I have been asked recently for the required steps to configure Autodiscover when having Multiple SMTP namespaces, I have started writing few lines then upon checking my favorites I found a great bunch of blogs which explains the two possible solutions...

In Exchange 2010 when a source mailbox is moved from Exchange 2003 to Exchange 2010 using the Mailbox Replication Service there is a potential issue can arise that source mailbox is not removed at the end of the move. All of the content in the mailbox...

If the witness server you specify isn't an Exchange 2010 server, you must add the "Exchange Trusted Subsystem" universal security group to the "local Administrators" group on the witness server. These security permissions are necessary to ensure that...

In many of the disaster recovery scenarios in Exchange 2007, one of the most useful cmdlets is the “Move-mailbox” with the “ConfigurationOnly” parameter. With the “ConfigurationOnly” parameter the mailbox content is not physically moved but instead mailbox...

from http://www.msexchange.org/articles_tutorials/exchange-server-2007/planning-architecture/uncovering-new-rpc-client-access-service-exchange-2010-part2.html On the CAS servers, for Mailbox connections, you need to use add a DWORD registry key named...