>I've been thinking about setting up a v6-to-v4 gateway, somewhat akin
>to what faith(4)/faithd(8) provide.  However, I want it to be
>port-independent.
>
>This means (a) a way to bind a listening TCP socket without specifying
>a port and (b) a way to bind a socket to just the /96 corresponding to
>the mapped address space.  (Actually, (b) is unnecessary if I'm willing
>to give up on all ordinary incoming v6 connections to the machine, but
>I'm not.)

	basically, faith(4) is used for tagging packets to be grabbed by
	IPV6_FAITH sockets.  if we can tag traffic by other means, we can
	grab these traffic.  my preference is to have some packet filter
	directive to mark traffic, and avoid tweaking pcb layer.

itojun