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SMTP TLS authentication Error Number: 0x800CCC0F

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  • SMTP TLS authentication Error Number: 0x800CCC0F

    HI,
    I'm runing exchange front-end server (last sp applied and update of OS right) in a perimeter network. OWA is still runing fine with SSL and a private Certificate.
    I setup IMAP/SMTP access to our outlook express mobile user's clients connecting from internet.
    IMAP is runing fine to retrieve mail, I still have a problem with SMTP.
    I had create a SMTP virtual server (with the same name as the name of the certificate I use on to the IIS server) on port 2525.
    In the user control access settings I just uncheck anonymous and check basic authentication with TLS checked.
    The certificate is the same as these installed for OWA and under communication "require secure channel" is also checked.
    using telnet from the internet I can access the smtp server who request SSL command , message STARTTLS
    But ... with the client I have the following error
    Your server has unexpectedly terminated the connection. Possible causes for this include server problems, network problems, or a long period of inactivity. Account: 'xxx', Server: 'xxx', Protocol: SMTP, Port: 2525, Secure(SSL): Yes, Error Number: 0x800CCC0F
    Do you have some ideas about this ...

  • #2
    Re: SMTP TLS authentication Error Number: 0x800CCC0F

    Did you try to connect from the internal network?
    Regards,
    Csaba Papp
    MCSA+messaging, MCSE, CCNA
    ...............................
    Remember to give credit where credit is due and leave reputation points where appropriate
    .................................

    Comment


    • #3
      Re: SMTP TLS authentication Error Number: 0x800CCC0F

      right, at this time not yet, I try it now
      but from the internet with a tenet session onto the concerning port (2525)
      I can connect to the smtp server who is requesting to start a tls session (STARTTLS)
      thanks

      Comment


      • #4
        Re: SMTP TLS authentication Error Number: 0x800CCC0F

        From de wan (internal and private metwork) behind the firewall I have the same issue ...and more crazy using outlook express onto the frontend self, the same issue.

        Comment


        • #5
          Re: SMTP TLS authentication Error Number: 0x800CCC0F

          Hi,
          I managed to recreate the issue.
          The secure communication worked only if I kept the default port 25. Why? Good question! I DON'T KNOW!
          As soon as I changed the port to 2525, 465 or any other number, Outlook Client returned the error message with Error Number: 0x800CCC0F.
          I hope to have time to investigate the problem and get back to you.
          Possible work around:
          1. Assign a second IP to your server. And use this for secure SMTP connection on port 25;
          2. Don't force the encryption. If you installed a certificate but in Secure Communication section did not put the check mark "Require secure channel", your server will accept both secure and unsecured communication on the same port 25;
          In this way your company users are able to securely send emails using ssl and Internet email server can also communicate normally with your Exchange.
          Attached Files
          Regards,
          Csaba Papp
          MCSA+messaging, MCSE, CCNA
          ...............................
          Remember to give credit where credit is due and leave reputation points where appropriate
          .................................

          Comment


          • #6
            Re: SMTP TLS authentication Error Number: 0x800CCC0F

            I am assuming that you have antivirus on the server.
            Are you using an Exchange Antivirus too?
            I have similar errors where a site has not installed Exchange AV and is relying on the file server version to protect the pop/smtp communications.
            The file server version does not support the STARTTLS commands and so the SMTP fails appearing as errors similar to what you have above.
            If you turn off the FILE SERVER AV, POP MAIL monitoring and have your Exchange level antivirus configure, the error should go away.

            So this why the error will occur on port 2525 verus 25, the Exchange AV will not interpret the verbs correctly.

            HTH

            IKE

            Comment


            • #7
              Re: SMTP TLS authentication Error Number: 0x800CCC0F

              The problem seems to be with Outlook Express.
              I tested with Outlook 2003 and Mozilla Thunderbird ver. 1.5.0.4 and worked just fine.
              Regards,
              Csaba Papp
              MCSA+messaging, MCSE, CCNA
              ...............................
              Remember to give credit where credit is due and leave reputation points where appropriate
              .................................

              Comment


              • #8
                Re: SMTP TLS authentication Error Number: 0x800CCC0F

                Hello, thanks for all this informations. In my case, our outlook clients connected onto the internet using the same ISP as us, are forced to use only the relay from th provider and cannot use smtp server on port 25 to send mail. For outlook client using an another ISP, they can use port 25 to send mail.
                This is why I want to use port 2525 for our smtp server and authenticated the client via TLS and/or SSL.
                I have try to turn off the AV software and have the same issue, with outlook 2003 aswell outlook express.
                I can connect via telnet onto port 2525, send an helo command and be asked to start a starttls session.
                I have also turn on all the logging for the smtp virtual server ..and nothing specially.
                My IMAP4 secure session run fine on the same preproduction front en server.

                fr

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