The Bubbling Load Monitor (or "Bubblemon" for short) is a system load monitor for the GNOME panel. It looks like a vial containing water. The water level indicates how much (electronic) memory is in use. The color of the liquid indicates how much swap space is used. The amount of bubbles reflects the system CPU load. A message in a bottle indicates there is unread mail. A reed-like graph shows I/O load. On multi-core systems the CPU with the highest load will bubble in the middle, and the others on the sides, so it's possible to see how well load gets distributed between CPUs.
EtherApe is a GNOME/pcap-based etherman, interman, and "tcpman" clone. It displays network activity graphically. Active hosts are shown as circles of varying size, and traffic among them is shown as lines of varying width. It supports Ethernet, FDDI, Token Ring, ISDN, PPP, WLAN, and SLIP transports. It knows about VLANs, IP, IPv6, TCP, UDP, FTP, and a number of other protocols. Additional statistics windows will let you concentrate on protocols or nodes.
Moodss is a modular monitoring application, which supports operating systems (Linux, UNIX, Windows, etc.), databases (MySQL, Oracle, PostgreSQL, DB2, ODBC, etc.), networking (SNMP, Apache, etc.), and any device or process for which a module can be developed (in Tcl, Python, Perl, Java, and C). An intuitive GUI with full drag'n'drop support allows the construction of dashboards with graphs, pie charts, etc., while the thresholds functionality includes emails and user defined scripts. Monitored data can be archived in a SQL database by both the GUI and the companion daemon, so that complete history over time can be made available from Web pages or common spreadsheet software. It can even be used for future behavior prediction or capacity planning, from the included predictor tool, based on powerful statistical methods and artificial neural networks.
MCS MyRoute helps diagnose connectivity problems with detailed network routing discovery and analysis, providing visibility to poor-performing networks and devices. It includes a Java applet that enables remote users to easily test connections from the MyRoute server. Essential diagnostic tools including traceroute, ping, reverse DNS, and whois are combined into a single graphical interface that analyzes Internet connections, reporting quick and essential data points for finding connectivity problems. An IP location database identifies the geographical location of IP addresses and Web servers, showing the path of an Internet connection on a global map.
ImSafe (Immune Security For your Enterprise) is a host-based intrusion detection tool. After a learning phase, it is able to detect changes in processes behavior, to detect buffer overflows, etc. It is implemented through a device driver (as a kernel patch) for the Linux kernel, but can also be run on other UNIX systems by using a "sensor" built upon strace.
PasTmon (Passive Application Response Time Monitor) passively monitors your application servers, measuring and reporting user response times, throughput and congestion. It currently works with HTTP, telnet, rlogin, rsh, FTP (control channel), SMTP, POP3, and IRC. Measurements are recorded in a PostgreSQL database and are presented graphically via a PHP Web front-end using R statistical analysis scripts to create the plots.