Linux Journal: Thwarting the System Cracker, Part 3Oct 08, 1999, 15:29 (0 Talkback[s])
(Other stories by Marcel Gagné)
"Getting to know your enemy through network ports and port scanners."
"For the serious newbies out there, here's how networks work on a really, really basic level. Your system's master process, the one that got the system going (after you pushed the 'on' switch that is) is called 'init'. init's process ID is 1. It is always 1. If you want to check it out, find init in your process table using 'ps'..."
"From a resources perspective, it makes sense to have a single process listening rather than one for each and every service. For those of you who can remember and visualize such things, picture Lily Tomlin as the telephone operator who (eventually) patches people through to the party to whom they wished to speak. She is inetd and the people to whom you wish to speak are the service deamons. You request extension 23 and eventually, she puts you through."