$cat /etc/nagios3/conf.d/www.gbweb.net.cfg
# A simple configuration file for monitoring the local host
# This can serve as an example for configuring other servers;
# Custom services specific to this host are added here, but services
# defined in nagios2-common_services.cfg may also apply.

define host{
use                     generic-host            ; Name of host template to use
host_name              www.gbweb.net
alias                   GBwebNet Webserver
address                 www.gbweb.net
}

$cat /etc/nagios3/conf.d/www.gbweb.net.cfg

define hostgroup {
hostgroup_name  http-servers
alias           HTTP servers
members         www.gbweb.net,www.soul2solechiropractic.co.uk,jakebrown.gbweb.net,wiki.gbweb.net
}

define hostgroup {
hostgroup_name  https-servers
alias           Secure HTTP servers
members         catchy.gbweb.net,webmail.gbmail.biz,monitoring.gbweb.net
}

$cat /etc/nagios3/conf.d/services_nagios2.cfg

#check that web services are running

define service {
hostgroup_name                 http-servers
service_description             HTTP
check_command                 check_http!H $host_name
use                                        generic-service
notification_interval            0 ; set > 0 if you want to be renotified
}

define service {
hostgroup_name                  https-servers
service_description             Secure HTTP
check_command                   check_http!-ssl -H $host_name
use                             generic-service
notification_interval           0 ; set > 0 if you want to be renotified
}

define service {
hostgroup_name                  dns-servers
service_description             Bind
check_commandcheck_dns!gbweb.net
use                             generic-service
notification_interval           0 ; set > 0 if you want to be renotified
}

$ cat ../../nagios-plugins/config/dns.cfg

#'check_dns' command definition

define command{
command_namecheck_dns
command_line/usr/lib/nagios/plugins/check_dns -H www.google.co.uk-s '$HOSTADDRESS$'
}

To:

$ cat ../../nagios-plugins/config/dns.cfg
#'check_dns' command definition
define command{
command_name	check_dns
command_line	/usr/lib/nagios/plugins/check_dns -H $ARG1$ -s '$HOSTADDRESS$'
}