X11-Forwarding (or) DISPLAY settings on Linux Servers

For Oracle installations, to launch GUI, we should have X11 to be enabled and set DISPLAY variables.

1) To enable X11 forwarding on Linux servers:

Install required packages as first step.

X11-forwarding  : ✔  (remote display is forwarded through SSH)

$ yum install xorg-x11-xauth xorg-x11-fonts-* xorg-x11-font-utils xorg-x11-fonts-Type1 xdpyinfo -y

Set below three parameters:

$ vi /etc/ssh/sshd_config 
    X11Forwarding yes
    X11DisplayOffset 10
    X11UseLocalhost no
 
$ systemctl restart sshd

$ systemctl status sshd.service

2) Set DISPLAY variable 

echo $DISPLAY, if not set then export DISPLAY=<hostname/IPADDRESS>:<port>

Ex: $ export DISPLAY=oracledemo:0.0
      $ echo $DISPLAY
   oracledemo:0.0