Nagios Support Forum

I'm trying to understand what Nagios XI uses to determine if a host is down. At first I thought it was Ping, but then I was reading online something to the effect that when Nagios receives an alert from a service running on a given host, it does some kind of check to see if the host is down, so I'm not sure how the protocol works.

I'm wanting to set up some kind of host down alert that I can use to alert a specific contact group, I also would like to be able to link that alert to different email notification template.

As always, any suggestions would be appreciated.

Hosts are checked according to the check command specified on the host or host template. A returned service check does not effect how the host is checked. When a service check is returned, nagios does check if the host is currently down/unreachable, but that is only for alerts/notifications/event handlers/etc. The host is still checked on its normal interval regardless of service checks/states.

Hmm, still not sure that's what I'm looking for.

I brought up a test server, I'll use it to test. See what alerts I get when I shut it down.

OK, so I unplugged the nic cable and watched the service status detail.

The first item to go red was Uptime. A minute or so later, the host name field went red. Then I got an email about the Uptime service going critical, then shortly thereafter I got the email about the host being down. No more alerts after that.

So that will work for me, if that's how it's supposed to work. Just wish I could do something a little more visible to make the Host Down alert stand out a little bit.

If this is working as it should, then you can close this with my thanks.

Mahalo

toleolu wrote:Just wish I could do something a little more visible to make the Host Down alert stand out a little bit.

It's all about getting your host and service retries and a number of retires fine tuned. If you don't want service alerts when a host is down, then make sure the host checks are more frequent than the service checks.

Have a read of this post and let me know if it helps.
http://support.nagios.com/forum/viewtop ... 10#p103689

Thanks, excellent post. Really helps me understand the process.

Mahalo