I've searched through the Apple Knowledge Database looking for answers to
this but the information given is cryptic at best.

Current setup - Five Macs (one airport capable Quicksilver) and one PC all
accessing the internet through a single Pentium 200MHz machine running
Smoothwall Linux.

Changes I want to make - have my WallStreet II and soon to be purchased
iBook use Airport for a wireless connection to the local network and be able
to access the internet through the Linux box. I know I'll have to get a
different kind of card for the WallStreet II and I'll look into finding the
right kind of card at the time I actually need it.

The questions - I don't want to use the Airport base station for the
internet connection. I want all connections to the internet to go through
the Linux box for security reasons.
Do I even need the base station since all I want to do is routing for the
wireless connection? The Knowledge Base seems to imply that simple routing
through a software access point (the Quicksilver with an airport card) is
not supported.
If that's true then is it possible to just hang the Airport Base Station off
the Quicksilver and have it do routing for the other wireless machines?
-- 
"Man is a dog's idea of what God should be." --Holbrook Jackson