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

ISSUE:

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.”

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[root@quickfixlinux01~]#xclock

PuTTY X11 proxy: Authorisation not recognised

Error: Can’t open display: localhost:10.0 [/stextbox]

RESOLUTION:

[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:

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[siva@quickfixlinux01~]$ env | grep -i display
DISPLAY=localhost:10.0

[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  [/stextbox]

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.

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

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.