You receive a "421 4.1.0 Dropping connection due to an error on this server" error message if you use Exchange Server 2003 to send an e-mail message from a Windows 2000 Service Pack 4-based computer (893380)

SYMPTOMS

Consider the following scenario. You send an e-mail message by using Microsoft Exchange Server 2003 on a Microsoft Windows 2000 Service Pack 4 (SP4)-based computer. The e-mail message has a single subject header and does not have an e-mail body. After you turn on the enable sender filter feature in Exchange System Manager (ESM), the connection is dropped, and you receive the following error message:

421 4.1.0 Dropping connection due to an error on this server.

RESOLUTION

Hotfix information

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that this article describes. Apply it only to systems that are experiencing this specific problem.

To resolve this problem, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

Restart requirement

You do not have to restart the computer.

File information

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
   --------------------------------------------------------------
   19-Jun-2003  04:05  5.0.2195.6654     322,320  Aqueue.dll       
   19-Jun-2003  04:05  5.0.2195.6666      67,344  Mailmsg.dll      
   19-Jun-2003  04:05  5.0.2195.6662      38,672  Ntfsdrv.dll      
   15-Mar-2005  14:00  5.0.2195.7035     446,736  Smtpsvc.dll      
   25-Feb-2005  01:43  6.1.22.4          371,936  Updspapi.dll

Important Windows File Protection (WFP) is disabled after you install this hotfix.

MORE INFORMATION

For more information about the standard terminology that is used to describe Microsoft software updates, click the following article number to view the article in the Microsoft Knowledge Base:

824684 Description of the standard terminology that is used to describe Microsoft software updates

For more information about RFC-821 and RFC-822, visit the following Web sites:

http://www.faqs.org/rfcs/rfc821.html
http://www.faqs.org/rfcs/rfc822.html