Where can I find doc to explain how xorg deals with hostname and DISPLAY?

[Adam Jackson]

On Wed, 2018-10-31 at 11:46 -0200, Alexander Franca Fernandes wrote:
> Hi.
> 
> I don't want a solution, only to understand what's happening, and where to find the explanation.
> 
> I'm using CentOS 7, despite I was an Slackware and Gentoo user (for more than 10 years).
> 
> After I connect into a VPN I get the message (when I'm trying to open X apps):
> 
> Invalid MIT-MAGIC-COOKIE-1 key
> (geeqie:12853): Gtk-WARNING **: cannot open display: :0

I suspect connecting to the VPN is changing your hostname? It probably
shouldn't, but that also shouldn't be an error. What does 'hostname'
and 'xauth list' print before and after you connect?

I'm still very confused by that though. The normal authentication path
on Fedora derivatives is xhost +si:localuser:$(id -u), you shouldn't
need a magic cookie at all.

- ajax