Originally Posted By: moribundman
Question 1: When would I want to "ping?" Is it only used to see if another IP address is available for data exchange?
Often I will try to log into a friend/ family/ neighbor's system to perform updates or troubleshoot. If I cannot connect, the first thing I try to do is ping the client machine to make sure that it is still breathing.
Pinging a site that you darn well know ought to be up and running, like Yahoo, will confirm for you that you have network connectivity, too.
Pinging can also report to you how much latency is involved in a connection.
Basically, though, it's just:
"Hey, you there?"
"Yup."
Originally Posted By: moribundman
Question 2: What's the purpose of "Finger?" Who do I want to finger and why?
I've only ever know finger to give rudimentary information about a user.
Originally Posted By: moribundman
Question 3: What's the "Port Scan" good for?
The best analogy for a port scan is when a hacker scans your system for an open port through which he or she wishes to gain access to your computer: It is like a burglar jiggling a door knob, then trying to open a window, then looking under the welcome mat for a spare key, etc.; they're just running through a list of potential vulnerabilities.
It's nice to visit a site that will conduct a port scan on your system so you know if you have any open that needn't be. A web server, for example, has to at least have port 80 open, as that is the port through which web sites are served. Email servers, SSL connections, FTP connections, etc. all require different ports, so computers that intend to use (as a server) these function needs those ports to be open.
For me to be able to access my client's machine, then, I have to have port 22 open on their machines so I can issue commands to them, and port 5900 open on their machines so I can take control of their screen. Their machines are running a SSH server on port 22 and a VNC server on port 5900.