Microsoft KB Archive/924237

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Article ID: 924237

Article Last Modified on 10/25/2007

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APPLIES TO


 * Microsoft Exchange Server 2003 Enterprise Edition
 * Microsoft Exchange Server 2003 Standard Edition

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Source: Microsoft Support

RAPID PUBLISHING

RAPID PUBLISHING ARTICLES PROVIDE INFORMATION IN RESPONSE TO EMERGING OR UNIQUE TOPICS, AND MAY BE UPDATED AS NEW INFORMATION BECOMES AVAILABLE.



SYMPTOMS
Mail between RGs is slow to non existent and sometimes the queues go into retry states.

Mail flow can be affected both ways and sometimes only one way RGs are connected via VPNs.

Telnet to server that is in retry state and ehlo returns:

220 servername Microsoft ESMTP MAIL Service, Version: 5.0.2195.6713 ready at Tue, 20 Dec 2005 14:34:09 -0800 ehlo 250-Computer.domain.com Hello [192.168.1.34] 250-XXXA 250-XXXB 250-SIZE 250-ETRN 250-PIPELINING 250-DSN 250-ENHANCEDSTATUSCODES 250-8bitmime 250-BINARYMIME 250-XXXXXXXC 250-XXXD 250-XXXXXXXXXXXXXXXXXXXXXXXE 250-XXXXXXXXXXXF 250-AUTH GSSAPI NTLM LOGIN 250-XXXXXXXXXG 250-XXXXXXXXXXXH 250-XXXXXXI 250 XJ

Netmon caps show OD OA in packet but not the completition of a second OD OA to signify the completion of the message. We never see the Fin sent or received. There is a 625+ second delay before we time the connection out.



CAUSE
CISCO Router filtering and then dropping what it deems as 'invalid SMTP command' packets. See resolution below for more information



RESOLUTION
Contacting CISCO to check configuration of the Firewall for SMTP

CISCO removing firewall feature set for testing

CISCO says it was logging an invalid SMTP command

ESMTP verbs cleaned up now

All mail dequed

The CISCO Feature set provides &quot;Firewall like&quot; features to inspect packets and prevent &quot;abnormal&quot; packets from being transmitted. The feature set does a stateful inspection of the packets looking for the abnormal packets and block these. In the log it was showing an invalid SMTP command



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Keywords: kbprb kbtshoot kbrapidpub KB924237

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