How do I port forward on a Mac? The tutorial at "portforward.com" didn't work for me. Anyone have any idea? (I have a Siemens Gigaset SE567 and know little about internet connection and whatnot.)

Uh... It's a router thing, not a OS thing.

But setting it up is different...i think.

I don't think so.. Enter your IP into your browser and access your router.

1 - Open Camino (NO FOLLOWING DIRECTIONS ALLOWED IF YOU DON'T USE CAMINO)
2 - Type 192.168.1.1 into the address bar
3 - ?
4 - Profit

You needa do two things.

The process depends on if you are on 10.4 or lower, or 10.5.

On 10.4, go to System Preferences->Sharing->Firewall and then add a new item, choose "other" and select a description for the entry. Enter the port range to be forwarded in the open fields.

Then go to 192.168.1.1 in the WEB BROWSER OF YOUR CHOICE (if anything, the password is probably "admin" if you haven't changed it) and forward the same ports. This will open it in both the OS X and router firewalls, and you should be set.

On 10.5, step 2 is the same, but for step 1 instead of Sharing->Firewall, go to Security->Firewall and add the port(s) there.