[Nagiosplug-help] check_dns oddity

[Subhendu Ghosh]

currently check_dns uses "nslookup" and the rever ip lookup is an artifact 
of nslookup.  Try the massive check_dns patch on source forge - bypasses 
/etc/resolv.conf or use check_dig.

-sg

On Thu, 12 Dec 2002, Bart Matthaei wrote:

> Hi,
> 
> when I use check_dns to query one of our nameservers, and the
> nameserver isn't authoritive for the ipspace it's running on, it times
> out.
> 
> When I did a tcpdump, and some log checking, it became clear to me
> that check_dns was doing a reverse lookup of the IP the nameserver is
> running on. But it's not querying the caching nameservers defined in
> /etc/resolv.conf .. It's querying the nameserver I'm doing the check
> on.
> 
> Now a lot of nameservers running BIND have recursive set to yes, so
> there's no problem there.
> But I'm running tinydns, and tinydns has no clue what-so-ever about
> the reverse of it's own IP address.
> 
> Example:
> 
> ./check_dns -H www.cysonet.com -s 62.58.71.5
> 
> The logs show me:
> 
> @400000003df85deb126db854 00000000000000000000ffffd9aa022a:a2dd:9313 - 000c 5.71.58.62.in-addr.arpa
> 
> Ofcourse, the check_dns time's out, because 62.58.71.5 isn't carying 
> any information about 5.71.58.62.in-addr.arpa.
> 
> 62.58.71.5 is our secondary nameserver running in another network 
> not under our administration.
> 
> Now I did the same lookup on our primary nameserver, which IS authoritive 
> for the space it's running on (217.170.2.0/23):
> 
> ./check_dns -H www.cysonet.com -s 217.170.2.38
> 
> @400000003df85ebf16e76934 00000000000000000000ffffd9aa022a:a358:8c6a + 000c 38.2.170.217.in-addr.arpa
> @400000003df85ebf16f301f4 00000000000000000000ffffd9aa022a:a358:8c6b + 0001 www.cysonet.com
> 
> Can anyone enlighten me on this issue ?
> 
> Kind Regards,
> 
> Bart Matthaei
> 
> p.s. I'm not a member of this list, so please keep the Reply-to intact
> ;)
> 
> 

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