In some email I received from Thomas Michael Wanka, sie wrote:
> 
> Hi all,
> 
> does anyone have resources (Howtos etc.) to help me set up 
> firewalling under netBSD? The only help I could find was from the 
> NetBSD.org homepage.

have a look at
http://coombs.anu.edu.au/ipfilter

there should be a link to a how-to type document down the bottom
of that somewhere.

Darren