Cracking lost or forgotten WEP and WPA-PSK keys on wireless networks just got a lot easier with aircrack-ng. A review of aircrack has also been published.
Download aircrack 1.1 (from Network Sniffers)

crack, hacking, wirelss, wlan, network, freeware network sniffers
Recommended Network Sniffer | 4.3 MB | For Windows 7, Windows 8 / Vista / XP | Free

A free multi-threaded IP, SNMP and NetBIOS scanner with several advanced features..
Download SoftPerfect Network Scanner 5.4.2 (from Network Sniffers)

hidden, netbios, network, resources, scanner, shared, shares, snmp,
1.92 MB | For Windows 7, Windows 8 (64-bit, 32-bit) / Vista / XP | Free

FreePortScanner is a freeware free port scanner for Windows. A review of FreePortScanner has also been published.
Download FreePortScanner 2.9 (from Network Sniffers)

event log, hacking, net tools, network tool, network utils, port scan, port scanner,
2.93 MB | For Windows 7, Windows 8 / Vista / XP | Free