How can i open a new Port on Firewall service (1200)

Question

Hello,
i need to open a port 1200 for one Application on my macmini server 10.6..
I have try to ad port to a Service and i did it, but is seams like the port
dont exist.
With Networkutility i make a port scan, but i don´t became succsses massage.
What is the best Way to open a port on Mac OS X Server 10.6.

Answer 1

You're probably working with broken client software (bad client test, bogus diagnostic, routing or IP error of some ilk), or the application server itself isn't starting correctly, or the firewall wasn't reconfigured correctly for the source address, or there's an intermediate firewall involved here.  
If it's the Mac OS X Server firewall that's blocking the traffic, you should see accesses in the log file, depending on the settings.  (If you have an external gateway-firewall at the edge of your network and a private LAN, then drop the server firewall and try it from a local client.  That'll provide clear evidence of which components are culprits and which are merely bystanders.)
If you're running the Mac OS X Server box as a gateway firewall, then IP routing errors can easily arise.
If you want to see if something is bound to port 1200 on the Mac OS X Server box, then launch Terminal.app and issue the command:
sudo lsof -i -P | grep -i ":1200"
and see what turns up.  You'll need to specify your administrative password for the sudo.
Port 1200 looks to be used for some Steam games and for some malware.  Most of the games seem to be UDP, though a few are both TCP and UDP.  The malware usually found on 1200 is reportedly largely using UDP.