Modem Sharing Clients Cause Stop 0x000001E on SBS

ID: Q193529

The information in this article applies to:

Microsoft BackOffice Small Business Server versions 4.0, 4.0a
Microsoft Windows NT Server version 4.0, Terminal Server Edition

SYMPTOMS

When a Small Business Server client attempts to perform a modem sharing function, it may define the user as "user-mode programmer" and when opening a remote COM port to send an IOCTL #0, generate the following blue screen error message:

Stop 0x0000001E (0x00830830, 0x0000000d, 0x00000001 0x800059f0) UNHANDLED_EXCEPTION

NOTE: The four parameters will vary according to the configuration of the system.

CAUSE

In the client's modem sharing driver code, there is a function dispatch table. It maps IOCTL requests (by their ID) to their handling functions. There is only a check for the upper limit of the IOCTL code but, in fact, the entry with ID 0 is invalid. Thus, sending an IOCTL with ID 0 causes an underflow in an array (for example, bad lookup) and a blue screen error message is generated.

RESOLUTION

To resolve this problem, obtain the latest service pack for Windows NT 4.0 or Windows NT Server 4.0, Terminal Server Edition. For additional information, please see the following article in the Microsoft Knowledge Base:

Q152734 How to Obtain the Latest Windows NT 4.0 Service Pack

Please note that this is a client-side issue and the fix must be applied on the Small Business Server client running on Windows NT version 4.0.

Additional query words:

Keywords : NT4SP4Fix kbbug4.00 SBS
Version : winnt:4.0,4.0a
Platform : winnt
Issue type : kbbug