Hi, all -I'm working with a college to help them partially migrate from an Oracle-based mail system to Exchange 2007. They have about 5,000 faculty/staff accounts and tens of thousands of student accounts, all currently housed on an Oracle mail system.Only the faculty & staff email accounts will be moved to Exchange. The student accounts will remain on the existing mail system.The challenge... I'm not sure that they want to change e-mail addresses for anyone during this transition and students, faculty & staff all share the same email suffix.This presents some obvious difficulties.I could recommend some kind of front-end appliance that directs mail to the right infrastructure for processing, but the sending of internal mail will remain difficult, at best. I had also considered the possibility that the college could create mail-enabled contact records in AD for all of their students and point those records at the Oracle solution so that Exchange users could email the students. I'd need to find out if it's possible to do something similar on the Oracle side.No matter how you slice it, keeping this dual environment/single domain architecture in place will result in long-term frustration, but for now, I'm not sure if they can do otherwise.Any insight or advice about this is much appreciated.Scott

Hi Scott,Below article explains you, how to configure Exchange to route message for the shared address space. You can use Exchange as a front-end appliance because it routes internet/internal messages to oracle system if email address doesn't exists in Exchange environment.How to Configure Exchange 2007 to Route Messages for a Shared Address Spacehttp://technet.microsoft.com/en-us/library/bb676395.aspxAmit Tank | MVP - Exchange | MCITP:EMA MCSA:M | http://ExchangeShare.WordPress.com