mailbox delivery queue

A group of temporary queues that hold messages that are being delivered to a Mailbox server by using encrypted Exchange RPC. Mailbox delivery queues exist on Hub Transport servers only. A different mailbox delivery queue exists for each Mailbox server destination. The destination Mailbox server must exist in the same Active Directory directory service site as the Hub Transport server. Mailbox delivery queues are dynamically created as needed and are automatically removed. [Exchange 2007]