INT 2F U - NETWORK REDIRECTOR - QUALIFY REMOTE FILENAME
        AX = 1123h
        DS:SI -> ASCIZ filename to canonicalize
        ES:DI -> 128-byte buffer for qualified name
Return: CF set if not resolved
Notes:  called by MSDOS 3.1+ kernel, but not called by DR-DOS 5.0 unless the
          filename matches the name of a character device
        called first when DOS attempts to resolve a filename (unless inside an
          AX=5D00h server call); if this fails, DOS resolves the name locally
SeeAlso: INT 21/AH=60h