We are in networking industry.We are using the nagios to monitor our different city network.It most powerful software to monitor network devices.It gives us alert when our any device goes down.Using nagios network monitoring becomes very easy.The performance of it is good.

We use Nagios XI to monitor our network infrastructure.It gives us early warning if device is critical.Interface is good.

In our organization use nagios for long period of time. Nagios provides monitoring of all mission-critical infrastructure components including applications, services, operating systems, network protocols, systems metrics, and network infrastructure. The application's user interface (UI) is quite simple and easy to use. Nagios application is open-soured, so it is freely available. Nagios is perfect for companies that don't have a budget for IT monitoring, but still expect systems to be up 24x7.