Re: in-addr.arpa problem

["W. Campbell" <wcampbel@xxxxxxxxxx>]

On Thu, 13 Jun 102, Dejan Petronijevic wrote:

> hello everyone
>
> we talked about this once on !ircd but let's move here as more people
> will join this discussion.
>
> why does ircd (2.10.3p3) sometimes does not show domain name but
> the *.in-addr.arpa domain ?
>
> example IP are:
>
> 210.248.220.18

The IP's reverse to a CNAME in the IN-ADDR.ARPA zone

wcampbel@botbay (wcampbel): host -t PTR 18.220.248.210.IN-ADDR.ARPA
18.220.248.210.IN-ADDR.ARPA is a nickname for
18.16.220.248.210.IN-ADDR.ARPA
18.16.220.248.210.IN-ADDR.ARPA domain name pointer ns.mmko.co.jp
18.16.220.248.210.IN-ADDR.ARPA domain name pointer ns.mmko.co.jp
wcampbel@botbay (wcampbel): host -t A 18.220.248.210.IN-ADDR.ARPA
18.220.248.210.IN-ADDR.ARPA is a nickname for
18.16.220.248.210.IN-ADDR.ARPA
wcampbel@botbay (wcampbel): host -t A 18.16.220.248.210.IN-ADDR.ARPA
wcampbel@botbay (wcampbel):

This is from a "normal" zone

wcampbel@botbay (wcampbel): host -t PTR 117.159.197.151.IN-ADDR.ARPA
117.159.197.151.IN-ADDR.ARPA domain name pointer kabel.pp.ru
wcampbel@botbay (wcampbel): host -t A 117.159.197.151.IN-ADDR.ARPA
wcampbel@botbay (wcampbel):


> 194.247.207.1

wcampbel@botbay (wcampbel): host 194.247.207.1
1.207.247.194.IN-ADDR.ARPA is a nickname for
1.0.207.247.194.IN-ADDR.ARPA
1.0.207.247.194.IN-ADDR.ARPA domain name pointer
seymoure.pclab.uni-bk.ac.yu
wcampbel@botbay (wcampbel): host -t A 1.0.207.247.194.IN-ADDR.ARPA
wcampbel@botbay (wcampbel): host -t A 1.207.247.194.IN-ADDR.ARPA
1.207.247.194.IN-ADDR.ARPA is a nickname for
1.0.207.247.194.IN-ADDR.ARPA
wcampbel@botbay (wcampbel):

Notice in both that the reversed CNAME has an extra "octet" which
seems odd to me.

It looks like it's mainly due to some oddness with the reverse DNS
setup of those IP's, but maybe someone who knows res.c internals
better can elaborate more.

>
> regards,
>
> Dejan
>