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Inbound Proxy Probe Undeliverable (Health Mailbox)

    Question

  • Hi, we've recently switched our anti spam filter to Mimecast and I've started noticing in the 'Bounce' section an email every couple of minutes being caught as undeliverable, shown below. This was most likely happening before, but our previous anti spam filter was useless!

    I'm aware of the HealthMailboxes and from my understanding they should be receiving these emails, rather than attempting to send them externally. I've managed to catch one of these emails and it contains the following content:

    Delivery has failed to these recipients or groups: HealthMailbox3ac30e4d99434adaa06f83ce3062fb1f@OurDomain.co.uk The email address you entered couldn't be found. Please check the recipient's email address and try to resend the message. If the problem continues, please contact your helpdesk. Diagnostic information for administrators: Generating server: mailserver2.OurDomain.lan HealthMailbox3ac30e4d99434adaa06f83ce3062fb1f@OurDomain.co.uk Remote Server returned '550 5.1.1 RESOLVER.ADR.RecipNotFound; not found' Original message headers: Received: from mailserver2.OurDomain.lan (192.168.0.10) by mailserver2.OurDomain.lan (192.168.0.10) with Microsoft SMTP Server (TLS) id 15.0.1130.7; Mon, 25 Jan 2016 11:15:44 +0000 Received: from InboundProxyProbe (127.0.0.1) by mailserver2.OurDomain.lan (127.0.0.1) with Microsoft SMTP Server id 15.0.1130.7 via Frontend Transport; Mon, 25 Jan 2016 11:15:44 +0000 X-MS-Exchange-ActiveMonitoringProbeName: OnPremisesInboundProxy_2 X-Exchange-Probe-Drop-Message: FrontEnd-CAT-250 Subject: Inbound proxy probe Message-ID: <1125c87ee52942dea2fd46d60221eec2@mailserver2.OurDomain.lan> From: <inboundproxy@contoso.com> To: Undisclosed recipients:; Return-Path: inboundproxy@contoso.com Date: Mon, 25 Jan 2016 11:15:44 +0000 MIME-Version: 1.0 Content-Type: text/plain

    The listed mailbox does exist and contains the SMTP address. I've followed steps to rebuild the mailboxes and they are recreated as expected, but then within moments of them all being recreated the issue starts happening again.

    Our system contains 3 mailbox servers all members of a DAG, each containing a copy of 4 databases. They are all running Exchange 2013 CU10.

    Thanks for any help.

    Monday, January 25, 2016 11:35 AM

Answers

  • Hi,

    Please see an explanation of the issue here: http://exchangeserverpro.com/exchange-server-2013-inboundproxy-com-ndr/

    Then follow the instructions here: http://blog.c7solutions.com/2013/06/queues-building-to-inboundproxycom.html.

    Let me know if you need more help troubleshooting the NDR.

    Thanks.


    Please mark as an answer if this answers your question

    Mark Gossa

    MCSE 2003, MCITP Enterprise Administrator 2008 R2, MCSA 2012 R2, MCTS Exchange 2010, MCTS SQL 2012, MCTS SharePoint 2007, VCP4, VCP5, CCNA

    Blog: http://markgossa.blogspot.com   LinkedIn:    Twitter:   

    Posts are provided “AS IS” without warranty of any kind, either expressed or implied.

    • Marked as answer by AndyH16 Monday, January 25, 2016 2:27 PM
    Monday, January 25, 2016 12:29 PM
  • Hi, always happy to help, obviously change the two references to 'yourdomain.co.uk' to your own domain:

    Get-Mailbox -Monitoring | %{ if(!($_.EmailAddresses -contains "smtp:$($_.Alias)@yourdomain.co.uk")) { Write-Host "Adding email address for $($_.Alias)"; Set-Mailbox $_.Alias -EmailAddresses @{add="$($_.Alias)@yourdomain.co.uk"} } }
    Bit of an annoying feature, I'm surprised more people haven't had this issue - or maybe they just haven't noticed it!
    • Edited by AndyH16 Wednesday, August 31, 2016 8:02 AM Added code formatting
    • Proposed as answer by Squidjigg Thursday, September 1, 2016 12:41 AM
    • Marked as answer by AndyH16 Thursday, September 1, 2016 8:03 AM
    Wednesday, August 31, 2016 8:02 AM

All replies

  • Hi,

    Please see an explanation of the issue here: http://exchangeserverpro.com/exchange-server-2013-inboundproxy-com-ndr/

    Then follow the instructions here: http://blog.c7solutions.com/2013/06/queues-building-to-inboundproxycom.html.

    Let me know if you need more help troubleshooting the NDR.

    Thanks.


    Please mark as an answer if this answers your question

    Mark Gossa

    MCSE 2003, MCITP Enterprise Administrator 2008 R2, MCSA 2012 R2, MCTS Exchange 2010, MCTS SQL 2012, MCTS SharePoint 2007, VCP4, VCP5, CCNA

    Blog: http://markgossa.blogspot.com   LinkedIn:    Twitter:   

    Posts are provided “AS IS” without warranty of any kind, either expressed or implied.

    • Marked as answer by AndyH16 Monday, January 25, 2016 2:27 PM
    Monday, January 25, 2016 12:29 PM
  • I had already gone through those articles but it appears I'm having a moment! I've just gone in again and noticed although it looks like the address is listed it was actually the SIP address, the SMTP format of the name it was expecting was missing. I've just ran a quick Powershell command to add the relevant email address to all of the Health Mailboxes, it now appears the undeliverable emails have stopped hitting Mimecast.

    Thanks for your help :)

    Monday, January 25, 2016 2:27 PM
  • Hi @AndyH16,

    We're experiencing the same issue you had with the SIP address listed in our NDR from the probe.

    I can change it in the Health Mailbox AD object, but would prefer to use Powershell. Any chance that you could provide the Powershell command you used to update these on the Health Mailboxes?

    Cheers.

    Wednesday, August 31, 2016 12:10 AM
  • Hi, always happy to help, obviously change the two references to 'yourdomain.co.uk' to your own domain:

    Get-Mailbox -Monitoring | %{ if(!($_.EmailAddresses -contains "smtp:$($_.Alias)@yourdomain.co.uk")) { Write-Host "Adding email address for $($_.Alias)"; Set-Mailbox $_.Alias -EmailAddresses @{add="$($_.Alias)@yourdomain.co.uk"} } }
    Bit of an annoying feature, I'm surprised more people haven't had this issue - or maybe they just haven't noticed it!
    • Edited by AndyH16 Wednesday, August 31, 2016 8:02 AM Added code formatting
    • Proposed as answer by Squidjigg Thursday, September 1, 2016 12:41 AM
    • Marked as answer by AndyH16 Thursday, September 1, 2016 8:03 AM
    Wednesday, August 31, 2016 8:02 AM
  • It would have gone unnoticed by us as well, only until a Microsoft engineer contacted us saying that they were seeing irregular mail traffic originating from our Office 365 tenant (we have a hybrid setup). Traced the cause to this inbound proxy probe!

    Thanks again for this, much appreciated :)

    Thursday, September 1, 2016 12:45 AM