IPV6 renumbering painless?

Thu Nov 11 23:24:47 UTC 2004

Wow, IPv6 misinformation is reaching unprecendented heights here on 
NANOG...

On 11-nov-04, at 18:46, Owen DeLong wrote:

>>> Seems to me that with a little
>>> bit of help from a "Change providers" tool, this
>>> would be virtually painless without the need to
>>> own or announce a small globally unique prefix.

>> That is how it has been designed, however there are some practical
>> problems with this system:

> I still think that we should pursue making the design work and not 
> adopt
> cruft as standards (ULA).

ULAs aren't cruft. They serve a purpose. If you don't need them, don't 
use them and they won't get in your way.

The actual distribution of new IP addresses to boxes is fairly trivial 
in IPv6. DNS is somewhat problematic but nothing a good search and 
replace can't handle. The real issues are IP address based access 
restrictions and problems with ingress filtering when addresses from 
two ISPs are in use at the same time.

>> - Until very recently DNS software did not support A6 records at
>>   all, and "chain" support for A6 records still seems to be a work
>>   in progress.

> This is getting resolved and I suspect will be long since functional by
> the time v6 comes to widespread deployment consideration.

Quite the opposite. There was A6 support in BIND AFAIK, but it's 
removed as it's unworkable. Learn to love AAAA.

> If your organization is large enough to involve reconfiguring a 
> significant
> number of routers, it is unlikely to be small enough to have to use PA
> space instead of getting PI space in the v6 world.

There is currently no PI in IPv6 unless you're an internet exchange or 
a root server. Whether there will be is anyone's guess, but it's not 
currently in the pipeline.

> I still think NAT is evil cruft that had a purpose in the V4
> world, but, is highly undesirable in the v6 world.

Regardless of the merit of NAT, there is little merit in IPv6+NAT as it 
has all the downsides of both. If you can live with NAT, stay in IPv4 
and talk to the IPv6 world over IPv4<->IPv6 NAT.