I am wondering how a netmask could be not contiguous when the network portion of the address must be contiguous. I suppose a bit mask could certainly be anything you want but a netmask specifically identifies the network portion of an address.
Steve
I seem to remember that before the advent of VLSM and CIDR there was
no requirement for the 1 bits in the netmask to be contiguous with no
intervening 0 bits and there was always someone who tested it out on a
production network just to prove a point (usually only once)