If you're looking for advice on configuring a firewall script, Oskar Andreasson's tutorial is excellent - go there first.

For the record, alamo is my gateway/firewall/router, and isotope is one of my workstations. Others have scripts very similar to it (but vary depending on what services are offered).

The rc.firewall.gateway.generic is a good starting point for a gateway/router box.

The rc.firewall.desktop.generic is a good starting point for a box directly connected to the internet.

The sshattacks file shows some example lines (and explanation) for using the recent match to help protect against the common brute force ssh attacks.

 Name                           Last modified      Size  Description
 Parent Directory                                    -   
 rc.firewall.alamo              16-Mar-2008 05:12   14K  
 rc.firewall.desktop.generic    17-Nov-2006 18:46  1.3K  
 rc.firewall.gateway.generic    19-Nov-2006 09:01  5.6K  
 rc.firewall.isotope            28-Aug-2006 16:43  6.8K  
 rc.firewall.startstopfunctions 18-Oct-2008 04:18  1.7K  
 sshattacks                     31-Dec-2008 05:47  3.3K