XIMS: Internet Mail Service Does Not Generate Non-Delivery Report Message If Number of Recipients Exceeds 32,766 (272672)

SYMPTOMS

A message in the Imcdata\In folder may never be delivered and may remain in that folder. If you stop and restart the Exchange Server Internet Mail Service, the message may be redelivered to most of the recipients of the message.

The following event ID 4120 error message is logged in the application event log:

Event ID: 4120
Type: Error
Source: MSExchangeIMC
Category: Internal Processing

Description:
In the process of creating a notification of delivery failure to the sender of a message, an error occurred causing the notification to be aborted. The sender will not be informed that his original message failed to be delivered.

Data:
0000: 9a 01 02 00 0e 00 07 80 ?......?
0008: 54 47 34 35 43 4c 50 36 TG45CLP6
0010: 00 .

The following event ID 4131 error message may be logged in the application event log as well:

Event ID: 4131
Type: Information
Source: MSExchangeIMC
Category: Internal Processing

Description:
An unexpected error occurred in the Internet Mail Service. Information about this error is stored in the data portion of this event.

Data:
0000: 3e 02 01 00 0e 00 07 80 >......?
0008: 54 47 34 35 43 4c 50 36 TG45CLP6
0010: 00

CAUSE

This problem can occur if the message has more than 32,766 (0x7FFE in hexadecimal numbers) recipients defined. The Internet Mail Service uses Messaging Application Programming Interface (MAPI) to create non-delivery report (NDR) messages, and attempts to add the recipients to an NDR message that MAPI is creating. MAPI uses the Emsmdb32.dll file to communicate with the information store, and the Emsmdb32.dll file has a limit of 32,766 recipients defined for the number of recipients on a single message.

RESOLUTION

A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that are experiencing this specific problem. This fix may receive additional testing. Therefore, if you are not severely affected by this problem, Microsoft recommends that you wait for the next Microsoft Exchange Server version 5.5 service pack that contains this hotfix.

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

http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS

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 typical support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

The English version of this fix should have the following file attributes or later:

Component: Internet Mail Service

File name	Version
Msexcimc.exe	5.5.2654.14
Imcmsg.dll	5.5.2654.14

MORE INFORMATION

This fix has two parts and addresses both the message that is already in the Imcdata\In folder and new messages that arrive to the Internet Mail Service with more than 32,766 recipients.

For the message in the Imcdata\In folder, the basic problem is the inability to create an NDR because of the number of recipients. This fix creates the NDR with 32,766 recipients and does not show the rest in the NDR. The following new event ID has been created to report this exceptional circumstance:

Event ID: 3041
Type: Warning
Source: MSExchangeIMC
Category: Internal Processing

Description:
Unable to deliver mail to all recipients. The total number of recipients exceeds 32766.

If a new message is delivered to the Internet Mail Service, the server sends a 452 response when the number of recipients being submitted exceeds 0x7FFE. This response is an indicator to the sender that another message needs to be submitted with the remaining recipients (in other words, that the sender needs to break the message into multiple messages with fewer recipients on each message).

Up to 0x7FFE recipients the SMTP Command/Reponse pair would look like this:

SMTP: Command = RCPT TO: USER@MAIL.COM
SMTP: Response = 250 OK - Recipient <USER@MAIL.COM>

For every recipient after this, the following command/response pair would result:

SMTP: Command = RCPT TO: TOOMANY@MAIL.COM
SMTP: Response = 452 Requested action not taken: Exceed Recipient Limit

For additional information about the hotfix in this article, click the article number below to view the article in the Microsoft Knowledge Base: