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Getting error: No SMTP server defined. Use real server address instead of 127.0.0.1 in your account. RRS feed

  • Question

  • This is happening more and more often.  A user gets a kickback stating the email was deliverable.  There have been no changes in the system for sometime so it is very interesting this error pops up like some sort of configuration error.  I've noticed this happens mostly with gmail and  comcast, but a few come from other domains.

    I'd like know where to find where the SMTP server is defined as 127.0.0.1.

    Thanks,

    Here is the actual (revised) email the user gets:

    From: Microsoft Outlook 
    Sent: Tuesday, August 20, 2019 9:12 AM
    To: FUser LUser
    Subject: Undeliverable: RE: Payment Needed - VMC Design Order


    EXCHANGE2016 rejected your message to the following email addresses:

    FRecp LRecp (Recp@gmail.com)
    A problem occurred while delivering your message to this email address. Try sending your message again. If the problem continues, please contact your email admin.



    EXCHANGE2016 gave this error:
    No SMTP server defined. Use real server address instead of 127.0.0.1 in your account. 








    Diagnostic information for administrators:

    Generating server: EXCHANGE2016.DAMIN.GOT


    Recp@gmail.com
    EXCHANGE2016
    Remote Server returned '550 No SMTP server defined. Use real server address instead of 127.0.0.1 in your account.'


    Original message headers:

    Received: from EXCHANGE2016.DAMIN.GOT (10.1.7.8) by EXCHANGE2016.DAMIN.GOT
     (10.1.7.8) with Microsoft SMTP Server (TLS) id 15.1.225.42; Tue, 20 Aug 2019
     09:11:48 -0500
    Received: from EXCHANGE2016.DAMIN.GOT ([fe80::4d0e:7a20:4aa0:90e1]) by
     EXCHANGE2016.DAMIN.GOT ([fe80::4d0e:7a20:4aa0:90e1%13]) with mapi id
     15.01.0225.041; Tue, 20 Aug 2019 09:11:42 -0500
    From: FUser LUser <user@inc.net>
    To: FFRecp LRecp LFRecp LRecp <Recp@gmail.com>
    Subject: RE: Payment Needed - VMC Design Order
    Thread-Topic: Payment Needed - VMC Design Order
    Thread-Index: AdVO5uopoQqQJ3urQyi6W+fJb7TlCQAL3KAAALdwjfAADmk+gAEYTI/gAD6dUAAAChE60A==
    Date: Tue, 20 Aug 2019 14:11:42 +0000
    Message-ID: <b9b88a1a5994480fa06dc14e3f9aeefd@inc.net>
    References: <936b8d6054c545a1b3e6fcb0d4715299@inc.net>
     <B97211AC-415F-4BE5-A474-128A1CB22260@gmail.com>
     <e619b685832a4c5791719ce673ee303e@inc.net>
     <DCF49E6C-C5FC-461A-8AC1-6BE0ECB8F06A@gmail.com>
     <1946286a00714a919b5852d9b2b95f2a@inc.net>
     <2E859AE7-400D-452B-847B-F2AC47CEC021@gmail.com>
    In-Reply-To: <2E859AE7-400D-452B-847B-F2AC47CEC021@gmail.com>
    Accept-Language: en-US
    Content-Language: en-US
    X-MS-Has-Attach: yes
    X-MS-TNEF-Correlator:
    x-originating-ip: [10.1.2.52]
    x-avast-antispam: clean, score=10
    x-original-content-type: application/ms-tnef
    Content-Type: multipart/mixed;
    boundary="_004_b9b88a1a5994480fa06dc14e3f9aeefdincnet_"
    MIME-Version: 1.0


    Thursday, August 29, 2019 12:33 PM

All replies

  • Hi,

    Do you mean you cannot send emails to external users sometimes?

    Are these emails sent successfully after sending them again?

    Based on my research, this error may have relations with antivirus software. Do you install any third party antivirus scanner or software? You can disable them temporarily, and check if the issue persists.

    Regards,

    Lydia Zhou


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

    Friday, August 30, 2019 3:09 AM
  • Yes sometimes...a few times a week and sometimes a few times a day.  Once the user gets the kickback email and re-sends it seems to work fine.

    I read about the antivirus and did disable the email scanning portion on the server and it did not change the outcome.

    Thanks,

    Damian

    Friday, August 30, 2019 2:42 PM
  • Hi Damian,

    Do all users in your organization have the same issue?

    When did this issue occur? Just after deploying the Exchange server?

    Please make sure there are no other protection applications using SMTP proxy with 127.0.0.1.

    Regards,

    Lydia Zhou


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

    Tuesday, September 3, 2019 9:55 AM
  • Hi Lydia,

    The error has been noted by several users.  I disabled our email scanning last week to see it that had any effect on the situation but there was no change.

    This morning I made some changes to the send connector.

    Checked : Used the external DNS lookup settings on server with transport roles
     Added FQDN: mail.inc.net

    Tuesday, September 3, 2019 5:47 PM
  • Problem still persists.  I ran a delivery report from email sent to gmail where the error has been received.

    It looks as if gmail is looking for the actual IP address of the server...

    [{LRT=9/4/2019 10:55:44 AM};{LED=550 No SMTP server defined. Use real server address instead of 127.0.0.1 in your account.};{FQDN=gmail-smtp-in.l.google.com};{IP=2607:f8b0:4001:c07::1b}]

    Wednesday, September 4, 2019 12:53 PM
  • Hi,

    What's the detailed version of your Exchange server?

    Can you provided more information about the configuration of Send connector?

    You can check with the steps in the following document: Create a Send connector in Exchange Server to send mail to the internet

    Regards,

    Lydia Zhou


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

    Friday, September 6, 2019 9:09 AM
  • I am having similar problems with an Exchange Server 2010 on Server 2008 R2. Started a couple of months ago.

    Now, I have repeatedly reviewed the Exchange configuration to see if there are any references to the loopback interface (especially since the problems are actually on an SBS 2011 platform which is known to have horrible problems with loopbacks). I have searched the registry for references as well. Only the SQL server has that address bound, along with others.

    I also checked to see if there were any references associated with DNS name resolution.

    I suspect this error simply indicates that the SMTP server cannot be found.

    What I have noticed is that the problem only occurs with sites that have MX records specifying IPv6 addresses (along with IPv4 addresses). The Message Tracking logs indicate that the Send connector is attempting to deliver to an IPv6 address when failures occur.

    I tried setting the registry to "Prefer IPv4", but both Exchange and DNS seem to ignore that setting.

    I had ignored IPv6 configuration since my ISP does not provide IPv6 transport over FIOS. I have undertaken a review of the configuration of my servers and router, but had no resolution so far.

    I am not willingly a system administrator. That said, I have noticed that there have been updates recently to the dual-stack implementation. While I know nothing, I do have suspicions.

    I have also noticed that there are group policy settings for IPv6 Transition settings that were not there when I last looked (a couple of years ago). There is none for "Prefer IPv4", but I have noticed that a local ISATAP connector on the server will not be established unless the new policy settings are configured. I expect the same is true for 6to4.

    So, I don't have any answers... but maybe this will help someone who has a clue. Let me know if you do.

    Sunday, September 22, 2019 6:42 AM
  • For my Exchange 2010, I enabled protocol logging and noticed that I am in fact connecting; and that my sender address is in fact ::1 for IPv6 and 127.0.0.1 for IPv4 traffic. This is because the Transport Server and the Send Connector are on the same host... in my case a Small Business Business Server. The sender address seems to be auto-configured.

    I only see this problem when sending to Google or Comcast servers using IPv6... since they are only doing address verification on IPv6 to screen for spammers. The error message originates at their end. IPv4 skates by unverified.

    Anyway, it sounds like you may have the same problem with Exchange 2013. Don't know if you are configured without Edge Servers. Try enabling protocol logging.

    I have not yet found a way to configure the address of the send connector. Haven't checked the SQL database yet though.

    Friday, September 27, 2019 8:17 PM