On the host you have chosen to be the Nagios server, install the RPMs:
[For RHEL and CentOS] yum -y install net-snmp net-snmp-utils php-pecl-json yum -y install wget httpd php net-snmp-perl perl-Net-SNMP fping nagios nagios-plugins nagios-www
[For SLES] zypper -n --no-gpg-checks install net-snmp zypper -n --no-gpg-checks install wget apache2 php php-curl perl-SNMP perl-Net-SNMP fping nagios nagios-plugins nagios-www
