PuTTY X11 proxy: Authorisation not recognised: Error: Can’t open display: localhost:10.0


I am trying to login to root as sudo user and launch the command “xclock” , I am getting the error message as “X11 Error while trying to launch the x-windows from your putty session.”


PuTTY X11 proxy: Authorisation not recognised

Error: Can’t open display: localhost:10.0


[a] You have done an su or a sudo to a switch user, without copying the correct MIT-MAGIC-COOKIE authentication.

[b] You should list these cookies by entering the following, under the account you used to login:

STEP [1] :

Login as the normal user to the below information:

[siva@quickfixlinux01~]$ env | grep -i display

[siva@quickfixlinux01~]$ xauth list
quickfixlinux01/unix:13 MIT-MAGIC-COOKIE-1 cc283cfe97bb7dd9d52033373ecaee88
quickfixlinux01/unix:12 MIT-MAGIC-COOKIE-1 fde7a475c557b63111fc3ca55191bd91
quickfixlinux01/unix:11 MIT-MAGIC-COOKIE-1 98e8669a8c1274a8bf1199c8401c6ca9
quickfixlinux01/unix:10 MIT-MAGIC-COOKIE-1 2a739990b2459b2db028a8e67c30ff26 

STEP [2]:

Now, we need to add the MIT-MAGIC-COOKIE’s into the root account to enable the xclock. ¬†Therefore, as the user (in this case, root) trying to run the X11 application, add the cookies manually.

[siva@quickfixlinux01~]$xuath add quickfixlinux01/unix:10 MIT-MAGIC-COOKIE-1 2A739990b2459b2db028a8e67c30ff26

STEP [3]:

Now Login as sudo to root and then execute the command “xclock” and you should be able to launch the x windows successfully.

Pre-Diagnostics Steps:

  1. Make sure you have enabled the X11forwarding in /etc/ssh/sshd_config file

  2. enable the X11 option in putty session.

  3. Install and launch the Xming or VcXsrv tool if you are using the windows machine.


You may also like...

Leave a Reply