Network monitors are an absolute must-have for any network administrator. But which tool, out of the thousands, should you consider for your tool kit? Jack Wallen offers up his five favorites.

Glasswire is a free real time firewall & network security monitor, analyzer software for Windows. It provides output as graphs and numbers. Read review.

Learn how easy it is to install a wide-ranging load monitor to Ubuntu Server so you look out for bottlenecks and other issues.

They allow for predefined items, triggers, and graphs that can be applied to multiple hosts, streamlining the setup process and ensuring consistency across your monitored environment. Monitoring Linux ...

Activity Monitor, the utility that comes with Mac OS X, is a pretty solid system statistics monitor. You can see CPU, memory, network, and disk activity/usage, plus it breaks down everything by task.

Network graphs, now growing in popularity, are designed to help us see connections, capturing the interplay between many dimensions.

The bpytop tool works a lot like other performance monitoring tools, but gives you tremendous control over what it shows you.

Security graphs are becoming indispensable for understanding system access and network activity and empowering security teams to anticipate, detect and contain breaches.

His suggestion for monitoring tools starts with Security Onion, a network security monitoring suite built on Ubuntu, but he covers a range of tools that work with it for analysing information further.