FAQ 3.7 KB

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  1. The Onion Routing (TOR) Frequently Asked Questions
  2. --------------------------------------------------
  3. 1. General.
  4. 1.1. What is tor?
  5. Tor is an implementation of version 2 of Onion Routing.
  6. Onion Routing is a connection-oriented anonymizing communication
  7. service. Users build a layered block of asymmetric encryptions
  8. (an "onion") which describes a source-routed path through a set of
  9. nodes. Those nodes build a "virtual circuit" through the network, in which
  10. each node knows its predecessor and successor, but no others. Traffic
  11. flowing down the circuit is unwrapped by a symmetric key at each node
  12. which reveals the downstream node.
  13. Basically tor provides a distributed network of servers ("onion
  14. routers"). Users bounce their tcp streams (web traffic, ftp, ssh, etc)
  15. around the routers, and recipients, observers, and even the routers
  16. themselves have difficulty tracking the source of the stream.
  17. 1.2. Why's it called tor?
  18. Because tor is the onion routing system. I kept telling people I was
  19. working on onion routing, and they said "Neat. Which one?" Even if onion
  20. routing has become a standard household term, this is the actual onion
  21. routing project, started out of the Naval Research Lab.
  22. (Theories about recursive acronyms are ok too.)
  23. 2. Compiling and installing.
  24. [Read the README file for now; check back here once we've got packages/etc
  25. for you.]
  26. 3. Running tor.
  27. 3.1. What's this about roles? What kind of server should I run?
  28. The same executable ("or") functions as both client and server, depending
  29. on the value of the config variable named 'Role'. Role represents a
  30. combination of which tasks this particular tor server will do. The default
  31. Role (role 15) is an onion router: it listens for onion routers, listens
  32. for onion proxies, listens for application proxies, and it connects to
  33. all other onion routers it learns about. A directory server (role 63)
  34. does all of the above and also serves directory requests. A simple
  35. onion proxy, on the other hand (role 8), only listens for application
  36. proxies. See part 3.1 of the HACKING document for more technical details.
  37. 3.2. So I can just run a full onion router and join the network?
  38. No. Users should run just an onion proxy (use the 'oprc' config file).
  39. If you start up a full onion router, the rest of the routers in the
  40. system won't recognize you, so they will reject your handshake attempts.
  41. 3.3. How do I join the network then?
  42. If you just want to use the onion routing network, you can run a proxy
  43. and you're all set. If you want to run a router, you must convince
  44. the directory server operators (currently arma@mit.edu) that you're a
  45. trustworthy person. From there, the operators add you to the directory,
  46. which propagates out to the rest of the network. All nodes will know
  47. about you within an hour.
  48. 3.4. I want to run a directory server too.
  49. If you run a very reliable node, you plan to be around for a long time,
  50. and you want to spend some time ensuring that router operators are
  51. people we know and like, we may want you to run a directory server
  52. too. We must manually add you to the 'dirservers' file that's part of
  53. the distribution; users will only know about you when they upgrade to
  54. a new version. Of course, you can always just start up your router as a
  55. directory server too --- but users won't know to ask you for directories,
  56. and more importantly, you'll never learn from the real directory servers
  57. about recently joined routers.
  58. 4. Development.
  59. 4.1. Who's doing this?
  60. 4.2. Can I help?
  61. 4.3. I've got a bug.
  62. 5. Anonymity.
  63. 5.1. So I'm totally anonymous if I use tor?
  64. 5.2. Where can I learn more about anonymity?
  65. 6. Comparison to related projects.
  66. 6.1. Onion Routing.
  67. Tor *is* onion routing.
  68. 6.2. Freedom.
  69. 7. Protocol and application support.
  70. 7.1. http? ftp? udp? socks? mozilla?