How to determine what software is using port 80 (or any other port)

For troubleshooting why the Web App Server says the port is in use...

Windows XP and 2003 have the tools built-in to determine what process is using a specific TCP/IP port. If you are using some other version of windows, you will not be able to continue as below. But there are still a number of third-party tools available which can be downloaded instead. One such tool that has been used successfully by several people is fport.


From a command prompt, run netstat -o. This will output a list of ports, along with the PID (process ID) that has that port open. The output looks something like:

Code:

C:\Documents and Settings\Administrator>netstat -o

Active Connections

  Proto  Local Address          Foreign Address        State           PID
  TCP    WEBAPPSERVER2:80       199.90.113.2:57434     TIME_WAIT       2636
  TCP    WEBAPPSERVER2:80       199.90.113.2:57589     TIME_WAIT       2636
  TCP    WEBAPPSERVER2:80       199.90.113.2:57600     TIME_WAIT       2636
  TCP    WEBAPPSERVER2:80       199.90.113.2:57608     TIME_WAIT       2636
  TCP    WEBAPPSERVER2:3389     12.110.143.84:6473     ESTABLISHED     964
  TCP    WEBAPPSERVER2:2325     192.168.0.13:netbios-ssn  TIME_WAIT       0

C:\Documents and Settings\Administrator>

The sample output above indicates that the local port 80 is being used by process id 2636.

To determine what executable is running as a process ID, open Windows Task Manager and switch to the Processes tab. Now click on View->Select Columns... On the screen that opens, make sure "PID (Process Identifier)" is checked and then click OK. Now click on the PID heading to sort the entries by PID. The screen below shows that PID 2636 is alpha5.exe, indicating that it is the Web Application Server using port 80 in this case.