lame reverse DNS?

[Mark Martinec]

>> The problem has been resolved but I still sometimes see "connect from
>> unknown[2610:1c1:1:606c::19:2]" in the maillog (today: 6 of 131
>> connections). Local unbound issue?
> That IPv6 has a valid reverse DNS record, so please try to investigate.

Looks like an intermittent problem. Tried the following, with different
resolvers (local and public):

   dig -t ptr 
2.0.0.0.9.1.0.0.0.0.0.0.0.0.0.0.c.6.0.6.1.0.0.0.1.c.1.0.0.1.6.2.ip6.arpa 
@9.9.9.9

For example the quad-9 public resolver returned SERVFAIL several times,
but eventually started returning the positive reply (NOERROR).

There seems to be some mess with NS records and delegations of the
domain 1.0.0.0.1.c.1.0.0.1.6.2.ip6.arpa . DNS checkers are complaining
about a mismatch between NS records of this domain between a parent
NS and domain's NS, e.g. auth1.ns.ny1.nyi.net vs. auth1.sea.ns.nyi.net .

Try the domain 1.c.1.0.0.1.6.2.ip6.arpa at the checkers:
   https://network-tools.webwiz.net/dns-report.htm
   https://intodns.com/1.c.1.0.0.1.6.2.ip6.arpa
   https://zonemaster.iis.se/en/?resultid=5e30b31d6f0061c5


Mark