Network DDE Applications Fail with TCP/IP-32 (120122)

SYMPTOMS

Network DDE Windows-based applications (like File Manager) fail to operate successfully between Windows for Workgroups workstations configured with TCP/IP-32 when they are in different sub-nets connected by routers. The following error message appears:

The computer name specified in the network path cannot be located

You can observe workstations with a protocol analyzer. Unsuccessful Name Query requests broadcasted to the local sub-net are transmitted by workstations to resolve the name of the workstation in question: "computername <1F>".

The NET USE command functions correctly.

CAUSE

The NetBIOS naming table on the workstation does not include the name required by Network DDE for computer names specified in the LMHOSTS file. This problem only occurs under TCP/IP-32 if you use the #PRE keyword.

When a name entry is parsed from the LMHOSTS file, three entries are added to the workstation's NetBIOS naming table. These are added to provide the computer name, messenger, and server functionality:

   computername   00h
   computername   20h
   computername   03h

RESOLUTION

TCP/IP-16 Real Mode

Use the ADDNAME2 keyword available from the LAN Manager resource kit. The following syntax adds an additional entry which can then be saved to the LMHOSTS file:

   addname2 "computername   " /p0x1f

The entire length of the name must be 16 characters including the hidden character (1f) in the 16th place. You must pad the computer name with spaces so that it equals 15 characters in length.

TCP/IP-32 for Windows for Workgroups 3.11

TCP/IP-32 can add the required NetBIOS name (if you are using the #PRE keyword) by having the two following lines in the LMHOSTS file of each remote computer:

   ipaddr computername #PRE
   ipaddr "COMPUTERNAME   \0x1F" #PRE

NOTE: The computer name in quotation marks on the second entry must equal 16 characters in length, and it must be in uppercase. The #PRE keyword is optional for the second entry above. #PRE speeds up resolution of the Network DDE name which helps to provide a successful connection accross routers providing a dialup or delayed remote link.