I have multiple exchange servers at multiple sites.
Site 1 - Exchange 2010
Site 2 - Exchange 2007
Site 3 - Exchange 2003
Site 1 is the main domain, Site 2 and Site 3 are child domains. Exchange -> Exchange e-mail works fine. Users can e-mail between servers without issue. The problem occurs with external e-mail. If I send an e-mail from an external source to Site 1, but the mailbox exists on Site 2, it will not be delivered. If I do a test using telnet to Site 1, it accepts the e-mail without issue, and I don't see it in any of the queues. It's almost like Site 1 delivers it, but has no record. I can't do a message tracking because the mailbox doesn't exist on Site 1. Site 2 or 3 see's nothing of the e-mail. It's strange, because internal e-mail works between the three servers but anything coming from the outside fails if it is sent to the wrong Site (where the mailbox isn't held). Any ideas?