[dns-operations] Strange reverse DNS entry

[Duane Wessels]

On Wed, 26 Sep 2007, Michael Monnerie said:

> # dig -x 12.4.146.152
>
> ;; ANSWER SECTION:
> 152.146.4.12.in-addr.arpa. 83000 IN     CNAME
> 152.128/26.146.4.12.in-addr.arpa.
>
> Could that ever be a valid entry? I believe no, but what could they have
> wanted to do with that form of CNAME?

Yes, its valid.  See RFC 2317 "Classless IN-ADDR.ARPA delegation"

DW