i am pasting this below info from
microsoft site
link:
http://support.microsoft.com/kb/842242
Identifying and opening ports
If your program still does not seem to work after you add the program to the list of exceptions, or if you cannot locate the program in step 4 of the previous section, you can open a port manually. Before you can add a port or ports manually, you have to identify the ports that are used by the program. A reliable method for identifying the ports that are used by the program is to contact the vendor. If you cannot do this, or if a list of ports that are used by the program is not available, you can use Netstat.exe to identify the ports that are used by the program.
Identify ports by using Netstat.exe
1. Start the program in question and try to use its network features. For a multimedia program, try to start an audio stream. For a Web server, start the service.
2. Click Start, click Run, type cmd in the Open box, and then click OK.
3. Obtain a list of all listening ports. To do this, type the following at a command prompt, and then press ENTER:
netstat –ano > netstat.txt
4. Obtain the process identifiers for the processes that are running. Type the following command at the command prompt, and then press ENTER:
tasklist > tasklist.txt
Note If the program in question is running as a service, add the /svc switch to list the services that are loaded in each process:
tasklist /svc > tasklist.txt
5. Open Tasklist.txt and locate the program that you are troubleshooting. Note the process identifier for the process.
6. Open Netstat.txt and note any entries that are associated with that process identifier. Also note the protocol that is used (TCP or UDP).
The number of ports that the process uses may affect how this issue is resolved: • If the process uses more than 1024 ports, the number of ports probably will not change.
• If the process uses less than 1024 ports, the program may be using a range of ports. Therefore, opening individual ports may not reliably resolve the issue.