Re: Proposal to apply mask to IP address set on rule

Mouse <[email protected]> Fri, 23 May 2025 22:37:17 -0400 (EDT)
Newsgroups gmane.os.netbsd.devel.network
Message-ID <[email protected]>
> RFC4652 clearly expects/requires CIDR prefix lengths be powers of
> two.

I think you probably don't mean that.  If you did, there would be only
six possible IPv4 prefix lengths: /1, /2, /4, /8, /16, and /32.  It's
the netblock size, not the prefix length, that must be a power of two.
CIDR cannot represent a non-power-of-two-sized block without expressing
it as the union of multiple blocks.  (To be fair, neither can non-CIDR
noncontiguous netmasks; inherent in the mask paradigm is that each
block be a power of two in size.)

/~\ The ASCII				  Mouse
\ / Ribbon Campaign
 X  Against HTML		[email protected]
/ \ Email!	     7D C8 61 52 5D E7 2D 39  4E F1 31 3E E8 B3 27 4B