1. Nagios The monitoring tool

2. Why ? Nagios is a powerful, modular network monitoring system that can be used to monitor many network services like smtp, http and dns on remote hosts. It also has support for snmp to allow you to check things like processor loads on routers and servers. Very configurable Very extendable

3. Install these packages nagios3-common - support files for nagios3 nagios3-dbg - debugging symbols and debug stuff for nagios3 nagios3-doc - documentation for nagios3 nagios3 - A host/service/network monitoring and management system

5. Use if possible Templates A lot of parts is defined as template. This definition can be in the host- and service template cfg files. Only when other requirements must be defined, define this in the service (or host) check.

6. /etc/nagios/conf.d/contacts.cfg define contact{ contact_name joe alias Joe Blow service_notification_period 24x7 # (is a template defenition) host_notification_period 24x7 # (is a template defenition) service_notification_options w,u,c,r # (is a template defenition) host_notification_options d,u,r # (is a template defenition) service_notification_commands notify-by-email,notify-by-pager host_notification_commands host-notify-by-email,host-notify-by-epager email joe@yourdomain.com pager 5555555@pager.yourdomain.com }

7. define contact{ contact_name paul alias Paul Shiznit service_notification_period 24x7 #(is a template defenition) host_notification_period 24x7 # (is a template defenition) service_notification_options w,u,c,r # (is a template defenition) host_notification_options d,u,r # (is a template defenition) service_notification_commands notify-by-email,notify-by-epager host_notification_commands host-notify-by-email,host-notify-by-epager email paul@yourdomain.com pager 5556666@pager.yourdomain.com }

8. /etc/nagios/conf.d/contactgroup s.cfg define contactgroup{ contactgroup_name router_admin alias Network Administrators members joe } define contactgroup{ contactgroup_name server_admin alias Systems Administrators members paul }

9. /etc/nagios/conf.d/hosts.cfg define host{ use generic-host host_name gw1.yourdomain.com alias Gateway Router address 10.0.0.1 check_command check-host-alive max_check_attempts 20 # (this is not done, because20 x 240= 4800minuten and this is 3days and 8 hours) #is also a template definition notification_interval 240 # (is a template definition) notification_period 24x7 # (is a template definition) notification_options d,u,r # (is a template definition) # sometimes you can specify the contact(group) in case not all the contacts must be notified }

10. define host{ use generic-host host_name mail.yourdomain.com alias Mail Server address 10.0.0.100 check_command check-host-alive max_check_attempts 20 # (this is not done, because20 x 240= 4800minuten and this is 3days and 8 hours) #is also a template definition notification_interval 240 # (is a template definition) notification_period 24x7 # (is a template definition) notification_options d,u,r # (is a template definition) # sometimes you can specify the contact(group) in case not all the contacts must be notified }

11. /etc/nagios/conf.d/hostgroups.cfg define hostgroup{ hostgroup_name routers alias Routers contact_groups router_admin members gw1.yourdomain.com } define hostgroup{ hostgroup_name servers alias Servers contact_groups server_admin members mail.yourdomain.com }

12. /etc/nagios/conf.d/services.cfg define service{ use generic-service host_name mail.yourdomain.com service_description SMTP is_volatile 0 # (is a template definition) check_period 24x7 # (is a template definition) max_check_attempts 3 # (is a template definition) normal_check_interval 5 # (is a template definition) retry_check_interval 1 # (is a template definition) contact_groups server_admin notification_interval 240 # (is a template definition) notification_period 24x7 # (is a template definition) notification_options w,u,c,r # (is a template definition) check_command check_smtp }

13. define service{ use generic-service host_name gw1.yourdomain.com service_description PING is_volatile 0 # (is a template definition) check_period 24x7 # (is a template definition) max_check_attempts 3 # (is a template definition) normal_check_interval 5 # (is a template definition) retry_check_interval 1 # (is a template definition) contact_groups router_admin notification_interval 240 # (is a template definition) notification_period 24x7 # (is a template definition) notification_options w,u,c,r # (is a template definition) check_command check_ping!100.0,20%!500.0,60% }

14. Check config #nagios3 -v /etc/nagios3/conf.d/nagios.cfg

15. Restart daemon # /etc/init.d/nagios3 restart

16. Surf to your nagios3 install http://your.nagios.server/nagios3

17. Comments Nagios is a very powerful tool for monitoring networks. I've only touched on the basics here, but it should be enough to get you up and running. Hopefully, once you do, you'll start experimenting with all the cool features and plugins that are available. The documentation included in the cgi interface is very detailed and helpful. If some one will take not must effort for nagios try Fully Automated Nagios (=FAN) http://fannagioscd.sourceforge.net/drupal/http://fannagioscd.sourceforge.net/drupal/ If some one will not change the configuration files, he can try NConf Enterprise Nagios configurator http://www.nconf.org/dokuwiki/doku.php http://www.nconf.org/dokuwiki/doku.php If some one will visualition the status of hosts, http://www.nagvis.org/http://www.nagvis.org/ Also Cacti and Nagios can exchange the results between each other (see c2n.cgi http://www.monitoringexchange.org/wiki/Addon:c2n.cgi http://www.monitoringexchange.org/wiki/Addon:c2n.cgi