Enable X11 Forwarding For AWS EC2 Linux Instance

Procedure :

i. [ec2-user@10-20-3-40 ~]$ xclock
    Warning: Missing charsets in String to FontSet conversion

ii. [ec2-user@10-20-3-40 ~]$ xauth list
    10-20-3-40/unix:12  MIT-MAGIC-COOKIE-1  7e53e7600ff4177d7bbc66bde0a1b1ca
    10-20-3-40/unix:11  MIT-MAGIC-COOKIE-1  e3d1a8915484c929ef3e809b047e6352


iii. [ec2-user@10-20-3-40 ~]$ env | grep DISPLAY
      DISPLAY=localhost:10.0

iv. [ec2-user@10-20-3-40 ~]$ xauth list | grep unix 'echo $DISPLAY | cut -c10-12' > /tmp/xauth
     [ec2-user@10-20-3-40 ~]$ ll /tmp/xauth ; cat /tmp/xauth
     -rw-rw-r-- 1 ec2-user ec2-user 78 Dec  7 14:47 /tmp/xauth

    10-20-3-40/unix:11  MIT-MAGIC-COOKIE-1  e3d1a8915484c929ef3e809b047e6352

v. [ec2-user@10-20-3-40 ~]$ sudo -i
    Last login: Fri Dec  7 14:43:12 UTC 2018 on pts/0


vi. [root@10-20-3-40 ~]$ xauth add 'cat /tmp/xauth'
     [root@10-20-3-40 ~]$ xauth list
     10-20-3-40/unix:11  MIT-MAGIC-COOKIE-1  e3d1a8915484c929ef3e809b047e6352

vi. [root@10-20-3-40 ~]$ env | grep DISPLAY
vii.[root@10-20-3-40 ~]$ export DISPLAY=localhost:11.0


viii.[root@10-20-3-40 ~]$ xclock 
     Warning: Missing charsets in String to FontSet conversion

Note :
After swtiching it from root to any other user please follow the step vi to step viii

[dinh@securehost ~]$ ssh -X ec2-user@ipaddress
Last login: Fri Dec  7 14:41:41 2018 from gw.ca.adm.pythian.com

       __|  __|_  )
       _|  (     /   Amazon Linux AMI
      ___|\___|___|

https://aws.amazon.com/amazon-linux-ami/2018.03-release-notes/
13 package(s) needed for security, out of 16 available
Run "sudo yum update" to apply all updates.

### Test xclock works from ec2-user
[ec2-user@ipaddress ~]$ xclock
Warning: Missing charsets in String to FontSet conversion
^C

### Show all magic cookie
[ec2-user@ipaddress ~]$ xauth list
ipaddress/unix:12  MIT-MAGIC-COOKIE-1  7e53e7600ff4177d7bbc66bde0a1b1ca
ipaddress/unix:11  MIT-MAGIC-COOKIE-1  e3d1a8915484c929ef3e809b047e6352
<strong>ipaddress/unix:10  MIT-MAGIC-COOKIE-1  07b3de3093cef835c19239ea952231b7</strong>

### Show DISPLAY variable
[ec2-user@ipaddress ~]$ env|grep DISPLAY
<strong>DISPLAY=localhost:10.0</strong>

### Create /tmp/xauth based on current DISPLAY variable
[ec2-user@ipaddress ~]$ xauth list | grep unix`echo $DISPLAY | cut -c10-12` > /tmp/xauth
[ec2-user@ipaddress ~]$ ll /tmp/xauth ; cat /tmp/xauth 
-rw-rw-r-- 1 ec2-user ec2-user 78 Dec  7 14:47 /tmp/xauth
<strong>ipaddress/unix:10  MIT-MAGIC-COOKIE-1  07b3de3093cef835c19239ea952231b7</strong>

### Sudo to oracle
[ec2-user@ipaddress ~]$ sudo su - oracle
Last login: Fri Dec  7 14:43:12 UTC 2018 on pts/0

### Add and Verify xauth
[oracle@ipaddress ~]$ xauth add `cat /tmp/xauth`
[oracle@ipaddress ~]$ xauth list
<strong>ipaddress/unix:10  MIT-MAGIC-COOKIE-1  07b3de3093cef835c19239ea952231b7</strong>

### Verify and Add DISPLAY variable
[oracle@ipaddress ~]$ env|grep DISPLAY
[oracle@ipaddress ~]$ export <strong>DISPLAY=localhost:10.0</strong>

### Test xclock works from oracle
[oracle@ipaddress ~]$ xclock
Warning: Missing charsets in String to FontSet conversion
^C
[oracle@ipaddress ~]$ 

### Example of failed xclock
[oracle@ipaddress ~]$ xclock
Error: Can't open display: 
[oracle@ipaddress ~]$ xclock