Determine Which Program is Blocking or Using a Port in Windows XP
Last Updated: Tue, 19 Apr 2011 > Related Articles
How to use DOS commands and the Windows Task Manager in order to determine which programs are using or blocking ports in Windows XP.
In Windows XP, use the netstat command to display the process identifier (PID) of the program that is currently using the displayed port. For example, entering the command netstat -ano would display the following results:
|Proto||Local Address||Foreign Address||State||PID|
To use the netstat command, perform the following steps:
- Click Start.
- Click Run.
- Type 'cmd' and click OK.
- In the DOS window type netstat -ano and press enter.
- This will give a list of all ports actively being used and the PID's that relate to the programs using those ports.
This shows us that port 80 is being monitored by the program with process identifier (PID) 888. Using the Windows Task Manager we can match this PID to the program that it is associated with. This will tell us what program is monitoring port 80.
To open Task Manager and match the PID's to a program:
- Press CTRL+ALT+DELTE.
- Click the Processes tab.
- If the PID column is not viewable then:
- Click View.
- Click Select Columns.
- Place a check mark next to PID (Processor Identifier).
- Click OK.
- Click the column header labeled as "PID." This will sort the processes by their PID number allowing the customer to easily find the PID they are looking for and the name of the process it is assigned to.
- Once this information is found, you can close the program that is using the port if you wish to do so.
All steps complete.