Passive Monitoring not showing Hosts Down

[stewartp]

I am a new user of Nagios XI, and have successfully set up passive monitoring on about 20 servers. These are my clients where their servers sit behind a firewall. The monitoring of services has worked well, and I am being alerted when a service stops or hasn't started.

Last night somebody 'stole' a telecoms cable on one of my clients site, leaving them without internet or telephones. My passive monitoring is over their internet connection, yet Nagios XI is still telling me that their servers are UP when clearly it is not receiving any data from them. I believe it should say 'Unreachable'.

I have set check_host_freshness=1, and execute_host_checks =1 but this doesn't appear to make any difference.

Any help would be appreciated

Stewart

[lmiltchev]

Do you see anything in your "/var/log/messages" regarding this host being down? If you don't, this means that you haven't setup your passive checks properly.
You can also try to change your freshness check interval to 30 min (for example) and see if this is going to help.

[stewartp]

I can't see anything about the host being down in the log. The last date in the log for that host is the day the cable was stolen.

If I haven't set the passive monitoring up correctly, where should I look to make the changes? As I said the services seem to be coming through OK.

Thanks

[lmiltchev]

OK, you should have:

passive checks: enabled
active checks: disabled
flap detection: disabled
freshness: enabled
freshness threshold: 300 (5 min) - you can try experimenting with different values.

If you haven't done so, go to the Core Config Manager, click on "Hosts", find your host and lick on the "Modify" Acton button. Under the "Common Settings" tab, you should set your "Check command" as "check_dummy" (from the drop-down menu). It takes two arguments. You can set it for example:
$ARG1$ = 2
$ARG2$ = "Service is Stale"

Hope this will help.

[stewartp]

Thanks for that. It is all working correctly now. I used the wizard, but didn't then configure any further options, so at least I can now start exploring the other options.

Thanks again.

[lmiltchev]

Great! Thanks for the feedback!