Knowledge Base

XCON: No Rerouting Needed When OU Field is Empty

Article ID: 166611

Article Last Modified on 10/28/2006

Microsoft Exchange Server 4.0 Standard Edition
Microsoft Exchange Server 5.0 Standard Edition

This article was previously published under Q166611

SYMPTOMS

If the following conditions are met, a message coming into a Microsoft Exchange Server, version 4.0 or 5.0, addressed to:

   C=cc; A=aa; P=pp; O=oo; OU=uu; S=surname

will generate a Non-Delivery Report (NDR) to the originator stating that a loop was detected:

The Microsoft Exchange Server's Site Addressing is set to:
```
      C=cc; A=aa; P=pp; O=oo
					
```
The Microsoft Exchange Server has a single X.400 connector to a X.400 provider whose Address Space set to:
```
      C=*
					
```
The X.400 provider forwards all messages with the following address to the Microsoft Exchange Server:
```
      C=cc; A=aa; P=pp
					
```
A mailbox exists on the Microsoft Exchange Server with an X.400 address of:
```
      C=cc; A=aa; P=pp; O=oo; S=surname
					
```

CAUSE

This happens because the recipient address does not exist in the Microsoft Exchange Directory. The existing mailbox's address does not include OU=uu. Microsoft Exchange Server sends the message back to the X.400 provider, which returns it to Microsoft Exchange Server, which then detects the loop.

STATUS

Microsoft has confirmed this to be a problem in Microsoft Exchange Server, version 4.0. This problem has been corrected in the latest U.S. Service Pack for Microsoft Exchange Server version 4.0. For information on obtaining the Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

   S E R V P A C K

Microsoft has confirmed this to be a problem in Microsoft Exchange Server version 5.0. This problem has been corrected in the latest U.S. Service Pack for Microsoft Exchange Server version 5.0. For information on obtaining the service pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

   S E R V P A C K

MORE INFORMATION

After the hotfix has been applied, the Microsoft Exchange Server will immediately generate an "Unrecognized OR Name" NDR to avoid the rerouting.

Keywords: kbbug kbfix kbqfe KB166611