How do I add obfs3 bridges in torrc?

Question

I have installed Tor on my Ubuntu system, not the Tor browser bundle. Now, I am aware that one can add obfs3 bridges into torrc file. How might I do this?

Answer 1

First you need to install obfsproxy package. Then configure torrc file like @user263485 said:

 UseBridges 1
 # This works for Ubuntu Linux, adjust the path according to your platform
 ClientTransportPlugin obfs3, scramblesuit exec /usr/bin/obfsproxy managed
 Bridge obfs3 <ip:port> <key>

To obtain obfs3 bridges visit BridgeDB (step 2) and instead of clicking the inviting just give me bridges button scroll down and specifically ask for obfs3 type bridges. Restart tor and it should work, it just did for me.

EDIT:
Note that obfsproxy support also scamblesuit bridges, bridge syntax is the same

Bridge scramblesuit <ip:port> <key>

Answer 2

Open torrc file.

After first two comment lines which start with # add:

Bridge obfs3 IP-address:port Fingerprint of bridge

and save the file. For more information take a look at freebsd-ports

Update: Do not post the bridges you use in public. It make it easier to track you. This is how your torrc should look like:

# This file was generated by Tor; if you edit it, comments will not be preserved
# The old torrc file was renamed to torrc.orig.1 or similar, and Tor will ignore it

Bridge obfs3 <IP-address 1:port 1> <Fingerprint of bridge 1>
Bridge obfs3 <IP-address 2:port 2> <Fingerprint of bridge 2>

DataDirectory C:\Program Files\Tor Browser\Data\Tor
DirReqStatistics 0
GeoIPFile C:\Program Files\Tor Browser\Data\Tor\geoip
GeoIPv6File C:\Program Files\Tor Browser\Data\Tor\geoip6
UseBridges 1