LibreNMS - fully featured network monitoring system that provides a wealth of features and device support
Automatically discover your entire network using CDP, FDP, LLDP, OSPF, BGP, SNMP and ARP.
Highly flexible alerting system, notify via email, irc, slack and more.
A full API to manage, graph and retrieve data from your install.
Generate bandwidth bills for ports on your network based on usage or transfer.
Stay upto date automatically with bug fixes, new features and more.
Horizontal scaling to grow with your network.
Native iPhone App is available which provides core functionality.