Snort is a network intrusion detection and prevention system. It is the most widely deployed technology of its kind in the world. It performs detection using a variety of methods including rules-based detection, anomaly detection, and heuristic analysis of network traffic. Its rules language is open source and available to the public as well.
GKrellM is a GTK-based stacked monitor program that charts SMP CPUs, disks, load, active net interfaces, and internet connections. There are also builtin monitors for memory and swap, file systems with mount/umount feature, mailbox checking including POP3 and IMAP, clock/calendar, laptop battery, sensors (temperatures, voltages, and fans), and uptime. It has LEDs for the net monitors and an on/off button and online timer for PPP. There is a GUI popup for configuration, plugin extensions can be installed, and many themes are available. It also features a client/server monitoring capability.
The sysstat package contains the sar, sadf, iostat, nfsiostat, cifsiostat, mpstat, and pidstat commands for Linux. The sar command collects and reports system activity information. The statistics reported by sar concern I/O transfer rates, paging activity, process-related activites, interrupts, network activity, memory and swap space utilization, CPU utilization, kernel activities, and TTY statistics, among others. The sadf command may be used to display data collected by sar in various formats. The iostat command reports CPU statistics and I/O statistics for tty devices and disks. The pidstat command reports statistics for Linux processes. The mpstat command reports global and per-processor statistics. The nfsiostat command reports I/O statistics for network filesystems. The cifsiostat command reports I/O statistics for CIFS filesystems.
DansGuardian is a Web content filtering proxy that uses Squid to do all the fetching. It filters using multiple methods including, but not limited to, phrase matching, file extension matching, MIME type matching, PICS filtering, and URL/domain blocking. It has the ability to switch off filtering by certain criteria including username, domain name, source IP, etc. The configurable logging produces a log in an easy to read format. It has the option to only log text-based pages, thus significantly reducing redundant information (such as every image on a page).
360-FAAR (Firewall Analysis Audit and Repair) is an offline, command line, Perl firewall policy manipulation tool to filter, compare to logs, merge, translate, and output firewall commands for new policies, in Checkpoint dbedit, Cisco ASA, or ScreenOS commands. It is all contained in one file. It can read policy and logs for: Checkpoint FW1 (in odumper.csv / logexport format), Netscreen ScreenOS (in get config / syslog format), and Cisco ASA (show run / syslog format). It uses both inclusive and exclusive CIDR and text filters, permitting you to split large policies into smaller ones for virutalization at the same time as removing unused connectivity. It supports policy to log association, object translation, rulebase reordering and simplification, rule moves, and duplicate matching automatically. It allows you to seamlessly move rules to where you need them. 'print' mode creates a spreadsheet for your audit needs with one command.
The Advanced Linux Sound Architecture is composed of several parts. The first is a fully modularized sound driver which supports module autoloading, devfs, isapnp autoconfiguration, and gives complete access to analog audio, digital audio, control, mixer, synthesizer, DSP, MIDI, and timer components of audio hardware. It also includes a fully-featured kernel-level sequencer, a full compatibility layer for OSS/Free applications, an object-oriented C library which covers and enhances the ALSA kernel driver functionality for applications (client/server, plugins, PCM sharing/multiplexing, PCM metering, etc.), an interactive configuration program for the driver, and some simple utilities for basic management.
Observium is an autodiscovering network monitoring system focused primarily on Cisco and Linux networks but includes support for a wide range of network hardware and operating systems. Observium has grown out of a lack of easy to use NMSes. It is intended to provide a more navigable interface to the health and performance of your network. Its design goals include collecting as much historical data about devices as possible, being completely autodiscovered with little or no manual intervention, and having a very intuitive interface.