We are currently migrating 600 users in various organizations outside our domain into our AD domain. We will be creating email accounts in Exchange 2007 as well. These users will keep their existing email addresses and not use the default addressing policy of my organization. For example, my domain is abc.com and my email address is alex@abc.com. We will be moving these users into our domain but they will be keeping their addresses, so john@xyz.com, kelly@def.com, etc. I have created an email address policy for the users, the accepted domain to reflect their domain,as well as the associated upn that reflects their email address. We are migrating users over one or two people at atime. So, if I create an email account called john@xyz.com and send a mail message to it internally, that person receives it fine. However, if I send a message tojane@xyz.com and she has not had her Exchange account made in my organization, the message will get rejected. So basically because the accepted domain and new email policy has been created I cannot send mail to users outside my organization with the same accepted domain or smtp domain as users that have been migrated to my organization...Exchange retruns the following: The recipient's e-mail address was not found in the recipient's e-mail system. Microsoft Exchange will not try to redeliver this message for you. Please check the e-mail address and try resending this message, or provide the following diagnostic text to your system administrator. Any ideas on a workaround in Exchange? I have looked through transport rules, etc. but can'tfind a work around. Thanks, Alex

The problem appears to be "the accepted domain to reflect their domain." My guess is you've made the accepted domain an Authoritative Domain. Make it an Internal Relay Domain.When the domain is authoritative, no other domains will be consulted. When Relay (non-authoritative), your domain will be checked first and then other domains, such as the old one from which the users are migrated.Exchange 2007 SMTP Namespace Sharing and Different Relay Domain Typeshttp://www.msexchange.org/articles_tutorials/exchange-server-2007/planning-architecture/exchange-2007-smtp-namespace-sharing-different-relay-domain-types.html Managing Accepted Domainshttp://technet.microsoft.com/en-us/library/bb124423.aspx How to Configure Exchange 2007 to Route Messages for a Shared Address Spacehttp://technet.microsoft.com/en-us/library/bb676395.aspx MCTS: Messaging | MCSE: S+M | Small Business Specialist