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Mail Flow

    Question

  • can someone please help me to understand the Hub Selector?

    how does it work? how does hub selector pick a server ?

    let's say i've 5 exchange servers

    i'm trying to send email from Ex1 server's user to EX2 server user

    how does hub selector know which server it has to select?


    • Edited by Habeeb0305 Wednesday, February 1, 2017 10:43 AM
    Wednesday, February 1, 2017 10:41 AM

All replies

  • I've never heard of a "hub selector".  In general, when you have multiple mailbox role servers (in Exchange 2013 there is no hub transport role, and you posted in an Exchange Server 2013 forum), any of them will be more or less randomly selected for transport by other Exchange servers.

    Send connectors have the SourceTransportServers property, which dictates which servers are used for the traffic defined in the connector.

    As for inbound mail, the first server is determined by the sending server.


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

    Thursday, February 2, 2017 1:30 AM
    Moderator
  • Hi,

    Now the Store Drive has been relocated to Mailbox Transport and split into two services (Submission and Delivery Services). The Mailbox Transport Submission service will pick up the message from the users Outbox, Run the Hub Selector process (in order to select the best Transport service which could be local or another server), and forward the message to the Default Receive connector in the Transport service (SMTP 25 or 2525).

    Firstly the Mailbox Transport Submission service uses the Store Driver to connect to the mailbox database using RPC and retrieves the e-mail.

    After resolving the message recipient to its mailbox database, the Mailbox Transport Submission service looks up the delivery group, a Mailbox delivery group in this case. So the Store Driver passes the e-mail to the Hub Selector for this to be sent over SMTP to the appropriate server.

    More details about exchange 2013 mail flow, please refer to the links below:

    https://blogs.technet.microsoft.com/rischwen/2013/03/13/exchange-2013-mail-flow-demystifiedhopefully/

    http://www.msexchange.org/articles-tutorials/exchange-server-2013/planning-architecture/exchange-2013-mail-flow-part3.html

    Please note: Since the website is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.


    Best Regards,
    David Wang
    TechNet Community Support


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    Thursday, February 2, 2017 2:48 AM
    Moderator
  • Hi,

    How about the issue?

    Are replies above clarify your question?


    Best Regards,
    David Wang
    TechNet Community Support


    Please remember to mark the replies as answers if they helped.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Tuesday, February 7, 2017 7:12 AM
    Moderator
  • The shadow redundancy maybe confusing you. What you need to know is the sending server will look up the recipients information within active directory. If exchange server will then send to that host via another host to make sure their is a copy of the message on another system until that message is acknowledge.

    If you are talking about how do I force the messages to a specific client access with the hub and outbound, you put them in the send  connector and use the proxy through client access server.

     
    Tuesday, February 7, 2017 3:25 PM