Introducing Exchange 2010 into Exchange 2003 Environment, need some quick insight regarding message flow
Posted on 2011-09-27
In the existing Exchange 2003 environment there are 2 servers. A mailbox server and a front-end server. The mailbox server receives inbound mail via a SonicWall appliance, which receives it from the Internet. The mailbox server is configured as the bridgehead server and is configured to forward all mail through the outbound connector to the smarthost, which is the front-end server. The front-end server hosts OWA, which is the primary email access method for over 500 of our users.
Here's my question: I am about to introduce Exchange 2010 into this environment and I want to know specifically how this is going to interfere with the current mailflow and at what point in the installation? Because of the time involved in creating/modifying DNS records, mx records, firewall rules, etc I need to be certain of these mailflow changes. Will mailflow change as soon as I introduce CAS into the environment on the 2010 box? Will 2003 want to start routing mail out through 2010 CAS? If so, I'll need to change rules on the SonicWall. Can I leave my inbound mail rules as they are and will 2003 automatically route inbound mail to 2010 if the mailbox is a 2010 mailbox? Or do I need to change inbound mail rules for SonicWall to point to 2010 CAS instead of 2003?
Idealy I'd like to have both 2003 and 2010 working simultaneously and to have OWA for both working at the same time as well.