Nmap - Nmap Free Security Scanner, Port Scanner, & Network Exploration Tool. Download open source software for Linux, Windows, UNIX, FreeBSD, etc.
Load Impact - How many users can my web site handle?
Angry IP Scanner - Open-source and cross-platform network scanner designed to be fast and simple to use
DataSunrise Database Security - DataSunrise Database Security Software secures the databases and data in real-time with high performance.
Advanced IP Scanner - Advanced IP Scanner shows all network devices, gives you access to shared folders, and can even remotely switch computers off. Download it Free.
Enterprise Security - Enterprise Security is a product of Protegrity that allows users to tailor the protection of their sensitive data to suit their needs.