der Mouse wrote:
and most modern network hardware will turn their nose up at them AFAIK.IMO anything that pretends to implement IPv4 but which doesn't do noncontiguous netasks is simply broken, I don't care whether it comes from Cisco or Netgear or NetBSD. Not, I suppose, that anyone necessarily cares what I consider broken. Slow-path them. Require a sysctl switch (the way we do for source routes). Fine. But outright desupport them? I'd call that a bug, even if it is done deliberately.
I believe that non-contiguous netmasks actually are illegal nowadays. They became illegal when CIDR was implemented.
That said, it might be worth having a way to enable the legacy view of network address classes and netmasks, if someone wants to...?
Johnny