Nagios Support Forum

Posted: **Fri May 31, 2013 3:04 pm**

Hello,

I was not entirely sure if this was possible with Nagios, but are we able to have Nagios check for switch port capacity and send alerts? For example, if our switches are down to 5 free ports ('not connect') I would like Nagios to send an alert for this. I've been trying to think of a way to do this but I'm not really sure how to go about doing so.

Any help would be greatly appreciated.

Thank you.

Posted: **Fri May 31, 2013 3:37 pm**

This would take a custom script that walks your ports, greps for down, if less that 6, exits with a warning. For example:
check_ports.sh:

Code: Select all

#!/bin/bash
ADDRESS=$1
COMMUNITY=$2
PORTS=$3

COUNT=$(snmpwalk -v1 -c $COMMUNITY $ADDRESS ifOperStatus | grep down | wc -l)

if [ $COUNT -lt $PORTS ]; then
        echo "WARNING! Less than $PORTS ports free | 'ports free'=$COUNT"
        exit 1
else
        echo "OK! $PORTS ports or more free! | 'ports free'=$COUNT"
        exit 0
fi

You would use the script as such:

Code: Select all

./check_ports.sh <ip address> <community string> <number of ports to warn under>

For example:

Code: Select all

./check_ports.sh 127.0.0.1 public 6

Posted: **Fri May 31, 2013 3:51 pm**

Wow, awesome. Thank you!

I will give this a shot and let you know if I have any issues.

Posted: **Fri May 31, 2013 4:44 pm**

This works great, however, I am trying to enter it into a cfg.

I've defined the command as follows:

Code: Select all

define command{
        command_name    check_ports
        command_line    $USER1$/check_ports $ARG1$ $ARG2$ $ARG3$
        }

The check_command in the defined service looks like this:

check_command check_ports!-H 10.10.1.2 secret 5

However, it's not working the way it was when I ran the command manually. Any thoughts?

Thanks again!

Posted: **Mon Jun 03, 2013 9:41 am**

Dump the -H from the check_command:

Code: Select all

check_command check_ports!10.10.1.2 secret 5

Posted: **Mon Jun 24, 2013 4:33 pm**

Does this have any issues with 52 port switches? It doesn't seem to be reporting for them:

root@vmnagios libexec]# ./check_ports 10.10.8.4 secret 8
Timeout: No Response from 10.10.8.4
WARNING! Less than 8 ports free | 'ports free'=0

However, on our 24 port switches it works fine. Any ideas?

Posted: **Mon Jun 24, 2013 4:38 pm**

First thought would be that snmp is not enabled on that switch. It seems that you are not getting a response. A simple nmap can verify.

nmap -p 161 -sU 10.10.8.4

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