XCON: Sockets Error When Connecting to Foreign X.400 MTA

ID: Q151626

The information in this article applies to:

Microsoft Exchange Server, version 4.0

SYMPTOMS

When you connect to foreign X.400 MTAs using the Microsoft Exchange X.400 Connector via TCP/IP, SOCKETS ERRORs might occur. The following errors may be written to the NT Event log when the connection is initiated from the foreign MTA.

message NMI9236: Internal Operating System Error, severity 12

(BASE IL TCP/IP DRVR(22) Proc 262) 04-10-96 05:52:10pm
Receive socket closed on CB 1
Socket error 0

message NMI1279: X.400 Service Event, severity 8

(PLATFORM KERNEL(6) Proc 94) 04-10-96 05:52:10pm
Session - Remote initiation of Transport Disconnection
Control block index 1, type 1

message NMI2036: Internal Processing Error, severity 10

(BASE TCP/IP DRVR(22) Proc 138) 04-10-96 05:52:10pm
Lost connections to locality 4

message NMI9225: Internal Processing Error, severity 14

(BASE IL TCP/IP DRVR(22) Proc 255) 04-10-96 05:52:10pm
Bad message type 769 for socket CB 1 in state 2

As a result, the foreign MTA is not able to establish a connection.

RESOLUTION

Analyzing the connection attempt shows that in the example below the remote MTA is not able to interpret a CONNECT CONFIRM. This frame was sent by Microsoft Exchange as an answer to a CONNECT REQUEST.

The following is a traced CONNECT CONFIRM frame sent by Microsoft Exchange:


ADDR  HEX                                                ASCII
0000  00 00 A2 00 C0 4A 00 80  5F D4 A0 48 08 00 45 00  .....J.._..H..E.
0010  00 54 E9 A6 40 00 20 06  04 0A 86 26 34 4D 86 26  .T..@.....&4M.&
0020  2C 5A 00 66 06 13 01 CF  46 C8 5D 5B 6A 31 50 18  ,Z.f....F.][j1P.
0030  22 09 60 73 00 00 03 11  00 2C 27 D0 01 CA 00 29  ".`s.....,'....)
0040  00 C1 0D 53 57 49 53 53  4C 49 46 45 54 53 41 50  ...SWISSLIFETSAP
0050  C2 0D 45 58 43 48 41 4E  47 45 54 53 41 50 31 C0  ..EXCHANGETSAP1.
0060  01 0B                                             ..

This trace shows Byte 37 as set to 11.
A receiving MTA may refuse this frame and disconnect.

STATUS

According to RFC-1006, the Byte at address 37 is reserved, meaning a receiving MTA should not try to interpret this Byte. Instead of refusing the frame it should accept it.

Additional query words:

Keywords : kb3rdparty XCON
Version : winnt:4.0
Platform : winnt
Issue type :