I have a large deployment where I'm putting ISA 2006 in front of an Exchange 2007 implementation to publish the Exchange resources through the Internet (OWA, ActiveSync). The Exchange implementation has an Edge server included and there's very little information from MS or anyone else on proper placement of the ISA server.
My dilemma is that if I put in the ISA server in front of the Edge server, I lose out on the ability of the ISA server to load balance traffic back to the Exchange CAS servers. If I put the ISA server behind the Edge server I lose the ability to have traffic load balanced to our ISA array (unless we add yet another load balancer in between which I want to avoid), plus the Edge server remains exposed.
Does anyone have suggestions on ow to approach this topology? I need the ISA array to be load balanced and I need to have traffic load balanced back to the CAS servers.