It's in the Demigod BIN directory.

Set your ports (about 20) and set up your router to forward them. Worked great for me!

I didn't have to set the 6073 port, I believe the range of ports is forwarded (by the game) through that 6073 port.

Also, using the reactor options file, you can limit those ports to a range of 20 instead of 100. Not a bad idea.

Easy: run 'impulsereactoroptions.exe' which is found in your <Demigod Install root>/bin directory.

That'll open a window where you have an (empty) cehck box, and under that a range of ports. Put a check in the box, use the default ports (6112 to 6132) or give your own, and then change your router to forawrd the new, smaller, range to your IP.