Forum Discussion
Hybrid Exchange Plus Addressing
I have an issue where inbound mail with plus addresses are not being delivered in our Hybrid setup with central mail transport.
Inbound mail-flow: Email Gateway >>> Ex2016 >>> Exchange Online (all user mailboxes in EXO)
The mail makes it to the onprem Ex2016 where I see "250 2.1.5 Recipient OK" on both the smtpreceive and smtpsend logs.
The messagetracking log shows:
recipient-status:> '[{LED=550 5.1.10 RESOLVER.ADR.RecipientNotFound; Recipient not found by SMTP address lookup};{MSG=};{FQDN=};{IP=};{LRT=}]'
custom-data:> S:ToEntity=Unknown;S:FromEntity=Internet;S:DeliveryPriority=Normal;S:AccountForest=<https://myDomain.com>
As the recipients are look-up-able in EXO by Exchange (remotemailbox) I thought it would attempt to resolve the address as a whole; once with the "+" as part of the username then attempt to resolve without the "+"and anything to the left.
It has been suggested that Exchange 2016 does not support Plus Addressing therefore this will not work. Is this the case? I cannot find any comment from Microsoft on this.
1 Reply
- Exchange 2016 does not support + addressing, but you can you the plus symbol in an admin created alias on any mail object in EX2016. EXO does support plus addressing, but the message would need to be received as such by EXO first.
