I have a G4 running OS-X Server 10.2.6.
It has a static IP x.y.z.1 netmask on the built-in
ethernet from our campus class B net

I also have aliassed to en0 a webserver and a QuickTimeStreamingServer
on x.y.z.2 with the various .conf files properly setup.

I also have a lab of several multimedia Macs connected to a Netgear
Gigabit switch, one port of which goes to the G4 server's 2nd enet port
on an Apple Gigabit card. This port's IP is x.y.z.80 with a netmask I have NAT running, firewall off. Firewall rules report:
65535 pass all from any to any

Client machines in the lab can ping all three IP nrs on the server, and
receive web and QT streams, but get no further out to the world.

Clients outside can receive web and QT streams, and ping the first 2
IPnrs, but cannot connect thru to the lab.

Yes I do want a configured firewall eventually, but first I would like
to route traffic thru the server. I've gone cross-eyed over man pages,
and seen so much conflicting and confusing advice for all the different
flavors of linux. There must be a simple trick to set the gateway for
the "inside" interface...