1. Install tor and dependencies

  • CentOS / RHEL:
yum install epel-release
yum install git golang tor policycoreutils-python-utils
  • OpenSUSE:
zypper install tor go git

2. Build obfs4proxy and move it into place.

Heavily outdated versions of git can make go get fail, so try upgrading to a more recent git version if you're running into this problem.

  • CentOS / RHEL:
export GOPATH=`mktemp -d`
go get gitlab.com/yawning/obfs4.git/obfs4proxy
sudo cp $GOPATH/bin/obfs4proxy /usr/local/bin/
chcon --reference=/usr/bin/tor /usr/local/bin/obfs4proxy
  • OpenSUSE:
export GOPATH=`mktemp -d`
go get gitlab.com/yawning/obfs4.git/obfs4proxy
sudo cp $GOPATH/bin/obfs4proxy /usr/local/bin/

3. Edit your Tor config file, usually located at /etc/tor/torrc and replace its content with:

  • CentOS / RHEL / OpenSUSE:
RunAsDaemon 1
BridgeRelay 1

# Replace "TODO1" with a Tor port of your choice.  This port must be externally
# reachable.  Avoid port 9001 because it's commonly associated with Tor and
# censors may be scanning the Internet for this port.
ORPort TODO1

ServerTransportPlugin obfs4 exec /usr/local/bin/obfs4proxy

# Replace "TODO2" with an obfs4 port of your choice.  This port must be
# externally reachable and must be different from the one specified for ORPort.
# Avoid port 9001 because it's commonly associated with
# Tor and censors may be scanning the Internet for this port.
ServerTransportListenAddr obfs4 0.0.0.0:TODO2

# Local communication port between Tor and obfs4.  Always set this to "auto".
# "Ext" means "extended", not "external".  Don't try to set a specific port
# number, nor listen on 0.0.0.0.
ExtORPort auto

# Replace "<address@email.com>" with your email address so we can contact you if
# there are problems with your bridge.  This is optional but encouraged.
ContactInfo <address@email.com>

# Pick a nickname that you like for your bridge.  This is optional.
Nickname PickANickname

Don't forget to change the ORPort, ServerTransportListenAddr, ContactInfo, and Nickname options.

  • Note that both Tor's OR port and its obfs4 port must be reachable. If your bridge is behind a firewall or NAT, make sure to open both ports. You can use our reachability test to see if your obfs4 port is reachable from the Internet.

4. Restart tor

  • CentOS / RHEL:
sudo semanage port -a -t tor_port_t -p tcp [OR port set earlier, in TODO1]
sudo semanage port -a -t tor_port_t -p tcp [obfs4 port set earlier, in TODO2]
  • CentOS / RHEL / OpenSUSE:

systemctl restart tor

5. Monitor your logs (usually in your syslog)

To confirm your bridge is running with no issues, you should see something like this:

[notice] Your Tor server's identity key fingerprint is '<NICKNAME> <FINGERPRINT>'
[notice] Your Tor bridge's hashed identity key fingerprint is '<NICKNAME> <HASHED FINGERPRINT>'
[notice] Registered server transport 'obfs4' at '[::]:46396'
[notice] Tor has successfully opened a circuit. Looks like client functionality is working.
[notice] Bootstrapped 100%: Done
[notice] Now checking whether ORPort <redacted>:3818 is reachable... (this may take up to 20 minutes -- look for log messages indicating success)
[notice] Self-testing indicates your ORPort is reachable from the outside. Excellent. Publishing server descriptor.

6. Final notes

If you are having troubles setting up your bridge, have a look at our help section. If your bridge is now running, check out the post-install notes.