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How to determine which program uses or blocks specific transmission control protocol ports in Windows
Article ID: 281336 - View products that this article applies to.
This article was previously published under Q281336
This article discusses how to determine which program uses or blocks specific Transmission Control Protocol (TCP) ports.
The Netstat.exe utility has a new switch, the -o switch, that can display the process identifier (ID) that is associated with each connection. This information can be used to determine which process (program) listens on a given port. For example, the netstat -ano command can produce the following output:
If you use Task Manager, you can match the process ID that is listed to a process name (program). This feature enables you to find the specific port that a program currently uses. Because this specific port is in use already by a program, another program is prevented from using that same port.
Proto Local Address Foreign Address State PID TCP 0.0.0.0:80 0.0.0.0:0 Listening 888