What ports need opened on client?

[pyro_dw]

In the main menu, you can see/change the server/client port, so I have the ports set to forward to my PC.

Are there additional ports that I should be fowarding through my firewall to allow me to connect to a DirectIP Server?

If I put my PC into a DMZ, I connect fine but not when I am behind my firewall. I do not want to place my PC in the DMZ...that is why I have a firewall.

[azalae]

I usually let my friend host the game. We play rarely so I never bother with MP.

Should only be those two ports. Tip: you can change the port number(client port).

Check your firewall access logs for additional ports.
For example: Zone Alarm (Standard/Free version):

• Go to "Alert & Logs".
• Select "Log Viewer" tab.
• @"Direction" column check for "Incoming".
• @"Source IP" should be your friend's and @"Destination IP" yours.
• The IP format is: ###.###.###.###:PPP
  ### = 1-255
  PPP = Port number. Which is what you want.
• Protocol: TCP/UDP

Hope this helps.

EDIT:
I assumed you want to host the game, not joining one.