Re: Should an IPv4 netmask be its own fieldtype?

[Jeffrey Smith <whydoubt () gmail com>]

RFC950: "Since the bits that identify the subnet are specified by a
bitmask, they need not be adjacent in the address. However, we recommend
that the subnet bits be contiguous and located as the most significant bits
of the local address."

So essentially any mask IS legal (even if not recommended).

The two standard subnets notations are dotted decimal (e.g. 255.255.255.0)
and network prefix (e.g. /24).  So recognizing just "24" may not be
terrible, but I find no precedent for doing so.
On Sep 30, 2015 11:03 PM, "Guy Harris" <guy () alum mit edu> wrote:

> On Sep 30, 2015, at 9:00 PM, Evan Huus <eapache () gmail com> wrote:
>
> > A pure netmask (without an associated address) is representable as
> > just a UINT8. Would it be terrible to write `protocolXYZ.netmask ==
> > 24`?
>
> Some are sent over the wire as a 32-bit mask, which could, conceivably,
> have holes in the middle.
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