Int 21 Fn 5F40  u - Lan Manager Enhanced Dos - Local Netmessagebuffersend  [N]

   AX = 5F40h
   DS:DX -> NetMessageBufferSend parameter structure (see #1392)

Return: AX = error code

Format of LAN Manager NetMessageBufferSend parameter structure:
Offset Size    Description (Table 1392)
 00h   DWORD   -> recipient name (name for specific user, name* for domain
             wide name, * for broadcast)
 04h   DWORD   -> buffer
 08h   WORD    length of buffer