OpenBSD Firewalls

1) No growth limitations! No limitations on...
the number of interfaces on the firewall,
the hosts behind the firewall,
the number of redundant firewalls,
other software to run on firewall.

2) Readily and cheaply upgradeable with common components

3) Large support/developer community

4) All the functionality of any commercial firewall system but tightly integrated with the operating system

5) System Administrators can easily learn how to manage their own firewalls

6) Price