Nagios Support Forum

I believe (not 100% positive) that it will use one defined in /etc/resolv.conf

That file looks like it'd be the right one. When view it I see 2 of our DNS servers in there already, likely added during the initial install I assume. I added the rest of our DNS servers and I'm still not getting anything back on the IPs that weren't working before. Is there a service or anything that needs to be restarted?

Your OS will pick a DNS server from the /etc/resolv.conf and do a reverse lookup.

Does it check all the servers in the resolv.conf file? Because some are still not working. I will PM you a couple screenshots.

I believe it pulls the first entry, if it fails, it goes to the next one. I don't think it uses all of them at the same time. Anyway, you can PM me the screenshots. I will get the Nagios NA developers involved as well. Thanks!

From what I can tell it looks like they are using different nameservers and the nameserver for the IPs that are working is actually quite far down the list (so I am assuming it checks all nameservers) but I don't see much documentation on the actual PHP function we are using - we don't specify the nameservers to look at anywhere in our scripts, the only thing we use is the core PHP function we were talking about earlier.

My first instinct is to ask if you have PTR records set up for the IPs you are using that are not showing hostnames. Are there PTR records for the IPs that are working? If there are then the lack of PTR records for the others may be causing the issue.

Forgot to clarify something on the server list. Sent a PM to jomann.

Can you also PM the same info to nscott? Thanks!

Done, thanks.

I sent you a PM.