Nagios Tutorials

Nagios is an open source monitoring system to monitor small to enterprise computer networks. With Nagios you can monitor servers, switches, applications and services. Nagios alerts you whenever there is a problem, and sends a notification when the problem has been resolved. You can receive notifications via email, SMS messages and even phone calls. Nagios is licensed under GNU GPLv2.

Features

Monitor network services like SMTP, HTTP, SNMP, FTP, SSH, POP, etc.
Monitor Servers resources like disk drives, memory, processor, server load usage, system logs, etc. you can extend Nagios capabilities with hundreds of plugins found in its official website repository.
With Nagios you can define network hosts as parents (Hyper-V, or VMware Hosts for example) so you don’t get flooded with alerts that all systems (VMs hosted in the hosts) are down. You will only receive notifications about the parent hosts.
You can set it to send you Emails, SMS, and even voice calls whenever there is a problem in the network.
You can setup Nagios in a distributed system if you need to have a monitoring system in multiple locations.
When you install Nagios it automatically installs a web portal where you can view current network status, problem history, log files, notifications that have been triggered by the system, etc.

Agent for Windows hosts

NSClient++ is the preferred Agent to monitor Windows server hosts. NSClient++ listens on theTCP port 12489, and the command you use to collect information from the host is check_nt. With NSClient++ you can monitor CPU load, RAM usage, disk drive usage, server running processes, etc. there are hundreds of custom plugins you can download from the Nagios official site repository to make Nagios monitor many other custom devices, services.

Agent for Linux Hosts

NRPE (Nagios Remote Plug-Ins Executor) is the preferred agent to monitor Linux hosts. The NRPE daemon binds to the 5666 port, and you collect information from the remote hosts using the check_nrpe command. With NRPE you can remotely execute Nagios plugins on other Linux/Unix machines. This allows you to monitor remote machine metrics (disk usage, CPU load, etc.).

Agent for other devices

There is no Nagios agent for embedded devices like Routers, Switches, UPSs, and many other devices were no custom software can be installed. In those devices Nagios use the NNTP protocol to gather information.

How to install and configure Nagios

Nagios is a very popular open source network monitoring system. with Nagios you can monitor your network resources, and receive email alerts or SMS messages on your cell phone anytime those resources run low or when any of your network devices go down. Nagios was designed to run on Linux, it cannot be installed in any other operating system as…

Monitor server room temperature with Nagios

If you want to monitor the temperature and humidity level of your server room with Nagios then there is a plugin for that. I personally don’t go to the server room regularly so I wouldn’t know if the AC failed in that room until probably its too late, so getting automatic alerts when the room gets too hot or too…

Check Dell OpenManage with Nagios

If you want to check the health status of a Dell server through OpenManage with Nagios then there is a plugin for that. You will get an alert from Nagios whenever there is a physical problem with the server like the RAID, battery, and many other components. Using this plugin Nagios will basically grab all the alerts reported on the…

Check the Status of Printer’s Cartridges using SNMP with Nagios

Don’t you hate getting those IT requests to replace toners in printers at the office? yep! me too, if you have Nagios installed and want Nagios to let you know when toner’s are running low in those printers then there is a script to quickly do that. Download the script from this link I used version 3 for my printers.…