X11 Forwarding – SSH using XMING

After many years of working with PeopleSoft I try not to get to worried about the little things, because so much changes every day that you could lose your mind trying to keep track of it all.

I was doing an install of the Oracle Database software on a new RHEL 5.8 server the other day and I could not get my X11 forwarding working.  Now I don’t claim to be an expert in SSH and never will be, but I use the Bitvise Tunnelier and then use XMing for the SSH/X11 client software.  On this server I had setup the SSH Daemon to run X11 forward on using the default off-set 10.  This basically means that the communication for X11 will be on port 6010 instead of 6000. This means that your display variable will need to be set differently.  This is the export command I used:

export DISPLAY=localhost:10.0

In a lot of cases it will just show you 0.0, but because of the offset you need to change to 10.0 when using the off-set of 10. When setting up my SSH connection in Tunnelier, under the terminal tab, you need to enable X11 forwarding, and you will need to change your Display variable appropriately, in my case I was using the offset: 10, so I entered:

Lastly, I found that the XMing client defaults to NO offset, so when I launched XMING launch, on the first page it asks what the offset should be be.  Once I changed that to 10, everything started working great.

It should also be noted that if you are using a firewall (in my case iptables) you will want to make sure port 6010 is open correctly if using the ssh-offset 10.

The common error I got with this configuration being wrong as: Windows TCP error code 10061.