Nagstamon is a Nagios status monitor with a UI that resides in the systray or as a floating statusbar on your desktop. It informs you in realtime about the status of your Nagios, Icinga, Opsview, Ninja, Check_MK/Multisite, Centreon, or Thruk-monitored network. It alerts you with sound and visual notification. Failed hosts and services are easy to connect with by SSH, RDP, and VNC. Custom actions can be run on certain events. It works best with GNOME, but also with KDE, Mac OS X, and Windows.
ProcMeter3 is a program for monitoring the system status and other information and displaying it in a series of graphs or as text. Most of the information comes from the /proc filesystem (cpu usage, load average , processes information, memory usage, network traffic, interrupts etc.). Other information is available for other sources (date, time, email status, log file length, disk status etc.). The program is modular and highly configurable.
dietsniff is a tiny tool for analyzing traffic on a network. It's not intended to replace well-known tools like tcpdump or ethereal. It's intended for the case when a small and especially static sniffer is required. Accordingly, it's also by far not that powerful, and is also bound to Linux as a platform. While it doesn't use or need the libpcap, it produces pcap-logs that can be analyzed by more sophisticated tools like tcpdump or Ethereal.
MCS MyVoIP very accurately measures the quality and performance of Internet connections for Voice over IP (VoIP) usage by simulating UDP voice data traffic between a server and browser clients. Connections are tested for jitter and packet loss and rated for the supported level of sound quality. The VoIP test can be set to various codecs or customized by packet size, packet rate, and test length. The test can further be combined with a bandwidth speed test or network route diagnostics for more in-depth connection analysis.
INSERT (the Inside Security Rescue Toolkit) aims to be a multi-functional, multi-purpose disaster recovery and network analysis system. It boots from a credit card-sized CD-ROM and is basically a stripped-down version of Knoppix. It features good hardware detection, fluxbox, emelfm, links-hacked, ssh, tcpdump, nmap, chntpwd, and much more. It provides full read-write support for NTFS partitions (using ntfs-3g), and the ClamAV virus scanner (including a fairly recent signature database and a GUI). It provides partition handling with gParted and also has a network boot facility.
ICPLD (Internet Connection Performance Logging Daemon) is a connection monitor that sends ICMP requests to IP addresses of your choice and monitors if your machine has a working network connection. It logs failed attempts to reach the hosts, and will stamp a log as soon as a reply is received. It keeps track of when and for how long the connection was unavailable and records both total down time and each occasion of interrupted connection. It supports IPv6 and can execute a command whenever a connection goes up or down, which is useful for alerting users.
Bartlby is a network and system monitor, completely written in C, to provide a scalable framework with the ability to monitor networks of various sizes. It consists of a core daemon, several plugins, and a Web GUI (PHP extension). The core daemon checks (over active/passive TCP) services/hosts and notifies users in case of critical service conditions (mail, SMS, ICQ, and custom triggers are supported). Bartlby provides an open plugin interface to give every administrator an easy to use option to extend the plugin base, and a fully customizable GUI (written in PHP using a C extension). Nearby everything can be controlled via an XML interface.