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.
bandwidthd tracks usage of TCP/IP network subnets and builds HTML files with graphs to display network utilization. Charts are built by individual IP to show their utilization over 2, 8, 45, and 400 day periods. It color codes HTTP, HTTPS, TCP,UDP, ICMP, VPN, and P2P traffic. Unlike MRTG, it tracks each individual IP address and subnets, not the status of any particular link. Static mode is fast and easy to set up and has few dependencies. Database mode supports filtering by subnet, multiple sensors, custom reports and intervals, and can process thousands of IPs efficiently. Network utilization can be logged in CDF or a backend database.
The libstatgrab library provides an easy-to-use interface for accessing system statistics and information. Available statistics include CPU, Load, Memory, Swap, Disk I/O, and Network I/O. It was developed to work on Linux, FreeBSD, and Solaris. The package also includes two tools: saidar provides a curses-based interface for viewing live system statistics, and statgrab is a sysctl-like interface to the statistics.
NetUP UTM is a universal billing system for internet service providers of any size. Its modern approach to traffic accounting makes the system compatible with all popular platforms and network devices. Its key features include realtime traffic processing, Cisco Netflow and IP Accounting data collection, support for RADIUS authentication, and cross-platform compatibility. The core of the system is a smart and reliable accounting engine working directly with network equipment. It supports up to 100,000 users at a total speed of up to 3 Gbps. A flexible ratings engine and efficient administration tools make UTM a complete solution for IP/VoIP/WiFi/dial-up billing.
Nets is a flexible and extensible network inventory and asset management system that works on all Unix and Windows platforms, and works with most SQL databases. Its complete GUI allows you to maintain details of your entire network, from network links down to interfaces and routers. It assists in provisioning, costing, reporting, and maintaining network details. It includes a network browser, an extension API, and plugins for IP address map visualisation, reports, schematics.