Why is the 'System' process listening on port 443?

Problem

I am having problems starting my Apache server, because port 443 is already in use. It turns out, the system process (PID 4) uses the port 443. I don't have IIS installed, the services.msc shows (predictably) no Exchange server running, nor WWW-Services, nor IIS. I have no idea how to find out what service uses that port, short of just disabling each service one after the other, and I am not even sure that would help. I would be grateful if someone could point me towards how I can get my SSL port back, thank you :) P.S.: Of course "just switch Apache to another port for SSL" would solve the problem of not being able to start Apache. But I'd still like to know what is so insistent about hogging port 443. :) I by now took the 'hard route' and disabled services one after the other. It turned out that the "Routing and RAS" service was the culprit. Thank you all for the valuable input and the new tools in the combat against "WTF does my system do now?".