title: Nagios not sending emails
body: <p>I want to setup nagios to send email notifications.
  I can send email notifications manually clicking the "Send custom service notification" in nagios web interface. The notification is being created and the email is being sent and delivered successfully. 
  But nagios doesn't send notifications automatically. I have tested it turning off PING service on the machine (echo 1 >/proc/sys/net/ipv4/icmp_echo_ignore_all). Nagios sets PING service to CRITICAL state, but doesn't send notification email.</p>
  
  <p>These are my config files:</p>
  
  <p><strong>Part of templates.cfg</strong></p>
  
  <pre><code>define contact{
          name                            generic-contact     ; The name of this contact template
          service_notification_period     24x7            ; service notifications can be sent anytime
          host_notification_period        24x7            ; host notifications can be sent anytime
          service_notification_options    w,u,c,r,f,s     ; send notifications for all service states, flapping events, and scheduled downtime events
          host_notification_options       d,u,r,f,s       ; send notifications for all host states, flapping events, and scheduled downtime events
          service_notification_commands   notify-service-by-email ; send service notifications via email
          host_notification_commands      notify-host-by-email    ; send host notifications via email
          register                        0               ; DONT REGISTER THIS DEFINITION - ITS NOT A REAL CONTACT, JUST A TEMPLATE!
  }
  </code></pre>
  
  <hr>
  
  <p><strong>Part of contacts.cfg</strong></p>
  
  <pre><code>define contact{
          contact_name                    nagiosadmin     ; Short name of user
          use                             generic-contact     ; Inherit default values from generic-contact template (defined above)
          alias                           Nagios Admin        ; Full name of user
          service_notification_options    w,u,c,r,f,s
          host_notification_options       d,u,r,f,s
          email                           MY-EMAIL@gmail.com      ; &lt;&lt;***** CHANGE THIS TO YOUR EMAIL ADDRESS ******
  }
  
  define contactgroup{
          contactgroup_name       admins
          alias                   Nagios Administrators
          members                 nagiosadmin
  }
  </code></pre>
  
  <hr>
  
  <p><strong>generic-host_nagios2.cfg</strong></p>
  
  <pre><code>define host{
          name                            generic-host    ; The name of this host template
          notifications_enabled           1       ; Host notifications are enabled
          event_handler_enabled           1       ; Host event handler is enabled
          flap_detection_enabled          1       ; Flap detection is enabled
          failure_prediction_enabled      1       ; Failure prediction is enabled
          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
          check_command                   check-host-alive
          max_check_attempts              10
          notification_interval           1
          notification_period             24x7
          notification_options            d,u,r,f,s
          contact_groups                  admins
          register                        0       ; DONT REGISTER THIS DEFINITION - ITS NOT A REAL HOST, JUST A TEMPLATE!
  }
  </code></pre>
  
  <hr>
  
  <p><strong>generic-service_nagios2.cfg</strong></p>
  
  <pre><code>define service{
          name                            generic-service ; The 'name' of this service template
          active_checks_enabled           1       ; Active service checks are enabled
          passive_checks_enabled          1       ; Passive service checks are enabled/accepted
          parallelize_check               1       ; Active service checks should be parallelized (disabling this can lead to major performance problems)
          obsess_over_service             1       ; We should obsess over this service (if necessary)
          check_freshness                 0       ; Default is to NOT check service 'freshness'
          notifications_enabled           1       ; Service notifications are enabled
          event_handler_enabled           1       ; Service event handler is enabled
          flap_detection_enabled          1       ; Flap detection is enabled
          failure_prediction_enabled      1       ; Failure prediction is enabled
          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
          notification_interval           1       ; Only send notifications on status change by default.
          is_volatile                     0
          check_period                    24x7
          normal_check_interval           5
          retry_check_interval            1
          max_check_attempts              4
          notification_period             24x7
          notification_options            w,u,c,r,f,s
          contact_groups                  admins
          register                        0       ; DONT REGISTER THIS DEFINITION - ITS NOT A REAL SERVICE, JUST A TEMPLATE!
  }
  </code></pre>
  
  <p>How can I force nagios to send notification emails?</p>