[181176] in North American Network Operators' Group
Re: Is it safe to use 240.0.0.0/4
daemon@ATHENA.MIT.EDU (Josh Luthman)
Wed Jun 17 22:34:15 2015
X-Original-To: nanog@nanog.org
In-Reply-To: <20150618021356.75689.qmail@ary.lan>
Date: Wed, 17 Jun 2015 22:34:10 -0400
From: Josh Luthman <josh@imaginenetworksllc.com>
To: John Levine <johnl@iecc.com>
Cc: NANOG list <nanog@nanog.org>
Errors-To: nanog-bounces@nanog.org
How many devices need IPs? Is there a reason ARIN can't be used?
Josh Luthman
Office: 937-552-2340
Direct: 937-552-2343
1100 Wayne St
Suite 1337
Troy, OH 45373
On Jun 17, 2015 10:18 PM, "John Levine" <johnl@iecc.com> wrote:
> >IIRC, the short answer why it wasn't repurposed as additional unicast
> >addresses was that too much deployed gear has it hardcoded as
> >"reserved, future functionality unknown, do not use." Following an
> >instruction to repurpose 240/4 as unicast addresses, such gear would
> >not receive new firmware or obsolete out of use quickly enough to be
> >worth the effort.
>
> More to the point, the amount of work required to fix all the existing
> equipment to handle 240/4 would not be a lot less than the work
> required to get it to handle IPv6, and it would only have pushed the
> IPv4 exhaustion out a few years. It was entirely reasonable to
> conclude that it would not have been a good use of anyone's time or
> money.
>
> Look at the bright side: you can use the money you didn't spend on
> 240/4 upgrades to buy slightly used IPv4 space on the grey market
> or CGN equipment.
>
> R's,
> John
>
