DOCUMENT:Q157015 05-APR-1999 [exchange] TITLE :XCON: MTA Outbound Connection Refused by X.400 Host PRODUCT :Microsoft Exchange PROD/VER:winnt:4.0 OPER/SYS: KEYWORDS:kb3rdparty kbnetwork ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Exchange Server, version 4.0 ------------------------------------------------------------------------------- SYMPTOMS ======== Outbound connections from Microsoft Exchange Server are refused by the destination Message Transfer Agent (MTA) using X.400. CAUSE ===== The reserved byte in the RFC1006 TPKT header is not necessarily 0x0 in the Microsoft Exchange MTA. This can cause connection attempts to remote MTAs to fail if the remote RFC1006 implementation requires this byte to be 0x0. This byte is not specified to be a particular value according to RFC1006. MORE INFORMATION ================ A trace of the faulting connection might yield a packet similar to the following. The line of interest in this particular situation is ISO: Reserved = 0 (0x0). The following sample shows the Reserved field with the new behavior, specifically the Reserved field will always be explicitly set to 0x0. If this field shows this to be any other value, this may be the cause of the connection failure and is corrected in SP3. TPDU Type: Connection Request, Len: 14 199.199.199.199 200.200.200.200 IP FRAME: Base frame properties ETHERNET: ETYPE = 0x0800 : Protocol = IP: DOD Internet Protocol IP: ID = 0xC6B5; Proto = TCP; Len: 58 TCP: .AP..., len: 18, seq: 93150219-93150236, ack: 508652377, win: 8760, src: 2185 dst: 102 ISO: RFC 1006 ISO Packet, ver: 3, Len: 4 ISO: Version = 3 (0x3) ISO: Reserved = 0 (0x0)<===== RIGHT HERE ISO: Length = 18 (0x12) ISO: Data: Number of data bytes remaining = 14 (0x000E) TPDU: Type: Connection Request, Len: 14 STATUS ====== Microsoft has confirmed this to be a problem in Microsoft Exchange Server version 4.0. This problem was corrected in the latest Microsoft Exchange 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: ====================================================================== Keywords : kb3rdparty kbnetwork Technology : kbExchangeSearch kbExchange400 kbZNotKeyword2 Version : winnt:4.0 ============================================================================= 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.