Yikes, was banging my head against a wall trying to get X11 forwarding working on my RHEL 6.1 box. Every time I ssh’d in and attempted to pop an X window back to my fedora desktop, I was greeted with the error message below.

# Error: no display specified

Ok, I thought to myself — X11 forwarding is not enabled in sshd — let’s go fix it. However, when I checked /etc/ssh/sshd_config, I found that X11 forwarding was enabled. See the config item below, these needs to exist, and not set to no.

X11Forwarding yes

Ok so let’s check what the display variable is set to. So I ran the command below, which returned absolutely nothing, which meant that it’s not set to anything at all.

# echo $DISPLAY

So I check my local box and check to make sure that forwarding is enabled. Which it is

#grep X11 /etc/ssh/ssh_config
ForwardX11 yes

After I bit of research on google – I found a bugzilla that suggested I make sure that the following rpm was installed – xorg-x11-xauth.x86_64.  It wasn’t..

yum install xorg-x11-xauth.x86_64

Then logout and back in again. You will be now be greeted by the line below.

/usr/bin/xauth:  creating new authority file /root/.Xauthority

Now check your display variable.

# echo $DISPLAY
localhost:10.0

Ah, much better.