Firewall 101

[Victor Odhner]

I am about to connect to Cox@Home.  Before I bring my Linux system
online for many hours at a time, what basic protection should I drop
into place? 

My planned use for the machine is all outgoing.  I want to initate
outgoing sessions in Telnet, FTP, HTTP, SSH, POP client, and maybe
an X server.  Considering this, if there's some simple FAQ that'll
tell me what services I should be sure to turn off, I'd appreciate
a reference.

And do I still need a firewall if I turn off unnecessary services?
E.g., do my console windows need telnetd, and if so does it have a
way to reject connects from the outside world?  If I bring up X,
is that an exposure?

BTW, One friend who uses Cox and Win98 has strongly recommended
ZoneAlarm < http://www.zonelabs.com/ > for the Win98 side. 

Vic