[Pdns-users] reverse zone /27 subnet - migrating from bind

[Brian Candler]

On 25/01/2019 08:54, Matthias Cramer wrote:
> You cant ask your dns directly, it only knows about the zone 118-31.82.119.85.in-addr.arpa.
> So you would need do do:
>
> dig 118.18-31.82.119.85.in-addr.arpa ptr @dnsip
>
> to get a correct result you have to ask the dns at the provider and there you get back a cname pointing to your entry,.

Yes, the "delegation" is a magic CNAME record:

$ dig @8.8.8.8 +trace -x 85.119.82.118

...

118.82.119.85.in-addr.arpa. 86400 IN    CNAME 
118.118-32.82.119.85.in-addr.arpa.
118-32.82.119.85.in-addr.arpa. 86400 IN    NS ns2.abominable.org.uk.
118-32.82.119.85.in-addr.arpa. 86400 IN    NS ns1.abominable.org.uk.

And therefore *in this particular example* you create the zone 
"118-32.82.119.85.in-addr.arpa" and create PTR record "118" within it.