Set DISPLAY variable

Set DISPLAY variable & Enable access control

Before starting the Oracle Universal Installer, the DISPLAY environment must be set correctly for display terminal support.
To set the DISPLAY environment run the following command where hostname is the hostname or IP address of the system where the X server is running:

$ export DISPLAY=hostname:0.0

It may be necessary to enable access control on the system where the X server is running, so that the clients can connect.
The "xhost" command is used to set access controls. The xhost command must be run on the console of the system where
the X server is running. It cannot be done remotely.

To enable access control so that clients from any host can connect to the X server, type the following command:

$ xhost +

access control disabled, clients can connect from any host

To enable access control only to certain clients run the following command
$ xhost +hostname
For ex:- $ xhost +server1
Server1 being added to access control list

if you face
1. Error: Can't open display
Error: Couldn't find per display Information

Solution:
1. Run xhost + to enable access control
2. Set your DISPLAY