SSH with X11

ssh -X user@host [command]
xauth list, xhost + [localhost]

Disable X11 Forwarding

To disable X11 forwarding by default on the client side of the SSH connection, the side that would display the applications, add the following to the bottom of your ~/.ssh/config file, or the global /etc/ssh/ssh_config file:

     Host *
     ForwardX11 no
     ForwardAgent no

Reference

HLE: Intro X11 use - introduction to X
HLE: Abuse X11 2/2 - be root and have fun taking over another’s X session, play with x-related toys
HLE: SSH and X11 - if root or any user on the server can access your ~/.XAuthority file, your X is their X. So disable X11 forwarding from your client side and use the “-X” flag whenever you need it.