Required Configuration Directives

Nagios requires the following configuration directives:

• host_name: Name of the host.
• alias: A descriptive name of the host.
• address: IP address of host.
• max_check_attempts: If a host returns other than OK status, then the number of times Nagios will attempt to retry the host check command.
• notification_interval: The number of time units to wait before re-notifying a contact about the host being still down or unreachable. Setting this to a value of 0, as in our example, would cause Nagios to send only one notification about the host being down or unreachable.
• notification_period: The time period during which notifications will occur.
• notification_options: Send notifications when the host is either down, unreachable, or in recovery.

Another configuration directive that is not required but is very important is the parents directive. The parents parameter lists the physical parent of the host. A physical parent is typically a router, switch, or firewall through which connectivity is established to the defined host. Nagios is dependency aware and will "walk" a dependency tree in order to determine the cause of a problem. You can find out more information about this at:

http://nagios.sourceforge.net/docs/1_0/networkreachability.html