SSH Tunnelling for Exceed

I have a following requirement. Source (Windows-Exceed) ---> Destination (Linux Running XServer xdm-kdm) I am able to get the complete X GUI when I connect using Exceed to Destination. This works!! I just wish to go one step further and make it secure by making use of SSH Tunnelling. I have SSH-Putty on Windows for this. I have gone through the documents on the Internet and followed the steps. As follows. Start Exceed in Passive Mode. Enable X11 Forwarding in Putty and then connect to Destination Host. Start xclock and the output gets forwarded correctly onto my local Windows Host. But in order to start a Tunnel , they suggest to do following setup in Putty, Under Tunneling , SourcePort : Destination : localhost: so e.g For SMTP , it would be localhost:25 I got this far as well. Now the big question is , which destination port I should set here if I am willing to connect to destination Host's desktop? So with Exceed, I would simply connect to localhost and get the GUI Desktop of remote Destination.