tor-webwml.git

1) ## translation metadata

2) # Revision: $Revision$

3) # Translation-Priority: 2-medium
4) 
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)     <a id="general"></a>

18)     <h4 style="margin-bottom: 18px"><a class="anchor" href="#general">General
19)     questions:</a></h4>

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

22)     <li><a href="#Torisdifferent">How is Tor different from other proxies?
23)     </a></li>
24)     <li><a href="#CompatibleApplications">What programs can I use with Tor?
25)     </a></li>

26)     <li><a href="#WhyCalledTor">Why is it called Tor?</a></li>
27)     <li><a href="#Backdoor">Is there a backdoor in Tor?</a></li>

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

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

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

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

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

34)     <li><a href="#Funding">What would The Tor Project do with more funding?
35)     </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="#Mobile">Can I use Tor on my phone or mobile device?</a></li>

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

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

42)     <li><a href="#NoDataScrubbing">Does Tor remove personal information from
43)     the data my application sends?</a></li>
44)     <li><a href="#Metrics">How many people use Tor? How many relays or exit
45)     nodes are there?</a></li>

46)     </ul>

47) 

48)     <a id="comp-install"></a>

49)     <h4 style="margin-bottom: 18px"><a class="anchor" href="#comp-install">
50)     Compilation and Installation:</a></h4>

51) 

52)     <ul>
53)     <li><a href="#HowUninstallTor">How do I uninstall Tor?</a></li>
54)     <li><a href="#PGPSigs">What are these "sig" files on the download
55)     page?</a></li>

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

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

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

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

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

63)     </ul>

64) 

65)     <a id="tbb"></a>

66)     <h4 style="margin-bottom: 18px"><a class="anchor" href="#tbb">Tor Browser
67)     (general):</a></h4>

68)     <ul>

69) 

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

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

73)     </a></li>

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

96)     </ul>
97) 

98)     <a id="tbb-3plus"></a>

99)     <h4 style="margin-bottom: 18px"><a class="anchor" href="#tbb-3plus">Tor
100)     Browser (3.x and later):</a></h4>

101) 
102)     <ul>

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

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

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

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

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

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

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

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

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

113)     </ul>
114) 

115)     <a id="advanced"></a>

116)     <h4 style="margin-bottom: 18px"><a class="anchor" href="#advanced">Advanced
117)     Tor usage:</a></h4>

118) 

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

122)     <li><a href="#datadir">Where's tor's data directory?</a></li>

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

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

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

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

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

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

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

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

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

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

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

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

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

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

142)     different computer than my applications.</a></li>
143)     <li><a href="#ServerClient">Can I install Tor on a central server, and
144)     have my clients connect to it?</a></li>

145)     </ul>

146) 

147)     <a id="relay"></a>

148)     <h4 style="margin-bottom: 18px"><a class="anchor" href="#relay">Running a
149)     Tor relay:</a></h4>

150)     <ul>

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

154)     <li><a href="#MostNeededRelayType">What type of relays are most needed?
155)     </a></li>

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

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

158)     <li><a href="#IDontHaveAStaticIP">Can I run a Tor relay using a dynamic IP
159)     address?</a></li>

160)     <li><a href="#IPv6Relay">Can I use IPv6 on my relay?</a></li>

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

189)     <li><a href="#OfflineED25519">How do offline ed25519 identity keys work?
190)     What do I need to know?</a></li>

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

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

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

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

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

198)     <li><a href="#OutgoingFirewall">How should I configure the outgoing filters
199)     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)     <a id="onion-services"></a>

211)     <h4 style="margin-bottom: 18px"><a class="anchor" href="#onion-services">
212)     Tor onion services:</a></h4>

213) 

214)     <ul>

215)     <li><a href="#AccessOnionServices">How do I access onion services?</a></li>

216)     <li><a href="#ProvideAnOnionService">How do I provide an onion service?
217)     </a></li>

218)     </ul>

219) 

220)     <a id="dev"></a>

221)     <h4 style="margin-bottom: 18px"><a class="anchor" href="#dev">Development:
222)     </a></h4>

223) 

224)     <ul>

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

226)     mean?</a></li>
227)     <li><a href="#PrivateTorNetwork">How do I set up my own private
228)     Tor network?</a></li>

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

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

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

233)     into Tor?</a></li>
234)     </ul>
235) 

236)     <a id="anonsec"></a>

237)     <h4 style="margin-bottom: 18px"><a class="anchor" href="#anonsec">Anonymity
238)     and Security:</a></h4>

239)     <ul>

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

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

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

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

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

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

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

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

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

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

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

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

252)     connections?</a></li>
253)     <li><a href="#PowerfulBlockers">What about powerful blocking mechanisms
254)     </a></li>

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

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

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

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

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

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

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

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

264)     </ul>

265) 

266)     <a id="altdesigns"></a>

267)     <h4 style="margin-bottom: 18px"><a class="anchor" href="#altdesigns">
268)     Alternate designs that we don't do (yet):</a></h4>

269) 

270)     <ul>
271)     <li><a href="#EverybodyARelay">You should make every Tor user be a
272)     relay.</a></li>

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

295)     </ul>

296) 

297)     <a id="abuse"></a>

298)     <h4 style="margin-bottom: 18px"><a class="anchor" href="#abuse">Abuse:
299)     </a></h4>

300)     <ul>

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

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

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

307)     </ul>

308) 

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

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

312) 

313)     <hr>

314) 

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

316)     <h2><a class="anchor" href="#General">General:</a></h2>

317) 

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

320) 

321)     <p>
322)     The name "Tor" can refer to several different components.
323)     </p>

324) 

325)     <p>

326)     Tor is a program you can run on your computer that helps keep
327)     you safe on the Internet. It protects you by bouncing your communications

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

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

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

331)     from learning your physical location.
332)     This set of volunteer relays is called the <b>Tor network</b>.
333)     The way most people use Tor is with <b>Tor Browser</b>,
334)     which is a version of Firefox that fixes many privacy issues.
335)     You can read more about how Tor works on the <a href="<page
336)     about/overview>">overview page</a>.

337)     </p>

338) 

339)     <p>

340)     The <b>Tor Project</b> is a non-profit (charity) organization that
341)     maintains and develops the Tor software.

342)     </p>

343) 

344)     <hr>

345) 

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

347)     <h3><a class="anchor" href="#Torisdifferent">How is Tor different from other
348)     proxies?</a></h3>
349)     <p>
350)     A typical proxy provider sets up a server somewhere on the Internet and
351)     allows you to use it to relay your traffic. This creates a simple, easy to
352)     maintain architecture. The users all enter and leave through the same server.
353)     The provider may charge for use of the proxy, or fund their costs through
354)     advertisements on the server.  In the simplest configuration, you don't have
355)     to install anything.  You just have to point your browser at their proxy
356)     server.
357)     Simple proxy providers are fine solutions if you do not want protections for
358)     your privacy and anonymity online and you trust the provider to not do bad
359)     things.  Some simple proxy providers use SSL to secure your connection
360)     to them, which protects you against local eavesdroppers, such as those at a
361)     cafe with free wifi Internet.
362)     </p>
363)     <p>
364)     Simple proxy providers also create a single point of failure. The provider
365)     knows both who you are and what you browse on the Internet. They can see
366)     your traffic as it passes through their server.  In some cases, they can
367)     even see inside your encrypted traffic as they relay it to your banking
368)     site or to ecommerce stores.
369)     You have to trust the provider isn't watching your traffic, injecting their
370)     own advertisements into your traffic stream, or recording your personal
371)     details.
372)     </p>
373)     <p>
374)     Tor passes your traffic through at least 3 different servers before sending
375)     it on to the destination. Because there's a separate layer of encryption for
376)     each of the three relays, somebody watching your Internet connection can't
377)     modify, or read, what you are sending into the Tor network. Your traffic is
378)     encrypted between the Tor client (on your computer) and where it pops out
379)     somewhere else in the world.
380)     </p>

381)     <p>
382)     <dl>

383)     <dt>Doesn't the first server see who I am?</dt>
384)     <dd>Possibly. A bad first of three servers can see encrypted Tor traffic
385)     coming from your computer. It still doesn't know who you are and what you
386)     are doing over Tor.  It merely sees "This IP address is using Tor".  Tor is
387)     not illegal anywhere in the world, so using Tor by itself is fine.  You are
388)     still protected from this node figuring out both who you are and where you
389)     are going on the Internet.
390)     </dd>
391)     <dt>Can't the third server see my traffic?</dt>
392)     <dd>Possibly.  A bad third of three servers can see the traffic you sent
393)     into Tor.  It won't know who sent this traffic.  If you're using encryption
394)     (like HTTPS), it will only know the destination. See
395)     <a href="https://www.eff.org/pages/tor-and-https">this visualization of Tor
396)     and HTTPS</a> to understand how Tor and HTTPS interact.
397)     </dd>

398)     </dl>
399)     </p>

400) 

401)     <hr>

402) 

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

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

406) 

407)     <p>

408)     Most people use Tor Browser,

409)     which includes everything you need to browse the web safely using

410)     Tor. Using other browsers is <a href="#TBBOtherBrowser">dangerous
411)     and not recommended</a>.

412)     </p>
413)     <p>
414)     There are plenty of other programs you can use with Tor,
415)     but we haven't researched the application-level anonymity

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

417)     configuration. Our wiki has a community-maintained list of
418)     instructions for <a

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

420)     specific applications</a>.

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

423) 

424)     <hr>

425) 

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

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

428) 

429)     <p>
430)     Because Tor is the onion routing network. When we were starting the
431)     new next-generation design and implementation of onion routing in
432)     2001-2002, we would tell people we were working on onion routing,
433)     and they would say "Neat. Which one?" Even if onion routing has
434)     become a standard household term, Tor was born out of the actual <a
435)     href="http://www.onion-router.net/">onion routing project</a> run by
436)     the Naval Research Lab.
437)     </p>

438) 

439)     <p>
440)     (It's also got a fine translation from German and Turkish.)
441)     </p>

442) 

443)     <p>

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

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

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

448)     spell it wrong.
449)     </p>

450) 

451)     <hr>

452) 

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

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

455) 

456)     <p>

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

461)     </p>

462) 

463)     <p>

464)     We will
465)     <a href="https://media.ccc.de/v/31c3_-_6251_-_en_-_saal_1_-_201412301400_-_state_of_the_onion_-_jacob_-_arma">
466)     never</a> put a backdoor in Tor.
467)     We think that putting a backdoor in Tor would be tremendously irresponsible
468)     to our users, and a bad precedent for security software in general. If we
469)     ever put a deliberate backdoor in our security software, it would ruin our
470)     professional reputations.
471)     Nobody would trust our software ever again &mdash; for excellent reason!

472)     </p>

473) 

474)     <p>

475)     But that said, there are still plenty of subtle attacks people might try.
476)     Somebody might impersonate us, or break into our computers, or something
477)     like that. Tor is open source, and you should always check the source (or
478)     at least the diffs since the last release) for suspicious things. If we (or
479)     the distributors) don't give you source, that's a sure sign something funny
480)     might be going on. You should also check the
481)     <a href="<page docs/verifying-signatures>">PGP signatures</a> on the
482)     releases, to make sure nobody messed with the distribution sites.

483)     </p>

484) 

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

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

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

489)     </p>

490) 

491)     <hr>

492) 

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

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

495) 

496)     <p>
497)     Yes.
498)     </p>

499) 

500)     <p>

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

504)     ask us for specific permission.
505)     </p>

506) 

507)     <p>

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

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

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

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

513) 

514)     <p>

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

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

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

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

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

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

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

526)     </p>

527) 

528)     <p>

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

532)     </p>

533) 

534)     <hr>

535) 

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

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

538) 

539)     <p>See the <a href="<page about/contact>#support">Support section
540)     on the contact page</a>.

541) 

542)     <hr>

543) 

544)     <a id="Forum"></a>
545)     <h3><a class="anchor" href="#Forum">Is there a Tor forum?</a></h3>
546) 

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

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

549)     </p>
550) 
551)     <hr>
552) 

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

555) 

556)     <p>
557)     There are many reasons why the Tor network is currently slow.
558)     </p>

559) 

560)     <p>

561)     Before we answer, though, you should realize that Tor is never going to
562)     be blazing fast. Your traffic is bouncing through volunteers' computers
563)     in various parts of the world, and some bottlenecks and network 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 network
570)     is quite small compared to the number of people trying to use it, and
571)     many of these users don't understand or care that Tor can't currently

572)     handle file-sharing traffic load.
573)     </p>

574) 

575)     <p>

576)     For the much more in-depth answer, see
577)     <a href="<blog>why-tor-is-slow">Roger's blog post on the topic</a>,
578)     which includes both a detailed PDF and a video to go with it.

579)     </p>

580) 

581)     <p>
582)     What can you do to help?
583)     </p>

584) 

585)     <ul>

586) 

587)     <li>

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

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

592) 

593)     <li>

594)     Help us make Tor more usable. We

595)     especially need people to help make it easier to configure your Tor
596)     as a relay. Also, we need help with clear simple documentation to
597)     walk people through setting it up.
598)     </li>

599) 

600)     <li>

601)     There are some bottlenecks in the current Tor network. Help us design
602)     experiments to track down and demonstrate where the problems are, and

603)     then we can focus better on fixing them.
604)     </li>

605) 

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

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

610)     get to spend more time on it.
611)     </li>

612) 

613)     <li>

614)     Help do other things so we can do the hard stuff. Please take a moment
615)     to figure out what your skills and interests are, and then
616)     <a href="<page getinvolved/volunteer>">look at our volunteer page</a>.

617)     </li>

618) 

619)     <li>

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

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

622)     competition's websites discreetly, or to connect back to the home servers
623)     when on the road without revealing affiliations? If your organization has
624)     an interest in keeping the Tor network working, please contact them about
625)     supporting Tor. Without sponsors, Tor is going to become even slower.

626)     </li>

627) 

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

630)     individually by <a href="<page donate/donate>">donating a bit of money to
631)     the cause</a>. It adds up!

632)     </li>

633) 

634)     </ul>

635) 

636)     <hr>

637) 

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

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

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

641) 
642)     <p>

643)     File sharing (peer-to-peer/P2P) is widely unwanted in the Tor network,
644)     and exit nodes are configured to block file sharing traffic by default.
645)     Tor is not really designed for it, and file sharing through Tor slows

646)     down everyone's browsing. Also, Bittorrent over Tor
647)     <a href="https://blog.torproject.org/blog/bittorrent-over-tor-isnt-good-idea">

648)     is not anonymous</a>!

649)     </p>
650) 
651)     <hr>
652) 

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

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

656) 

657)     <p>

658)     The Tor network's
659)     <a href="https://metrics.torproject.org/networksize.html">several thousand
660)     </a> relays push <a href="https://metrics.torproject.org/bandwidth.html">
661)     around 100 Gbps on average</a>. We have
662)     <a href="https://metrics.torproject.org/userstats-relay-country.html">
663)     millions of daily users</a>. But the Tor network is not yet self-sustaining.

664)     </p>

665) 

666)     <p>

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

668)     </p>

669) 

670)     <ul>

671) 

672)     <li>

673)     Scalability: We need to keep scaling and decentralizing the Tor architecture
674)     so it can handle thousands of relays and millions of users. The upcoming
675)     stable release is a major improvement, but there's lots more to be done next
676)     in terms of keeping Tor fast and stable.

677)     </li>

678) 

679)     <li>

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

683)     </li>

684) 

685)     <li>

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

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

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

691)     Tor relays have problems on Win XP currently.

692)     </li>

693) 

694)     <li>

695)     Usability: Beyond documentation, we also need to work on usability of the
696)     software itself. This includes installers, clean GUIs, easy configuration
697)     to interface with other applications, and generally automating all of

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

700)     </li>

701) 

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

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

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

708) 

709)     <li>

710)     Research: The anonymous communications field is full of surprises and
711)     gotchas. In our copious free time, we also help run top anonymity and
712)     privacy conferences like <a href="http://petsymposium.org/">PETS</a>.
713)     We've identified a set of critical
714)     <a href="<page getinvolved/volunteer>#Research">Tor research questions</a>
715)     that will help us figure out how to make Tor secure against the variety of
716)     attacks out there. Of course, there are more research questions waiting

717)     behind these.
718)     </li>

719) 

720)     </ul>

721) 

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

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

725)     can keep up</a>.

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

727)     so we can continue to grow the network.
728)     </p>

729) 

730)     <p>
731)     We are also excited about tackling related problems, such as
732)     censorship-resistance.
733)     </p>

734) 

735)     <p>

736)     We are proud to have
737)     <a href="<page about/sponsors>">sponsorship and support</a> from the Omidyar
738)     Network, the International Broadcasting Bureau, Bell Security Solutions,
739)     the Electronic Frontier Foundation, several government agencies and research
740)     groups, and hundreds of private contributors.

741)     </p>

742) 

743)     <p>

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

747)     director for information on making grants or major donations.
748)     </p>

749) 

750)     <hr>
751) 
752) 
753)     <a id="Mobile"></a>

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

755)     device?</a></h3>
756) 
757)     <p>

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

761)     working to make this a reality in the future.
762)     </p>
763) 

764)     <hr>
765) 

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

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

769)     <p>

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

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

775)     </p>
776)     <p>

777)     When using Tor as a client, you could probably get away with opening only
778)     those four ports. Since Tor does all its connections in the background, it
779)     will retry ones that fail, and hopefully you'll never have to know that it
780)     failed, as long as it finds a working one often enough. However, to get the
781)     most diversity in your entry nodes — and thus the most security

782)     — as well as the most robustness in your connectivity, you'll
783)     want to let it connect to all of them.
784)     See the FAQ entry on <a href="#FirewallPorts">firewalled ports</a> if
785)     you want to explicitly tell your Tor client which ports are reachable
786)     for you.
787)     </p>

788) 

789)     <hr>

790) 

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

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

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

794) 
795)     <p>

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

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

800)     </p>

801) 

802)     <hr>

803) 

804)     <a id="FTP"></a>
805)     <h3><a class="anchor" href="#FTP">How do I use my browser for ftp with Tor?
806)     </a></h3>
807) 

808)     <p>

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

811)     ftp client, we've heard good things about  FileZilla for Windows. You can
812)     configure it to point to Tor as a "socks4a" proxy on "localhost" port
813)     "9050".

814)     </p>

815) 

816)     <hr>

817) 

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

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

820)     information from the data my application sends?</a></h3>
821) 

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

824)     it sends. Tor Browser tries to keep application-level data,
825)     like the user-agent string, uniform for all users. Tor Browser can't

826)     do anything about text that you type into forms, though. <a

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

828)     careful and be smart.</a>
829)     </p>
830) 
831)     <hr>
832) 

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

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

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

836) 

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

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

840)     <hr>

841) 

842)     <a id="CompilationAndInstallation"></a>

843)     <h2><a class="anchor" href="#CompilationAndInstallation">Compilation And
844)     Installation:</a></h2>

845) 

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

847)     <h3><a class="anchor" href="#HowUninstallTor">How do I uninstall Tor?
848)     </a></h3>

849) 
850)     <p>

851)     Tor Browser does not install itself in the classic sense of applications.
852)     You just simply delete the folder or directory named "Tor Browser" and it
853)     is removed from your system.

854)     </p>

855) 

856)     <p>

857)     If this is not related to Tor Browser, uninstallation depends entirely on
858)     how you installed it and which operating system you have. If you installed
859)     a package, then hopefully your package has a way to uninstall itself.
860)     The Windows packages include uninstallers.

861)     </p>

862) 

863)     <p>

864)     For Mac OS X, follow the
865)     <a href="<page docs/tor-doc-osx>#uninstall">uninstall directions</a>.

866)     </p>

867) 

868)     <p>

869)     If you installed by source, I'm afraid there is no easy uninstall method.
870)     But on the bright side, by default it only installs into /usr/local/ and it
871)     should be pretty easy to notice things there.

872)     </p>

873) 

874)     <hr>

875) 

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

877)     <h3><a class="anchor" href="#PGPSigs">What are these "sig" files on the
878)     download page?</a></h3>
879) 
880)     <p>
881)     These are PGP signatures, so you can verify that the file you've downloaded
882)     is exactly the one that we intended you to get.
883)     </p>
884) 
885)     <p>
886)     Please read the
887)     <a href="<page docs/verifying-signatures>">verifying signatures</a>
888)     page for details.
889)     </p>
890) 
891)     <hr>
892) 
893)     <a id="GetTor"></a>
894)     <h3><a class="anchor" href="#GetTor">Your website is blocked in my country.
895)     How do I download Tor?</a></h3>
896) 
897)     <p>
898)     Some government or corporate firewalls censor connections to Tor's website.
899)     In those cases, you have three options. First, get it from a friend &mdash;
900)     <a href="<page projects/torbrowser>">Tor Browser</a> fits nicely on a USB
901)     key. Second, find the
902)     <a href="https://encrypted.google.com/search?q=tor+mirrors">google cache</a>
903)     for the <a href="<page getinvolved/mirrors>">Tor mirrors</a> page and see if
904)     any of those copies of our website work for you. Third, you can download Tor
905)     Browser via email: log in to your email account and send an email to
906)     '<tt>gettor@torproject.org</tt>' with one of the following words in the
907)     body of the message: <tt>windows</tt>, <tt>osx</tt> or <tt>linux</tt>
908)     (case insensitive).
909)     You will receive a reply with links from popular cloud services to download
910)     Tor Browser for Windows, Mac OS X or Linux, depending on the option you
911)     chose. Currently, the only cloud service supported is Dropbox. If you send
912)     a blank message or anything different from the options mentioned, you will
913)     receive a help message with detailed instructions to ask for Tor Browser
914)     via email. Please note that you can use this service from any email address:
915)     gmail, yahoo, hotmail, riseup, etc. The only restriction is that you can do
916)     a maximum of three requests in a row, after that you'll have to wait 20
917)     minutes to use it again. See the
918)     <a href="../projects/gettor.html">GetTor</a> section for more information.
919)     </p>
920) 
921)     <p>
922)     Be sure to <a href="<page docs/verifying-signatures>">verify the
923)     signature</a> of any package you download, especially when you get it from
924)     somewhere other than our official HTTPS website.
925)     </p>

926) 

927)     <hr>

928) 

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

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

932)     <p>

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

938)     pick a better vendor.
939)     </p>

940) 

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

943)     recompile it yourself.</p>
944) 
945)     <hr>
946) 

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

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

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

950) 
951)     <p>
952)     Tar is a common archive utility for Unix and Linux systems. If your

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

955) 
956)     <pre>tar xzf &lt;FILENAME&gt;.tar.gz</pre>
957)     or
958)     <pre>tar xJf &lt;FILENAME&gt;.tar.xz</pre>
959) 

960)     <p>

961)     as documented on tar's man page.

962)     </p>
963) 
964)     <hr>
965) 

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

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

969) 

970)     <p>

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

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

973)     </p>

974) 

975)     <hr>
976) 
977)     <a id="TBBGeneral"></a>
978)     <h2><a class="anchor" href="#TBBGeneral">Tor Browser (general):</a></h2>
979) 
980)     <a id="TBBFlash"></a>
981)     <h3><a class="anchor" href="#TBBFlash">Why can't I view videos on some
982)     Flash-based sites?</a></h3>
983) 
984)     <p>
985)     Some sites require third party browser plugins such as Flash.
986)     Plugins operate independently from Firefox and can perform activity on your
987)     computer that ruins your anonymity. This includes but is not limited to:
988)     completely disregarding proxy settings, querying your
989)     <a href="http://forums.sun.com/thread.jspa?threadID=5162138&amp;messageID=9618376">
990)     local IP address</a>, and
991)     <a href="http://epic.org/privacy/cookies/flash.html">storing their
992)     owncookies</a>. It is possible to use a LiveCD solution such as or
993)     <a href="https://tails.boum.org/">The Amnesic Incognito Live System</a>
994)     that creates a secure, transparent proxy to protect you from proxy bypass,
995)     however issues with local IP address discovery and Flash cookies still remain.
996)     </p>
997) 
998)     <hr>
999) 
1000)     <a id="Ubuntu"></a>
1001)     <h3><a class="anchor" href="#Ubuntu">I'm using Ubuntu and I can't start Tor
1002)     Browser.</a></h3>
1003)     <p>
1004)     You'll need to tell Ubuntu that you want the ability to execute shell
1005)     scripts from the graphical interface. Open "Files" (Unity's explorer), open
1006)     Preferences-> Behavior Tab -> Set "Run executable text files when they are
1007)     opened" to "Ask every time", then OK.
1008)     </p>
1009) 
1010)     <p>You can also start Tor Browser from the command line by running </p>
1011) 
1012)     <pre>./start-tor-browser</pre>
1013) 
1014)     <p>
1015)     from inside the Tor Browser directory.
1016)     </p>
1017) 
1018)     <hr>
1019) 
1020)     <a id="SophosOnMac"></a>
1021)     <h3><a class="anchor" href="#SophosOnMac">I'm using the Sophos anti-virus

1022)     software on my Mac, and Tor starts but I can't browse anywhere.</a></h3>

1023) 
1024)     <p>
1025)     You'll need to modify Sophos anti-virus so that Tor can connect to the
1026)     internet. Go to Preferences -> Web Protection -> General, and turn off
1027)     the protections for "Malicious websites" and "Malicious downloads".
1028)     </p>
1029) 
1030)     <p>
1031)     We encourage affected Sophos users to contact Sophos support about
1032)     this issue.
1033)     </p>
1034) 
1035)     <hr>
1036) 
1037)     <a id="XPCOMError"></a>
1038)     <h3><a class="anchor" href="#XPCOMError">When I start Tor Browser I get an
1039)     error message: "Cannot load XPCOM".</a></h3>
1040) 
1041)     <p>
1042)     This <a href="https://trac.torproject.org/projects/tor/ticket/10789">
1043)     problem</a> is specifically caused by the Webroot SecureAnywhere Antivirus
1044)     software.
1045)     From the Webroot control panel, go to Identity Protection &rarr; Application
1046)     Protection, and set all the files in your Tor Browser folder to 'Allow'.
1047)     We encourage affected Webroot users to contact Webroot support about this
1048)     issue.
1049)     </p>
1050) 
1051)     <hr>
1052) 
1053)     <a id="TBBOtherExtensions"></a>
1054)     <h3><a class="anchor" href="#TBBOtherExtensions">Can I install other
1055)     Firefox extensions?</a></h3>
1056) 
1057)     <p>
1058)     Tor Browser is free software, so there is nothing preventing you from
1059)     modifying it any way you like. However, we do not recommend installing any
1060)     additional Firefox add-ons with Tor Browser. Add-ons can break
1061)     your anonymity in a number of ways, including browser fingerprinting and
1062)     bypassing proxy settings.
1063)     </p>
1064) 
1065)     <p>
1066)     Some people have suggested we include ad-blocking software or anti-tracking
1067)     software with Tor Browser. Right now, we do not think that's such a good
1068)     idea. Tor Browser aims to provide sufficient privacy that additional add-ons
1069)     to stop ads and trackers are not necessary. Using add-ons like these may
1070)     cause some sites to break, which

1071)     <a href="/projects/torbrowser/design/#philosophy">

1072)     we don't want to do</a>. Additionally, maintaining a list of "bad" sites
1073)     that should be black-listed provides another opportunity to uniquely
1074)     fingerprint users.
1075)     </p>
1076) 
1077)     <hr>
1078) 
1079)     <a id="TBBJavaScriptEnabled"></a>
1080)     <a id="TBBCanIBlockJS"></a>
1081)     <h3><a class="anchor" href="#TBBJavaScriptEnabled">Why is NoScript
1082)     configured to allow JavaScript by default in Tor Browser?
1083)     Isn't that unsafe?</a></h3>
1084) 
1085)     <p>
1086)     We configure NoScript to allow JavaScript by default in Tor Browser because
1087)     many websites will not work with JavaScript disabled. Most users would give
1088)     up on Tor entirely if a website they want to use requires JavaScript,
1089)     because they would not know how to allow a website to use JavaScript
1090)     (or that enabling JavaScript might make a website work).
1091)     </p>
1092) 
1093)     <p>
1094)     There's a tradeoff here. On the one hand, we should leave JavaScript
1095)     enabled by default so websites work the way users expect. On the other hand,
1096)     we should disable JavaScript by default to better protect against browser
1097)     vulnerabilities (
1098)     <a href="https://blog.torproject.org/blog/tor-security-advisory-old-tor-browser-bundles-vulnerable">
1099)     not just a theoretical concern!</a>). But there's a third issue: websites
1100)     can easily determine whether you have allowed JavaScript for them, and if
1101)     you disable JavaScript by default but then allow a few websites to run
1102)     scripts (the way most people use NoScript), then your choice of whitelisted
1103)     websites acts as a sort of cookie that makes you recognizable (and
1104)     distinguishable), thus harming your anonymity.
1105)     </p>
1106) 
1107)     <p>
1108)     Ultimately, we want the default Tor bundles to use a combination of
1109)     firewalls (like the iptables rules in
1110)     <a href="https://tails.boum.org/">Tails</a>) and
1111)     <a href="https://trac.torproject.org/projects/tor/ticket/7680">sandboxes</a>
1112)     to make JavaScript not so scary. In the shorter term, TBB 3.0 will hopefully
1113)     <a href="https://trac.torproject.org/projects/tor/ticket/9387">allow users
1114)     to choose their JavaScript settings more easily</a> &mdash; but the
1115)     partitioning concern will remain.
1116)     </p>
1117) 
1118)     <p>
1119)     Until we get there, feel free to leave JavaScript on or off depending
1120)     on your security, anonymity, and usability priorities.
1121)     </p>
1122) 
1123)     <hr>
1124) 
1125)     <a id="TBBOtherBrowser"></a>
1126)     <h3><a class="anchor" href="#TBBOtherBrowser">I want to use
1127)     Chrome/IE/Opera/etc with Tor.</a></h3>
1128) 
1129)     <p>
1130)     In short, using any browser besides Tor Browser with Tor is a really bad idea.
1131)     </p>
1132) 
1133)     <p>
1134)     Our efforts to work with the Chrome team to
1135)     <a href="https://blog.torproject.org/blog/google-chrome-incognito-mode-tor-and-fingerprinting">
1136)     add missing APIs</a> were unsuccessful, unfortunately. Currently, it is
1137)     impossible to use other browsers and get the same level of protections as
1138)     when using Tor Browser.
1139)     </p>
1140) 
1141)     <hr>
1142) 
1143)     <a id="GoogleCAPTCHA"></a>
1144)     <h3><a class="anchor" href="#GoogleCAPTCHA">Google makes me solve a CAPTCHA
1145)     or tells me I have spyware installed.</a></h3>
1146) 
1147)     <p>
1148)     This is a known and intermittent problem; it does not mean that Google
1149)     considers Tor to be spyware.
1150)     </p>
1151) 
1152)     <p>
1153)     When you use Tor, you are sending queries through exit relays that are
1154)     also shared by thousands of other users. Tor users typically see this
1155)     message when many Tor users are querying Google in a short period of time.
1156)     Google interprets the high volume of traffic from a single IP address
1157)     (the exit relay you happened to pick) as somebody trying to "crawl" their
1158)     website, so it slows down traffic from that IP address for a short time.
1159)     </p>
1160) 
1161)     <p>
1162)     An alternate explanation is that Google tries to detect certain kinds of
1163)     spyware or viruses that send distinctive queries to Google Search. It notes
1164)     the IP addresses from which those queries are received (not realizing that
1165)     they are Tor exit relays), and tries to warn any connections coming from
1166)     those IP addresses that recent queries indicate an infection.
1167)     </p>
1168) 
1169)     <p>
1170)     To our knowledge, Google is not doing anything intentionally specifically
1171)     to deter or block Tor use. The error message about an infected machine
1172)     should clear up again after a short time.
1173)     </p>
1174) 
1175)     <hr />
1176) 
1177)     <a id="ForeignLanguages"></a>
1178)     <h3><a class="anchor" href="#ForeignLanguages">
1179)     Why does Google show up in foreign languages?</a></h3>
1180) 
1181)     <p>
1182)     Google uses "geolocation" to determine where in the world you are, so it
1183)     can give you a personalized experience. This includes using the language
1184)     it thinks you prefer, and it also includes giving you different results
1185)     on your queries.
1186)     </p>
1187) 
1188)     <p>
1189)     If you really want to see Google in English you can click the link that
1190)     provides that. But we consider this a feature with Tor, not a bug --- the
1191)     Internet is not flat, and it in fact does look different depending on
1192)     where you are. This feature reminds people of this fact.
1193)     </p>
1194) 
1195)     <p>
1196)     Note that Google search URLs take name/value pairs as arguments and one
1197)     of those names is "hl". If you set "hl" to "en" then Google will return
1198)     search results in English regardless of what Google server you have been
1199)     sent to. On a query this looks like:
1200)     </p>
1201) 
1202)     <pre>https://encrypted.google.com/search?q=online%20anonymity&hl=en</pre>
1203) 
1204)     <p>
1205)     Another method is to simply use your country code for accessing Google.
1206)     This can be google.be, google.de, google.us and so on.
1207)     </p>
1208) 
1209)     <hr />
1210) 
1211)     <a id="GmailWarning"></a>
1212)     <h3><a class="anchor" href="#GmailWarning">Gmail warns me that my account
1213)     may have been compromised.</a></h3>
1214) 
1215)     <p>
1216)     Sometimes, after you've used Gmail over Tor, Google presents a pop-up
1217)     notification that your account may have been compromised.
1218)     The notification window lists a series of IP addresses and locations
1219)     throughout the world recently used to access your account.
1220)     </p>
1221) 
1222)     <p>
1223)     In general this is a false alarm: Google saw a bunch of logins from
1224)     different places, as a result of running the service via Tor, and decided
1225)     it was a good idea to confirm the account was being accessed by it's
1226)     rightful owner.
1227)     </p>
1228) 
1229)     <p>
1230)     Even though this may be a biproduct of using the service via tor, that
1231)     doesn't mean you can entirely ignore the warning. It is <i>probably</i> a
1232)     false positive, but it might not be since it is possible for someone to
1233)     hijack your Google cookie.
1234)     </p>
1235) 
1236)     <p>
1237)     Cookie hijacking is possible by either physical access to your computer or
1238)     by watching your network traffic.  In theory only physical access should
1239)     compromise your system because Gmail and similar services should only send
1240)     the cookie over an SSL link. In practice, alas, it's
1241)     <a href="http://fscked.org/blog/fully-automated-active-https-cookie-hijacking">
1242)     way more complex than that</a>.
1243)     </p>
1244) 
1245)     <p>
1246)     And if somebody <i>did</i> steal your google cookie, they might end up
1247)     logging in from unusual places (though of course they also might not). So
1248)     the summary is that since you're using Tor, this security measure that
1249)     Google uses isn't so useful for you, because it's full of false positives.
1250)     You'll have to use other approaches, like seeing if anything looks weird on
1251)     the account, or looking at the timestamps for recent logins and wondering
1252)     if you actually logged in at those times.
1253)     </p>
1254) 
1255)     <hr>
1256) 
1257)     <a id="NeedToUseAProxy"></a>
1258)     <h3><a class="anchor" href="#NeedToUseAProxy">My internet connection
1259)     requires an HTTP or SOCKS Proxy</a></h3>
1260) 
1261)     <p>
1262)     You can set Proxy IP address, port, and authentication information in
1263)     Tor Browser's Network Settings. If you're using Tor another way, check out
1264)     the HTTPProxy and HTTPSProxy config options in the
1265)     <a href="<page docs/tor-manual>">man page</a>, and modify your torrc file
1266)     accordingly. You will need an HTTP proxy for doing GET requests to fetch
1267)     the Tor directory, and you will need an HTTPS proxy for doing CONNECT
1268)     requests to get to Tor relays. (It's fine if they're the same proxy.)
1269)     Tor also recognizes the torrc options Socks4Proxy and Socks5Proxy.
1270)     </p>
1271) 
1272)     <p>
1273)     Also read up on the HTTPProxyAuthenticator and HTTPSProxyAuthenticator
1274)     options if your proxy requires auth. We only support basic auth currently,
1275)     but if you need NTLM authentication, you may find
1276)     <a href="http://archives.seul.org/or/talk/Jun-2005/msg00223.html">this post
1277)     in the archives</a> useful.
1278)     </p>
1279) 
1280)     <p>
1281)     If your proxies only allow you to connect to certain ports, look at the
1282)     entry on <a href="#FirewallPorts">Firewalled clients</a> for how
1283)     to restrict what ports your Tor will try to access.
1284)     </p>
1285) 
1286)     <hr>
1287) 
1288)     <a id="TBBSocksPort"></a>
1289)     <h3><a class="anchor" href="#TBBSocksPort">I want to run another
1290)     application through Tor.</a></h3>
1291) 
1292)     <p>
1293)     If you are trying to use some external application with Tor, step zero
1294)     should be to <a href="<page download/download>#warning">reread the set
1295)     of warnings</a> for ways you can screw up. Step one should be to try
1296)     to use a SOCKS proxy rather than an HTTP proxy.
1297)     Typically Tor listens for SOCKS connections on port 9050. Tor Browser
1298)     listens on port 9150.
1299)     </p>
1300) 
1301)     <p>
1302)     If your application doesn't support SOCKS proxies, feel free to install
1303)     <a href="http://www.privoxy.org/">privoxy</a>.
1304)     However, please realize that this approach is not recommended for novice
1305)     users. Privoxy has an
1306)     <a href="http://www.privoxy.org/faq/misc.html#TOR">
1307)     example configuration</a> of Tor and Privoxy.
1308)     </p>
1309) 
1310)     <p>
1311)     If you're unable to use the application's native proxy settings, all hope is
1312)     not lost. See <a href="#CantSetProxy">below</a>.
1313)     </p>
1314) 
1315)     <hr>
1316) 
1317)     <a id="CantSetProxy"></a>
1318)     <h3><a class="anchor" href="#CantSetProxy">What should I do if I can't
1319)     set a proxy with my application?</a></h3>
1320) 
1321)     <p>
1322)     On Unix, we recommend you give
1323)     <a href="https://github.com/dgoulet/torsocks/">torsocks</a> a try.
1324)     Alternative proxifying tools like
1325)     <a href="http://www.dest-unreach.org/socat/">socat</a> and
1326)     <a href="http://proxychains.sourceforge.net/">proxychains</a> are also
1327)     available.</p>
1328) 
1329)     <p>
1330)     The Windows way to force applications through Tor is less clear.
1331)     <a href="http://freecap.ru/eng/">Some</a>
1332)     <a href="http://www.freehaven.net/~aphex/torcap/">tools</a> have been
1333)     <a href="http://www.crowdstrike.com/community-tools/index.html#tool-79">
1334)     proposed</a>, but we'd also like to see further testing done here.
1335)     </p>
1336) 
1337)     <hr>
1338) 
1339)     <a id="TBB3.x"></a>
1340)     <h2><a class="anchor" href="#TBB3.x">Tor Browser (3.x and later):</a></h2>

1341)     <a id="WhereDidVidaliaGo"></a>

1342)     <h3><a class="anchor" href="#WhereDidVidaliaGo">Where did the world map

1343)     (Vidalia) go?</a></h3>
1344) 

1345)     <p>Vidalia has been replaced with Tor Launcher, which is a Firefox

1346)     extension that provides similar functionality.</p>

1347) 
1348)     <hr>
1349) 
1350)     <a id="DisableJS"></a>
1351)     <h3><a class="anchor" href="#DisableJS">How do I disable JavaScript?</a>
1352)     </h3>
1353) 

1354)     <p>Alas, Mozilla decided to get rid of the config checkbox for JavaScript
1355)     from earlier Firefox versions. And since TBB 3.5 is based on Firefox 24
1356)     (FF17 is unmaintained), that means TBB 3.5 doesn't have the config

1357)     checkbox anymore either, which is unfortunate.</p>
1358) 

1359)     <p>The simplest way to disable JavaScript in TBB 3.5 is to click on the
1360)     Noscript "S" (between the green onion and the address bar), and select
1361)     "Forbid scripts globally". Note that vanilla NoScript actually whitelists
1362)     several domains even when you try to disable scripts globally, whereas

1363)     Tor Browser's NoScript configuration disables all of them. </p>
1364) 

1365)     <p>The more klunky way to disable JavaScript is to go to about:config,

1366)     find javascript.enabled, and set it to false.</p>
1367) 
1368)     <p>There is also a very simple addon available at addons.mozilla.org
1369)     called QuickJS, which provides a toolbar toggle for the javascript.enabled

1370)     about:config control. There are no configuration options for the addon,
1371)     it just switches the javascript.enabled entry between true and false and

1372)     provides a button for it. </p>
1373) 

1374)     <p>If you want to be extra safe, use both the about:config setting and

1375)     NoScript. </p>
1376) 

1377)     <p>As for whether you should disable it or leave it enabled, that's <a

1378)     href="#TBBJavaScriptEnabled">a tradeoff we leave to you</a>.</p>

1379) 
1380)     <hr>
1381) 
1382)     <a id="VerifyDownload"></a>
1383)     <h3><a class="anchor" href="#VerifyDownload">How do I verify the download
1384)     (sha256sums.txt)?</a></h3>
1385) 

1386)     <p>Instructions are on the <a
1387)     href="<page docs/verifying-signatures>#BuildVerification">verifying

1388)     signatures</a> page.</p>

1389) 
1390)     <hr>

1391) 

1392)     <a id="NewIdentityClosingTabs"></a>

1393)     <h3><a class="anchor" href="#NewIdentityClosingTabs">Why does "New

1394)     Identity" close all my open tabs?</a></h3>
1395) 
1396)     <p>

1397)     That's actually a feature, since it's discarding your application-level

1398)     browser data too.

1399)     </p>
1400) 
1401)     <p>

1402)     We're working on ways to make the behavior less surprising, e.g. a popup

1403)     warning or auto restoring tabs. See ticket
1404)     <a href="https://trac.torproject.org/projects/tor/ticket/9906">#9906</a>
1405)     and ticket
1406)     <a href="https://trac.torproject.org/projects/tor/ticket/10400">#10400</a>

1407)     to follow progress there.

1408)     </p>
1409) 
1410)     <hr>
1411) 
1412)     <a id="ConfigureRelayOrBridge"></a>

1413)     <h3><a class="anchor" href="#ConfigureRelayOrBridge">How do I configure Tor
1414)     as a relay or bridge?</a></h3>

1415) 
1416)     <p>

1417)     You've got three options.

1418)     </p>
1419) 
1420)     <p>

1421)     First (best option), if you're on Linux, you can install the
1422)     <a href="<page download/download-unix>">system Tor package</a>
1423)     (e.g. apt-get install tor) and then set it up to be a relay
1424)     (<a href="https://www.torproject.org/docs/tor-relay-debian">instructions</a>).
1425)     You can then use TBB independent of that.

1426)     </p>
1427) 
1428)     <p>

1429)     Second (complex option), you can edit your <a href="#torrc">torrc file</a>

1430)     directly to add the following lines:

1431)     </p>

1432) 

1433)     <pre>
1434)     ORPort 443
1435)     Exitpolicy reject *:*
1436)     BridgeRelay 1  # only add this line if you want to be a bridge
1437)     </pre>
1438) 
1439)     <hr>
1440) 
1441)     <a id="Timestamps"></a>

1442)     <h3><a class="anchor" href="#Timestamps">Why are the file timestamps

1443)     from 2000?</a></h3>
1444) 

1445)     <p>One of the huge new features in TBB 3.x is the "deterministic build"

1446)     process, which allows many people to build Tor Browser and verify that they
1447)     all make exactly the same package. See Mike's
1448)     <a href="https://blog.torproject.org/blog/deterministic-builds-part-one-cyberwar-and-global-compromise">
1449)     first blog</a> post for the motivation, and his
1450)     <a href="https://blog.torproject.org/blog/deterministic-builds-part-two-technical-details">
1451)     second blog post</a> for the technical details of how we do it.

1452)     </p>
1453) 

1454)     <p>Part of creating identical builds is having everybody use the same
1455)     timestamp. Mike picked the beginning of 2000 for that time. The reason

1456)     you might see 7pm in 1999 is because of time zones. </p>
1457) 
1458)     <hr>
1459) 

1460)     <a id="TBBSourceCode"></a>
1461)     <h3><a class="anchor" href="#TBBSourceCode">Where is the source code for
1462)     Tor Browser? How do I verify a build?</a></h3>
1463) 
1464)     <p>
1465)     Tor Browser is built from the
1466)     <a href="https://gitweb.torproject.org/builders/tor-browser-build.git/">
1467)     tor-browser-build.git git repository</a>. You can have a look at the
1468)     <a href="https://gitweb.torproject.org/builders/tor-browser-build.git/tree/README">
1469)     README file</a> for the build instructions.
1470)     There is also some informations in the
1471)     <a href="https://trac.torproject.org/projects/tor/wiki/doc/TorBrowser/Hacking">

1472)     Tor Browser Hacking Guide</a>. Also see our
1473)     <a href="<page docs/verifying-signatures>">fingerprint verification guide</a>.

1474)     </p>
1475) 
1476)     <hr>
1477) 
1478)     <a id="AdvancedTorUsage"></a>
1479)     <h2><a class="anchor" href="#AdvancedTorUsage">Advanced Tor usage:</a></h2>
1480) 

1481)     <a id="torrc"></a><a id="datadir"></a>

1482)     <h3><a class="anchor" href="#torrc">I'm supposed to "edit my torrc".

1483)     What does that mean? Where's tor's data directory?</a></h3>

1484) 
1485)     <p>
1486)     Tor uses a text file called torrc that contains configuration
1487)     instructions for how your Tor program should behave. The default
1488)     configuration should work fine for most Tor users.
1489)     </p>
1490) 
1491)     <p>

1492)     If you installed Tor Browser on Windows or Linux, torrc is in the data
1493)     directory, which is <code>Browser/TorBrowser/Data/Tor</code> inside your
1494)     Tor Browser directory. For the tor service on Windows see
1495)     <a href="#NTService">Windows NT</a>.
1496)     </p>
1497) 
1498)     <p>
1499)     If you're on macOS, the torrc is in the data directory at

1500)     <code>~/Library/Application Support/TorBrowser-Data/Tor</code>.
1501)     To get to it, press cmd-shift-g while in Finder and copy/paste that
1502)     directory into the box that appears.
1503)     </p>
1504) 
1505)     <p>

1506)     Otherwise, if you are using Tor without Tor Browser, it looks for torrc at
1507)     differentt possible locations:

1508)     </p>

1509)     <ul>
1510)     <li>
1511)     <code>/usr/local/etc/tor/torrc</code> if you compiled tor from source
1512)     </li>
1513)     <li>
1514)     <code>/etc/tor/torrc</code> or <code>/etc/torrc</code> if you installed a
1515)     pre-built package. The data directory usually is
1516)     <code>/var/lib/tor/</code>, if not defined otherwise with
1517)     <code>DataDirectory</code> in torrc.
1518)     </li>
1519)     <li><code>$HOME/.torrc</code>: fallback location if above file is not found.
1520)     </li>
1521)     <li>
1522)     You can define a different location for torrc with <code>-f FILE</code> and
1523)     set another data directory with <code>--DataDirectory DIR</code> as options
1524)     to tor.
1525)     </li>
1526)     </ul>

1527) 
1528)     <p>

1529)     Once you've created or changed your torrc file, you will need to restart or
1530)     reload tor for the changes to take effect. On Debian use
1531)     <code>system tor reload</code>. (For advanced users, note that you
1532)     actually only need to send Tor a HUP signal, not actually restart it.)

1533)     </p>
1534) 
1535)     <p>
1536)     For other configuration options you can use, see the
1537)     <a href="<page docs/tor-manual>">Tor manual page</a>. Have a look at
1538)     <a href="https://gitweb.torproject.org/tor.git/tree/src/config/torrc.sample.in">
1539)     the sample torrc file</a> for hints on common configurations. Remember, all
1540)     lines beginning with # in torrc are treated as comments and have no effect
1541)     on Tor's configuration.
1542)     </p>
1543) 
1544)     <hr>
1545) 
1546)     <a id="Logs"></a>
1547)     <h3><a class="anchor" href="#Logs">How do I set up logging, or see Tor's
1548)     logs?</a></h3>
1549) 
1550)     <p>
1551)     You'll have to go find the log files by
1552)     hand. Here are some likely places for your logs to be:
1553)     </p>
1554) 
1555)     <ul>
1556)       <li>On OS X, Debian, Red Hat, etc, the logs are in /var/log/tor/
1557)       </li>
1558)       <li>On Windows, there are no default log files currently. If you enable

1559)       logs in your <a href="#torrc">torrc</a> file, they default to <code>\username\Application

1560)       Data\tor\log\</code> or <code>\Application Data\tor\log\</code>
1561)       </li>
1562)       <li>If you compiled Tor from source, by default your Tor logs to
1563)       <a href="http://en.wikipedia.org/wiki/Standard_streams">"stdout"</a>
1564)       at log-level notice. If you enable logs in your torrc file, they
1565)       default to <code>/usr/local/var/log/tor/</code>.
1566)       </li>
1567)     </ul>
1568) 
1569)     <p>
1570)     To change your logging setup by hand, <a href="#torrc">edit your
1571)     torrc</a>
1572)     and find the section (near the top of the file) which contains the
1573)     following line:
1574)     </p>
1575) 
1576)     <pre>
1577)     \## Logs go to stdout at level "notice" unless redirected by something
1578)     \## else, like one of the below lines.
1579)     </pre>
1580) 
1581)     <p>
1582)     For example, if you want Tor to send complete debug, info, notice, warn,
1583)     and err level messages to a file, append the following line to the end
1584)     of the section:
1585)     </p>
1586) 
1587)     <pre>
1588)     Log debug file c:/program files/tor/debug.log
1589)     </pre>
1590) 
1591)     <p>
1592)     Replace <code>c:/program files/tor/debug.log</code> with a directory
1593)     and filename for your Tor log.
1594)     </p>
1595) 
1596)     <hr>
1597) 
1598)     <a id="LogLevel"></a>
1599)     <h3><a class="anchor" href="#LogLevel">What log level should I use?</a></h3>
1600) 
1601)     <p>
1602)     There are five log levels (also called "log severities") you might see in
1603)     Tor's logs:
1604)     </p>
1605) 
1606)     <ul>
1607) 
1608)     <li>"err": something bad just happened, and we can't recover. Tor will
1609)     exit.</li>
1610)     <li>"warn": something bad happened, but we're still running. The bad
1611)     thing might be a bug in the code, some other Tor process doing something
1612)     unexpected, etc. The operator should examine the message and try to
1613)     correct the problem.</li>
1614)     <li>"notice": something the operator will want to know about.</li>
1615)     <li>"info": something happened (maybe bad, maybe ok), but there's
1616)     nothing you need to (or can) do about it.</li>
1617)     <li>"debug": for everything louder than info. It is quite loud indeed.</li>
1618) 
1619)     </ul>
1620) 
1621)     <p>
1622)     Alas, some of the warn messages are hard for ordinary users to correct --
1623)     the developers are slowly making progress at making Tor automatically react
1624)     correctly for each situation.
1625)     </p>
1626) 
1627)     <p>
1628)     We recommend running at the default, which is "notice". You will hear about
1629)     important things, and you won't hear about unimportant things.
1630)     </p>
1631) 
1632)     <p>
1633)     Tor relays in particular should avoid logging at info or debug in normal
1634)     operation, since they might end up recording sensitive information in
1635)     their logs.
1636)     </p>
1637) 
1638)     <hr>
1639) 
1640)     <a id="DoesntWork"></a>
1641)     <h3><a class="anchor" href="#DoesntWork">I installed Tor but it's not
1642)     working.</a></h3>
1643) 
1644)     <p>
1645)     Once you've got Tor Browser up and running, the first question to ask is
1646)     whether your Tor client is able to establish a circuit.
1647)     </p>
1648) 
1649)     <p>If Tor can establish a circuit, Tor Browser will automatically launch
1650)     the browser for you. You can also check in the <a href="#Logs">Tor logs</a>
1651)     for a line saying that Tor "has successfully opened a circuit. Looks like
1652)     client functionality is working."
1653)     </p>
1654) 
1655)     <p>
1656)     If Tor can't establish a circuit, here are some hints:
1657)     </p>
1658) 
1659)     <ol>
1660) 
1661)     <li>Check your system clock. If it's more than a few hours off, Tor will
1662)     refuse to build circuits. For Microsoft Windows users, synchronize your
1663)     clock under the clock -&gt; Internet time tab. In addition, correct the
1664)     day and date under the 'Date &amp; Time' Tab. Also make sure your time
1665)     zone is correct.</li>
1666)     <li>Is your Internet connection <a href="#FirewallPorts">firewalled
1667)     by port</a>, or do you normally need to use a
1668)     <a href="<#NeedToUseAProxy">proxy</a>?
1669)     </li>
1670)     <li>Are you running programs like Norton Internet Security or SELinux that
1671)     block certain connections, even though you don't realize they do? They
1672)     could be preventing Tor from making network connections.</li>
1673)     <li>Are you in China, or behind a restrictive corporate network firewall
1674)     that blocks the public Tor relays? If so, you should learn about
1675)     <a href="<page docs/bridges>">Tor bridges</a>.</li>
1676)     <li>Check your <a href="#Logs">Tor logs</a>. Do they give you any hints
1677)     about what's going wrong?</li>
1678) 
1679)     </ol>
1680) 
1681)     <hr />
1682) 
1683)     <a id="TorCrash"></a>
1684)     <h3><a class="anchor" href="#TorCrash">My Tor keeps crashing.</a></h3>
1685)     <p>
1686)     We want to hear from you! There are supposed to be zero crash bugs in Tor.
1687)     This FAQ entry describes the best way for you to be helpful to us. But even
1688)     if you can't work out all the details, we still want to hear about it, so
1689)     we can help you track it down.
1690)     </p>
1691)     <p>
1692)     First, make sure you're using the latest version of Tor (either the latest
1693)     stable or the latest development version).
1694)     </p>
1695) 
1696)     <p>
1697)     Second, make sure your version of libevent is new enough. We recommend at
1698)     least libevent 1.3a.
1699)     </p>
1700) 
1701)     <p>
1702)     Third, see if there's already an entry for your bug in the
1703)     <a href="https://bugs.torproject.org/">Tor bugtracker</a>. If so, check if
1704)     there are any new details that you can add.
1705)     </p>
1706) 
1707)     <p>
1708)     Fourth, is the crash repeatable? Can you cause the crash? Can you isolate
1709)     some of the circumstances or config options that make it happen? How
1710)     quickly or often does the bug show up?
1711)     Can you check if it happens with other versions of Tor, for example the
1712)     latest stable release?
1713)     </p>
1714) 
1715)     <p>
1716)     Fifth, what sort of crash do you get?
1717)     </p>
1718) 
1719)     <ul>
1720) 
1721)     <li>
1722)     Does your Tor log include an "assert failure"? If so, please tell us that
1723)     line, since it helps us figure out what's going on. Tell us the previous
1724)     couple of log messages as well, especially if they seem important.
1725)     </li>
1726)     <li>
1727)     If it says "Segmentation fault - core dumped" then you need to do a bit
1728)     more to track it down. Look for a file like "core" or "tor.core" or
1729)     "core.12345" in your current directory, or in your Data Directory.
1730)     If it's there, run "gdb tor core" and then "bt", and include the output.
1731)     If you can't find a core, run "ulimit -c unlimited", restart Tor, and try
1732)     to make it crash again. (This core thing will only work on Unix -- alas,
1733)     tracking down bugs on Windows is harder. If you're on Windows, can you get
1734)     somebody to duplicate your bug on Unix?)
1735)     </li>
1736) 
1737)     <li>
1738)     If Tor simply vanishes mysteriously, it probably is a segmentation fault
1739)     but you're running Tor in the background (as a daemon) so you won't notice.
1740)     Go look at the end of your log file, and look for a core file as above.
1741)     If you don't find any good hints, you should consider running Tor in the
1742)     foreground (from a shell) so you can see how it dies. Warning: if you
1743)     switch to running Tor in the foreground, you might start using a different

1744)     <a href="#torrc">torrc</a> file, with a different default Data Directory; see the

1745)     <a href="#UpgradeOrMove">relay-upgrade FAQ entry</a>
1746)     for details.
1747)     </li>
1748)     <li>
1749)     If it's still vanishing mysteriously, perhaps something else is killing it?
1750)     Do you have resource limits (ulimits) configured that kill off processes
1751)     sometimes? On Linux, try running "dmesg" to see if the out-of-memory killer
1752)     removed your process. (Tor will exit cleanly if it notices that it's run
1753)     out of memory, but in some cases it might not have time to notice.) In very
1754)     rare circumstances, hardware problems could also be the culprit.
1755)     </li>
1756)     </ul>

1757) 
1758)     <p>

1759)     Sixth, if the above ideas don't point out the bug, consider increasing your
1760)     log level to "loglevel debug". You can look at the log-configuration FAQ
1761)     entry for instructions on what to put in your torrc file. If it usually
1762)     takes a long time for the crash to show up, you will want to reserve a
1763)     whole lot of disk space for the debug log. Alternatively, you could just
1764)     send debug-level logs to the screen (it's called "stdout" in the torrc),
1765)     and then when it crashes you'll see the last couple of log lines it had
1766)     printed.
1767)     (Note that running with verbose logging like this will slow Tor down
1768)     considerably, and note also that it's generally not a good idea
1769)     security-wise to keep logs like this sitting around.)
1770)     </p>
1771) 
1772)     <hr />

1773) 

1774)     <a id="ChooseEntryExit"></a>

1775)     <h3><a class="anchor" href="#ChooseEntryExit">Can I control which nodes
1776)     (or country) are used for entry/exit?</a></h3>

1777) 

1778)     <p>

1779)     Yes. You can set preferred entry and exit nodes as well as
1780)     inform Tor which nodes you do not want to use.

1781)     The following options can be added to your config file
1782)     <a href="#torrc">torrc</a> or specified on the command line:

1783)     </p>
1784)     <dl>
1785)       <dt><tt>EntryNodes $fingerprint,$fingerprint,...</tt></dt>

1786)         <dd>A list of preferred nodes to use for the first hop in the
1787) circuit, if possible.

1788)         </dd>
1789)       <dt><tt>ExitNodes $fingerprint,$fingerprint,...</tt></dt>

1790)         <dd>A list of preferred nodes to use for the last hop in the
1791) circuit, if possible.

1792)         </dd>
1793)       <dt><tt>ExcludeNodes $fingerprint,$fingerprint,...</tt></dt>

1794)         <dd>A list of nodes to never use when building a circuit.

1795)         </dd>
1796)       <dt><tt>ExcludeExitNodes $fingerprint,$fingerprint,...</tt></dt>

1797)         <dd>A list of nodes to never use when picking an exit.

1798)             Nodes listed in <tt>ExcludeNodes</tt> are automatically in
1799) this list.

1800)         </dd>
1801)     </dl>
1802)     <p>

1803)     <em>We recommend you do not use these</em>

1804)     — they are intended for testing and may disappear in future
1805) versions.

1806)     You get the best security that Tor can provide when you leave the
1807)     route selection to Tor; overriding the entry / exit nodes can mess
1808)     up your anonymity in ways we don't understand.

1809)     </p>
1810)     <p>

1811)     Note also that not every circuit is used to deliver traffic outside of
1812)     the Tor network. It is normal to see non-exit circuits (such as those

1813)     used to connect to onion services, those that do directory fetches,

1814)     those used for relay reachability self-tests, and so on) that end at
1815)     a non-exit node. To keep a node from being used entirely, see
1816)     <tt>ExcludeNodes</tt> and <tt>StrictNodes</tt> in the

1817)     <a href="<page docs/tor-manual>">manual</a>.

1818)     </p>
1819)     <p>

1820)     Instead of <tt>$fingerprint</tt> you can also specify a
1821)     <a href="https://secure.wikimedia.org/wikipedia/en/wiki/ISO_3166-1_alpha-2">
1822)     2 letter ISO3166 country code</a> in curly braces (for example
1823)     <tt>{de}</tt>), or an ip address pattern (for example 255.254.0.0/8).
1824)     Make sure there are no spaces between the commas and the list items.

1825)     </p>

1826) 

1827)     <p>

1828)     If you want to access a service directly through Tor's Socks interface
1829)     (eg. using ssh via connect.c), another option is to set up an internal
1830)     mapping in your configuration file using <tt>MapAddress</tt>.

1831)     See the manual page for details.
1832)     </p>

1833) 

1834)     <hr>

1835) 

1836)     <a id="FirewallPorts"></a>
1837)     <h3><a class="anchor" href="#FirewallPorts">My firewall only allows a
1838)     few outgoing ports.</a></h3>
1839) 
1840)     <p>
1841)     If your firewall works by blocking ports, then you can tell Tor to only
1842)     use the ports when you start your Tor Browser. Or you can add the ports
1843)     that your firewall permits by adding "FascistFirewall 1" to your

1844)     <a href="#torrc">torrc configuration file</a>.

1845)     By default, when you set this Tor assumes that your firewall allows only
1846)     port 80 and port 443 (HTTP and HTTPS respectively). You can select a
1847)     different set of ports with the FirewallPorts torrc option.
1848)     </p>
1849) 
1850)     <p>
1851)     If you want to be more fine-grained with your controls, you can also
1852)     use the ReachableAddresses config options, e.g.:
1853)     </p>
1854) 
1855)     <pre>
1856)       ReachableDirAddresses *:80
1857)       ReachableORAddresses *:443
1858)     </pre>
1859) 
1860)     <hr>

1861) 

1862)     <a id="DefaultExitPorts"></a>

1863)     <h3><a class="anchor" href="#DefaultExitPorts">Is there a list of default exit

1864)     ports?</a></h3>

1865)     <p>

1866)     The default open ports are listed below but keep in mind that, any port or

1867)     ports can be opened by the relay operator by configuring it in
1868)     <a href="#torrc">torrc</a> or modifying the source code.
1869)     <!-- TODO should we update this? -->
1870)     The default according to src/or/policies.c from the source code release
1871)     tor-0.2.4.16-rc:

1872)     </p>
1873)     <pre>
1874)   reject 0.0.0.0/8
1875)   reject 169.254.0.0/16
1876)   reject 127.0.0.0/8
1877)   reject 192.168.0.0/16
1878)   reject 10.0.0.0/8
1879)   reject 172.16.0.0/12
1880)   reject *:25
1881)   reject *:119
1882)   reject *:135-139
1883)   reject *:445
1884)   reject *:563
1885)   reject *:1214
1886)   reject *:4661-4666
1887)   reject *:6346-6429
1888)   reject *:6699
1889)   reject *:6881-6999
1890)   accept *:*
1891)     </pre>
1892)     <p>

1893)     A relay will block access to its own IP address, as well local network
1894)     IP addresses. A relay always blocks itself by default. This prevents
1895)     Tor users from accidentally accessing any of the exit operator's local
1896)     services.

1897)     </p>
1898) 
1899)     <hr>
1900) 

1901)     <a id="WarningsAboutSOCKSandDNSInformationLeaks"></a>

1902)     <h3><a class="anchor" href="#WarningsAboutSOCKSandDNSInformationLeaks">I
1903)     keep seeing these warnings about SOCKS and DNS information leaks.

1904)     Should I worry?</a></h3>
1905)     <p>

1906)     The warning is:

1907)     </p>
1908)     <p>

1909)     Your application (using socks5 on port %d) is giving Tor only an IP
1910)     address. Applications that do DNS resolves themselves may leak
1911)     information. Consider using Socks4A (e.g. via Polipo or socat) instead.

1912)     </p>
1913)     <p>

1914)     If you are running Tor to get anonymity, and you are worried about an
1915)     attacker who is even slightly clever, then yes, you should worry. Here's why.

1916)     </p>
1917)     <p>

1918)     <b>The Problem.</b> When your applications connect to servers on the
1919)     Internet, they need to resolve hostnames that you can read (like
1920)     www.torproject.org) into IP addresses that the Internet can use (like
1921)     209.237.230.66). To do this, your application sends a request to a DNS
1922)     server, telling it the hostname it wants to resolve. The DNS server
1923)     replies by telling your application the IP address.

1924)     </p>
1925)     <p>

1926)     Clearly, this is a bad idea if you plan to connect to the remote host
1927)     anonymously: when your application sends the request to the DNS server,
1928)     the DNS server (and anybody else who might be watching) can see what
1929)     hostname you are asking for. Even if your application then uses Tor to
1930)     connect to the IP anonymously, it will be pretty obvious that the user
1931)     making the anonymous connection is probably the same person who made
1932)     the DNS request.

1933)     </p>
1934)     <p>

1935)     <b>Where SOCKS comes in.</b> Your application uses the SOCKS protocol
1936)     to connect to your local Tor client. There are 3 versions of SOCKS you
1937)     are likely to run into: SOCKS 4 (which only uses IP addresses), SOCKS 5
1938)     (which usually uses IP addresses in practice), and SOCKS 4a (which uses
1939)     hostnames).

1940)     </p>
1941)     <p>

1942)     When your application uses SOCKS 4 or SOCKS 5 to give Tor an IP address,
1943)     Tor guesses that it 'probably' got the IP address non-anonymously from a
1944)     DNS server. That's why it gives you a warning message: you probably aren't
1945)     as anonymous as you think.

1946)     </p>
1947)     <p>

1948)     <b>So what can I do?</b> We describe a few solutions below.

1949)     </p>
1950)     <ul>
1951)     <li>If your application speaks SOCKS 4a, use it. </li>

1952)     <li>If you only need one or two hosts, or you are good at programming,
1953)     you may be able to get a socks-based port-forwarder like socat to work
1954)     for you; see <a
1955)     href="https://trac.torproject.org/projects/tor/wiki/doc/TorifyHOWTO">the

1956)     Torify HOWTO</a> for examples. </li>

1957)     <li>Tor ships with a program called tor-resolve that can use the Tor
1958)     network to look up hostnames remotely; if you resolve hostnames to IPs
1959)     with tor-resolve, then pass the IPs to your applications, you'll be fine.

1960)     (Tor will still give the warning, but now you know what it means.) </li>
1961) 

1962)     <!-- TODO I'm not sure if this project is still maintained or not

1963)     <li>You can use TorDNS as a local DNS server to rectify the DNS leakage.
1964)     See the Torify HOWTO for info on how to run particular applications
1965)     anonymously.</li>
1966)     !-->

1967)     </ul>

1968) 

1969)     <p>If you think that you applied one of the solutions properly but still
1970)     experience DNS leaks please verify there is no third-party application
1971)     using DNS independently of Tor. Please see <a
1972)     href="#AmITotallyAnonymous">the FAQ entry on whether you're really
1973)     absolutely anonymous using Tor</a> for some examples.

1974)     </p>
1975) 
1976)     <hr>
1977) 

1978)     <a id="SocksAndDNS"></a>

1979)     <h3><a class="anchor" href="#SocksAndDNS">How do I check if my application
1980)     that uses SOCKS is leaking DNS requests?</a></h3>

1981) 
1982)     <p>

1983)     These are two steps you need to take here. The first is to make sure
1984)     that it's using the correct variant of the SOCKS protocol, and the
1985)     second is to make sure that there aren't other leaks.

1986)     </p>
1987) 
1988)     <p>

1989)     Step one: add "TestSocks 1" to your torrc file, and then watch your
1990)     logs as you use your application. Tor will then log, for each SOCKS
1991)     connection, whether it was using a 'good' variant or a 'bad' one.
1992)     (If you want to automatically disable all 'bad' variants, set
1993)     "SafeSocks 1" in your <a href="#torrc">torrc</a> file.)

1994)     </p>
1995) 
1996)     <p>

1997)     Step two: even if your application is using the correct variant of
1998)     the SOCKS protocol, there is still a risk that it could be leaking
1999)     DNS queries. This problem happens in Firefox extensions that resolve
2000)     the destination hostname themselves, for example to show you its IP
2001)     address, what country it's in, etc. These applications may use a safe
2002)     SOCKS variant when actually making connections, but they still do DNS
2003)     resolves locally. If you suspect your application might behave like
2004)     this, you should use a network sniffer like <a
2005)     href="https://www.wireshark.org/">Wireshark</a> and look for
2006)     suspicious outbound DNS requests. I'm afraid the details of how to look
2007)     for these problems are beyond the scope of a FAQ entry though -- find
2008)     a friend to help if you have problems.

2009)     </p>
2010) 
2011)     <hr>
2012) 

2013)     <a id="TorClientOnADifferentComputerThanMyApplications"></a>

2014)     <h3><a class="anchor" href="#TorClientOnADifferentComputerThanMyApplications">
2015)     I want to run my Tor client on a different computer than my applications.

2016)     </a></h3>
2017)     <p>
2018)     By default, your Tor client only listens for applications that
2019)     connect from localhost. Connections from other computers are
2020)     refused. If you want to torify applications on different computers

2021)     than the Tor client, you should edit your <a href="#torrc">torrc</a> to define

2022)     SocksListenAddress 0.0.0.0 and then restart (or hup) Tor. If you
2023)     want to get more advanced, you can configure your Tor client on a
2024)     firewall to bind to your internal IP but not your external IP.
2025)     </p>
2026) 
2027)     <hr>
2028) 
2029)     <a id="ServerClient"></a>
2030)     <h3><a class="anchor" href="#ServerClient">Can I install Tor on a
2031)     central server, and have my clients connect to it?</a></h3>
2032)     <p>
2033)      Yes. Tor can be configured as a client or a relay on another
2034)      machine, and allow other machines to be able to connect to it
2035)      for anonymity. This is most useful in an environment where many
2036)      computers want a gateway of anonymity to the rest of the world.
2037)      However, be forwarned that with this configuration, anyone within
2038)      your private network (existing between you and the Tor
2039)      client/relay) can see what traffic you are sending in clear text.
2040)      The anonymity doesn't start until you get to the Tor relay.
2041)      Because of this, if you are the controller of your domain and you
2042)      know everything's locked down, you will be OK, but this configuration
2043)      may not be suitable for large private networks where security is
2044)      key all around.
2045)     </p>
2046)     <p>

2047)     Configuration is simple, editing your <a href="#torrc">torrc</a> file's SocksListenAddress

2048)     according to the following examples:

2049)     </p>
2050) 

2051)     <pre>

2052)   #This provides local interface access only,
2053)   #needs SocksPort to be greater than 0
2054)   SocksListenAddress 127.0.0.1
2055) 
2056)   #This provides access to Tor on a specified interface
2057)   SocksListenAddress 192.168.x.x:9100
2058) 
2059)   #Accept from all interfaces
2060)   SocksListenAddress 0.0.0.0:9100
2061)    </pre>

2062) 

2063)     <p>

2064)     You can state multiple listen addresses, in the case that you are
2065)     part of several networks or subnets.

2066)     </p>

2067) 

2068)     <pre>

2069)       SocksListenAddress 192.168.x.x:9100 #eth0
2070)       SocksListenAddress 10.x.x.x:9100 #eth1

2071)     </pre>

2072) 

2073)     <p>

2074)     After this, your clients on their respective networks/subnets would specify
2075)     a socks proxy with the address and port you specified SocksListenAddress
2076)     to be.

2077)     </p>

2078) 

2079)     <p>

2080)     Please note that the SocksPort configuration option gives the port ONLY for
2081)     localhost (127.0.0.1). When setting up your SocksListenAddress(es), you need
2082)     to give the port with the address, as shown above.
2083)     </p>
2084) 

2085)     <p>

2086)     If you are interested in forcing all outgoing data through the central Tor
2087)     client/relay, instead of the server only being an optional proxy, you may
2088)     find the program iptables (for *nix) useful.

2089)     </p>
2090) 
2091)     <hr>
2092) 

2093)     <a id="RunningATorRelay"></a>

2094)     <h2><a class="anchor" href="#RunningATorRelay">Running a Tor relay:</a></h2>

2095) 

2096)     <a id="HowDoIDecide"></a>

2097)     <h3><a class="anchor" href="#HowDoIDecide">How do I decide if I should

2098)     run a relay?</a></h3>
2099)     <p>

2100)     We're looking for people with reasonably reliable Internet connections, 
2101)     that have at least 1 MByte/second (that is 8 MBit/second) available
2102)     bandwidth each way. If that's you, please consider
2103)     <a href="<wiki>TorRelayGuide">running a Tor relay</a>.

2104)     </p>

2105) 

2106)     <p>

2107)     Even if you do not have at least 8 MBit/s of available bandwidth you can
2108)     still help the Tor network by running a
2109)     <a href="<page docs/pluggable-transports>#operator">Tor bridge with obfs4
2110)     support</a>.
2111)     In that case you should have at least 1 MBit/s of available bandwidth.

2112)     </p>

2113) 

2114)     <hr>

2115) 

2116)     <a id="MostNeededRelayType"></a>

2117)     <h3><a class="anchor" href="#MostNeededRelayType">What type of relays are
2118)     most needed?</a></h3>

2119)     <p>
2120)     <ul>

2121)     <li>The exit relay is the most needed relay type but it also comes with the
2122)     highest legal exposure and risk (and you should NOT run them from your
2123)     home).</li>
2124)     <li>If you are looking to run a relay with minimal effort, fast guard
2125)     relays are also very useful</li>

2126)     <li>followed by bridges.</li>
2127)     </ul>
2128)     </p>
2129) 
2130)     <hr>
2131) 

2132)     <a id="WhyIsntMyRelayBeingUsedMore"></a>

2133)     <h3><a class="anchor" href="#WhyIsntMyRelayBeingUsedMore">Why isn't my

2134)     relay being used more?</a></h3>
2135)     <p>

2136)     If your relay is relatively new then give it time. Tor decides which
2137)     relays it uses heuristically based on reports from Bandwidth
2138)     Authorities. These authorities take measurements of your relay's
2139)     capacity and, over time, directs more traffic there until it reaches
2140)     an optimal load. The lifecycle of a new relay is explained in more

2141)     depth in <a href="https://blog.torproject.org/blog/lifecycle-of-a-new-relay">
2142)     this blog post</a>.
2143)     </p>
2144)     <p>

2145)     If you've been running a relay for a while and still having issues

2146)     then try asking on the <a href=
2147)     "https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-relays/">

2148)     tor-relays list</a>.

2149)     </p>

2150) 

2151)     <hr>
2152) 

2153)     <a id="IDontHaveAStaticIP"></a>

2154)     <h3><a class="anchor" href="#IDontHaveAStaticIP">Can I run a Tor relay
2155)     using a dynamic IP address?</a></h3>

2156) 
2157)     <p>

2158)     Tor can handle relays with dynamic IP addresses just fine. Just leave the
2159)     "Address" line in your <a href="#torrc">torrc</a> blank, and Tor will guess.

2160)     </p>
2161) 
2162)     <hr>
2163) 

2164)     <a id="IPv6Relay"></a>
2165)     <h3><a class="anchor" href="#IPv6Relay">Can I use IPv6 on my relay?</a></h3>
2166) 
2167)     <p>

2168)     Tor has <a href="<wiki>org/roadmaps/Tor/IPv6Features">partial</a> support
2169)     for IPv6 and we encourage every relay operator to
2170)     <a href="<wiki>TorRelayGuide#IPv6">enable IPv6 functionality</a> in their

2171)     <a href="#torrc">torrc</a> configuration files when IPv6 connectivity is
2172)     available. For the time being Tor will require IPv4 addresses on relays,
2173)     you can not run a Tor relay on a host with IPv6 addresses only.

2174)     </p>
2175) 
2176)     <hr>

2177)     <a id="PortscannedMore"></a>

2178)     <h3><a class="anchor" href="#PortscannedMore">Why do I get portscanned

2179)     more often when I run a Tor relay?</a></h3>
2180) 
2181)     <p>

2182)     If you allow exit connections, some services that people connect to
2183)     from your relay will connect back to collect more information about you.
2184)     For example, some IRC servers connect back to your identd port to record
2185)     which user made the connection. (This doesn't really work for them,
2186)     because Tor doesn't know this information, but they try anyway.) Also,
2187)     users exiting from you might attract the attention of other users on the
2188)     IRC server, website, etc. who want to know more about the host they're
2189)     relaying through.

2190)     </p>
2191)     <p>

2192)     Another reason is that groups who scan for open proxies on the Internet
2193)     have learned that sometimes Tor relays expose their socks port to the
2194)     world. We recommend that you bind your socksport to local networks only.

2195)     </p>
2196)     <p>

2197)     In any case, you need to keep up to date with your security. See this
2198)     <a href="https://trac.torproject.org/projects/tor/wiki/doc/OperationalSecurity">
2199)     article on operational security for Tor relays</a> for more suggestions.

2200)     </p>
2201) 
2202)     <hr>
2203) 

2204)     <a id="HighCapacityConnection"></a>

2205)     <h3><a class="anchor" href="#HighCapacityConnection">How can I get Tor to
2206)     fully make use of my high capacity connection?</a></h3>

2207) 

2208)     <p>

2209)     See <a href="http://archives.seul.org/or/relays/Aug-2010/msg00034.html">
2210)     this tor-relays thread</a>.

2211)     </p>

2212) 
2213)     <hr>
2214) 

2215)     <a id="RelayFlexible"></a>

2216)     <h3><a class="anchor" href="#RelayFlexible">How stable does my relay need
2217)     to be?</a></h3>

2218) 

2219)     <p>
2220)     We aim to make setting up a Tor relay easy and convenient:
2221)     </p>

2222) 

2223)     <ul>

2224)     <li>It's fine if the relay goes offline sometimes. The directories
2225)     notice this quickly and stop advertising the relay. Just try to make
2226)     sure it's not too often, since connections using the relay when it
2227)     disconnects will break.
2228)     </li>

2229)     <li>Each Tor relay has an <a href="#ExitPolicies">exit policy</a> that
2230)     specifies what sort of outbound connections are allowed or refused from
2231)     that relay. If you are uncomfortable allowing people to exit from your
2232)     relay, you can set it up to only allow connections to other Tor relays.

2233)     </li>
2234)     <li>Your relay will passively estimate and advertise its recent

2235)     bandwidth capacity, so high-bandwidth relays will attract more users than
2236)     low-bandwidth ones. Therefore having low-bandwidth relays is useful too.

2237)     </li>
2238)     </ul>

2239) 

2240)     <hr>

2241) 

2242)     <a id="OutgoingFirewall"></a>

2243)     <h3><a class="anchor" href="#OutgoingFirewall">How should I configure

2244)     the outgoing filters on my relay?</a></h3>

2245) 
2246)     <p>

2247)     All <em>outgoing</em> connections must be allowed, so that each relay can 
2248)     communicate with every other relay.

2249)     </p>
2250)     <p>

2251)     In many jurisdictions, Tor relay operators are legally protected by the 
2252)     same <em>common carrier</em> regulations that prevent internet service 
2253)     providers from being held liable for third-party content that passes 
2254)     through their network. Exit relays that filter some traffic would 
2255)     likely forfeit those protections. 

2256)     </p>
2257)     <p>

2258)     Tor promotes free network access without interference. 
2259)     Exit relays must not filter the traffic 
2260)     that passes through them to the internet. 
2261)     Exit relays found to be filtering traffic will get the <a 

2262)     href="#WhatIsTheBadExitFlag">BadExit</a> flag once detected.
2263)     </p>
2264) 
2265)     <hr>
2266) 

2267)     <a id="BandwidthShaping"></a>

2268)     <h3><a class="anchor" href="#BandwidthShaping">What bandwidth shaping

2269)     options are available to Tor relays?</a></h3>
2270) 
2271)     <p>

2272)     There are two options you can add to your <a href="#torrc">torrc</a> file:

2273)     </p>
2274)     <ul>
2275)     <li>

2276)     BandwidthRate is the maximum long-term bandwidth allowed (bytes per

2277)     second). For example, you might want to choose "BandwidthRate 10 MBytes"
2278)     for 10 megabytes per second (a fast connection), or "BandwidthRate 500

2279)     KBytes" for 500 kilobytes per second (a decent cable connection).

2280)     The minimum BandwidthRate setting is 75 kilobytes per second.

2281)     </li>
2282)     <li>

2283)     BandwidthBurst is a pool of bytes used to fulfill requests during
2284)     short periods of traffic above BandwidthRate but still keeps the
2285)     average over a long period to BandwidthRate. A low Rate but a high
2286)     Burst enforces a long-term average while still allowing more traffic
2287)     during peak times if the average hasn't been reached lately. For example,

2288)     if you choose "BandwidthBurst 500 KBytes" and also use that for your
2289)     BandwidthRate, then you will never use more than 500 kilobytes per second;
2290)     but if you choose a higher BandwidthBurst (like 5 MBytes), it will allow

2291)     more bytes through until the pool is empty.
2292)     </li>
2293)     </ul>
2294)     <p>

2295)     If you have an asymmetric connection (upload less than download) such
2296)     as a cable modem, you should set BandwidthRate to less than your smaller
2297)     bandwidth (Usually that's the upload bandwidth). (Otherwise, you could
2298)     drop many packets during periods of maximum bandwidth usage -- you may
2299)     need to experiment with which values make your connection comfortable.)
2300)     Then set BandwidthBurst to the same as BandwidthRate.

2301)     </p>
2302)     <p>

2303)     Linux-based Tor nodes have another option at their disposal: they can
2304)     prioritize Tor traffic below other traffic on their machine, so that

2305)     their own personal traffic is not impacted by Tor load. A
2306)     <a href="https://gitweb.torproject.org/tor.git/tree/contrib/operator-tools/linux-tor-prio.sh">
2307)     script to do this</a> can be found in the Tor source distribution's contrib

2308)     directory.

2309)     </p>
2310)     <p>

2311)     Additionally, there are hibernation options where you can tell Tor to
2312)     only serve a certain amount of bandwidth per time period (such as 100
2313)     GB per month). These are covered in the <a
2314)     href="#LimitTotalBandwidth">hibernation entry</a> below.

2315)     </p>
2316)     <p>

2317)     Note that BandwidthRate and BandwidthBurst are in <b>Bytes</b>, not Bits.

2318)     </p>
2319) 
2320)     <hr>
2321) 
2322)     <a id="LimitTotalBandwidth"></a>

2323)     <h3><a class="anchor" href="#LimitTotalBandwidth">How can I limit the

2324)     total amount of bandwidth used by my Tor relay?</a></h3>
2325)     <p>

2326)     The accounting options in the <a href="#torrc">torrc</a> file allow you to specify the maximum

2327)     amount of bytes your relay uses for a time period.

2328)     </p>
2329)     <pre>
2330)     AccountingStart day week month [day] HH:MM
2331)     </pre>
2332)     <p>

2333)     This specifies when the accounting should reset. For instance, to setup
2334)     a total amount of bytes served for a week (that resets every Wednesday
2335)     at 10:00am), you would use:

2336)     </p>
2337)     <pre>
2338)     AccountingStart week 3 10:00

2339)     AccountingMax 500 GBytes

2340)     </pre>
2341)     <p>

2342)     This specifies the maximum amount of data your relay will send during an
2343)     accounting period, and the maximum amount of data your relay will receive
2344)     during an account period. When the accounting period resets (from

2345)     AccountingStart), then the counters for AccountingMax are reset to 0.
2346)     </p>
2347)     <p>

2348)     Example: Let's say you want to allow 50 GB of traffic every day in each

2349)     direction and the accounting should reset at noon each day:

2350)     </p>
2351)     <pre>
2352)     AccountingStart day 12:00

2353)     AccountingMax 50 GBytes

2354)     </pre>
2355)     <p>

2356)     Note that your relay won't wake up exactly at the beginning of each
2357)     accounting period. It will keep track of how quickly it used its
2358)     quota in the last period, and choose a random point in the new interval
2359)     to wake up. This way we avoid having hundreds of relays working at the
2360)     beginning of each month but none still up by the end.

2361)     </p>
2362)     <p>

2363)     If you have only a small amount of bandwidth to donate compared to your
2364)     connection speed, we recommend you use daily accounting, so you don't
2365)     end up using your entire monthly quota in the first day. Just divide
2366)     your monthly amount by 30. You might also consider rate limiting to
2367)     spread your usefulness over more of the day: if you want to offer X GB

2368)     in each direction, you could set your RelayBandwidthRate to 20*X KBytes.

2369)     For example,

2370)     if you have 50 GB to offer each way, you might set your RelayBandwidthRate
2371)     to 1000 KBytes: this way your relay will always be useful for at least half
2372)     of each day.

2373)     </p>

2374) 

2375)     <pre>
2376)     AccountingStart day 0:00
2377)     AccountingMax 50 GBytes
2378)     RelayBandwidthRate 1000 KBytes
2379)     RelayBandwidthBurst 5000 KBytes # allow higher bursts but maintain average
2380)     </pre>

2381) 
2382)     <hr>
2383) 
2384)     <a id="RelayWritesMoreThanItReads"></a>

2385)     <h3><a class="anchor" href="#RelayWritesMoreThanItReads">Why does my relay

2386)     write more bytes onto the network than it reads?</a></h3>

2387) 

2388)     <p>You're right, for the most part a byte into your Tor relay means a

2389)     byte out, and vice versa. But there are a few exceptions:</p>
2390) 

2391)     <p>If you open your DirPort, then Tor clients will ask you for a copy of
2392)     the directory. The request they make (an HTTP GET) is quite small, and the
2393)     response is sometimes quite large. This probably accounts for most of the

2394)     difference between your "write" byte count and your "read" byte count.</p>
2395) 

2396)     <p>Another minor exception shows up when you operate as an exit node, and
2397)     you read a few bytes from an exit connection (for example, an instant
2398)     messaging or ssh connection) and wrap it up into an entire 512 byte cell

2399)     for transport through the Tor network.</p>
2400) 
2401)     <hr>
2402) 
2403)     <a id="Hibernation"></a>

2404)     <h3><a class="anchor" href="#Hibernation">Why can I not browse anymore

2405)     after limiting bandwidth on my Tor relay?</a></h3>

2406) 

2407)     <p>The parameters assigned in the <a
2408)     href="#LimitTotalBandwidth">AccountingMax</a> and <a
2409)     href="#BandwidthShaping">BandwidthRate</a> apply to both client and
2410)     relay functions of the Tor process. Thus you may find that you are unable
2411)     to browse as soon as your Tor goes into hibernation, signaled by this

2412)     entry in the log:</p>
2413) 

2414)     <pre>Bandwidth soft limit reached; commencing hibernation. No new

2415)     connections will be accepted</pre>
2416) 

2417)     <p>The solution is to run two Tor processes - one relay and one client,
2418)     each with its own config. One way to do this (if you are starting from a

2419)     working relay setup) is as follows:</p>
2420) 
2421)     <ul>

2422)         <li>In the relay Tor <a href="#torrc">torrc</a> file, simply set the SocksPort to 0.</li>

2423)         <li>Create a new client torrc file from the torrc.sample and ensure
2424)         it uses a different log file from the relay. One naming convention

2425)         may be torrc.client and torrc.relay.</li>

2426)         <li>Modify the Tor client and relay startup scripts to include

2427)         '-f /path/to/correct/torrc'.</li>

2428)         <li>In Linux/BSD/Mac OS X, changing the startup scripts to Tor.client

2429)         and Tor.relay may make separation of configs easier.</li>
2430)     </ul>
2431) 

2432)     <hr>

2433) 

2434)     <a id="ExitPolicies"></a>

2435)     <h3><a class="anchor" href="#ExitPolicies">I'd run a relay, but I
2436) don't want to deal with abuse issues.</a></h3>

2437) 

2438)     <p>
2439)     Great. That's exactly why we implemented exit policies.
2440)     </p>

2441) 

2442)     <p>
2443)     Each Tor relay has an exit policy that specifies what sort of

2444)     outbound connections are allowed or refused from that relay. The exit

2445)     policies are propagated to Tor clients via the directory, so clients
2446)     will automatically avoid picking exit relays that would refuse to
2447)     exit to their intended destination. This way each relay can decide

2448)     the services, hosts, and networks it wants to allow connections to,

2449)     based on abuse potential and its own situation. Read the FAQ entry on
2450)     <a href="<page docs/faq-abuse>#TypicalAbuses">issues you might encounter</a>

2451)     if you use the default exit policy, and then read Mike Perry's

2452)     <a href="<blog>tips-running-exit-node">tips

2453)     for running an exit node with minimal harassment</a>.
2454)     </p>

2455) 

2456)     <p>

2457)     The default exit policy allows access to many popular services

2458)     (e.g. web browsing), but <a href="#DefaultExitPorts">restricts</a> some due
2459)     to abuse potential (e.g. mail) and some since the Tor network can't handle
2460)     the load (e.g. default file-sharing ports). You can change your exit policy
2461)     by editing your <a href="<page docs/faq>#torrc">torrc</a> file. If you want
2462)     to avoid most if not all abuse potential, set it to <var>"reject *:*"</var>.
2463)     This setting means that your relay will be used for relaying traffic inside
2464)     the Tor network, but not for connections to external websites or other
2465)     services.
2466)     </p>
2467) 
2468)     <p>
2469)     If you do allow any exit connections, make sure name resolution works

2470)     (that is, your computer can resolve Internet addresses correctly).

2471)     If there are any resources that your computer can't reach (for example,

2472)     you are behind a restrictive firewall or content filter), please

2473)     explicitly reject them in your exit policy — otherwise Tor users

2474)     will be impacted too.
2475)     </p>

2476) 

2477)     <hr>

2478) 

2479)     <a id="PackagedTor"></a>

2480)     <h3><a class="anchor" href="#PackagedTor">Should I install Tor from my

2481)     package manager, or build from source?</a></h3>
2482)     <p>

2483)     If you're using Debian or Ubuntu especially, there are a number of benefits
2484)     to installing Tor from the <a

2485)     href="<page docs/debian>">Tor Project's repository</a>.

2486)     </p>
2487)     <ul>
2488)       <li>

2489)       Your ulimit -n gets set to 32768 — high enough for Tor to
2490)       keep open all the connections it needs.

2491)       </li>
2492)       <li>

2493)       A user profile is created just for Tor, so Tor doesn't need to run as

2494)       root.
2495)       </li>
2496)       <li>
2497)       An init script is included so that Tor runs at boot.
2498)       </li>
2499)       <li>

2500)       Tor runs with --verify-config, so that most problems with your
2501)       config file get caught.

2502)       </li>
2503)       <li>
2504)       Tor can bind to low level ports, then drop privileges.
2505)       </li>
2506)     </ul>
2507) 
2508)     <hr>
2509) 

2510)     <a id="WhatIsTheBadExitFlag"></a>

2511)     <h3><a class="anchor" href="#WhatIsTheBadExitFlag">What is the

2512)     BadExit flag?</a></h3>
2513) 

2514)     <p>When an exit is misconfigured or malicious it's assigned the BadExit
2515)     flag. This tells Tor to avoid exiting through that relay. In effect,

2516)     relays with this flag become non-exits.</p>
2517) 
2518)     <hr>
2519) 
2520)     <a id="IGotTheBadExitFlagWhyDidThatHappen"></a>
2521)     <h3><a class="anchor" href="#IGotTheBadExitFlagWhyDidThatHappen">I got
2522)     the BadExit flag why did that happen?</a></h3>
2523) 

2524)     <p>If you got this flag then we either discovered a problem or suspicious

2525)     activity when routing traffic through your exit and weren't able to contact
2526)     you. Please reach out to the
2527)     <a href="mailto:bad-relays@lists.torproject.org">bad-relays team</a>

2528)     so we can sort out the issue.
2529)     </p>

2530) 
2531)     <hr>
2532) 
2533)     <a id="MyRelayRecentlyGotTheGuardFlagAndTrafficDroppedByHalf"></a>

2534)     <h3><a class="anchor" href="#MyRelayRecentlyGotTheGuardFlagAndTrafficDroppedByHalf">
2535)     My relay recently got the Guard flag and traffic dropped by half.</a></h3>

2536)     <p>

2537)     Since it's now a guard, clients are using it less in other positions, but
2538)     not many clients have rotated their existing guards out to use it as a
2539)     guard yet. Read more details in this <a
2540)     href="https://blog.torproject.org/blog/lifecycle-of-a-new-relay">blog
2541)     post</a> or in <a href="http://freehaven.net/anonbib/#wpes12-cogs">Changing
2542)     of the Guards: A Framework for Understanding and Improving Entry Guard

2543)     Selection in Tor</a>.
2544)     </p>

2545) 

2546)     <hr>
2547) 

2548)     <a id="RelayOrBridge"></a>

2549)     <h3><a class="anchor" href="#RelayOrBridge">Should I be a normal relay or
2550)     bridge relay?</a></h3>

2551) 

2552)     <p><a href="<page docs/bridges>">Bridge relays</a> (or "bridges" for short)
2553)     are <a href="<wiki>TorRelayGuide">Tor relays</a> that aren't listed in the
2554)     public Tor directory. That means that ISPs or governments trying to block
2555)     access to the Tor network can't simply block all bridges.

2556)     </p>

2557) 

2558)     <p>Being a normal relay vs being a bridge relay is almost the same

2559)     configuration: it's just a matter of whether your relay is listed publicly
2560)     or not.

2561)     </p>

2562) 

2563)     <p>

2564)     So bridges are useful a) for Tor users in oppressive regimes, and b) for
2565)     people who want an extra layer of security because they're worried somebody
2566)     will recognize that it's a public Tor relay IP address they're contacting.

2567)     </p>

2568) 

2569)     <p>