comcast ipv6 PTR

Tue Oct 15 02:58:22 UTC 2013

That gets to the core of the original question.  I figured there must be a
reason for the conscious omission.  However, I've noticed also that Comcast
hasn't bothered to give PTR to their routers, either.

I think that's a horse of a different color.  Leaving out PTR on the last
hop for the residential customer?  Sure.

Leaving out v6 PTR on your core/backbone/edge routers?  Surely that's not
acceptable...

On Mon, Oct 14, 2013 at 9:47 PM, John Levine <johnl at iecc.com> wrote:

> >Is there any reason other than email where clients might demand RDNS?
>
> There's a few other protocols that want rDNS on the servers.  IRC maybe.
>
> Doing rDNS on random hosts in IPv6 would be very hard.  Servers are
> configured with static addresses which you can put in the DNS and
> rDNS, but normal user machines do SLAAC where the low 64 bits of the
> address are quasi-random.  To get any sort of DNS you'd need for the
> routers to watch when new hosts come on line and somehow tell the
> relevant DNS servers what hosts need names.
>
> This would be a lot of work, so nobody does it.
>
> R's,
> John
>
>