X11 Forwarding no longer working after CentOS update

[MarkEHansen]

I recently upgraded my CentOS machine from 7.0.1406 to 7.1.1503 and since then, I am no longer able to ssh/Putty from my local Windows PC (running cygwin and the cygwin XServer) to the CentOS machine and have X11 Forwarding work.

Previously, I would ssh -Y from my local PC to the CentOS machine and my DISPLAY would be set to something like localhost:10.0. I would be able to run X clients and they would display on my local PC's X Server.

Now when I ssh or Putty to the CentOS machine, DISPLAY is not getting set.

I do have X11Forwarding set to yes in /etc/ssh/sshd_config on the CentOS machine and use the -Y argument to ssh. When using Putty, it does have the X11 Forwarding feature enabled in the setting.

I'm guessing there must be some new restriction to getting X11Forwarding to work. Does anyone know what I need to do to get this working again?

Thanks,

[MarkEHansen]

Bump.

Any ideas why this stopped working? It was working before the upgrade to CentOS 7.1.

I sure could use some help with this.

Thanks,

[TrevorH]

Is xorg-x11-xauth installed?

[MarkEHansen]

Yes:

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xorg-x11-xauth-1.0.7-6.1.el7.x86_64

which xauth returns /bin/xauth

This was working just before the upgrade to 7.1 (it was running 7.0 at the time).

Thanks,

[TrevorH]

which xauth returns /bin/xauth

That sounds like the reason why then.

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[trevor@centos7 ~]$ which xauth
/usr/bin/xauth

[MarkEHansen]

How is that the problem? I'm not following:

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# ls -li /bin/xauth /usr/bin/xauth
1143264 -rwxr-xr-x. 1 root root 41720 Jun  9  2014 /bin/xauth*
1143264 -rwxr-xr-x. 1 root root 41720 Jun  9  2014 /usr/bin/xauth*

They seem to be the same. Notice that I didn't place the file in /bin. I assume the O/S installation did that.

Thanks again,

[MarkEHansen]

I found a thread on another forum which helped me. It seems I was getting the following error from sshd in my system log which led me to the solution:

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error: Failed to allocate internet-domain X11 display socket

Searching for this, I came across the following thread: http://dbaspot.com/solaris/397531-s10-s ... oblem.html

Specifically, post number 6. It seems the problem is due to the fact that I have the ipv6 network interface disabled. I just added the following to my /etc/ssh/sshd_config file and restarted the sshd service and now it is working again:

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AddressFamily inet

I'm including this here in the event someone else has the same problem.

Thanks again for all the help.