[OS] Find out what process is using which TCP port in Windows 2008 Server

This is a useful tip while tracing TCP connection problems.

To list all network port numbers in use, use the following command

C:\>netstat –ano Active Connections   Proto  Local Address          Foreign Address        State           PID   TCP    0.0.0.0:135            0.0.0.0:0              LISTENING       872   TCP    0.0.0.0:445            0.0.0.0:0              LISTENING       4   TCP    0.0.0.0:1025           0.0.0.0:0              LISTENING       556   TCP    0.0.0.0:1026           0.0.0.0:0              LISTENING       964   TCP    0.0.0.0:1027           0.0.0.0:0              LISTENING       108   TCP    0.0.0.0:1028           0.0.0.0:0              LISTENING       644

To find out port numbers which is in “Listening” status, use the following command

C:\netstat –ano | find /i  “listening” TCP    0.0.0.0:135            0.0.0.0:0              LISTENING       872 TCP    0.0.0.0:445            0.0.0.0:0              LISTENING       4 TCP    0.0.0.0:1025           0.0.0.0:0              LISTENING       556 TCP    0.0.0.0:1026           0.0.0.0:0              LISTENING       964 TCP    0.0.0.0:1027           0.0.0.0:0              LISTENING       108 TCP    0.0.0.0:1028           0.0.0.0:0              LISTENING       644

To find out the service name behind the PID, use the following command

C:\>tasklist /FI “PID eq 8504” Image Name                     PID Session Name        Session#    Mem Usage ========================= ======== ================ =========== ============ taskmgr.exe                   8504 Console                    1     13,736 K

You should replace 8504 to whatever PID you would like to look for