IPFW with user-ppp's NAT

[Wojciech Puchar]

>>
>> what's wrong in userland natd?
>
> Performance.  With userland natd, every packet that passes through natd
> must pass from kernel to userland (causing one context switch) and back
> again (causing another context switch).  This will be slower and use more
> CPU than doing it all inside the kernel, without any context switches.

true, anyway for my two 2Mbps symmetric connection (all for nat), and 
three 4/0.5Mbit connections (part for nat, mostly for squid) all natd 
processes takes at most 3 percent of single core (core2duo).