Lets Understand the Configuration overview of Nagios.
As per my installation all the configuration files are stored in
--- /usr/local/nagios/etc/ ---- Directory
The main configuration file
The above file contains a number of directives that affect how Nagios operates.
Object Configuration Files
Object configuration files (historically called "host" configuration files) are used to define hosts, services, hostgroups, contacts, contactgroups, commands, etc. This is where you define what things you want monitor and how you want to monitor them.
CGI Configuration File
This contains a number of directives that affect the operation of the CGIs
When you look at the directory /usr/local/nagios/etc
You will find the following files :
You will need to take a backup of the above files and rename the *.cfg-sample to *.cfg