Query on DL email delivery

Question

Hi All

I am using exchange 2016 hybrid environment. we create users in onprem and migrate to online.

We have two domains. mydomain1 and mydomain2. we have our exchange/office365 infrastruture in mydomain1. mydomain2 is an external domain. mydomain2 is added as accepted domain in exchange onprem hosted on mydomain1, in exchange online it is added as remote domain.

Mydomain2 is triggering an email from an application using the from address as smb@mydomain1.com(smb@mydomain1.com is shared mailbox in mydomain1.com, smb created in onprem and migrated to online).

The email is triggered to an office365 DL in mydomain1.com. This DL has the below settings

Delivery Management: Senders inside my organization

Senders who will be able to send to the group: smb@mydomain1.com

Will this DL get the email?

Answer 1

If you are sending as an authenticated user through a correctly configured hybrid Transport connector from on-prem to 365, then yes the message will be treated as internal. If the messages are being sent anonymously from an application through on-prem Exchange and is not through an on-prem receive connector that has the perms set for "Externally authenticated", then message is considered external and will not be delivered to the 365 DL.