
1923)     the Tor network. It is normal to see non-exit circuits (such as those
1924)     used to connect to hidden services, those that do directory fetches,
1925)     those used for relay reachability self-tests, and so on) that end at
1926)     a non-exit node. To keep a node from being used entirely, see
1927)     <tt>ExcludeNodes</tt> and <tt>StrictNodes</tt> in the

1928)     <a href="<page docs/tor-manual>">manual</a>.

1929)     </p>
1930)     <p>

1931)     Instead of <tt>$fingerprint</tt> you can also specify a <a

1932) 
1933) href="https://secure.wikimedia.org/wikipedia/en/wiki/ISO_3166-1_alpha-2"
1934) >2

1935)     letter ISO3166 country code</a> in curly braces (for example <tt>{de}</tt>),

1936)     or an ip address pattern (for example 255.254.0.0/8).
1937)     Make sure there are no spaces between the commas and the

1938)     list items.

1939)     </p>
1940)     <p>

1941)     If you want to access a service directly through Tor's Socks
1942) interface

1943)     (eg. using ssh via connect.c), another option is to set up an

1944)     internal mapping in your configuration file using
1945) <tt>MapAddress</tt>.

1946)     See the manual page for details.
1947)     </p>

1948) 

1949)     <hr>

1950) 

1951) <a id="FirewallPorts"></a>

1952) <h3><a class="anchor" href="#FirewallPorts">My firewall only allows a
1953) few outgoing ports.</a></h3>

1954) 
1955) <p>
1956) If your firewall works by blocking ports, then you can tell Tor to only

1957) use the ports when you start your Tor Browser. Or you can add the ports
1958) that your firewall permits by adding "FascistFirewall 1"

1959) to

1960) your <a href="<page docs/faq>#torrc">torrc

1961) configuration file</a>.

1962) By default, when you set this Tor assumes that your firewall allows only
1963) port 80 and port 443 (HTTP and HTTPS respectively). You can select a
1964) different set of ports with the FirewallPorts torrc option.
1965) </p>
1966) 
1967) <p>
1968) If you want to be more fine-grained with your controls, you can also
1969) use the ReachableAddresses config options, e.g.:
1970) </p>
1971) 
1972) <pre>
1973)   ReachableDirAddresses *:80
1974)   ReachableORAddresses *:443
1975) </pre>
1976) 
1977) <hr>

1978) 

1979)     <a id="DefaultExitPorts"></a>

1980)     <h3><a class="anchor" href="#DefaultExitPorts">Is there a list of default exit

1981)     ports?</a></h3>

1982)     <p>

1983) The default open ports are listed below but keep in mind that, any port or
1984) ports can be opened by the relay operator by configuring it in torrc or
1985) modifying the source code. But the default according to src/or/policies.c
1986) from the source code release tor-0.2.4.16-rc is:

1987)     </p>
1988)     <pre>
1989)   reject 0.0.0.0/8
1990)   reject 169.254.0.0/16
1991)   reject 127.0.0.0/8
1992)   reject 192.168.0.0/16
1993)   reject 10.0.0.0/8
1994)   reject 172.16.0.0/12
1995)   reject *:25
1996)   reject *:119
1997)   reject *:135-139
1998)   reject *:445
1999)   reject *:563
2000)   reject *:1214
2001)   reject *:4661-4666
2002)   reject *:6346-6429
2003)   reject *:6699
2004)   reject *:6881-6999
2005)   accept *:*
2006)     </pre>
2007)     <p>

2008)     A relay will block access to its own IP address, as well local network
2009)     IP addresses. A relay always blocks itself by default. This prevents
2010)     Tor users from accidentally accessing any of the exit operator's local
2011)     services.

2012)     </p>
2013) 
2014)     <hr>
2015) 

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

2017)     <h3><a class="anchor" href="#WarningsAboutSOCKSandDNSInformationLeaks">I
2018)     keep seeing these warnings about SOCKS and DNS information leaks.

2019)     Should I worry?</a></h3>
2020)     <p>

2021)     The warning is:

2022)     </p>
2023)     <p>