Config for FrontEnd/BackEnd Exchange Server

[KARR]

All,

I will be bringing Microsoft Exchange into my environment in the next 1-2 months and wanted to run a configuration by you guys/gals and possibly get some pointers/suggestions on how to make it as secure as possible:

The idea is to have the Front End Server of Exchange to sit in a perimeter network.

Heres the config:

Internet
||
||
Firebox 1000 (Top Firewall)
External (Public IP Address)
Trusted (Internal IP Address) ==>Internal Network
Optional (Public IP Address) ==>Cabled to NIC1of Front End Server

Front End Exchange Server
NIC1- Public IP Address
NIC2- Private IP Address ==> Cabled to External Interface on Firebox 500

Firebox 500 (Second Firewall)
External (Private IP Address)
Trusted (Internal IP Address) ==>Internal Network
Optional (Public IP Address) ==>Not used

BackEnd Server will sit on Trusted Network.

Is this possible and secure? Any help would be greatly appreciated as this is my first time doing something like this.

Thanks

Rob Wasiewicz