INT 7A - Novell NetWare - IPX Driver - CLOSE SOCKET
        BX = 0001h
        DX = socket number (high byte in DL)
Notes:  also cancels events set by any Event Control Blocks for the socket
        the program must close all open sockets before terminating
        this function is supported by Advanced NetWare 1.02+
SeeAlso: BX=0000h