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Disable external users to send email to exchange distribution group

    Question

  • hi

    i need to create a transport rule to full file below task . we are having Exchange 2010. 

    01. Restrict, outside organization users to send email to inside Organization distribution groups.

    02. if any email target to distribution groups , sender will receive NDR with explanation message.

    03. in some cause , outside users send emails with TO or CC above mention distribution groups emails address with other email address . when this happen normal users should deliver the email and only distribution group must block the email . 

    ex: TO : sysadmin@abc.com,kavin@abc.com

    sysadmin@abc.com must not deliver the email and kavin@abc.com should receive the email without any issue .

    Monday, July 2, 2018 6:08 AM

All replies

  • Hi chaminda1985,

    By default, only senders inside your organization can send mails to group. Mails from external sender will be blocked.

    Regards,

    Kyle Xu


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

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    Tuesday, July 3, 2018 7:07 AM
  • Hi chaminda1985,

    Update some information about this thread:

    1. In Exchange 2010, we can use command below to check the value of RequireSenderAuthenticationEnabled:

    The function of this value:

    2. When user send mails to this group from outside of your group, they will receive a NDR with 550 550 5.1.1 User unknown (state 14) or 550 5.7.1 RESOLVER.RST.AuthRequired; authentication required

    3. In this case, normal account will receive this mail however group cannot receive this mail.

    Regards,

    Kyle Xu


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

    Click here to learn more. Visit the dedicated forum to share, explore and talk to experts about Microsoft Teams.

    Thursday, July 5, 2018 7:25 AM
  • Hi chaminda1985,

    Any update now?

    If the above suggestion helps, please be free to mark it as answer for helping more people.

    Regards,

    Kyle Xu


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

    Click here to learn more. Visit the dedicated forum to share, explore and talk to experts about Microsoft Teams.

    Tuesday, July 10, 2018 10:49 AM
  • Hi chaminda1985,

    Haven't received your update for a long time, any update now?

    If the above suggestion helps, please be free to mark it as answer for helping more people.

    Regards,

    Kyle Xu


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

    Click here to learn more. Visit the dedicated forum to share, explore and talk to experts about Microsoft Teams.

    Monday, July 16, 2018 10:01 AM