I'm setting up a new Exchange 2010 environment with two mailbox servers in a DAG group. I have two NICs per server that I'm using. One for MAPI and one for Replication. According to Technet and several other articles I need to deselect "Replication" on the MAPI DAG Network so it will only be used for MAPI/DATA traffic. Only the Replication (Private) network will have the "replication" checkbox enabled. My Sr. Sys Admin disagrees with me and believes that both the MAPI and Replication DAG networks need to have the "Replication" option selected.
This is the only way he could get the DAG Cluster Name/IP to come online in Failover Cluster Manager. The DAG Cluster IP is on the MAPI network. If the "Replication" option is not enabled then the MAPI network shows as "cluster: disabled" in Failover Cluster Manager. The Cluster IP can not be brought online unless that network is Cluster: Enabled. It will only show as cluster: enabled if the "replication" option is selected.