Network problem

Hi everyone, hope you can help me out with the problem i have. On the main pc we are running comodo firewall on windows xp. We do not use a router to network the PC’s, just a hub/switch. On the secondary PC i can access the internet and connect to things just fine. However, when i try to play Modern Warfare 2, my NAT status on the game is Strict. I have disabled the firewall momentarily to see if it is that what is causing the strict status. It instantly went to open. Any ideas what im to enable or allow in the firewall to turn the status to open. I’ve tried a couple of things but im quite unsure of what to change and how to do it. Please if you can help me i would be really greatfull. Thanks.

Here is a little tutorial that describes how to open one port. Just use the same procedure for other ports or protocol.

To open the port TCP 1723 for example

First step is to determine the MAC or Physical address of you network connector. Go to Start → Run → cmd → enter → a black box will show up and enter the following → ipconfig /all (notice the space before /all) → enter → now look up the Physical address and write it down.

Notice that Physical address = MAC address

Firewall → Advanced → Network Security policy → Global Rules → Add → fill in the following:
Action: Allow
Protocol: TCP
Direction: In
Description: Incoming Port

Source address: Any
Destination Address: Choose MAC address and fill in the found MAC/Physical address
Source Port: Any
Destination Port: 1723

Then push Apply → Now make sure that the new rule is somewhere above the basic block rule(s) as the bottom (the block rules have red icons); you can drag and drop the rules → Ok.