Companies using public IP space owned by others for internal routing

ITechGeek ITG at
Tue Dec 19 19:56:58 CST 2017

While a single network gets at /64, isn't the practice suppose to be
providers allocating a /56 or a /60 for home users (you know so your IOT,
wired lan, wifi, guest network, gaming systems, bathroom, bedroom, etc. can
all be on their own networks)?

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On Mon, Dec 18, 2017 at 6:09 PM, William Herrin <bill at> wrote:

> On Sun, Dec 17, 2017 at 11:31 PM, Eric Kuhnke <eric.kuhnke at>
> wrote:
> > some fun examples of the size of ipv6:
> >
> >
> >
> >
> > 2qxgxw/self_just_how_big_is_ipv6/
> Hi Eric,
> Lies, damn lies and statistics. Both projections assume that IPv6 addresses
> are assigned the same way we assign IPv4 addresses. They are not.
> There are several practices which consume IPv6 at a drastically higher rate
> than IPv4. The most notable is the assignment of a /64 to every LAN. Your
> /26 LAN that used to consume 2^6th IP addresses? Now it's 2^64th. Used to
> consume RFC1918 addresses? Now it's 2^64th of the global IPv6 addresses.
> Why did we need a /64 for each LAN? So we could incorporate the Ethernet
> MAC address in to the IP address. Only we can't actually do that because it
> turns out to be crazy insecure. Nevertheless, the 3 computers in your
> basement will still consume 2^64th IPv6 addresses between them. But hey,
> what's 20 orders of magnitude between friends.
> We have ISPs that have received allocations of entire /19s. A /19 in IPv6
> is exactly the same percentage of the total address space as a /19 in IPv4.
> Before considering reserved addresses, it's 1/2^19th of the total address
> space. For a single ISP. Think about it.
> Meanwhile the IETF has learned nothing from the gargantuan waste that is
> ($2billion at current prices). They went and assigned
> FC00::/7.
>  /7!! Almost 1% of the IPv6 address space gone in a single RFC.
> I haven't attempted to compute the actual rate of IPv6 consumption but it's
> not inconceivable that we could exhaust them by the end of the century
> through sheer ineptitude.
> On the plus side, we're mostly only screwing around with 2000::/3 right
> now. After we burn through that in the next 20 years, we can if we so
> desire change the rules for how (and how quickly) we use 4000::/3.
> Regards,
> Bill Herrin
> --
> William Herrin ................ herrin at  bill at
> Dirtside Systems ......... Web: <>

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