This is a short guide on how to setup an obfsproxy obfs2/obfs3 bridge
on a Debian/Ubuntu system.

Step 0: Install Python

 To use obfsproxy you will need Python (>= 2.7) and pip. If you use
 Debian testing (or unstable), or a version of Ubuntu newer than
 Oneiric, this is easy:

   # apt-get install python2.7 python-pip python-dev build-essential libgmp-dev


Step 1: Install Tor

 You will also need a development version of Tor. To do this, you
 should use the following guide to install tor and
 deb.torproject.org-keyring:
 https://www.torproject.org/docs/debian.html.en#development

 You need Tor 0.2.4.x because it knows how to automatically report
 your obfsproxy address to BridgeDB.


Step 2: Install obfsproxy

  If you have pip, installing obfsproxy and its dependencies should be
  a matter of a single command:

    $ pip install obfsproxy


Step 3: Setup Tor

  Now setup Tor. Edit your /etc/tor/torrc to add:

    SocksPort 0
    ORPort 443 # or some other port if you already run a webserver/skype
    BridgeRelay 1
    Exitpolicy reject *:*

    ## CHANGEME_1 -> provide a nickname for your bridge, can be anything you like
    #Nickname CHANGEME_1
    ## CHANGEME_2 -> provide some email address so we can contact you if there's a problem
    #ContactInfo CHANGEME_2

    ServerTransportPlugin obfs2,obfs3 exec /usr/local/bin/obfsproxy managed

  Don't forget to uncomment and edit the CHANGEME fields.


Step 4: Launch Tor and verify that it bootstraps

  Restart Tor to use the new configuration file. (Preface with sudo if
  needed.)

    # service tor restart

  Now check /var/log/tor/log and you should see something like this:

    Nov 05 16:40:45.000 [notice] We now have enough directory information to build circuits.
    Nov 05 16:40:45.000 [notice] Bootstrapped 80%: Connecting to the Tor network.
    Nov 05 16:40:46.000 [notice] Bootstrapped 85%: Finishing handshake with first hop.
    Nov 05 16:40:46.000 [notice] Bootstrapped 90%: Establishing a Tor circuit.
    Nov 05 16:40:48.000 [notice] Tor has successfully opened a circuit. Looks like client functionality is working.
    Nov 05 16:40:48.000 [notice] Bootstrapped 100%: Done.

  If Tor is earlier in the bootstrapping phase, wait until it gets to 100%.


Step 5: Set up port forwarding if needed

  If you're behind a NAT/firewall, you'll need to make your bridge
  reachable from the outside world — both on the ORPort and the
  obfsproxy port. The ORPort is whatever you defined in step two
  above. To find your obfsproxy port, check your Tor logs for two
  lines similar to these:

    Oct 05 20:00:41.000 [notice] Registered server transport 'obfs2' at '0.0.0.0:26821
    Oct 05 20:00:42.000 [notice] Registered server transport 'obfs3' at '0.0.0.0:40172

  The last number in each line, in this case 26821 and 40172, are the
  TCP port numbers that you need to forward through your
  firewall. (This port is randomly chosen the first time Tor starts,
  but Tor will cache and reuse the same number in future runs.) If you
  want to change the number, use Tor 0.2.4.7-alpha or later, and set
  "ServerTransportListenAddr obfs2 0.0.0.0:26821" in your torrc.