creates network weather maps based on existing images creaetd by other software. It uses SNMP to collect data from other devices and it does not depend on MRTG or any other statistics program
NetChat is a network version of the "chat" utility that comes with PPP. It is a general purpose network "conversations" tool, designed for network testing. It can also be used for (very) quick setup of a server for a new protocol.
Cctt, "Covert Channel Tunneling Tool" is a tool presenting several exploitation
techniques allowing the creation of arbitrary data transfer channels in the data
streams (TCP, UDP, HTTP) authorized by a network access control system.
Netleak is a collection of small perlscripts that detects connectivity between network segments. It is mostly useful to detect "leaks" in large organizations that have private network segments physically separated from the Internet.
Protoscope is a utility that aids Web developers by revealing the HTTP communication in their own applications. It is a nice tool for Web developers who want to "look under the hood" as they develop.