We are an organisation that has recently allied with another with the eventual aim of a full merger (I think a few months down the line). They have a W2K3 domain and Exchange 2007, while we also have a W2K3 domain and run Exchange 2003 (although we have built a 2007 cluster and plan to migrate to it in a month or so). The allied company needs it users to be able to send emails as users of our new domain which will later be the joint name of our merged organisation. How can I do this? Our two IT departments are going to be mostly seperate for the time being, although we do have a transitive trust in place between our two domains (so the respective domains' DCs have the right to access the others Active Directory). I guess we could have forwarders on our domain for the users of the other organisation, so outside emails going to their names with our domain name will be passed on to them. Obviously, this would not be ideal as the other users will see their mailboxes as belonging to their domain, not ours. Also, emails that get sent out to third parties will appear as belonging to their existing organisation. They could aslo be set up with accounts on our domain, which they could access with OWA from their domain, but this is messy and wasteful for their users to have mailboxes on both our system and theirs. I have never done this kind of merger work before, so don't really know what to offer. Any help would be much appreciated. Thanks, QH

Hi, In total how many people are you talking about?

Well a simple way would be to configure their Outlook to connect to your Exchange using RPC over HTTP, thereby doesnt matter where they are they connect to your exchange.

Maybe about 50 (from the other organisation) at first.

Instead of establishing a new domain, existing domains, one can rename the domain. then migrate the users can complete the process. have less number of usersDomain Renamehttp://technet.microsoft.com/en-us/windowsserver/bb405948.aspx

Hi,I suggest we configure the shared address space to work on this issue, below is the article for your reference:How to Configure Exchange 2007 to Route Messages for a Shared Address Spacehttp://technet.microsoft.com/en-us/library/bb676395.aspxThanksAllen