[Nanog] Re: IPv6 rDNS - how will it be done?

James Hess mysidia at gmail.com
Tue Apr 27 21:31:13 CDT 2010

On Tue, Apr 27, 2010 at 7:58 PM, Jason 'XenoPhage' Frisvold
<xenophage at godshell.com> wrote:
> On Apr 27, 2010, at 8:50 PM, Richard Barnes wrote:
>...However, I was under the impression that having both forward and reverse for >dynamic IPs was a best practice..

Perhaps we should back up a bit and delete 'how' from the subject line
of this thread, and first ask 'Will it be done?'  and where will RDNS
be implemented?

It is best practice within IPv4 networks.   The IPv6 internet is a new
network,  and prevalent practices will not necessarily turn out to be
what we consider best from V4.     'Best practice'  is going to have
to meet with administrative necessity  in some form at some point.

A reality may be that not all hosts necessarily have a meaningful
hostname that they should be addressed by,  or that the 'operator'
(web browser user) wants to be known;  Useful RDNS records may become
more confined to hosts  that  actually  provide a globally accessible

Residential subscribers of ISP    you-are-not-allowed-to-run-a-server
level of DSL/Cable service   will likely not  have their   own domain
name,  providing RDNS delegation would be mostly a waste of resources.

Providing  DDNS updates to RDNS is likely to be abused  in various
ways, even if it can be secured  (malware would love this -- instant
fully RDNS-cognizant mail server).

The prevalent practice is almost certainly going to be for res. ISPs
to provide a NXDOMAIN response to  RDNS queries,  or a generic
response  like is common with V4.

Probably  "custom RDNS"  would be considered a business service, and
like all business services, have its own pricing schedule,  and
involve subscriber  providing IP addresses of DNS servers to delegate

If  Res.  subscribers are lucky  the big ISPs  might provide a
proprietary app to run on their PC to  magically register it with
RDNS, and enable for connectivity.

With the downside that there can now be an  enforced  per-PC  surcharge.
Consumer DSL providers would probably love this....   $60/month,
connectivity for one PC to the internet at X/speed  included..... .
 $1/day  extra  for  each additional PC   registered with the DNS,
$0.10/hour  for each Xbox/gaming console/HTPC/Media streaming device
registered for internet access.

*zip bang voom*   4 years later...   IPv6  NAT,  the prevalent
technology present in every $50  IPv6 router,  an unofficial hack that
might some day get an RFC made about it....


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