X11 forward not working with Debian/Ubuntu, but OK with CentOS

[Thomas Mejer Hansen]

Hi 

I have for some time had the problem that I am unable forward X11 traffic using ssh when connecting to Debian/Ubuntu (12.04 and 12.10 I tested) servers running on GCE.

If I run an instance of CentOS it works fine after xauth is installed. But, I would like to use Ubuntu as my server.

I conect using:

"

>> gcloud compute ssh --zone "europe-west1-b" --ssh-flag="-X" instance-1

X11 forwarding request failed on channel 0

Welcome to Ubuntu 12.04.5 LTS (GNU/Linux 3.13.0-44-generic x86_64)

"

in /var/log/auth I notice the following entry

"

Feb 19 09:21:27 instance-1 sshd[2459]: error: Failed to allocate internet-domain X11 display socket.

"

Searching google I find that many have solved this problem by adding 

"

      AddressFamily inet

"

to /etc/ssh/ssh_config, followed by restarting ssh

However. This has no effect for me..

BTW. I connect from an laptop running Ubuntu.

I hope anyone can help me fix this. I really need X11 forwarding for a few crucial things.

- Thomas

[Adrian Barbachano]

Hi,

As per your message I understand that you modified the SSH client configuration file (/etc/ssh/ssh_config) instead of the SSH daemon configuration file (/etc/ssh/sshd_config).

I have been able to forward X11 in Debian and Ubuntu 12.10 (official images) by adding ‘AddressFamily inet’ to the /etc/ssh/sshd_config and restarting the server: sudo /etc/init.d/ssh restart.

Could you confirm if it was a typo? Did you manage to make it work?

Thanks,

Adrián B.

[Thomas Mejer Hansen]

Hi Adrian

Thank you very much. It was not a typo.. I edited the wrong file. Thank you for pointing that out..

I did though find that 

sudo /etc/init.d/ssh restart 

did not have any effect (nor did it provide any output)

But,  when I tried 

sudo service ssh restart

all was good, and I can now use SSH with X11 forwarding.

Thank you very much for the help

- Thomas