XCON: Messages Not Delivered Over an Association

• Microsoft Exchange Server, versions 4.0 and 5.0
• Microsoft Windows NT Server, version 4.0

SYMPTOMS

The Microsoft Exchange message transfer agent (MTA) has a backlog of messages (up to the default threshold) waiting to be delivered. The MTA makes an association with another LAN-MTA (RPC connection), but does not deliver mail over this connection.

Various errors may appear in the applications event log concerning RPC problems. These may include the following events and other similar errors that indicate RPC problems:

   Event id = 9316
   Category = Interface
   Source = MSExchangeMTA
   An RPC communications error occurred. No data was sent over the RPC
   connection. Locality table (LTAB) index: 53. Windows NT error: 1727. The
   MTA will attempt to recover the RPC connection. [BASE IL KERNEL 24 512]
   (12)

   Event id = 9277
   Category = Interface
   Source = MSExchangeMTA
   The MTA has issued an RPC Cancel call for thread 1, Locality Table
   Index: 160, Time (ms): 1275740, Cancel result: 0
   [SLPS100 MtaBind ncacn_ip_tcp:100.5.51.16[1911] BASE IL] (14)

CAUSE

The Windows NT RPC component on the receiving computer puts the association in the wrong address space. Therefore, when the next bind arrives on the correct address, it cannot find the association and sends a Bind NAK.

STATUS

Microsoft has confirmed this to be a problem in Windows NT Server version 4.0. A supported fix is now available, but has not been fully regression-tested and should be applied only to systems experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft recommends that you wait for the next Service Pack that contains this fix. Contact Microsoft Technical Support for more information.

MORE INFORMATION

The initiating MTA tries to send mail to the receiving MTA, but the receiving MTA does not believe it has an association with it because the RPC put the association in the wrong address. It will NAK the RPC Bind request.

After the message threshold has been reached (default value is 50) on one of the MTAs, it will make a new association and begin delivering messages again.