Top Ubuntu Security Tools
We picked our top Ubuntu security tools and feature each one in further detail here. For more information on using Ubuntu, visit the Ubuntu web site.
Get Notified when a Device Joins the Network
I like the immediate notifications afforded by arpwatch. Arpwatch notifies in the system log and via e-mail. This is attitude of awareness is crucial in maintaining a secure network of computers and hardening this system.
However, as added requirements, our system must be able to identify malicious activity, block it, and report it.
All In One Security Tool
I think the best all in one tool to fill that role is the excellent application called fail2ban.
Block Malicious Activity
Each attack vector is individually configurable for the actions to take once malicious activity is identified.
Fail2ban is capable of notifying via email (my preferred method), desktop, and log files.