DOCUMENT:Q177006 14-MAR-1999 [exchange] TITLE :XADM: MTA May Fail During Mailstorms Involving Large DLs PRODUCT :Microsoft Exchange PROD/VER:WinNT:5.0 OPER/SYS: KEYWORDS: ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Exchange Server, version 5.0 ------------------------------------------------------------------------------- SYMPTOMS ======== If a brief, intense flurry of messages and replies (also known as a mailstorm) occurs in an Exchange Server organization and involves one or more very large distribution lists (DLs), the Microsoft Exchange message transfer agent (MTA) may fail repeatedly. The Event Log will typically show events 2051 and 9405 for the MTA preceding the failures, and the exceptions generated will usually all have the same error code, 0xe0050803. MORE INFORMATION ================ Under certain conditions, a message sent to a very large DL may generate a large volume of replies and replies-to-replies over a short period, all addressed to the same DL. This can cause a mailstorm that increases the load on messaging servers exponentially over a period of minutes or hours. Under these high-stress conditions, occasional failures of the MTA as described in this article may occur. WORKAROUND ========== Temporarily or permanently place delivery restrictions on the distribution list(s) involved in the mailstorm, to prevent the message traffic from escalating as multiple users reply to messages sent to the lists. When the traffic drops, the MTAs will stop failing. Under extreme conditions, it may be necessary to delete the MTA queues or take other urgent action to reduce traffic. STATUS ====== Microsoft has confirmed this to be a problem in Microsoft Exchange Server version 5.0. This problem has been corrected in the latest Microsoft Exchange Server 5.0 U.S. Service Pack. 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 Additional query words: volume alias traffic storm ====================================================================== Keywords : Technology : kbExchangeSearch kbExchange500 kbZNotKeyword2 Version : WinNT:5.0 Issue type : kbbug Solution Type : kbfix ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 1999.