Network monitoring software is an important tool to monitor and administer network devices
and services. It reduces a burden of network administrators with automatic checking of device and
service status and error reports. Nagios is a flexible and extensible open-source network monitoring
software that is widely used and has a big user and developer community. However, Nagios is not
perfect because of many limitations. Some limitations, such as difficult configuration and unattractive
user interface, can be improved with third-party add-ons, but some limitations require an art of writing
configuration and other tools to fix it. Moreover, most add-ons are not straightforward and userfriendly.
Administrators still need to tweak and adapt them to suit each network. Thus the task to adjust
Nagios according to specific networks demands expertise of network and system administrators.
Nevertheless, with the flexibility, extensibility and variety of add-ons of Nagios, it can be used as a
framework for building more powerful and easy-to-use network monitoring software.