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Outlook app for iPhone and Android RRS feed

  • Question

  • I've been searching quite a bit online for an answer to this question, but have come up empty.  Hopefully we can get an answer without running down a firewall log/wireshark rabbit hole.

    We run a completely on-prem exchange 2013 system.  Our users connect via ActiveSync or OWA.  We have recently noticed a message header we would like to understand better on messages specifically sent via the Outlook app on the mobile device.

    Message-ID: <234234-23423423-23423@mail.outlook.com>

    Is the @mail.outlook.com just a generic address added to the Message ID from within the app?  Or is this an indication the message itself has somehow moved through the MS cloud email system?  Again this is using our company hosted email accounts.

    We have no cloud presence at all.  AD and Exchange is completely on-prem.. I'm under the impression logging in to the app on the mobile device would log the user directly into our mail system.  It wouldn't make sense for any of that information to move through a third-party system.  Does anyone have a definitive answer to why that message ID is using that domain?  

    Tuesday, November 19, 2019 9:17 PM

Answers

  • I read this official article and get the same results as yours. It mentions that Outlook for iOS and Android is a cloud-based application. Our experience consists of a locally installed app powered by a secure and scalable service running in the Microsoft cloud. The Exchnage ActiveSync comnnection between Exchnage Online and Exchnage on-premise enables synchronization of the user's on-prem data.

    Currently, after researhcing a lot, I haven't seen a way to change this behavior. From the official article, this should be by design. As it doesn't lead to any mail flow issues and on the contrary, aims to improve user experience, we can just ignore it. If you still have concern about this feature, I'd like to recommend you submit your feedback to Outlook for Android/iOS UserVoice forum.

    Thank you for your understanding and support:)

    Regards,

    Perry


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

    Saturday, November 23, 2019 5:24 AM

All replies

  • Hi steelie,

    Do all messages sent from Outlook app for iPhone and Android show this message-ID?

    If we send emails from OWA, will same situation occur?

    Message-ID is generated by the server. Normally, it should not be related with mail clients/apps.

    You can analyze the message header via this link. Or run following cmdlet:

    Get-MessageTrackingLog -MessageId <> |fl

    You will see which server process the email delivery.

    Besides, do you use EOP in your environment? This is a cloud-based email filtering service that helps protect your organization against spam and malware.

    Any updates, please feel free to post back.

    Regards,

    Perry


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

    Wednesday, November 20, 2019 5:54 AM
  • Messages sent via OWA or ActiveSync connections do NOT contain this message ID.  They contain the ID@ourdomain.com of our internal mail servers.  Only messages sent through the Outlook App are showing this ID@mail.outlook.com tracking ID.  We do not use EOP nor do we have any Office365 accounts.

    Using the Get-MessageTrackingLog command returns our internal mail servers, with three hops.  The first server hop in the log is 

    ClientHostname          : ourinternalserver.com
    EventId                 : RECEIVE
    MessageId               : <blah.guid@mail.outlook.com

    The other two servers' event IDs are SUBMIT and DELIVER, as expected.  To me this looks like the message was first received on our mail host from the mobile app itself, then processed as through our system to the user's mailbox.  It appears the app is adding mail.outlook.com even though it never actually goes through that system.  But based on this reference:

    https://docs.microsoft.com/en-us/exchange/clients/outlook-for-ios-and-android/use-basic-auth?view=exchserver-2019

    It looks like it may move through some portion of the cloud, even though we don't have any Exchange Online presence.  If it is moving through the cloud regardless of our completely on-prem solution, I would like to know if we can alter this behavior. 
    Wednesday, November 20, 2019 12:55 PM
  • I read this official article and get the same results as yours. It mentions that Outlook for iOS and Android is a cloud-based application. Our experience consists of a locally installed app powered by a secure and scalable service running in the Microsoft cloud. The Exchnage ActiveSync comnnection between Exchnage Online and Exchnage on-premise enables synchronization of the user's on-prem data.

    Currently, after researhcing a lot, I haven't seen a way to change this behavior. From the official article, this should be by design. As it doesn't lead to any mail flow issues and on the contrary, aims to improve user experience, we can just ignore it. If you still have concern about this feature, I'd like to recommend you submit your feedback to Outlook for Android/iOS UserVoice forum.

    Thank you for your understanding and support:)

    Regards,

    Perry


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

    Saturday, November 23, 2019 5:24 AM
  • Just check if there are anything else I can do for you.

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

    Tuesday, November 26, 2019 6:05 AM
  • Thank you, I appreciate the info.  Unfortunately we are not in a position of 'ignoring' the behavior due to security concerns, so we will be restricting the use of the app.  Thanks again.
    Tuesday, November 26, 2019 12:54 PM
  • You are welcome :)

    Here I will provide a brief summary of this post for your information.

      

    [Issue Symptiom]

    ====================

    When sending email from Outlook for Android/iOS, message ID become Message-ID: <234234-23423423-23423@mail.outlook.com>

         

    [Possible Cause]

    ====================

    Outlook for iOS and Android is a cloud-based application. Our experience consists of a locally installed app powered by a secure and scalable service running in the Microsoft cloud. The Exchnage ActiveSync comnnection between Exchnage Online and Exchnage on-premise enables synchronization of the user's on-prem data.

         

    [Reference Link]

    ====================

     https://docs.microsoft.com/en-us/exchange/clients/outlook-for-ios-and-android/use-basic-auth?view=exchserver-2019

    Wednesday, November 27, 2019 8:47 AM