NAT (ipfw/natd) broken in latest -CURRENT

[Li, Qing]

> 
> The problem is, many NAT-PMP utilizing programs (e.g. p2p-clients)
> according
> to protocol specs do lookup of default gateway's IP address. FreeBSD
> ppp implementations tend to include correct address of gateway, so
> lookup works, while some other ppp implementations specify something
> other, e.g. inetrface route, self address... Will this change break
> those
> progs on FreeBSD too?
> 

AFAIK these programs should continue to function but let me know if you
think something is broken.

-- Qing