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

Question

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, thats it, not extension... nothing, just "SYSTEM". Whats going on here?

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

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UPDATE:

I've solved this through a stackoverflow question. Follow this link to find the solution for how to get IIS to stop listening on port 80 for a specified IP address.

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Answer 1

It sounds like IIS is listening to port 80 for HTTP requests.

Try stopping IIS by going into Control Panel/Administrative Tools/Internet Information Services, right-clicking on Default Web Site, and click on the Stop option in the popup menu, and see if the listener on port 80 has cleared.

Answer 2

Try netstat -b, that may hopefully shed some light on the situation (showing what .exe is using the port). Good luck.

Answer 3

the IP adress is 0.0.0.0, state = LISTENING: means that port 80 is listening to all interfaces (not used)

How to read NETSTAT -AN results

Answer 4

This wouldn't explain the PID side of things, but if you run Skype, it likes to use Port 80 for some reason.

Answer 5

Also, try stopping Microsoft SQL Reporting Services, that apparently defaults to 80. I did that and port 80 freed up. PID identified the culprit as "System", but apparently that System can mean multiple things.