When mail is sent from a mailbox in Microsoft Office 365 Dedicated/ITAR (vNext) to an on-premises mailbox, an external Out of Office (OOF) message is received instead of an internal one.
This behavior is by default and by design. Microsoft is investigating, and this functionality may change in the future.
To enable cross-forest users to receive internal OOF messages, create a new remote domain for the on-premises domain, and make sure that the AllowedOOFType parameter set to InternalLegacy. To do this, run the following cmdlet:
New-RemoteDomain -DomainName <onpremdomain.com> -Name <name> -AllowedOOFType:InternalLegacyThe new remote domain will have the IsInternal parameter set to True. You can change the settings for the remote domain after it's created by running the Set-RemoteDomain cmdlet.
Article ID: 3188538 - Last Review: Aug 30, 2016 - Revision: 1