ntop
ntopng High-Speed Web-based Traffic Analysis and Flow Collection ntopng is the next generation version of the original ntop, a network traffic probe that monitors network usage. ntopng is based on …
18 Alternatives To ntop
Cacti
Cacti is a complete network graphing solution. It provides a fast poller, advanced graph templating, multiple data acquisition methods, and user management features.
Monit
Monit is a free open source utility for managing and monitoring, processes, files, directories and filesystems on a UNIX system. Monit conducts automatic maintenance and repair and can execute meaningful causal actions in error situations.
SyWatchdog
sys_watchdog keeps your *NIX servers green by performing periodic checks and optionally actions like service restarts and notifications.