MD4/5 password brute forcer for testing the security of passwords.
{membres.lycos.fr/mdcrack}
Utility for network exploration or security auditing.
{insecure.org/nmap}
{sourceforge.net/projects/nmapwin}
Reads and writes data across network connections.
{atstake.com/research/tools/network_utilities}
Reads and writes encrypted data across network connections.
{sourceforge.net/projects/cryptcat}
Multipurpose sniffer/interceptor/logger for switched LAN.
{ettercap.sourceforge.net}
Network sniffer/analyzer (port of tcpdump).
{windump.polito.it}
Network query tool.
{samspade.org/ssw}
Password cracker for detecting weak Unix passwords.
{openwall.com/john}