ipfw question...

[Xpression]

Hi list, I've this network configuration:

router (169.158.120.177)
server1 (169.158.120.178) running bind (named), tacacs+, exim, and a pop3
server
server2 (169.158.120.179) running squid, apache2, mysql, proftpd (is acting
as a GATEWAY)

I've a LAN (192.168.1.0/24) and a breaking apart "LAN" (192.168.2.0/8,
192.168.2.8/8, 192.168.2.16/8), my question is: I want to protect my LAN,
"LAN" and servers from the outside, I want to use ipfw, I have compiled a
kernel in server2 (FreeBSD-4.8 on both servers) and I'm blocked (in & out),
I've some doubts about adding rules 'cause I've been seeing so many samples
on the net and I'm a little bit confused...any suggestion about
configuration ???