snort

Snort  is an open source network intrusion prevention and detection system (IDS/IPS) developed by Sourcefire. Combining the benefits of signature, protocol, and anomaly-based inspection, Snort is the most widely deployed IDS/IPS technology worldwide. With millions of downloads and more than 300,000 registered users, Snort has become the de facto standard for IPS.




For Download   :  http://www.snort.org/snort-downloads?

LanSpy - network security & port scanner

LanSpy is a set of network utilities brought together in a single program with simple and easy-to-use interface. LanSpy help network administrators maintain and manage their networks.

LanSpy includes fast port scanner for gathering information about open ports on remote computer, LanSpy displays services using these ports.

For Downloading

http://lantricks.com/download/