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@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