DOCUMENT:Q278444 08-MAY-2002 [exchange] TITLE :XCON: MTA Queue Building Up with No Association Opening PRODUCT :Microsoft Exchange PROD/VER::5.5 OPER/SYS: KEYWORDS:exc55 kbExchange550preSP5fix ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Exchange Server, version 5.5 ------------------------------------------------------------------------------- SYMPTOMS ======== Messages may loop in a site when high-priority messages are sent. Message loops result in non-delivery reports (NDRs). CAUSE ===== This problem can occur because of the way that high-priority messages are handled. The sequence of events is as follows: - High-priority messages are submitted on a server with a local X.400 connector to the destination site. A new association is opened for each message; as a result, nine associations are opened between the two sites. - When the next message arrives, the server tries again to open a new association. The attempt does not work; it is rejected by the remote end because the limit has been reached (the remote server logs a 57 event). If there are other servers in the site that have equal-cost X.400 connectors to the remote site, the message transfer agent (MTA) relays new high-priority messages to a second bridgehead server. A similar process occurs; up to nine associations are made between this second server and the remote site. - After all these associations are used, messages are relayed to a third server. - After all the associations have been used on the third server, messages are relayed back to the first. The first server now generates an NDR for the message with a loop detect. The loop is detected by using the internal trace information for each message extension. - After all the associations are open, even normal priority messages start to loop. RESOLUTION ========== A supported fix is now available from Microsoft, but it is only intended to correct the problem described in this article and should be applied only to systems experiencing this specific problem. This fix may receive additional testing at a later time, to further ensure product quality. 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 fix. 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, please go to the following address on the World Wide Web: http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS NOTE: In special cases, charges that are normally incurred for support calls may be canceled, if a Microsoft Support Professional determines that a specific update will resolve your problem. Normal 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: MTA +----------------------------+ | Dbserver.sch | 5.5.2654.38 | +----------------------------+ | Dcprods.cat | 5.5.2654.38 | +----------------------------+ | Emsmta.exe | 5.5.2654.38 | +----------------------------+ | Ems_rid.dll | 5.5.2654.38 | +----------------------------+ | Mtacheck.exe | 5.5.2654.38 | +----------------------------+ | Infoplog.cfg | 5.5.2654.38 | +----------------------------+ | Mtamsg.dll | 5.5.2654.38 | +----------------------------+ | Mtaperf.dll | 5.5.2654.38 | +----------------------------+ | P42.tpl | 5.5.2654.38 | +----------------------------+ | P772.tpl | 5.5.2654.38 | +----------------------------+ | P2.xv2 | 5.5.2654.38 | +----------------------------+ | X400om.dll | 5.5.2654.38 | +----------------------------+ STATUS ====== Microsoft has confirmed this to be a problem in Microsoft Exchange Server version 5.5. Additional query words: looping fails ====================================================================== Keywords : exc55 kbExchange550preSP5fix Technology : kbExchangeSearch kbExchange550 kbZNotKeyword2 Version : :5.5 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. 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