Re: all zeroes/all ones used in host IP's...

From: Michael H. Warfield (mhw@wittsend.com)
Date: Fri Jan 28 2000 - 23:16:32 EST


On Sat, Jan 29, 2000 at 02:53:57AM +0100, Magnus Danielson wrote:

> Please enligthen me if you can find an error in my reasoning, all under the
> assumption of an non-CIDR case.

        Your reasoning is not at fault, it's your premise. It's just that
a lot of us (I won't say all of us) who actually have responsibilities for
larger address spaces (I have a /16 plus ISS has a /19, two /20s and a /21
in the corporation), and have to run them, consider the non-CIDR case to be
either a "legacy" situation, an annoyance at best, or an excuse by vendors
for why their routers #$@$#@ up at worse. It really ends up boiling down
to netmask and netmask and netmask and nothing much else. Class A, Class B,
and Class C degenerate into nothing more than the DEFAULT initial netmasks
(/8, /16, and /14 respectively) to be modified by appropriate routing
tables and configurations. I have lots of networks where I see the
"illegal" one bit wide subnet masks. Those restrictions from RFC 1122 are
largely meaningless in a CIDR world.

        To paraphrase uncounted paraphrases of a paraphrase of an
expression...

        There are two classes of networks...

        Those that are CIDR and those that will be CIDR. The "non-CIDR
case" is a non-op in the real world of the current internet.

        Hmmm... That may be a BIT strong... Non-CIDR can interact with
the core internet. It's not a non-op per se... It's much more of a pain
in the fanny than a non-op.

> Cheers,
> Magnus

        Mike

-- 
 Michael H. Warfield    |  (770) 985-6132   |  mhw@WittsEnd.com
  (The Mad Wizard)      |  (770) 331-2437   |  http://www.wittsend.com/mhw/
  NIC whois:  MHW9      |  An optimist believes we live in the best of all
 PGP Key: 0xDF1DD471    |  possible worlds.  A pessimist is sure of it!

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