From: Warner Losh <imp@bsdimp.com>
To: Bakul Shah <bakul@iitbombay.org>
Cc: TUHS main list <tuhs@minnie.tuhs.org>
Subject: Re: [TUHS] conventions around zero padding in ip4
Date: Sat, 7 May 2022 17:49:46 -0600 [thread overview]
Message-ID: <CANCZdfpuyNDjHceUgAF5fYwD+mDG07RwZOzSLjRRgMvds8PEtg@mail.gmail.com> (raw)
In-Reply-To: <FA943880-F763-4548-A7AC-0BDB9991E731@iitbombay.org>
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On Sat, May 7, 2022, 5:19 PM Bakul Shah <bakul@iitbombay.org> wrote:
> On May 7, 2022, at 12:14 PM, Warner Losh <imp@bsdimp.com> wrote:
> >
> > 10.2 is ambiguous. In a network context, it means, typically,
> 10.2.0.0/16 (though your mileage may vary).
> > In a host context, it means 10.0.0.2. It's this confusion that has lead
> to many efforts
> > to outright kill this notation.
>
> On FreeBSD:
> ping 10.2 tries to ping 10.0.0.2 and
> ping 192.168.300 tries to ping 192.168.1.44 (1*2^8+44 == 300)
> ping 10.2.300 tries to ping 10.2.1.44
> ping 192.1000000 tries to ping 192.15.66.64 (15*2^15+66*2^8+64 == 1000000)
> ping 1000000001 tries to ping 59.154.202.1 (59*2^24+154*2^16+202*2^8+1)
> ping 300.300 tries to ping 23.217.138.110 (I haven't worked this out!
> Prob. a bug)
> So the last number is treated as the host number on a given net.
> This may have some sense in the classful network world but is
> very confusing in the CIDR world.
>
We just know the dotted quad world. In the early days of sparse addresses
and crappy name service (or out of date host files) these shortcuts were a
lifesaver.
Warner
>
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next prev parent reply other threads:[~2022-05-07 23:54 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-07 16:14 ron minnich
2022-05-07 16:38 ` Bakul Shah
2022-05-07 16:48 ` Erik E. Fair
2022-05-07 18:49 ` Steffen Nurpmeso
2022-05-07 19:14 ` Warner Losh
2022-05-07 19:50 ` ron minnich
2022-05-07 19:57 ` ron minnich
2022-05-07 23:19 ` Bakul Shah
2022-05-07 23:49 ` Warner Losh [this message]
2022-05-08 10:28 ` Ralph Corderoy
2022-05-08 5:21 ` jason-tuhs
2022-05-08 10:22 ` Ralph Corderoy
2022-05-09 14:08 ` Steffen Nurpmeso
2022-05-10 10:49 ` Ralph Corderoy
2022-05-07 19:43 Noel Chiappa
2022-05-08 14:54 ` Michael Kjörling
2022-05-09 16:14 Noel Chiappa
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