From time to time I use X11 forwarding to connect to various web management interfaces on remote servers, I had just done a new install of CenOS6.4 64-bit minimal to try out Backuppc, went to run the webGUI by doing the usual

ssh -X mrfoo@foo firefox --no-remote

and got the following error…

process 5513: D-Bus library appears to be incorrectly set up; failed to read machine uuid: Failed to open "/var/lib/dbus/machine-id": No such file or directory

Easy fix I think, minimal install, now Firefox, so I install Firefox, still no joy, same error persist.

Some things seem to have changed, and they may have done this to make things a little bit more secure, but if you need X11 forwarding,  here is what I did to fix it.

In /etc/ssh/sshd_config, uncomment and set to “yes” and “10” the following and then reload ssh

X11Forwarding yes
X11DisplayOffset 10
X11UseLocalhost yes

Now you need to install xorg-x11-auth.x86_64

[root@foo .ssh]# yum install xorg-x11-xauth.x86_64

This will not fix it yet, if you look in /var/lib/dbus you will see that either the file ‘‘machine-id” is empty or missing, to fix do:

 dbus-uuidgen --ensure

Now when you look at /var/lib/dbus/machine-id you should see a id string there.

That’s it, it should now work.