Penetration Testing Tools

Packet
Shaper:

Nemesis:
a command line packet shaper
Packit:
The Packet Toolkit – A network packet shaper.
Hping
by Antirez: a command line TCP/IP packet shaper
Sing:
stands for ‘Send ICMP Nasty Garbage’; sends fully customizeable ICMP
packets
Scapy:
a new python-based packet generator

Password
Cracker/Login Hacker:

John
the Ripper: a well-known
password cracker for Windows and *nix Systems
Djohn:
a distributed password cracker based on "John
the Ripper"
Cain
& Abel: an advanced
password recovery [...]