Exchange 2019 Onprem - Accepting external email sent to for

Michael L 1 Reputation point


I'm having trouble setting up what is essentially a domain alias so that my new Exchange server can receive mail for addresses from my old domain.

I am trying to send mail to but allow Exchange at to receive it and deliver it to specific users with aliased secondary SMTP addresses. I have my MX records for pointing to and a distribution group with as an additional entry under the "email addresses" menu. I am a member of this group. This alias works great internally ( can email and it delivers), but when an email comes to from the internet it is not delivering. It does not make it past the Transport server.

I can see in my Exchange transport server log (MessageTracking logs) that the email is hitting, so my MX records are working, but the Transport server is just not delivering it to the Mailbox server. I don't see anything in this log that indicates that it is being rejected, but not showing up in my inbox.

I have specified in ECP on the Mailbox server as Authoritative and my distribution group allows external senders. Not sure what else I am missing here since it works internally if I email from another internal user's email. Do I need to change something on the Transport server itself? Receive and send connector mis-configuration? I am stumped.


Exchange Server Management
Exchange Server Management
Exchange Server: A family of Microsoft client/server messaging and collaboration software.Management: The act or process of organizing, handling, directing or controlling something.
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  1. KyleXu-MSFT 26,211 Reputation points

    @Michael L

    I would suggest you try to add the old domain name to one of your mailbox rather than distribution group, then send emails to this mailbox from the Internet. It could help us check whether the MX created correctly.

    Exchange distribution group will not receive email from the Internet by default, you need to set the "-RequireSenderAuthenticationEnabled" to false for this distribution group.

    Set-DistributionGroup -Identity groupname -RequireSenderAuthenticationEnabled $false  

    If you still cannot send emails to this group from external mailbox, whether this external mailbox receive NDR?

    I also suggest you provided information about command below:

    Get-TransportService | Get-MessageTrackingLog -Sender -Recipients -MessageSubject "subject" -Start 10/04/2022 -End 10/06/2022  

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    1 person found this answer helpful.