We are planning a migration of Exchange 2003 to Exchange 2010. This is a multi domain environnement and I need your input on what I'm about to propose them. I'm only migrating the corporate site and the remaining sites are waiting for me to deploy the CAS Internet-facing before starting there migration.
We have one DMZ, one SCZ and than the LAN, they are all separeted by firewalls.
In the DMZ, they will be the IRONMAIL (incoming Internet emails)
In the SCZ I will put a NLB of CAS array internet facing with HUB role install on it. The IronMail will send all email to those servers.
In the LAN, a NLB of CAS array with HUB role install and receiving the mail from the SCZ zone. Two mailbox servers with a DAG configure between those servers. I was also thinking to add another mailbox server for the latency replication.
We have 2200 mailboxes in the corporate site and 6400 mailboxes in the remaining domains.
Any input on this will be appreciated