SuSE

Is there a command line interface to the firewall?

iptables?

Thanks, the man page is 1200 lines, I think I'll wait til Monday.

Much like how 'man perl' doesn't tell you how to program in perl, the iptables manpage doesn't tell you how to make firewalls, and unfortunately iptables is a language of sorts. I had to start from base principles to try and understand it, and ended up having to draw flowcharts for the first time in a decade.

Utilities like firehol exist to make generating firewalls easier.

The Netfilter site has quite an index of documentation, including an Tutorial. Note that Netfilter/iptables is "only" a network firewall, and can't restrict certain applications, and doesn't do content inspection.