Nagios to monitor network firewall, router, switch and wireless equipments

Question

I need to find a Linux based tool to monitor network equipment. I have very quickly played with Nagios core, MRTG and Cacti. RIght now I am stick to Nagios core 4 (until you tell me that it can't do what I need) and doing more study on it. I am seeking some advice

1. What plug-in do you recommend to monitor the interface stats not only bytes-in/out, but also errors and discards? I am trying nagiosgraph but having some difficulty however I would like to know if there is a better choice before continuing troubleshooting. I don't necessarily need a "graph" tool and a web-interface. I just need a counter along with timestamps to be stored somewhere either in text format or in DB like RRD.

2. There will be some custom MIB/OID that I will need to monitor for the firewall and wireless equipments. Is it possible to specify an OID, pull the data, compare with some preset value, and generate alert if needed? Is it possible to store historical data of the value of the OID? Is there some tool for that or do I need to write a plug-in...?

I am from the networking background (Cisco mostly) and don't have much experience with Linux and programming. I can write simply python code. If I need to write my code, is Python natively supported by Nagios?

Answer 1

Merry Christmas to you as well. To get right to the answers:

1. In my opinion, the best thing to do this is MRTG. In fact, that is what we use in our enterprise software Nagios XI. You have to configure MRTG to poll the bandwidth, and then you use the nagios-plugins check_rrdtraf to generate alerts based on bandwidth consumption, etc. To check for errors and discards, you can use the nagios-plugins check_ifstatus plugin. This is exactly what it was designed to do.
2. Custom MIB/OID is where the nagios-plugin check_snmp shines! This plugin already does exactly what you're describing.

You should be able to get all of that up and running in no time if you've already been playing with Nagios Core, MRTG, and Cacti.