switch
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1. Enable switch.cfg in nagios.cfg
Uncomment the switch.cfg line in /usr/local/nagios/etc/nagios.cfg as shown below.
cfg_file=/usr/local/nagios/etc/objects/switch.cfg
2. Add new hostgroup for switches in switch.cfg
Add the following switches hostgroup to the /usr/local/nagios/etc/objects/switch.cfg file.
define hostgroup
{
hostgroup_name switches
alias Network Switches
}
3. Add a new host for the switch to be monitered
In this example, I’ve defined a host to monitor the core switch in the /usr/local/nagios/etc/objects/switch.cfg file. Change the address directive to your switch ip-address accordingly.
define host
{
use generic-switch
host_name core-switch
alias Cisco Core Switch
address 192.168.1.50
hostgroups switches
}
4. Add common services for all switches
Displaying the uptime of the switch and verifying whether switch is alive are common services for all switches. So, define these services under the switches hostgroup_name as shown below.
# Service definition to ping the switch using check_ping
define service
{
use generic-service
hostgroup_name switches
service_description PING
check_command check_ping!200.0,20%!600.0,60%
normal_check_interval 5
retry_check_interval 1
}
# Service definition to monitor switch uptime using check_snmp
define service
{
use generic-service
hostgroup_name switches
service_description Uptime
check_command check_snmp!-C public -o sysUpTime.0
}
5. Add service to monitor port bandwidth usage
check_local_mrtgtraf uses the Multil Router Traffic Grapher – MRTG. So, you need to install MRTG for this to work properly. The *.log file mentioned below should point to the MRTG log file on your system.
define service
{
use generic-service
host_name core-switch
service_description Port 1 Bandwidth Usage
check_command check_local_mrtgtraf!/var/lib/mrtg/192.168.1.11_1.log!AVG!1000000,2000000!5000000,5000000!10
}
6. Add service to monitor an active switch port
Use check_snmp to monitor the specific port as shown below. The following two services monitors port#1 and port#5. To add additional ports, change the value ifOperStatus.n accordingly. i.e n defines the port#.
# Monitor status of port number 1 on the Cisco core switch
define service
{
use generic-service
host_name core-switch
service_description Port 1 Link Status
check_command check_snmp!-C public -o ifOperStatus.1 -r 1 -m RFC1213-MIB
}
# Monitor status of port number 5 on the Cisco core switch
define service
{
use generic-service
host_name core-switch
service_description Port 5 Link Status
check_command check_snmp!-C public -o ifOperStatus.5 -r 1 -m RFC1213-MIB
}
7. Add services to monitor multiple switch ports together
Sometimes you may need to monitor the status of multiple ports combined together. i.e Nagios should send you an alert, even if one of the port is down. In this case, define the following service to monitor multiple ports.
# Monitor ports 1 – 6 on the Cisco core switch.
define service
{
use generic-service
host_name core-switch
service_description Ports 1-6 Link Status
check_command check_snmp!-C public -o ifOperStatus.1 -r 1 -m RFC1213-MIB, -o ifOperStatus.2 -r 1 -m RFC1213-MIB, -o ifOperStatus.3 -r 1 -m RFC1213-MIB, -o ifOperStatus.4 -r 1 -m RFC1213-MIB, -o ifOperStatus.5 -r 1 -m RFC1213-MIB, -o ifOperStatus.6 -r 1 -m RFC1213-MIB
}
8. Validate configuration and restart nagios
Verify the nagios configuration to make sure there are no warnings and errors.
# /usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg
Total Warnings: 0
Total Errors: 0
Things look okay – No serious problems were detected during the pre-flight check
Restart the nagios server to start monitoring the VPN device.
# /etc/rc.d/init.d/nagios stop
Stopping nagios: .done.
# /etc/rc.d/init.d/nagios start
Starting nagios: done.
Check: http://Your-server-ip/nagios or http://localhost/nagios in browsers
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