In my post just the other day I provided a link to the new guide covering Exchange publishing via Forefront TMG or UAG. One poster followed up by asking, “How do I set things up when I have both TM...
Updated Jul 01, 2019
Version 2.0
Blog Post
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Combining Web Farm publishing with Software or Hardware Based Load Balanced CAS arrays
Hi Mike, you would still need to create an RPC Client Access array, for Outlook users to connect to, and to enable you to set on each database. But from a TMG/UAG perspective, you would add each server individually as members of the web farm you create. Then TMG/UAG can pick one CAS for each connecting client to use when connecting over HTTPS.
The fact that the same CAS is also probably part of the user's RPC Client Access array (which it would be if the users mailbox database were in that same AD site and using those CAS for it's MAPI endpoint), means the https traffic hits the rpc proxy on the CAS, then effectively loops on the same box to the RPC Client Access array (on TCP ports 6001, 2 and 4).
So yes, still create an array, for MAPI usage, but add each server individually, to get the rpc traffic, inside the HTTPs traffic, to the CAS.
The fact that the same CAS is also probably part of the user's RPC Client Access array (which it would be if the users mailbox database were in that same AD site and using those CAS for it's MAPI endpoint), means the https traffic hits the rpc proxy on the CAS, then effectively loops on the same box to the RPC Client Access array (on TCP ports 6001, 2 and 4).
So yes, still create an array, for MAPI usage, but add each server individually, to get the rpc traffic, inside the HTTPs traffic, to the CAS.