We are upgrading exchange 2007 to 2010 this weekend. I am trying to catch up on reading the technical issues but was hoping someone could answer this questions. We currently have all roles on one exchange server. OWA, ActiveSync, Outlook Anywhere, Blackberry. If I introduce exchange 2010 to the ENV. And start to move mailboxes will mail still flow through exchange 2007 by default until I change it? will 2010 route through exchange 2007? I have to move everyone;s mailbox before I change SSL Cert, Firewall ..... so I was hoping if I move mailboxes all I can still utilize services like OWA, Blackberry from 2007. Thanks - SJMP

As long as you have a HUB role of each version, email will flow. As far as to and from the internet goes, you can control this by your send and recieve connectors. Until you move the send connector to 2010 server, email will continue to flow out of your organization from 2007. Here is a good link for interop: http://technet.microsoft.com/en-us/library/dd346708.aspx Now talking about OWA/Activesync. A 2007 CAS server can not be the "front-end" server for users on a 2010 mailbox server. The proper and only supported method is to move client connectivity to the 2010 CAS server first. When doing this, the 2010 CAS will proxy/redirect communications to the Exch2007 server for 2007 mailboxes. Here is a good link for interop: http://technet.microsoft.com/en-us/library/dd351133.aspxTim Harrington - Catapult Systems - http://HowDoUC.blogspot.com

Also take a look at these articles: http://msexchangeteam.com/archive/2009/12/02/453367.aspx http://msexchangeteam.com/archive/2009/12/08/453472.aspx /MartinExchange is a passion not just a collaboration software.

Thanks guys - this is exactly what I needed. can you tell me re: co-existence and the legacy DNS entry. I understand I need to redirect my internal/external DNS mail & autodiscover A Records to the exchange 2010 server. And add legacy A record for the 2007 server. But what services/ports on firewall am I still pointing to my exchange 2007 server? From what I understand all mail should be directed to 2010 server. And adding a route internally on that server to 2007 server for mail flow. Do I point legacy.company.com to 2010 server and it will handle the routing based on internal DNS? Confused sorry. how does it work with OWA/Activesync that have mail.company.com, this A record now points to 2010 server, but mailbox sits on 2007 server? How would a outlook client on the internet know that legacy.company.com will redirect them to 2007 server?

Hi, You will point your current external DNS entries to the Exchange 2010 server ie. mail.company.com and autodiscover.company.com etc. You will create a new entry called legacy.company.com and point that to the Exchange 2007 server. Port 443 should be the only port open to the Exchange 2007 server and port 25 and 443 to the Exchange 2010 server. The internal mailflow should work out of the box, so no need for extra entries and routes here. Your clients should automatically discover what home server it should connect to and then change its configuration by itself. /MartinExchange is a passion not just a collaboration software.

Hi, This link would be helpful for you: Transitioning Client Access to Exchange Server 2010 http://msexchangeteam.com/archive/2009/11/20/453272.aspxPlease remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. Thanks Gen Lin-MSFT