Tiger's Improved Firewall (and How to Use It)
Subject:   IPv6 ip6fw
Date:   2005-11-16 06:30:55
From:   RacerZero
It should be noted that most Mac OS X systems have IPv6 on by default. In early versions of 10.3 the GUI firewall only set rules for ipfw (IPv4 addresses) and not rules for ip6fw (IPv6 addresses). This changed in later 10.3 systems, not sure when. 10.4 client system do set firewall rules for ipfw and ip6fw when the GUI is used. Manually set rules in ipfw do not get mirrored in ip6fw settings.

In 10.4 Server the GUI firewall settings being made in Server Admin are only being set of IPv4 addressing. The ip6fw firewall is not set by default.

You can turn off IPv6 networking in the Network control panel. Turn it off for each network interface.