Port 80 is being used by SYSTEM (PID 4), what is that?

I am trying to use port 80 for my application server, but when I perform netstat -aon I get:

TCP 0.0.0.0:80 0.0.0.0:0 LISTENING 4

When I look up the process in task manager, it shows PID 4 is SYSTEM, that’s it. No extension… nothing. Just “SYSTEM“. What’s going on here?

I’m afraid to end this process, what do I do?

There are many services, which can listen port 80 on windows.

Luckily you can detect and stop them all running simple console command:

NET stop HTTP

When you’ll start it, you will get list first:

To avoid this problem in future go to Local Services and disable listed services.

N.B. – Some services will restart themselves immediately, just run ‘NET stop HTTP’ few times.