We are working on an Exchange 2003 to 2010 migration. The customer wants redundancy wherever possible. We are planning two Transport servers and I understand shadow redundancy for messages coming in from the edge transport. These transport servers will also be used for internal relay from various scanners and other machines need relay service.
My question is this. What can I do to build in some redundancy for these various machines needing internal relay. I can only put one relay server address into most of these machines. Can I use some sort of network load balancer to accomplish redundancy? Is there some more accepted method of accomplishing redundancy for internal relay machines?