Why buy expensive ‘branded’ servers? Build one yourself using off-the-shelf hardware.
Regular vulnerability assessment of your systems/networks is a must. OpenVAS is one such tool that can assist you.
Some network connectivity and troubleshooting tools.
Just because you’re using a WEP key on your wireless access point doesn’t mean you’re safe from crackers in the neighbourhood.
Graphs always make work easier, especially when we need to monitor things. This article discusses Cacti, a simple graphical network monitor.