Is it possible to set an ipv6 PTR record

Joe Abley jabley at
Tue Dec 18 14:21:24 CET 2018

On 18 Dec 2018, at 08:06, Robert Chalmers via Unbound-users <unbound-users at> wrote:

> Thanks Joe.
> Ok, I should have known that.  Looking better now.
> Remembering that this machine is on a SKY Dynamic IP router port forwarded to the server, which is a Mac. OSX 10.14.2 
> It otherwise runs well, but some mail is falling over the issue of the PTR record pointing to the SKY server, not mine. 
> So it’s that I’m trying to solve - if at all possible.

Ah, then also bear in mind that the PTR record you've installed on unbound is only visible to people using that unbound instance in their resolver chain. The rest of the world won't see it. You need to ask Sky to install the PTR record you need (or to delegate a zone to your servers, somewhere else on the Internet). If the v6 address they assign to you is really dynamic (not just in theory, but in practical terms) then this might be a challenge.

However, I seem to remember drinking beer with v6 people from Sky in some European city or other at some point (Helsinki, maybe?) and I seem to think they will send you a static prefix over DHCPv6 if you request a prefix delegation. If you can get a /48 or /56 or whatever it is they hand out and number your mail server out of there, you will likely have more luck. You still need to talk to Sky to get the PTR record installed, though.

(Random advice found on Internet, in case it's useful: "sky's dhcp requires the router to initiate the prefix delegation request and not request an ip instead of waiting for a RA. next that on disconnection dhcp should "not" send a release otherwise the prefix will change on reconnection.")

I'll leave it to others in a better timezone to look at your Unbound-specific questions. I'm only two espressos into the day, here.


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