I've setup a new 2010 in Exchange 2003 (1 server) environment, I have both 2003 and 2008 Domain Controllers co existing also. 1) I've tested creating mail box on the new server and am able to send and receive e-mail when I create an account on either server. 2) I'm not able to share free/busy if the account is on the 2003 server 3) What else do I need to check to insure that the co existance is oeprating properly? 4) Is the next step after all the above is verified to move the mail boxes slowly to the new server? Thanks

Hello Look at this rapid guide to migrate/co existence of Exch 2003 and Exch 2010 by msexchangegeek. All the relevenat info you need is here. http://msexchangegeek.com/2010/01/30/rapid-transition-guide-from-exchange-2003-to-exchange-Isaac Oben MCITP:EA, MCSE

Thank you this was very helpful. One question though, once I created the new "send connector" if I disconnect the new server, the old server is not sending e-mail out. What do I need to do to correct this problem? Thanks

After Exchange 2010 Hub Transport role installation, by default the way out is through Ex2010 server. So you shoul not disconnect it :) During deployment you should disable Link state protocol, so Exchange 2003 is not able to recalculate routing if delivery of external mail changes.Regards, Konrad Sagala, MCT, 5xMCITP, MCTS: Exchange 2010

Hello In the scenario of Exchange 2010 which is installed in an existing Exchange 2003 organisation a Routing Group Connector (RGC) is configured during the installation of the Exchange 2010, Exchange server to allow mailflow between the legacy server and the new one. Exchange 2003 servers communicate with Exchange 2010 by utilising the Default SMTP Virtual Server. So you have to allow the SMTP relay from Exchange 2003 to 2010 server. In additions to Isaac Please try this article also for Migration of 2003 to 2010 http://www.networkworld.com/community/node/47632 Thanks Mhussain