Hi Koie, I agree with the others about the hardware setup: use a PIII-class box for ISA, and properly dimensioned servers for app/exchange purposes. As to the distribution of services, I'd use a 3 server setup as well, for different reasons. Isolating the firewall from other services does not only enhance the inherent security of the box, it also gives you some independence from the every day network business for maintenance, troubleshooting and the like. Further, by adding redundance, you distribute the possible points-of-failure more evenly which I regard as a very good argument. Exchange does need a good deal of resources (depending of course of the specifics of your setup and environment), and if you're planning to use OWA I would add an extra few percents to the calculated specs. Cheers Mark