Antwort: Re: [Nagiosplug-devel] check_dns: DNS WARNING - nslookup returned error status

Ton Voon ton.voon at
Mon Sep 5 03:40:15 CEST 2005

On 2 Sep 2005, at 16:08, srunschke at wrote:
> If it is of any help, I would like to offer to escalate this issue
> to the RedHat Support. Since we have a dozen support subscribtions
> for RH Enterprise, I can easily create a ticket and let them solve
> it for us ;-)
> I just need some technical description of the problem so that
> someone not into Nagios would be able to understand it. I'm not
> sure I could word it properly myself.


I would like to take you up on this offer.

I've managed to reduce the test case down to the included tar file,  
so there are no nagios plugins involved. Instructions are:

gunzip and untar and cd
./run_tests 10

On my RHEL4 server (Red Hat Enterprise Linux version 4 Update 1,  
2.6.9-11.EL) , this will fail anywhere between 40% to 70% of the  
time. Running the same on MacOS10.4.1 and Debian 3.1 gives me 100%  

In child_test.c, you can amend the command that is executed. These  
were the results I got (after 100 runs):

   - /bin/date 100%
   - /bin/cat /etc/hosts 100%
   - /usr/bin/dig 69%
   - /bin/sleep 1 100%
   - /usr/bin/nslookup 90% (after 100 runs), 40% (after 10  
   - /bin/ping -c 1 localhost 100%
   - /bin/ping -c 1 100%

So it looks like only DNS resolution stuff is causing problems. Using  
Peter's trick of waiting for childtermd to be set by the SIGCHLD  
handler (commented in child_test.c) changes it to 100% success at all  

Definitely looks like a Redhat problem. Can you escalate to them. I  
think a technical summary could be: "wait() sometimes fails if child  
executes nslookup/dig command".

I'm happy for you to contact me if you need more information.

T: +44 (0)870 787 9243
F: +44 (0)845 280 1725
Skype: tonvoon

The contents of this email and any files transmitted with it are
confidential and intended solely for the use of the individuals to  
whom it
is addressed. If you are not the intended recipient or have received  
e-mail in error please notify the sender and destroy this e-mail
immediately. Any unauthorised copying, disclosure or distribution of the
material in this e-mail is strictly prohibited.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: rhel4_child.tar.gz
Type: application/x-gzip
Size: 1474 bytes
Desc: not available
URL: <>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <>

More information about the Devel mailing list