I am migrating users/mail between forest A (domainA.com) and forest B (domainB.com). Forest A uses Exchange 2003, and Forest B uses Exchange 2007. Once pilot users are migrated to the new forest, they need to receive email for both email addresses (@domainA.com and @domainB.com). This will be done by adding the appropriate proxy addresses. The remaing users that have not been migrated still need to receieve email from only the @domainA.com address. Inbound internet mail will go to an SMTP gateway that directs mail to the appropriate mail server. Once the pilot group is migrated, how will they receive email for the @domainA.com address since that mail will be sent to the maill server in domainA. Would configuring forwarding on each migrated mailbox be the simplest way to do this?