Mac Mini Server running Mountain Lion (10.8.2) is freezing during boot (last line: IPv6 packet filtering initialized) Starting in verbose mode (Cmd+V), the last line I see on the console is:

IPv6 packet filtering initialized, default to accept, logging disabled


This happens regardless of having an ethernet cable plugged in or not.

Starting in single user mode (Cmd+S), I can look around the filesystem, can remount it read write, everything looks ok. I can even start the network using:

mount -uw /
launchctl load /System/Library/LaunchDaemons/com.apple.kextd.plist
launchctl load /System/Library/LaunchDaemons/com.apple.notifyd.plist
launchctl load /System/Library/LaunchDaemons/com.apple.configd.plist


And ping systems on the local network.

When I exit the shell, the boot stops on the same spot.

Any ideas?
A possibility

The lack of progress, beyond the firewall-related message, may be unrelated to the firewall or networking. For example, these two lines from Intel Mac Pro Stuck on Gray Apple screen before OS load (2010-07-17): 

IPv6 packet filtering initialized, default to accept, logging disabled
Jul 15 22:08:39 kextd[25]: kextd_watch_volumes: Couldn't set up diskarb sessions


– that's not to say that your issue may be the same; just to encourage thinking beyond networking. 

Preliminary advice

Use Recovery OS: 


Disk Utility to verify the file system of the OS X startup volume
verify permissions of the OS X startup volume.


Then – if the file system is OK – get the full installer for OS X (at another Mac, if necessary); install to the outdated Mac.