Some good steps for securing your Unix installation

1. Uninstall unused services
2. Setup the ipf firewall on your FreeBSD install.
3. Update your ports directory
4. Setup snort on your internal network and try out SnortALog (Google it) It’s a nice tool that greps your firewall logs for info and ports it to Apache for a nice status website showing incidents.
5. Install patches when they’re released.