Announcement

Collapse
No announcement yet.

Can not receive mail from certain domains

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • Can not receive mail from certain domains

    Hello, we have an Windows Small business server 2003 that runs exchange 2003. Lately , a lot of our customers have been unable to send mail to us.

    After a while they get the following error message :

    The original message was received at Fri, 18 Jul 2008 11:06:20 +0200 from [email protected] [x.x.200.1]

    ----- Transcript of session follows -----
    451 4.4.1 reply: read error from mail.mydmain.xx.no.
    <[email protected]>... Deferred: Connection reset by mail.mydmain.xx.no.
    Warning: message still undelivered after 1 day Will keep trying until message is 3 days old

    from a customers domain i manage to run a telnet session towards the server on port 25 and send mail from the telnet window.

    Does anyone have any ideas on what can be wrong ?

    Yours Sincerly
    Stein Arvid Lid , Norway

  • #2
    Re: Can not receive mail from certain domains

    Do you have AV/AS scanning software installed.
    Do you have anything in between your Exchange and your internet connection?
    Is there a PIX firewall involved?

    Have you checked your domain for grey/blacklisting www.mxtoolbox.com is good for that
    cheers
    Andy

    Please read this before you post:


    Quis custodiet ipsos custodes?

    Comment


    • #3
      Re: Can not receive mail from certain domains

      Between the exchange server and internet , i have an Zyxel Zywall 5.


      Here are logs from the tests run at mx.toolbox.org:


      Checking x.x.227.218 against 123 known blacklists...
      Listed: 0 time(s)
      Timeouts:5

      RESULT: mail.mydmain.xx.no
      Banner: exchange.mydomain.xx.no Microsoft ESMTP MAIL Service, Version: 6.0.3790.3959 ready at Mon, 21 Jul 2008 11:49:30 +0200 [172 ms]
      Connect Time: 0.172 seconds - Good
      Transaction Time: 6 seconds - Warning
      Relay Check: OK - This server is not an open relay.
      Rev DNS Check: OK - xx.xx.227.218 resolves to mydomain.xx.no
      GeoCode Info: Geocoding server is unavailable
      Session Transcript: HELO please-read-policy.mxtoolbox.com
      250 exchange.mydomain.xx.no Hello [64.20.227.131] [156 ms]
      MAIL FROM: <[email protected]>
      250 2.1.0 [email protected]er OK [172 ms]
      RCPT TO: <[email protected]>
      550 5.7.1 Unable to relay for [email protected] [5172 ms]
      QUIT
      221 2.0.0 exchange.mydomain.xx.no Service closing transmission channel [156 ms]

      Comment


      • #4
        Re: Can not receive mail from certain domains

        There are antivirus software (Norman Anti Virus) on the server , but no Av / AS that works towards the exchange system

        Comment


        • #5
          Re: Can not receive mail from certain domains

          looks like the sending domain might be sending from a different IP than their MX record.
          This message represents the official view of the voices in my head

          Comment


          • #6
            Re: Can not receive mail from certain domains

            Originally posted by graycat View Post
            looks like the sending domain might be sending from a different IP than their MX record.
            Could you please explain ?

            Comment


            • #7
              Re: Can not receive mail from certain domains

              Please check Sending ip and MX ip are same or different, if different but registered it works but some mail server discard the sessionl;
              Last edited by Pushkar; 21st July 2008, 14:14.

              Comment


              • #8
                Re: Can not receive mail from certain domains

                Originally posted by SuperLid View Post
                Could you please explain ?
                Sorry that was a bit terse. Work got in the way!

                What I meant is that some companies only register one IP address as their MX record so all incoming mail is routed through that. However, if they have multiple sites they may well be send e-mails out from a different IP address. Normally this doesn't cause too much of an issue unless the receiver does a reverse lookup for that domain and takes the MX record as where mail should be sent from. If the mail is not sent from this record then it is taken as being spoofed and dropped.

                I've also had cases where a company will have 4 MX records but the receiver will only look at the first one. Which makes things interesting.

                If you were to do an nslookup for that domain and located the MX records you could compare it with where you were getting mail from. if the addresses differ, I would then start looking for the IP blocks the company might have and see if this coincides with where you're receiving from. If so, it might be as I said above in that they're sending from a non-MX registered IP address.

                I hope that clears things up a bit for you.
                This message represents the official view of the voices in my head

                Comment


                • #9
                  Re: Can not receive mail from certain domains

                  It's not the MX record that is checked during reverse DNS but the banner host name.

                  Comment


                  • #10
                    Re: Can not receive mail from certain domains

                    I have verified on the exchange server that "Perform reverse DNS lookup on incoming messages" are not checked.

                    Any other ideas ?

                    Comment


                    • #11
                      Re: Can not receive mail from certain domains

                      Originally posted by SuperLid View Post
                      I have verified on the exchange server that "Perform reverse DNS lookup on incoming messages" are not checked.
                      Even if that setting was set in Exchange it wouldn't stop the email from being delivered. Exchange cannot block the connection based on that setting.

                      Have you checked the firewall to see if it has any kind of SMTP scanning functionality. If it does, then disable it. Also ensure that any AV software installed on the server does not have SMTP Scanning enabled.

                      Simon.
                      --
                      Simon Butler
                      Exchange MVP

                      Blog: http://blog.sembee.co.uk/
                      More Exchange Content: http://exchange.sembee.info/
                      Exchange Resources List: http://exbpa.com/
                      In the UK? Hire me: http://www.sembee.co.uk/

                      Sembee is a registered trademark, used here with permission.

                      Comment

                      Working...
                      X