I have a Linux server (slowly being phased out by my OS X server) connected directly to the internet with a static IP address. Then I have an old PowerMac 9500 running OS 9.1 with Retrospect and a tape library to back up my Linux server. I like to be able to check the status of my backups remotely. This is how I did it.
First I installed VNC on the 9500 (OS9vnc Server v3.5.0) and set it up so that VNC runs as soon as it boots. It also auto-connects to the shares to be backed up. And it has a static IP address. Second, I installed VNCDimension on my PowerBook and created a session that connects to 127.0.0.1 and saved it. Here's how it looks:
PowerBook --internet-> Linux Server --intranet-> 9500
Then I run this script on the PowerBook. I called it vnc9500 as this works with my other computers. All I need to do is copy the script, rename it and change the IP of the computer I want to remote control.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20051019082720889