Traffic Monitoring (5)
Solution that let you define the state of a system via a baseline. Then you can monitor and alert for changes with an option to automatically enforce the correct configuration to ensure the right services are up and running, on the right platforms. This can ensure that correct security configurations remain in place and also assist in intrusion detection.
P0f is a tool that utilizes an array of sophisticated, purely passive traffic fingerprinting mechanisms to identify the players behind any incidental TCP/IP communications (often as little as a single normal SYN) without interfering in any way. Version 3 is a complete rewrite of the original codebase, incorporating a significant number of improvements to network-level fingerprinting, and introducing the ability to reason about application-level payloads (e.g., HTTP).
Nagios Core is the monitoring and alerting engine that serves as the primary application around which hundreds of Nagios projects are built. It serves as the basic event scheduler, event processor, and alert manager for elements that are monitored. It features several APIs that are used to extend its capabilities to perform additional tasks, is implemented as a daemon written in C for performance reasons, and is designed to run natively on Linux/*nix systems.
EtherApe is a graphical network monitor for Unix modeled after etherman. Featuring link layer, IP and TCP modes, it displays network activity graphically. Hosts and links change in size with traffic. Color coded protocols display. It supports Ethernet, FDDI, Token Ring, ISDN, PPP, SLIP and WLAN devices, plus several encapsulation formats. It can filter traffic to be shown, and can read packets from a file as well as live from the network. Node statistics can be exported.
Argus is Network activity audit tool, they call it a "next-generation network flow technology tool", going from packets on the wire to advanced network flow data, to network forensics data; all in support of Network Operations, Performance and Security Management. If you need to know what is going on in your network, right now or historically, you will find Argus a useful tool. It currently runs on Mac OS X, Linux, Solaris, FreeBSD, OpenBSD, NetBSD, AIX, IRIX, Windows (under Cygwin) and OpenWrt, and has been ported to many hardware accelerated platforms, such as Bivio, Pluribus, Arista, and Tilera.