There are two forms of using x2x: without ssh and with ssh. In this document we refer of two hosts: *slave* and *master*, where slave is the one who receive connections and the master is the one who controls the slave and where x2x is installed.
Using x2x without ssh
If you are using x2x without ssh, you need to approve access to the hosts with
xhost command. So, the host that will receive the connection need to
authorize the controller host.
$ xhost +master
$ x2x -to slave:0 -east
Using x2x with ssh
Although you one can be using x2x without ssh, make use of ssh turns things much easier. On slave, just do::
$ ssh -X master 'x2x -to :0 -east'
Error "No protocol specified"
If you get an error like "No protocol specified", you are probably trying to
be using x2x without ssh but you forgot to add permissions to the master
host with the
xhost command. Check it out.