Is there any way to change the MAC address of a machine? IP address is
> assigned by ISP. My understanding is that IP address is based on the
> MAC address of a machine, is that correct concept?
No. Your IP address has nothing whatsoever to do with your MAC address. Your ISP assigns it from their pool of available addresses. On my tiny network, when someone plugs in a new computer, it just assigns the lowest numbered unused IP address.
R's,
John