Messages Loop or NDR went sent to a DL / DG in Mixed Org (298561)

SYMPTOMS

In a mixed Microsoft Exchange Server 5.5 and Exchange 2000 environment with a distribution list expansion server, mail sent to a distribution list with members on other servers may not work, and may be returned as undeliverable. In very "complex/large" routing environments, the message will not NDR but a loop will occur; mail will loop between the MTA and Routing engine.

CAUSE

This problem can occur if the members of the distribution list on Exchange Server 5.5 computers have a HomeMDB (the server on which the member's mail account was created) of only the network basic input/output system (NetBIOS) name. If this is the case, the lookup for that HomeMDB does not work.

RESOLUTION

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

301378 XGEN: How to Obtain the Latest Exchange 2000 Server Service Pack

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

Component: Transport

File name	Version
Reapi.dll	6.0.4419.10
Resvc.dll	6.0.4419.10
Phatq.dll	6.0.4419.10
Tranmsg.dll	6.0.4419.10
Mtaroute.dll	6.0.4419.10

STATUS

Microsoft has confirmed that this is a problem in Microsoft Exchange 2000 Server. This problem was first corrected in Microsoft Exchange 2000 Server Service Pack 1.