MX record failover does not occur when the remote SMTP Host responds with a 4xx error (303889)



The information in this article applies to:

  • Microsoft Windows 2000 Server SP1
  • Microsoft Windows 2000 Server SP2
  • Microsoft Windows 2000 Server SP4
  • Microsoft Windows 2000 Advanced Server SP1
  • Microsoft Windows 2000 Advanced Server SP2
  • Microsoft Windows 2000 Advanced Server SP4
  • Microsoft Exchange 2000 Server

This article was previously published under Q303889

SYMPTOMS

When an external DNS resolver is used on your Simple Mail Transfer Protocol (SMTP) virtual server, the next MX record is not tried when the host for the first MX record returns a "4xx" error.

RESOLUTION

Windows 2000 Service Pack 1 and Service Pack 2

To resolve this problem, obtain the latest service pack for Windows 2000. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

260910 How to Obtain the Latest Windows 2000 Service Pack

The English version of this fix should have the following file attributes or later:
   Date      Time   Version        Size     File name
   ----------------------------------------------------
   09/13/01  10:52  5.0.2195.4051  320,784  Aqueue.dll
   09/13/01  10:52  5.0.2195.4051   66,832  Mailmsg.dll
   09/13/01  10:52  5.0.2195.4051   38,160  Ntfsdrv.dll
   09/13/01  10:52  5.0.2195.4236  435,472  Smtpsvc.dll
				

Note Before you apply the hotfix that is described in this article, install Windows 2000 Service Pack 2 (SP2) and Exchange 2000 Service Pack 1 (SP1).

Windows 2000 Service Pack 4

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.
   Date         Time   Version            Size    File name
   ----------------------------------------------------------
   08-Nov-2003  01:23  5.0.2195.6872     322,320  Aqueue.dll       
   08-Nov-2003  01:23  5.0.2195.6824      67,856  Mailmsg.dll      
   08-Nov-2003  01:23  5.0.2195.6872      38,672  Ntfsdrv.dll      
   08-Nov-2003  01:23  5.0.2195.6872     444,688  Smtpsvc.dll   

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.

Modification Type:MinorLast Reviewed:9/26/2005
Keywords:kbHotfixServer kbQFE kbbug kbenv kberrmsg kbfix kbnetwork kbSysAdmin kbWin2000PreSP3Fix kbWin2000sp3fix KB303889