Controlling Network Traffic Direction

[Lap Yun Yau]

In our environment, we have a backbone (ethernet) with 4 independent
networks hook to it.  We want to make one of the network, say, network A,
to be a highly secure net.  Any node in network A can access any node on
the backbone or the other networks, but not vice versa.  Do you have any
good suggestion?

Right now we use a Sun 4/110 with a 2nd ethernet card in it as the router.
Can we set any parameter in the router to restrict the traffic flow?

Please email your advice/suggestions to me. Thanks
uunet!smosjc!lapyun