Internal Mailrelay for two Exchange Organizations for same SMTP-Domain


  • Hello all,

    the goal is to forward incoming emails over an edge server to smarthost, only if the recipient dose not have a mailbox in exchange organization.

    I did create an "Internal Relay" accepted domain for Domain. In coexisting phase some mailboxes with email address are in exchange Org. A and some of them in exchange Org. B.

    Problem: If a migrated user try to send an email to a not migrated recipient with address, Edge Server Role forward it to Smarthost, which is ok. But, if a not migrated user send an email to a migrated user with address, Edge Server Role does not send this email to the backend exchange server and forward it directly to smarthost.

    Backend Server are multirole Exchange Server.

    thanks in advance,


    Tuesday, October 24, 2017 1:51 PM


All replies

  • Post specifics on how you configured this.

    Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."
    Celebrating 20 years of providing Exchange peer support!

    Tuesday, October 24, 2017 2:53 PM
  • Hi.

    Scenario 1.

    You can enable forward message to Second Org B domain with save copy on original mailbox.  you need create power shell script with csv file for work with big list user.

    Scenario 2.

    You can use IMAP Sync for sync two different exchange organization with different name, but with special compared table .

    MCITP, MCSE. Regards, Oleg

    • Edited by Oleg.Kovalenko Tuesday, October 24, 2017 5:30 PM
    • Proposed as answer by Alex Sun MS Friday, October 27, 2017 3:45 PM
    Tuesday, October 24, 2017 5:26 PM
  • Check what is the target address of the mailboxes. may be the primary smtp is different and you may just be sending email to an alias.

    Thanks & Regards Ramandeep Singh

    Tuesday, October 24, 2017 9:37 PM
  • Hi,

    You can refer to this article for guidance about Internal relay domain. Regarding your scenario, could you please let us know some more details: where are the migrated mailboxes and the not migrated mailboxes host? On which side the domain is added as Internal relay and authoritative? And how you configured the MX record and the send connector.


    Alex Sun

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    • Proposed as answer by Alex Sun MS Friday, October 27, 2017 3:45 PM
    Wednesday, October 25, 2017 8:41 AM
  • Hi Soheil,

    Just checking in to see if above information was helpful. Please let us know if you would like further assistance. If the issue has been resolved, please mark the helpful replies as answers, this will make answer searching in the forum easier and be beneficial to other community members as well.

    Thanks for your understanding.

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    Niko Cheng
    TechNet Community Support

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    Thursday, November 2, 2017 2:42 AM
  • Hi all,

    sorry for my late replay.

    The Problem and the solution is well described here:

    In my case the edge Server dose not check if the Recipient has a Mailbox on backend CAS/MBX/HUB Server or not. The solution was to let backend CAS/MBX/HUB Server directly to send E-Maisl for  "Internal Relay" accepted domain for That was behavior by design of edge Server.

    Best regards,


    • Marked as answer by Mr. Bugfinder Saturday, January 6, 2018 1:49 PM
    Saturday, January 6, 2018 1:48 PM