Is there anything weird I should know about using ipfw on alias addresses?

[Brett Davidson]

ifconfig shows the alias addresses correctly bound.
Creating an ipfw rule and testing it from the command line works 
(connects out from master address, not alias)

 From website on alias address, the firewall blocks the packets.

The weird thing is that it tags them (in the security log) as coming 
from the master address (not the alias) out the correct interface. In a 
normal world that would mean the packet would match!!!!!

What's goin' on here Willis?