Linux network security poll

[Zach <netrek@gmail.com>]

I need to get serious about security since I will be soon connected to
the net almost 24x7 (barring a power outage etc.) so I was wondering
if list members could explain their security setup (network
configuration, DMZ, firewalls, IDS, logging, etc.). Also what would
you recommend for someone like me who is still on an entry level in
terms of my understanding of Linux and network security and what would
recommend for later on down the road once I get more sophisticated? I
run Debian lenny with a 2.6.18 kernel. I will be getting ADSL next
week and plan on having a DSL modem/router doing NAT. I only have one
machine now but plan on adding another one within the next 3 months or
so.

Zach