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Hybrid Mail Flow

    Question

  • There is a hybrid environment with exchange 2010.

    Some users mailboxes on exchnage online, some others in on-prem exchange.

    My question is;

    when a user from external domain send mail to my  domain where mailbox is on exchange online not in on-prem.

    --mail comes my firewall to check this user on my on-prem or not ...and then ? if not ? how this flow works ?

    Friday, June 3, 2016 7:48 AM

Answers

  • Can you send mail from an external source to Exchange on-premises?

    Can you send mail from an on-premises mailbox to a cloud mailbox?

    You say you have a hybrid configuration, so you have configured Azure AD Connect, right?

    The address for the cloud mailbox you're trying to send to has a corresponding mail-enabled user object in your on-premises AD with a RemoteRoutingAddress of the tenant e-mail address, right?

    Is your hybrid send connector properly configured?

    You might have to change the security setting in the Exchange Online inbound connector.  Often the certificate selection doesn't work right and you have to relax the setting.


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


    Saturday, June 4, 2016 4:57 PM
    Moderator
  • oh....after spent couple days...just disable/enable connectors on on-prem all started to work ! 
    Tuesday, June 7, 2016 8:23 AM

All replies

  • Your MX record can point to on-premises Exchange or to Exchange Online.  When the mail reaches either side, if the recipient is on the other, it is routed appropriately.

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

    Friday, June 3, 2016 8:12 AM
    Moderator
  • Your MX record can point to on-premises Exchange or to Exchange Online.  When the mail reaches either side, if the recipient is on the other, it is routed appropriately.

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

    When the mail reaches either side, if the recipient is on the other, it is routed appropriately. 

    Actually i am curious about this part. when mx records address on-prem but the mailbox on Exchange online. 

    How mail flow works ? Does DC answer that the mailbox on O365 and the flow go on via connector to O365 ?  or DC point to mx records of microsoft server ? Really confused..



    • Edited by Maclane Saturday, June 4, 2016 10:00 AM 1
    Saturday, June 4, 2016 9:59 AM
  • Actually my problem is on hybrid environment. Who has mailbox on exchange online cant get message from externel domains like yahoo, gmail.

    Sending mail;

    Exchange online to Exchange online is ok.

    Exchange online to on-prem  ( also vice versa ) is  ok.

    Exchange online to External domain (yahoo,gmail) is ok.

    from external to exchange online dosent work. ! my mx records point on-prem exchange. also i can see the mails on queue with 400.4.4.7 message delayed status.

    Saturday, June 4, 2016 11:44 AM
  • Can you send mail from an external source to Exchange on-premises?

    Can you send mail from an on-premises mailbox to a cloud mailbox?

    You say you have a hybrid configuration, so you have configured Azure AD Connect, right?

    The address for the cloud mailbox you're trying to send to has a corresponding mail-enabled user object in your on-premises AD with a RemoteRoutingAddress of the tenant e-mail address, right?

    Is your hybrid send connector properly configured?

    You might have to change the security setting in the Exchange Online inbound connector.  Often the certificate selection doesn't work right and you have to relax the setting.


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


    Saturday, June 4, 2016 4:57 PM
    Moderator
  • oh....after spent couple days...just disable/enable connectors on on-prem all started to work ! 
    Tuesday, June 7, 2016 8:23 AM