{"id":1345,"date":"2016-06-08T17:15:20","date_gmt":"2016-06-08T14:15:20","guid":{"rendered":"http:\/\/www.systemcodegeeks.com\/?p=1345"},"modified":"2017-12-01T17:24:44","modified_gmt":"2017-12-01T15:24:44","slug":"nagios-monitoring-snmp","status":"publish","type":"post","link":"https:\/\/www.systemcodegeeks.com\/monitoring\/nagios\/nagios-monitoring-snmp\/","title":{"rendered":"Nagios monitoring through SNMP"},"content":{"rendered":"

This article is part of our Academy Course titled Nagios Tutorial for IT Monitoring<\/a>.<\/p>\n

In this course, we provide a compilation of Nagios tutorials that will help you set up your own monitoring infrastructure. We cover a wide range of topics, from installation and configuration, to plugins and NRPE. With our straightforward tutorials, you will be able to get your own projects up and running in minimum time. Check it out here<\/a>!<\/em><\/p>\n

In the previous two articles (Nagios Core Installation and Configuration on Ubuntu Server<\/a> and Using Nagios plugins and NRPE to check network services and metrics on remote hosts<\/a>) we discussed how to install Nagios Core, plugins and NRPE to monitor host status (up \/ down), several network services running on Linux servers, and machine-specific metrics such as the number of logged-on users, processes, and CPU load, to name a few examples.<\/p>\n

Additionally, you can use the Simple Network Management Protocol (SNMP) with Nagios to manage other types of network devices, such as printers, routers, and switches. This will be the topic that we will address in this guide.<\/p>\n

SNMP not only allows to collect information about a network device, but also to modify the behavior of such device. Under the hood, this protocol exposes device data in the form of variables, which can then be queried and \/ or set by controlling applications. A classic example of modifying device data consists of changing the date and time on network printers, and retrieving print counts. However, not all variables are rw (read and write), and most of them are only read-only. If in doubt, refer to the device documentation.<\/div>\n

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Prerequisites<\/h2>\n

As explained earlier, you will typically use SNMP with Nagios to monitor network devices, as opposed to using plugins or NRPE to check services and system information associated with a Linux system. However, you can still use SNMP in the latter case as well. For simplicity, we will use the same CentOS 7 box we have been utilizing so far.<\/p>\n

In order to use the CentOS 7 box to simulate a regular network device, we will need to perform some preliminary work before proceeding. This prework will consist of the following steps:<\/p>\n

Step 0 –<\/b> Review basic SNMP concepts. Although a thorough discussion about SNMP is out of the scope of this article, we will try to point out the basics as we go. However, should you need a more detailed explanation, feel free to take a look at this excellent question<\/a> (with answers) in the Ubuntu forums. Bookmark that page in case you need to refer to it for clarifications later.<\/p>\n

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Our test environment consists of the following key components (essential in SNMP monitoring):<\/p>\n