Redeploying most of 127/8, 0/8, 240/4 and *.0 as unicast

Fri Nov 19 15:37:28 UTC 2021

On Fri, Nov 19, 2021 at 7:15 AM Nick Hilliard <nick at foobar.org> wrote:
>
> Joe Maimon wrote on 19/11/2021 14:30:
> > Its very viable, since its a local support issue only. Your ISP can
> > advise you that they will support you using the lowest number and you
> > may then use it if you can....all you may need is a single
> > patched/upgraded router or firewall to get your additional static IP
> > online.

This already works in many cases and the value of the extra IP address
declines as a function of the /cidr. /29s are pretty common.

> That would be an entertaining support phone call with grandma.
>
> So, she gets a new CPE which issues 192.168.1.0 to her laptop and .1 to
> her printer, and then her printer can no longer talk to her laptop.

In all honesty, I view the "zeroth" address as being primarily for
internet facing hosts on
small subnets, and not /24s, for the small businesses that are using
them today. A subset of 1 router,
1 device, needs to be checked for compatibility.

As for customer CPE RFC1918/24s, CeroWrt used /27s extensively in our
attempt to
route, rather than bridge wifi networks (to try and mitigate the wifi
multicast problem).
Remarkably we had only one end user device that did not deal with that properly
reported to us, (a sony dvd player) over the lifetime of the project.

Routing the home network as we did then did remarkably reduce wifi
multicast traffic,
but also exposed issues with mdns since solved. I would still rather
like it if we routed
guest and mesh networks rather than bridge them but that seems to be a
lost cause.

> I'm sure that the ISP would be happy to walk her through doing a
> firmware upgrade on her printer or that her day would end up better for
> having learned about DHCP assignment policies on her CPE.
>
> They could even email her a copy of the RFC and a link to the IETF
> working group if she felt there was a problem.

Setting up a home network with IPv6 only, and finding that printer, is
still hard today. Going back to mdns discovery, I recently found that
my new chromebook didn't support it, and can't print. Asking grandma
to type in fd87:3253:1343:deed:b33f:abd1:3217:1177 is no fun either.

>
> Nick

-- 
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Dave Täht CEO, TekLibre, LLC