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luvsql's avatar
luvsql
Iron Contributor
Dec 14, 2022
Solved

Auto Forwarding to External Emails Not Working with Exception Added to Allow It

We have a shared mailbox that we need to setup auto fowarding so these emails can hit another application that uses an external email address.  The emails only forward when using an internal email address and not an external email address.

 

We do have an existing Exchange Rule set to block forwarding to external email address, so I added an exception to the rule for Sent to and this email address.  The emails are still failing to get forwarded.  

 

Except if

Is sent to 'email address removed for privacy reasons' - where this is the forwarding email address
 
I have contacted Microsoft support but they are now wanting to me globally modify our Anti-Spam automatic forwarding setting from System-Controlled to ON which is crazy.  We don't have an issue with internal so why do we have to globally allow all accounts to forward?  I just want ONE to allow external forwarding and all others to be disabled.
 
This is what the message trace shows:
 
Event:  Drop
Reason: [{LED=250 2.1.5 RESOLVER.MSGTYPE.AF; handled AutoForward addressed to external recipient};{MSG=};{FQDN=};{IP=};{LRT=}]
 
exchange online
  • VasilMichev's avatar
    VasilMichev
    Dec 15, 2022
    Hm, seems I overlooked/misread the drop message above - this is caused by the Remote domain settings, not the Outbound policy controls. Check the Default remote domain settings, or better yet, create a separate object:

    New-RemoteDomain blabla -DomainName blabla.com
    Set-RemoteDomain blabla -AutoForwardEnabled $false

8 Replies

  • Bardi's avatar
    Bardi
    Copper Contributor
    May 30, 2025

    This fixed the issue. Thank you Vasil.

    Additionally, use: Get-RemoteDomain | Select Name, DomainName, AutoForwardEnabled
    to display the remote domain settings on powershell.

  • VasilMichev's avatar
    VasilMichev
    MVP
    Dec 15, 2022
    You don't need to toggle it globally, simply create a new policy targeted to the mailbox in question and toggle it therein.
    • luvsql's avatar
      luvsql
      Iron Contributor
      Dec 15, 2022

      I disabled my Exchange Rule completely, that is set to block forwarding to external emails, and email forwarding still failed with the same error so it is not this policy causing the issue.

      If it's not exchange, how are we to find what's blocking this if the error doesn't tell us? In Defender > Policies and Rules >Threat Policies > Anti Spam, if I create a new Outbound there is nothing about internal or external forwarding. Only external forwarding fails. Also, the "Sender" is not possible to choose as a user since the mailbox is a shared mailbox, all forwarded emails show the sender as the original sender which is different for every email.

       

      I also changed the global policy to On and still all emails forwarded externally fail with the same error.  

      • VasilMichev's avatar
        VasilMichev
        MVP
        Dec 15, 2022
        Hm, seems I overlooked/misread the drop message above - this is caused by the Remote domain settings, not the Outbound policy controls. Check the Default remote domain settings, or better yet, create a separate object:

        New-RemoteDomain blabla -DomainName blabla.com
        Set-RemoteDomain blabla -AutoForwardEnabled $false

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