Forward zone not working

Woodworth, John R John.Woodworth at CenturyLink.com
Mon May 16 18:28:10 UTC 2016


> -----Original Message-----
> From: bind-users-bounces at lists.isc.org [mailto:bind-users-bounces at lists.isc.org] On Behalf Of MegaBrutal
> Sent: Monday, May 16, 2016 1:31 PM
> To: bind-users at lists.isc.org
> Subject: Forward zone not working
>
> Hi all,
>
> I have an IPv6 reverse PTR zone for a /48 subnet delegated to my BIND
> server, and one of its /64 subnets are used with SLAAC + Privacy Extensions.
> I want to have valid reverse & forward hostnames set up for this /64 subnet.
> Generating 2 ^ 64 reverse & forward records for BIND would be wasteful if
> not impossible, so I found out that another DNS server, AllKnowingDNS
> [http://all-knowing-dns.zekjur.net/] is built for this particular purpose.
> So far so good, I set up an AllKnowingDNS on another IP address, and delegated
> the /64's PTR zone for it.
>
> It seemed to work at first, but then I discovered that PTR resolutions are
> not reliable. Some services are unable to resolve my reverse PTRs.
> You know, in 2016, I assumed that the majority of recursive DNS servers are
> IPv6-ready (especially those that deal with IPv6 reverse PTRs – I thought
> services those see my IPv6 address and want to reverse-resolve it, most
> probably have access to IPv6-enabled recursive NS-es), so I didn't see any
> problem with having only an IPv6 address for my AllKnowingDNS server. I was wrong.
>
> So let's see my options:
> 1. Reserve a public static IPv4 address for my AllKnowingDNS server. I simply
> can't afford that. IPv4 addresses are expensive.
> 2. Configure my BIND to forward the reverse PTR requests for the reverse /64
> zone to the AllKnowingDNS server, and directly answer queries on its behalf.
> Since my BIND is dual-stack, it would have no problem with receiving requests
> on its IPv4 interface and forwarding them on IPv6. Dnsmasq can easily do that
> (to forward requests for specific zones to specific NS servers), but I don't
> have public Dnsmasq anywhere around, all my authoritative name servers are BIND.
>
> So this how I came around to try a forward-type zone:
>
> zone "y.y.y.y.x.x.x.x.x.x.x.x.x.x.x.x.ip6.arpa" {
>     type forward;
>     forward only;
>     forwarders { zzzz::zzzz; }; // IPv6 address of AllKnowingDNS.
> };
>
> Where x substitutes digits of my /48, y substitutes digits of my /64, and z
> substitutes digits of the AllKnowingDNS IPv6 address.
>
> It simply doesn't work. In query logs, I see BIND treats requests for the zone
> as if they were requests for recursion, thus rejects them appropriately. DiG
> backs this up with "status: REFUSED". It doesn't seem like if BIND does any
> effort in forwarding the zone, it just treats it as non-authoritative, which
> would need recursion, and of course recursion is very properly disabled. It's
> like the zone entry weren't even there.
>
> Does anyone have any insights or suggestions?
>
> Thanks in advance!
>

MegaBrutal,

Unfortunately, I don't have an answer for "how to do this today" but I have an
I-D in the works targeting the scalability of large datasets with an emphasis on
the IPv6 namespace (http://tools.ietf.org/html/draft-woodworth-bulk-rr-01).

We've spent a lot of time and effort developing our solution and hope to gain
some traction so for others that might ask this next year I can have an answer.

We are also working on our own implementation for bind and unbound which I would
be glad to share once it is mature enough.


Regards,
John

>
> MegaBrutal
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