Wireshark - Wireshark is a network protocol analyzer for Unix and Windows. It lets you capture and interactively browse the traffic running on a computer network.
Unimus - Unimus is a Network Automation and Configuration management (NCM) solution designed for fast deployment network-wide and ease of use. Unimus does not require learning any abstraction or templating languages, and does not require any coding skills.
Ettercap - Ettercap is a suite for man in the middle attacks on LAN.
Oxidized - configuration backup software (IOS, JunOS) - silly attempt at rancid
tcpdump - tcpdump is a common packet analyzer that runs under the command line.
RANCID - RANCID - Really Awesome New Cisco confIg Differ.