I cannot start apache2 server because some other process is blocking port 80. From the Netstat I have learned that it is a System process who has a socket open to port 80 with an IP address of 0.0.0.0. This does not help much. What exactly in System process is listening on the port 80? How do I stop System process from using port 80? What the hell is IP address 0.0.0.0? Any thoughts?