We use Nagios to monitor our network. Our DNS server is Red Hat 7

Each morning I receive a notice from nagios:


Notification Type: PROBLEM

Service: DNS
Host: dns0
Address: 172.31.1.233
State: CRITICAL

Date/Time: Thu Sept 29 09:58:01 EDT 2005

Additional Info:

CRITICAL - Plugin timed out after 10 seconds

---------

After a about 4-5 minutes I receive a recovery response:

Notification Type: RECOVERY

Service: DNS
Host: dns0
Address: 172.31.1.233
State: OK

Date/Time: Thu Sept 29 10:02:12 EDT 2005

Additional Info:

DNS ok - 2 seconds response time, Address(es) is/are 207.68.183.32


I wanted to check my logs in /var/logs/messages

this is a huge log file. but i scanned it, and did not notice anything out of the ordinary. where would the next place to look to find out why this is happening?

i do not notice what DNS routing stops, but i am wondering why nagios says DNS is down.

I'm not familiar with Nagios but 2 seconds seems an excessive response time for state OK. Do you have a heavy load and/or packetloss on your network?

packets loss is at a minimum for the most part.

depends.

but i could say there is a 'heavy load' or a lot of traffic.

Wild guess: The DNS probe failed due to packet loss but a retry 5 mins later succeeded.

what logs should i check next?

If this was my network, I'd set up a script to ping the dns server every second for 24 hours and dump the results to a file for analysis. If packet loss was any way significant at certain times of the day, I'd look at network configuration and bandwidth management.

Bump. Any other input???

I think we will be updating BIND next to resolve this issue.