[101337] in North American Network Operators' Group
RE: Assigning IPv6 /48's to CPE's?
daemon@ATHENA.MIT.EDU (michael.dillon@bt.com)
Mon Dec 31 04:28:25 2007
Date: Mon, 31 Dec 2007 09:30:54 -0000
In-Reply-To: <b4504ba0712310025h39c9b6dbg53ab720cd19cd757@mail.gmail.com>
From: <michael.dillon@bt.com>
To: <nanog@merit.edu>
Errors-To: owner-nanog@merit.edu
> I believe someone posted the ARIN recommendation that=20
> carriers assign out /64's and /56's, and in a few limited cases, /48.=20
>=20
> I can understand corporations getting more than a /64 for=20
> their needs, but certainly this does not mean residential ISP=20
> subscribers, right?
Then you misunderstand ARIN's recommendations. The basic IPv6
assignment size is /48. ARIN recommends assigning a /48 to all
customers who cannot be guaranteed to only need a single subnet.
It is possible that some ISPs offer a specialty service, say
IPv6 connectivity to CCTV cameras, which only needs a single
/64 but general purpose ISPs providing general Internet accesss
to consumers and businesses should assign a /48. Some ISPs have
very large numbers of consumer customers and feel that the large
number of /48s they will need may be excessive, therefore ARIN
also recommends that in the case of providing connectivity to
a private residence, a /56 may be used. In order to support the
use of a /56 assignment in this situation, ARIN has adjusted some
parts of their policy to do with counting, so that they measure
/56 assinments rather than /48 assignments. But a /48 assignment
is still fully justified.
> There are also serious privacy concerns with having a MAC=20
> address within an IP address. Aside from opening the doors to=20
> websites to share information on specific users, lack of NAT=20
> also means the information they have is more detailed in=20
> households where separate residents use different computers.
Aside from the fact that you can change your MAC at will,=20
there is no need to use the MAC as the IPv6 node address.
You can change your IPv6 node address every day if you wish.
=20
> I can become an IPv4 stranger to websites once a week by=20
> deleting cookies, IPv6 means they can profile exactly what I=20
> do over periods of years from work, home, starbucks, it=20
> doesn't matter. I don't see NAT going away any time soon.=20
This only works if your ISP assigns your IP address dynamically
and your lease times out without renewal, i.e. you power down
your gateway device long enough to get a new IP address. Same
applies to IPv6.
--Michael Dillon
