XDISPLAY Over SSH With Putty & Xming/VcXsrv - UxOra

Quick article about how to transfer GUI display on local machine over SSH using PuTTY (or KiTTY) and XServer like Xming/VcXsrv.

Before starting, you'll need - A windows machine (as local machine) - A Linux machine (as a remote server)

On local Windows

X Server

Install one of the X Server below on your local Windows:

• Xming : Slower but lighter than VcXrv (https://sourceforge.net/projects/xming/)
• VcXsrv: Heavier but faster than Xming (https://sourceforge.net/projects/vcxsrv/)

Once install, just click on the program recently installed and a X logo (as below) will appear on the bottom right notification icons.

It means that the XServer is running in the background.

SSH/Telnet client

Install one of theses SSH/Telnet client on your local Windows:

• Putty (https://www.chiark.greenend.org.uk/~sgtatham/putty/latest.html)
• KiTTY (http://kitty.9bis.net/)

Run the program, and configure it as follow:

Under Connection > SSH > X11 :

• Check Enable X11 forwarding
• Enter localhost:0 for "X display location"
• Check MIT-Magic-Cookie-1

Under Session:

• Select SSH
• Select "Default Settings"
• Click Save button

On remote Linux

SSH session

From your local Windows, Open ssh remote session on your Linux machine with PuTTY/KiTTY

• Check that MIT-MAGIC-COOKIE-1 key has been added with: xauth list
• Make sure DISPLAY is set to: export DISPLAY=localhost:10
• Try to display something like: xclock & (if not present, install it with yum install xorg-x11-apps.x86_64)

# Check if MIT-MAGIC-COOKIE-1 key has been added [user@oralab01]$ xauth list oralab01.uxora.com/unix:10 MIT-MAGIC-COOKIE-1 1a1f7af9b7ca3c11183b529e51529e51 # Make sure DISPLAY variable is set [user@oralab01]$ env | grep DISPLAY= DISPLAY=localhost:10.0 # Display a x11 gui app [user@oralab01]$ xclock &

An xclock like below should display on your windows desktop :

Note Please note that display number DISPLAY=localhost:10 should match with the one in xauth list. Because it can be different from 10.

Tips

SU command

After a su command, you may have the following error if you try to xdisplay something:

KiTTY X11 proxy: Unsupported authorisation protocol Error: Can't open display: localhost:10.0

su open a new session and it does not transfer the session key, so you'll need to manually add the MIT-MAGIC-COOKIE-1 key after the su command.

# Check if MIT-MAGIC-COOKIE-1 key has been added [root@oralab01]$ xauth list oralab01.uxora.com/unix:10 MIT-MAGIC-COOKIE-1 1a1f7af9b7ca3c11183b529e51529e51 # Change user with su [root@oralab01]$ su - oracle # Add the MIT-MAGIC-COOKIE-1 from previous command [oracle@oralab01]$ xauth add oralab01.uxora.com/unix:10 MIT-MAGIC-COOKIE-1 1a1f7af9b7ca3c11183b529e51529e51 xauth: file /home/oracle/.Xauthority does not exist # Check if MIT-MAGIC-COOKIE-1 key has been added [oracle@oralab01]$ xauth list oralab01.uxora.com/unix:10 MIT-MAGIC-COOKIE-1 1a1f7af9b7ca3c11183b529e51529e51 # Set DISPLAY variable [oracle@oralab01]$ export DISPLAY=localhost:10 # Display a x11 gui app [oracle@oralab01]$ xclock &

Or you can use the following command before executing the su command:

su - oracle -c "xauth add $(xauth list | grep MIT-MAGIC-COOKIE-1 | head -1)" su - oracle

Or do not use su, but open a new PuTTY/KiTTY session and login with the right user.

Missing charsets warning

Warning: Missing charsets in String to FontSet conversion Warning: Unable to load any usable fontset

If you encounter this warning, set export LC_ALL=C to remove it.

HTH, Michel.

About MIT-MAGIC-COOKIE-1 A key is only available during the current session open by PuTTY/KiTTY. For each new PuTTY session, a new key will be generated and display number incremented if already used.

Enjoyed this article? Please like it or share it.