Originally Posted by man ssh
Code:
-X Enables X11 forwarding. This can also be specified on a per-
host basis in a configuration file.
X11 forwarding should be enabled with caution. Users with the
ability to bypass file permissions on the remote host (for the
user's X authorization database) can access the local X11 dis‐
play through the forwarded connection. An attacker may then be
able to perform activities such as keystroke monitoring.
For this reason, X11 forwarding is subjected to X11 SECURITY
extension restrictions by default. Please refer to the ssh -Y
option and the ForwardX11Trusted directive in ssh_config(5) for
more information.
-x Disables X11 forwarding.