I am in process of building a new Microsoft Exchange Server on a new domain. I will be using Exmerge to move the mailboxes from the old server to the new server. My plan is to shutdown the old mail server and to run Exmerge to create the pst files. After running the second phase of Exmerge to upload the pst files to the new Exchange server I would like to setup a gateway SMTP host that will direct all new inbound mail to both Exchange Servers. This allows me to the merge the old mail from the original Exchange with any new mail now coming into the new Exchange server. I prefer this method as it allows me to gradually move over users from the old Exchange Server to the new Exchange Server. Does anyone know of a method or third-party software that will allow inbound SMTP mail to be routed to two mail server whereby each mail server has the same copy of the email?
BTW the two Exchange servers are set-up with the same email addresses so internally both Exchange Servers will accept the same email.