with the option of getting public IP addresses from my ISP, I'd like to
involve Border Manager 3.8 for security reasons to my network. With that
step I like to change my old email system to Groupwise. What is the best
network structure for this expansion? Here are my thoughts:

1.) I thought about bringing the BM into a DMZ and the GW system into the
internal network. So I could get maximum secure to my GW system in my eyes,
because all request to my public IP addresses could be managed with BM. With
the use of package filtering my GW system should be save from attackers. Is
this advisable? Or should I do it that way:

2.) Bring the BM and the GW Server into the DMZ and leave all other
requests except email requests to BM. Mail goes directly to GW system. Or,

3.) Is it advisable to use different trees. One for the internal network
and on for the DMZ, independent from the servers are in the DMZ.

Which is the best way to keep GW alive (for a long time), be able to manage
request to public IP addresses and have a secure network structure?

Thanks for the suggestions.