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Namespace sharing between 2 Domains (Exhcange 2010) without contacts.

    Question

  • Hi

    following these articles to share a domain between 2 differnent exchange orgs works ok without contacts.

    http://exchangeserverpro.com/how-to-share-an-email-domain-between-two-mail-systems/

    https://technet.microsoft.com/en-us/library/bb676395(v=exchg.141).aspx

    DomainC address is setup as an accepted "Internal relay" domain on DomainA "Receiving" and as Authorative on DomainB.

    A send connector is done from DomainA to DomainB.

    Mail flow works fine and email is delivered to both orgs and NDRs are also created.

    Without using a contact if a user in DomainB sends an email to someone in DomainA using DOMAINC as the email address then delivery fails as there is no connector back from DomainB to DomainA for it to forward this way for checking.

    IF a connector is put in back in this direction is there now a definite chance of mail looping ?

    thanks for any responses

    Friday, October 14, 2016 11:49 AM

Answers

  • If DomainB is authoritative for a namespace, it will fail on delivery if it doesn't have the address in its directory.  If DomainB needs to send to DomainA users, it should always use DomainA addresses.  If this is a merger/acquisition scenario, you need to add contacts to one or the other organization (most often, they go into both).  Can you give us more details on the scenario and why contacts can't be used?

    Will Martin ...
    -join ('77696c6c406d617274696e2d66616d696c6965732e6f7267' -split '(?<=\G.{2})' | ? { $_ } | % { [char][int]"0x$_" })

    Friday, October 21, 2016 12:35 PM

All replies

  • Let me be sure I understand your setup here - you have DomainA with both DomainB (authoritative) and DomainC (internal relay).  You don't say how DomainB and DomainC are configured - is DomainB separate from DomainA, or is it another valid domain for DomainA?  Are we talking about three orgs here, or just two?

    Now, also, where do your MX records point?  I assume the DomainA MX record points to DomainA, but if the DomainB MX record also points to DomainA, mail will never get to DomainB (if it is external to DomainA), unless you have contacts for DomainB in DomainA.  And where does the DomainC MX record point?  How would someone from DomainB send email to DomainA if it is bound for a DomainC address?


    Will Martin ...
    -join ('77696c6c406d617274696e2d66616d696c6965732e6f7267' -split '(?<=\G.{2})' | ? { $_ } | % { [char][int]"0x$_" })

    Friday, October 14, 2016 12:50 PM
  • Hi Willl..

    DomainA and DomainB are seperate exchange orgs in different forests.  (DomainA B and C are just examples of the setup) DomainC is the shared namespace domain.

    DomainC is configured as Accepted Internal Relay on DomainA exchange server and Accepted Authorative on DomainB exchange server

    There is a connector from DomainA pointing to DomainB  The Mx record for DomainC Points to DomainA's exchange server.

    Monday, October 17, 2016 7:35 AM
  • If DomainB is authoritative for a namespace, it will fail on delivery if it doesn't have the address in its directory.  If DomainB needs to send to DomainA users, it should always use DomainA addresses.  If this is a merger/acquisition scenario, you need to add contacts to one or the other organization (most often, they go into both).  Can you give us more details on the scenario and why contacts can't be used?

    Will Martin ...
    -join ('77696c6c406d617274696e2d66616d696c6965732e6f7267' -split '(?<=\G.{2})' | ? { $_ } | % { [char][int]"0x$_" })

    Friday, October 21, 2016 12:35 PM