I'm upgrading to 2010 in a domain that contains a single 2007 Exchange server. We're not using edge servers. Do I have to worry about the message routing issues described in http://technet.microsoft.com/en-us/library/dd346708.aspx for this scenario? Do I have to set up send/receive SMTP connectors between the 2007/2010 hub transports? Thanks.

What are the specific message routing issues that you are referring to? You do not have to setup specific send/receive connectors for email to flow from 2007 to 2010. The HUBs will be able to deliver email between themselves natively. You will have to maintain both versions of HUBs as only a 2010 HUB can deliver to a 2010 MB and same with 2007. In the link you referenced: http://technet.microsoft.com/en-us/library/dd346708.aspx#MR, note the "Message Routing Between Versions" section. If you are not utlizing Edge servers then it is very straight forward. The other considerations have to do with journaling or use of transport rules. Are you using either of those? Tim Harrington - Catapult Systems - http://HowDoUC.blogspot.com

Hiya, So long as you have an Exchange 2010 and Exchange 2007 hub transport (for example, you install a Exchange 2010 "typical" install), in the same AD site, then mail routing will work fine. You don't need any connectors, it should just work. When you switch over incoming mail to 2010, you would set the same setting on the 2010 Hub Transport (anonymous permission on the default receive connector, for example), then change your MX records, or NAT firewall settings, to deliver mail to the 2010 server instead, along with Send Connector setup so that Exchange 2010 sends mail instead of 2007. When you do this step, it should be pretty painless and won't affect routing inbound mail to the 2007 server. Steve Edit: See Tim answered too at the same time :-) As he says, pretty straightforward and watch the transport rules, you need to create matching ones in Exchange 2010. Steve Goodman Check out my Blog for more Exchange info or find me on Twitter

Thanks Tim and Steve. I'll give it a try and mark them as answers if it works.