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Sender not Validated : Mails when sent from another accepted domains

    Question

  • We are running Exchange 2013 with multiple accepted domains.

    We are stuck with some external recipients reporting that mails sent from 'Domain B' are going to SPAM folder with the reason as "sender not validated' 

    We have single send connector with HELO response  FQDN set as the primary default domain (Domain A)and all other accepted domain mails  using the same connector for sending mail. We are using a wildcard certificate as *.domainA.com.

    Is there a way  to define another send connector with Smart host and HELO responce FQDN as that of Domain B so that emails sent from Domain B users,  take a different route with different source address and reach gracefully.



    • Edited by Shireesh1 Monday, May 16, 2016 12:10 PM
    Monday, May 16, 2016 8:22 AM

Answers

  • Hi,

    We can create a specific connector for Domain B as your expectation, for your reference:
    https://technet.microsoft.com/en-us/library/jj839710%28v=exchg.141%29.aspx

    For your question about "sender not validated", I want to confirm:
    1. Whether this issue only occur on some special external domain or all external domain?
    2. Does it return NDR if this issue occur?
    3. Do you register relevant A record and SPF record for each domain name in public DNS?

    If it only occur on special external domain, it might be cause by anti-spam settings on destination domain. You can contact administrator for target domain to check whether your domain add as block domain list.

    Moreover, if it only occur on some Outlook client, please check the Junk Email filter setting, try to remove your domain or email address in block list.


    Please remember to mark the replies as answers if they help, and unmark the answers if they provide no help. If you have feedback for TechNet Support, contact tnmff@microsoft.com.

    Allen Wang
    TechNet Community Support

    • Marked as answer by Shireesh1 Wednesday, May 18, 2016 7:57 AM
    Tuesday, May 17, 2016 9:49 AM
    Moderator
  • Thank you Allen

    How would the connector learn if the mail is coming from a user from DomainA or DomainB in order to route it thru appropriate send connector since I have a default connector that directly submits the mail to internet . so how would creating a new send connector route only mails from DomainB through a smart host if chosen to.

    There is no NDR but yes you are right in saying that the recipient domain anti spam traps it as 'sender not validated'

    Creating TXT /SPF for the domainB worked for us, authorizing appropriate IP address to send mails for domainB.

    But I would like to understand if we can somehow route mails thru a connector on the basis of sending domain.


    • Edited by Shireesh1 Tuesday, May 17, 2016 1:53 PM
    • Marked as answer by Shireesh1 Wednesday, May 18, 2016 7:57 AM
    Tuesday, May 17, 2016 1:52 PM
  • Hi,

    We can modify the value of cost for each connector, it is used to set the priority of this connector when two or more connectors are configured for the same address space. The lower the cost, the higher the priority.


    Please remember to mark the replies as answers if they help, and unmark the answers if they provide no help. If you have feedback for TechNet Support, contact tnmff@microsoft.com.

    Allen Wang
    TechNet Community Support

    • Marked as answer by Shireesh1 Wednesday, May 18, 2016 7:57 AM
    Wednesday, May 18, 2016 1:56 AM
    Moderator

All replies

  • How is your mailflow, is this Any Antispam appliance using? both domain on same forest or different? are they external emails? 

    sachin hodge

    Monday, May 16, 2016 1:40 PM
  • Hi,

    We can create a specific connector for Domain B as your expectation, for your reference:
    https://technet.microsoft.com/en-us/library/jj839710%28v=exchg.141%29.aspx

    For your question about "sender not validated", I want to confirm:
    1. Whether this issue only occur on some special external domain or all external domain?
    2. Does it return NDR if this issue occur?
    3. Do you register relevant A record and SPF record for each domain name in public DNS?

    If it only occur on special external domain, it might be cause by anti-spam settings on destination domain. You can contact administrator for target domain to check whether your domain add as block domain list.

    Moreover, if it only occur on some Outlook client, please check the Junk Email filter setting, try to remove your domain or email address in block list.


    Please remember to mark the replies as answers if they help, and unmark the answers if they provide no help. If you have feedback for TechNet Support, contact tnmff@microsoft.com.

    Allen Wang
    TechNet Community Support

    • Marked as answer by Shireesh1 Wednesday, May 18, 2016 7:57 AM
    Tuesday, May 17, 2016 9:49 AM
    Moderator
  • Thank you Allen

    How would the connector learn if the mail is coming from a user from DomainA or DomainB in order to route it thru appropriate send connector since I have a default connector that directly submits the mail to internet . so how would creating a new send connector route only mails from DomainB through a smart host if chosen to.

    There is no NDR but yes you are right in saying that the recipient domain anti spam traps it as 'sender not validated'

    Creating TXT /SPF for the domainB worked for us, authorizing appropriate IP address to send mails for domainB.

    But I would like to understand if we can somehow route mails thru a connector on the basis of sending domain.


    • Edited by Shireesh1 Tuesday, May 17, 2016 1:53 PM
    • Marked as answer by Shireesh1 Wednesday, May 18, 2016 7:57 AM
    Tuesday, May 17, 2016 1:52 PM
  • Hi,

    We can modify the value of cost for each connector, it is used to set the priority of this connector when two or more connectors are configured for the same address space. The lower the cost, the higher the priority.


    Please remember to mark the replies as answers if they help, and unmark the answers if they provide no help. If you have feedback for TechNet Support, contact tnmff@microsoft.com.

    Allen Wang
    TechNet Community Support

    • Marked as answer by Shireesh1 Wednesday, May 18, 2016 7:57 AM
    Wednesday, May 18, 2016 1:56 AM
    Moderator