Hello, I use Exchange 2007. I'm thinking on migrating to Exchange 2010, though, I have the next questions:1. Is there any good document on that topic? I haven't found one.2. According to this: http://technet.microsoft.com/en-us/library/aa998604.aspxThe two Ex servers can coexist, during that period, how would they work? how would OWA work?3. What problems have you faced on this transition?Best Regards,John 3D

That would be the perfect place to start with: http://technet.microsoft.com/en-us/exdeploy2010/default.aspx#Home Select Upgrade from Exchange 2007. The utility will ask you few questions and generate instructions on all the needed steps.Elie B. MCITP: EMEA|EA|SA; MCTS: Microsoft Exchange Server 2010, Configuration; Blog: http://blog.elieb.info

HI, Exchange 2010 Client Access servers don’t proxy to the Exchange 2007 mailbox servers and Exchange 2010 CAS only proxy to the Exchange 2010 mailbox owners. Exchange 2007 CAS servers do the proxy to the Exchange 2007 mailbox servers. So you have to create new legacy url for the Exchange 2007 CAS servers and use it for redirection. When request came to exchange 2010 CAS server, if it is for Exchange 2007 mailbox owner, it will redirect to the exchange 2007 CAS server. It’s completely signal sign on solution, so users don’t want to know the new legacy url. Resources Transitioning Client Access to Exchange Server 2010 Regards Chinthaka Shameera | MCITP: EA | MCSE: M | http://howtoexchange.wordpress.com/