Scanrand : An unusually fast stateless network service and topology discovery system Scanrand is a stateless host-discovery and port-scanner similar in design to Unicornscan. It trades off reliability for amazingly fast speeds and uses cryptographic techniques to prevent attackers from manipulating scan results. This utility is a part of a software package called Paketto Keiretsu, which was written by Dan Kaminsky. Scanrand and Paketto are no longer actively maintained, but the latest released version can… Scanrand

Unicornscan : Not your mother’s port scanner Unicornscan is an attempt at a User-land Distributed TCP/IP stack for information gathering and correlation. It is intended to provide a researcher a superior interface for introducing a stimulus into and measuring a response from a TCP/IP enabled device or network. Some of its features include asynchronous stateless TCP scanning with all variations of TCP flags, asynchronous stateless TCP banner grabbing, and active/passive remote OS, application, and component… Unicornscan

Angry IP Scanner : IP address and port scanner Angry IP Scanner is a small open source Java application which performs host discovery (“ping scan”) and port scans. The old 2.x release was Windows-only, but the new 3.X series runs on Linux, Mac, or Windows as long as Java is installed. Version 3.X omits the vampire zebra logo. As with all connect()-based scanners, performance on Windows XP SP2 and Vista can be poor due to… Angry IP Scanner

Superscan : A Windows-only port scanner, pinger, and resolver SuperScan is a free Windows-only closed-source TCP/UDP port scanner by Foundstone. It includes a variety of additional networking tools such as ping, traceroute, http head, and whois.