my Red hat 6.2 dist.. is it extremly necesary (i don't want to do so because in two years i had no probs with my server and want to mantain this "stability"...)
gotta love Linux

Ipchains available in the kernel 2.2 package(oldest version Linux), is ipfwadm successor and supports all the functionality of ipfwadm and more.

With the release of kernel 2.4 (actually, kernel 2.3.15), ipchains support has been phased out for the next generation firewall utility:iptables.
In later versions, the linux kernel includes netfilter,networking infrastructure that supports plug-in network traffic management utilities. Iptables program provides the user interface to netfilter.
So ampm2003..thankfully, if you've used ipchains, you'll be familiar with how "iptables" operates.
I agree with MsMitten here, RH Linux 7.3 it's stable (for me..) or upgrade your kernel if you like to get your hands "dirty" on Linux and you can start play around with your "iptables" and your "toys"

Cheerss