Nagios 4 : Notification Setting2026/03/27

	This is the Email Notification Settings section. It is enabled on some items by default but if you change it, configure like follows.
[1]	Install and start SMTP Server, refer to here.
[2]	Set notification recipients. And aldo Nagios sends notifications with [mail] command, so install it.

[root@dlp ~]#

dnf -y install s-nail

[root@dlp ~]#

vi /etc/nagios/objects/contacts.cfg

# line 32 : set recipient email address

root@localhost

[root@dlp ~]#

systemctl reload nagios

[3]

It's possible to change notification setting on Nagios admin site.
Login to it and click [Services] link, then services list is displayed. The icons which are displayed near a service name are just the one which notification is disabled.
(HTTP and SSH corresponds to the example below)
To enable notification on a service, click service name first.

[4]	Click [Enable notifications for this service].

[5]	Click [Commit] button.

[6]	That's OK all.

[7]	If notification is enabled and a service has some troubles, the notification like follows are sent to the recipients you set.

Date: Fri, 27 Mar 2026 09:40:05 +0900
To: root@localhost
Subject: ** PROBLEM Service Alert: localhost/SSH is CRITICAL **
Message-Id: <20260327004005.70F132020FEA@dlp.srv.world>
From: nagios@dlp.srv.world

***** Nagios *****

Notification Type: PROBLEM

Service: SSH
Host: localhost
Address: 127.0.0.1
State: CRITICAL

Date/Time: Fri Mar 27 09:40:05 JST 2026

Additional Info:

connect to address 127.0.0.1 and port 22: Connection refused

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