Configurando o arquivo de contato para o administrador da rede:
# mcedit /etc/Nagios/contacts.cfg
############################
define contact{
            contact_name Nagios #nome do contato
            alias Nagios Admin
            service_notification_period 24x7
            host_notification_period 24x7
            service_notification_options w,u,c,r
            host_notification_options d,u,r
            service_notification_commands notify-by-email,notify-by-epager
            host_notification_commands host-notify-by-email,host-notify-by-epager
            email 67XXXXXXXX@clarotorpedo.com.br # email para o contato, aqui no meu caso eu estou mandando para o meu celular da claro
            pager pagenagios-admin@localhost # pagina do contato
}
# Adicionei um novo contato
define contact{
            contact_name buzaneli
            alias Jose Leandro Buzaneli dos Santos
            service_notification_period 24x7
            host_notification_period 24x7
            service_notification_options w,u,c,r
            host_notification_options d,u,r
            service_notification_commands notify-by-email
            host_notification_commands host-notify-by-email,host-notify-by-epager
            email buzaneli@gmail.com
            pager pagenagios-admin@localhost
}
############################
Salve o arquivo.
Criando grupos para os contatos:
# mcedit /etc/nagios/contactgroups.cfg
############################
define contactgroup{
    contactgroup_name       router-admins
    alias                   Router Technicians
    members                 nagios
}
# 'router-admins' contact group definition
define contactgroup{
    contactgroup_name       tecnicos
    alias                   Tecnico da Empresa
    members                 buzaneli
}
############################
Salve o arquivo e reinicie o Nagios.
Criando hosts para monitorar
Agora criaremos os hosts a serem monitorados.
# mcedit /etc/nagios/hosts.cfg
############################
# no generic host dever estar estas configurações e depois é só adicionar mais hosts
define host{
     name                            generic-host    ; The name of this host template - referenced in other host definitions, used for template recursion/resolution
      notifications_enabled           1       ; Host notifications are enabled
     event_handler_enabled           1       ; Host event handler is disabled
       flap_detection_enabled          1       ; Flap detection is disabled
      process_perf_data               1       ; Process performance data
      retain_status_information       1       ; Retain status information across program restarts
      retain_nonstatus_information    1       ; Retain non-status information across program restarts
     register                        0       ; DONT REGISTER THIS DEFINITION - ITS NOT A REAL HOST, JUST A TEMPLATE!
}
# Default gateway host definition
define host{
     use                     generic-host            ; Name of host template to use
      host_name               gw
      alias                   Default Gateway
      address                 10.1.1.1
      check_command           check-host-alive
     max_check_attempts      20
      notification_interval   60
      notification_period     24x7
     notification_options    d,u,r
}
############################
 
# comecei a criar os meus host a partir daqui
define host{
      use                     generic-host            ; Name of host template to use
      host_name               proxy
      alias                   Servidor Proxy
     address                 192.168.200.1
     check_command           check-host-alive
    parents                 gw	# esse comando diz que o proxy está ligado ao gw ou modem adsl
     max_check_attempts      20
     notification_interval   60
     notification_period     24x7
    notification_options    d,u,r
}
define host{
     use                     generic-host            ; Name of host template to use
    host_name               Radio
     alias                   Radio Wan
     address                 192.168.100.2
     check_command           check-host-alive
    parents                 proxy 		# o Radio depende o proxy para funcionar
     max_check_attempts      20
    notification_interval   60
    notification_period     24x7
     notification_options    d,u,r
     }
define host{
      use                     generic-host            ; Name of host template to use
      host_name               Voip
     alias                   Servidor Voip
     address                 192.168.200.11
     check_command           check-host-alive
     parents                 Radio
     max_check_attempts      20
     notification_interval   60
     notification_period     24x7
     notification_options    d,u,r
     }
define host{
     use                     generic-host            ; Name of host template to use
     host_name               lucilene
    alias                   Maq Lucilene
     address                 192.168.200.10
     check_command           check-host-alive
     parents                 Radio
     max_check_attempts      20
     notification_interval   60
     notification_period     24x7
      notification_options    d,u,r
      } 
                    
Criando grupos para os hosts
Agora devemos criar os grupos para os hosts, pois se não criarmos o Nagios dará erro.
# mcedit /etc/nagios/hostgroups.cfg
############################
# observe que o grupo de contato é aquele criado lá no arquivo contacts.cfg e contactgroups.cfg 
define hostgroup{
    hostgroup_name  gateways
     alias           Routers and Gateways
     contact_groups  router-admins
     members         gw,proxy
}
define hostgroup{
     hostgroup_name  servidores
     alias           Servidores 
Linux
     contact_groups  tecnicos
     members         proxy,Voip
    }
define hostgroup{
     hostgroup_name  Radios
     alias           Radios Servidores
     contact_groups  router-admins
     members         Radio
}
define hostgroup{
     hostgroup_name  Cliente intranet
     alias           Rede Interna
     contact_groups  tecnicos
     members         lucilene
}
############################