SNASERVR.EXE Traps When it Receives an Illegal SIGNAL Command

• Microsoft SNA Server for Windows NT, versions 2.0, 2.1, and 2.11

SYMPTOMS

The SNA Server generates a Dr. Watson error when it receives an illegal SIGNAL command from a host system. The DRWTSN32.LOG file indicates that an Application Exception has occurred in SNASERVR.EXE. In addition, SNA Server logs Event 624 in the Windows NT application log when the SNASERVR.EXE trap occurs. The Event 624 has a description similar to the following:

   Creating dump file C:\SNA\traces\snadump.log for SNASERVR.EXE

   EXPLANATION
   A process (SNASERVR.EXE) ended abnormally due to a protection
   violation or similar condition and a dump file SNADUMP.LOG has been
   created that contains information about the state of the process at
   the time of the exception. Register information is contained in your
   Windows NT root directory in the file DRWTSN32.LOG.

CAUSE

The SIGNAL command consists of the command byte and a four-byte value, according to the IBM SNA Formats Guide. Therefore, any SIGNAL command that consists of fewer than five bytes is illegal. The SNA Server Node (SNASERVR.EXE) will trap as described above if it receives an illegal SIGNAL command containing fewer than 5 bytes. In addition, a similar trap on the receipt of an illegal LUSTAT command containing too few bytes is also possible.

NOTE: Please refer to the RU section of the IBM SNA Formats Guide (GA27-3136) for more specifics on format of SNA commands.

RESOLUTION

Microsoft has updated the file SNASERVR.EXE to correct this problem.

MORE INFORMATION

This problem was encountered by a customer when sending an illegal SIGNAL command data message to SNA Server from a host simulator. This problem has not been encountered when running SNA Server against actual SNA connectivity products from IBM or any other vendor.

STATUS

Microsoft has confirmed this to be a problem in SNA Server for Windows NT. This problem was corrected in the latest SNA Server for Windows NT, 2.11 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