Nagios Support Forum

Did you run these two commands on the Nagios server?

how do I install tail?

I believe it's part of the coreutils package (base repo), but you should have it installed... What is the output of the following command?

[ronb@nagios ~]$ which tail
/usr/bin/tail
[ronb@nagios ~]$

Can you log in as root, run these two commands, and show us the output?

[root@nagios ~]# tail /var/log/messages
Oct 4 13:35:25 nagios nagios: SERVICE ALERT: Barracuda;Barracuda Queue;WARNING;SOFT;1;WARNING: outQueue=100
Oct 4 13:36:05 nagios nagios: SERVICE ALERT: Barracuda;Barracuda Queue;OK;SOFT;2;OK: Queues and Average Latency are ok
Oct 4 13:36:25 nagios nagios: SERVICE ALERT: Barracuda;Barracuda Queue;WARNING;SOFT;1;WARNING: outQueue=100
Oct 4 13:37:05 nagios nagios: Auto-save of retention data completed successfully.
Oct 4 13:37:25 nagios nagios: SERVICE ALERT: Barracuda;Barracuda Queue;WARNING;SOFT;2;WARNING: outQueue=100
Oct 4 13:38:25 nagios nagios: SERVICE ALERT: Barracuda;Barracuda Queue;WARNING;SOFT;3;WARNING: outQueue=102
Oct 4 13:39:25 nagios nagios: SERVICE ALERT: Barracuda;Barracuda Queue;WARNING;SOFT;4;WARNING: outQueue=102
Oct 4 13:40:25 nagios nagios: SERVICE ALERT: Barracuda;Barracuda Queue;WARNING;HARD;5;WARNING: outQueue=100
Oct 4 13:40:25 nagios nagios: SERVICE NOTIFICATION: Nagios_Alerts;Barracuda;Barracuda Queue;WARNING;xi_service_notification_handler;WARNING: outQueue=100
Oct 4 13:45:05 nagios nagios: SERVICE ALERT: Woden3;Physical Memory Usage;WARNING;HARD;5;Physical Memory: 89%used(3661MB/4096MB) (>80%) : WARNING
[root@nagios ~]#
[root@nagios ~]#
[root@nagios ~]# tail /usr/local/nagios/var/nagios.log
[1349372125] SERVICE ALERT: Barracuda;Barracuda Queue;WARNING;SOFT;1;WARNING: outQueue=100
[1349372165] SERVICE ALERT: Barracuda;Barracuda Queue;OK;SOFT;2;OK: Queues and Average Latency are ok
[1349372185] SERVICE ALERT: Barracuda;Barracuda Queue;WARNING;SOFT;1;WARNING: outQueue=100
[1349372225] Auto-save of retention data completed successfully.
[1349372245] SERVICE ALERT: Barracuda;Barracuda Queue;WARNING;SOFT;2;WARNING: outQueue=100
[1349372305] SERVICE ALERT: Barracuda;Barracuda Queue;WARNING;SOFT;3;WARNING: outQueue=102
[1349372365] SERVICE ALERT: Barracuda;Barracuda Queue;WARNING;SOFT;4;WARNING: outQueue=102
[1349372425] SERVICE ALERT: Barracuda;Barracuda Queue;WARNING;HARD;5;WARNING: outQueue=100
[1349372425] SERVICE NOTIFICATION: Nagios_Alerts;Barracuda;Barracuda Queue;WARNING;xi_service_notification_handler;WARNING: outQueue=100
[1349372705] SERVICE ALERT: Woden3;Physical Memory Usage;WARNING;HARD;5;Physical Memory: 89%used(3661MB/4096MB) (>80%) : WARNING
You have new mail in /var/spool/mail/root
[root@nagios ~]#

Does your exchange server or SMTP port have any kind of a connection limit on it? About the only scenario I can think of that would cause something like this would be if there's some sort of max connections limit on the Exchange side. It would still be sending out emails, but the check plugin might be getting refused?

(Bear with me in that I'm completely unfamiliar with Exchange servers).

nope, there are no limitations, it is very baffling.

Additionally, severally of these are checked via NSClient++ so that would be being blocked as well...

I'm leaning toward believing it is some sort of firewall between the Nagios XI server and the Exchange server, or the exchange server is rebooting.....

no firewall between them, the server firewall on the exchange server is diabled, they are both VM's on the same appliance, and on the same network.