====== X over SSH with sudo/su ======

X over SSH is a nice feature which allow the X traffic to be encrypted in the SSH tunnel.\\
Executing su / sudo will although break the X traffic and result in a error\\

X11 connection rejected because of wrong authentication.\\
X connection to localhost:10.0 broken (explicit kill or server shutdown).

The problem is that the MIT-MAGIC-COOKIE not will survive sudo/su\\

Here is a little trick to add the originating users MIT-MAGIC-COOKIE to the end user

  # ssh -X <username>@<hostname>
  # xauth list
Output similar to:

  <hostname>/unix:<display>  MIT-MAGIC-COOKIE-1  <unique MIT-MAGIC-COOKIE key>


Copy output from xauth list (whole line), then sudo / su

As new user:

  # xauth add <the output of the above xauth list>
  # export DISPLAY=<hostname>:<display>

Hostname & DISPLAY variable, which is also seen in the xauth list.\\
You might skip the EXPORT DISPLAY command if the DISPLAY variable is already configured correct.