General SMTP Failures on inbound E-Mail

Posted on 2009-04-16
Last Modified: 2013-11-30
I'm having some difficulty receiving some email messages.  One sender in particular is seeing a 10% failure rate on mail to my domain.  We are also starting to see some errors with mail from g-mail and others.  The message from that one particular domain come back with the following:

Your message has been delayed.  The server will continue trying to forward the message.  You do not need to resend the message.  

Apparent cause of delivery failure:
              An SMTP protocal error occured while sending this message.

The delay affects the following recipients:

The messages from gmail are getting bounced with the following:

This is an automatically generated Delivery Status Notification

Delivery to the following recipient failed permanently:


Technical details of permanent failure:
Unspecified Error (SENT_MESSAGE): Connection timed out

According to our internet provider, our connection has been up and stable for 45+ days.  No changes have been made to our exchange environment either.  We did have to reinstall SMSMSE recently with assistance from Symantec support.  

Here is the breakdown of my network

TW Business Class Internet
Cisco ASA 5505
MS Server 2003SE R2 SP2/Exchange 2003 SP3

Any recommendations?  I've checked the message logs and don't see the messages ever getting to exchange based on the times I've seen failures.  Thanks for all of your help.
Question by:glenmetz
    LVL 65

    Expert Comment

    Well the fact that Symantec is involved would normally mean I would point the finger at their product. It is the usual cause of problems in my experience.

    What is between Exchange and the Internet? Firewall of some kind?


    Author Comment

    I would not be surprised if its Symantec, but senders are experiencing time outs while sending.

    A Cisco ASA 5505 is between the our internet connection and exchange server.
    LVL 65

    Accepted Solution

    The Ciscos have an SMTP scanning feature, mail guard or something like that. Ensure that is disabled. It is well known for causing problems with email delivery on Exchange servers - at one point Microsoft had a KB article on it - the problem was that common.


    Author Comment

    It is actually an ESMTP scanner, which I've now disabled.  We'll see how we do.

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