PROBLEM:
How to See what process is using a TCP port in Windows Server 2008, 2008 R2?
SOLUTION:
The following command will show what network traffic is in use at the port level:
Netstat -a -n -o
The -o parameter will display the associated process identifier (PID) using the port. This command will produce an output similar to what is below.
(http://adventech.net/downloads/techfortechs/netstatano.jpg)
With the PIDs listed in the netstat output, you can use the following command to see the application that is using the port.
tasklist /svc /FI "PID eq 1812"
In this example I was looking for what application is using port 1812.
(http://adventech.net/downloads/techfortechs/tasklistsvrfipid1812.jpg)