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Exchange Server 2007 - Truncated e-mails

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  • Exchange Server 2007 - Truncated e-mails

    Hello,

    I have Exchange Server 2007 Standard Edition SP1, Update Rollup 2 (and ISA Server 2006).

    The problem is that we keep receiving truncated emails (on Microsoft Office Outlook 2003 and Outlook Web Access), the body begins normally, text is shown and then I get something like the following lines for example:

    ------_=extPart_001_01C8D5C7.24EA1386
    Content-Type: text/html; charset=s-ascii"
    Content-Transfer-Encoding: quoted-printable


    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
    <html xmlns: o="urn: schemas-microsoft-com: office: office" xmlns: st1="urn: schemas-microsoft-com: office: smarttags">
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
    <title>Message</title>
    <meta content="MSHTML 6.00.2900.3020" name="GENERATOR">
    </head>
    <body>
    <div>&nbsp;</div>
    <div></div>
    <div class="OutlookMessageHeader" lang="en-us" dir="ltr" align="left"><font face="Tahoma" size="2">-----Original Message-----<br>
    <b>From:</b> John <br>
    <b>Sent:</b> 18 June 2008 18:08<br>
    <b>To:</b>Michael<br>
    <b>Subject:</b> FW: message<br>
    <br>
    </font></div>

    or just that Next Part Reference
    ------_=extPart_002_01C8D525.3E7DB44D--

    For the first example, Internet Headers look like this:

    Content-Class: urn:content-classes:message
    MIME-Version: 1.0
    Content-Type: multipart/alternative;
    boundary="----_=_NextPart_001_01C8D5C7.24EA1386"
    X-MimeOLE: Produced By Microsoft Exchange V6.5

    Subject: FW: message
    Date: Tue, 24 Jun 2008 09:54:24 +0300
    Message-ID: <[email protected]ain.ro>
    X-MS-Has-Attach:
    X-MS-TNEF-Correlator:

    I have also checked the Internet Headers for some other truncated e-mails and most of them look like this:

    Received: from dc.domain.com ([192.168.200.100]) by dc.domain.com
    ([192.168.200.100]) with mapi; Mon, 23 Jun 2008 14:38:35 +0300
    Content-Type: application/ms-tnef; name="winmail.dat"
    Content-Transfer-Encoding: binary

    From: John <[email protected]>
    To: Michael <[email protected]>
    Date: Mon, 23 Jun 2008 14:38:34 +0300
    Subject: FW:
    Thread-Index: AcjSl6OQt2qIR5KkREGdnFQxFDcSjwAAAZEAAAb0+kAAkUxoAA ALOjmA
    Message-ID: <[email protected] .local>
    Accept-Language: en-US
    Content-Language: en-US
    X-MS-Has-Attach: yes
    X-MS-Exchange-Organization-SCL: -1
    X-MS-TNEF-Correlator: <[email protected] ain.com>
    MIME-Version: 1.0

    Based on this, I have found on microsoft.com only one tnef-related issue
    http://support.microsoft.com/kb/944153/
    I tried those settings, but it didn't work.

    I have also seen on some forums that Microsoft fixed this issue by making a change to the IIS metabase, but no further details on how they did it exactly. If anybody knows, please reply.

    I also read on microsoft.com:
    Messages that are composed by MIME clients as a multipart/mixed MIME message without a "name" parameter for the "content-type" or an optional "filename" parameter for the "content-disposition" header may not be rendered correctly when received by Exchange.

    Does anyone know a solution to this problem?

  • #2
    Re: Exchange Server 2007 - Truncated e-mails

    Do you have any AV/AS scanning the inbound SMTP?
    cheers
    Andy

    Please read this before you post:


    Quis custodiet ipsos custodes?

    Comment


    • #3
      Re: Exchange Server 2007 - Truncated e-mails

      Yes, I have an antivirus for Exchange Server 2007, but I have disabled it in the last two days and I keep receiving those emails.
      Maybe ISA has an issue with the headers?

      Comment


      • #4
        Re: Exchange Server 2007 - Truncated e-mails

        What does your rule look like for SMTP?
        cheers
        Andy

        Please read this before you post:


        Quis custodiet ipsos custodes?

        Comment


        • #5
          Re: Exchange Server 2007 - Truncated e-mails

          In ISA Server Management Console, Add-ins, I have a SMTP Filter that includes the following SMTP commands:

          (Commands - Maximum Length)
          AUTH - 1024
          BDAT - 60
          DATA - 6
          EHLO - 71
          EXPN - 71
          HELO - 71
          HELP - 6
          MAIL FROM - 266
          NOOP - 6
          QUIT - 6
          RCPT TO - 266
          RSET - 6
          SAML FROM - 268
          SEND FROM - 268
          SOML FROM - 268
          STARTTLS - 10
          TLS - 5
          VRFY - 71

          Comment


          • #6
            Re: Exchange Server 2007 - Truncated e-mails

            I would guess it is ISA causing the issue rather than Exchange. Is there anything in the ISA logs for a particular moment when you receive a truncated message?

            EDIT: The commands and lengths look standard from the few numbers I recognise
            cheers
            Andy

            Please read this before you post:


            Quis custodiet ipsos custodes?

            Comment


            • #7
              Re: Exchange Server 2007 - Truncated e-mails

              ISA is not the cause, I have uninstalled it today, but this did not solve the issue. I still receive those "scrambled" e-mails.

              Comment


              • #8
                Re: Exchange Server 2007 - Truncated e-mails

                Uninstalling it is a bit more than I expected, possibly just re-directing them smtp would have been easier.

                Are we sure the inbound messages are good? Is there a pattern to who or where they come from?
                cheers
                Andy

                Please read this before you post:


                Quis custodiet ipsos custodes?

                Comment


                • #9
                  Re: Exchange Server 2007 - Truncated e-mails

                  Finally solved it!

                  I have a third party antivirus for Exchange, when I tested if that could be the cause, I stopped all services related to that application, restarted Exchange services, re-did my tests and nothing...

                  Now I have disabled them and everything looks perfect!

                  I could not imagine a small difference like "stopped" or "disabled" could cause all this.

                  Thanks to all who replied!

                  Comment


                  • #10
                    Re: Exchange Server 2007 - Truncated e-mails

                    Glad you have!
                    I should have checked more when you said it was disabled.
                    cheers
                    Andy

                    Please read this before you post:


                    Quis custodiet ipsos custodes?

                    Comment


                    • #11
                      Re: Exchange Server 2007 - Truncated e-mails

                      Due to the way that AV integrates with Exchange, in most scenarios disabling it is not enough. You have to remove the product to confirm it isn't the cause of the problem. When the product is disabled then it is still scanning the traffic, just taking no action.

                      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

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