Migrating from 2007 to 2013. The 2013 servers are separated (2 CAS, 2 MBX) because client wanted to just use WNLB. Therefore, the CAS servers have two NICs. I thought I had this set up correctly with WNLB, but mail is not flowing from 2013 to 2007. However, mail does flow from 2007 to 2013. These are the modifications I made to the Receive Connectors on 2013 CAS.
The Default Front-End had the original IP range removed and replaced with only the IP Addresses of the Internal Exchange servers (both 2007 & 2013). The Scoping was set to the primary LAN NIC and not the NIC used for WNLB.
A new FrontEndTransport Receive Connector was created with Anonymous to accept mail from the Spam Appliance and was set to use the NLB NIC (thinking that the Spam appliance would be set to send email to the NLB VIP).
Can't send out from 2013 to 2007. The email is stuck in the Outbound queue "SMTP Relay to Mailbox Delivery Group." The connectors on the mailbox servers were not touched.
MCITP Exchange 2010 | MCITP Lync Server 2010 | MCTS Windows 2008