Linux Networking Cookbook

13.11. Monitoring a Mail Server

Problem

You want to know how to use Nagios to monitor your mail server. You want it to keep an eye on SMTP, POP, SSH, and IMAP services.

Solution

Add new host and service definition entries to the hosts.cfg and services.cfg files. You may also need some new command definitions in commands.cfg.

First, make sure these entries exist in commands.cfg:

	# 'check_pop' command definition
	define command{
	        command_name    check_pop
	        command_line    $USER1$/check_pop -H $HOSTADDRESS$
	        }
	
	# 'check_smtp' command definition
	define command{
	        command_name    check_smtp
	        command_line    $USER1$/check_smtp -H $HOSTADDRESS$
	        }
	
	# 'check_imap' command definition
	define command{
	        command_name    check_imap
	        command_line    $USER1$/check_imap -H $HOSTADDRESS$
	        }
	
	# 'check_ssh' command definition
	define command{
	        command_name    check_ssh
	        command_line    $USER1$/check_ssh -H $HOSTADDRESS$
	        }

Next, create a host definition for the server:

	# define a Mail server host
	define host{
	        use                     generic-host
	        host_name               postfix1
	        alias                   mail server1
	        address                 192.168.1.27
	        check_command           check-host-alive
	        max_check_attempts      10
	        check_period           24x7
	        notification_interval   120
	        notification_period     24x7
	        notification_options    d,r
	        contact_groups          admins
	        }

Add your new server to an existing group; or, create a new group for it, as this example shows:

	define hostgroup{
	        hostgroup_name  mail_servers
	        alias           Mail Servers
	        members         postfix1
	        }

Next, define the four services (POP, IMAP, SMTP, and SSH) in services.cfg. Each service requires a separate definition. ...