Zabbix - Track, record, alert and visualize performance and availability of IT resources

DCImanager - DCImanager is a platform for managing physical equipment. Connect any physical equipment to a single platform. Use the platform to manage your servers, switches, PDU as well as physical and virtual networks.

FastNetMon - FastNetMon is a very fast DDoS analyzer with sflow/netflow/mirror support.

NetBox - NetBox is an open source web application designed to help manage and document computer networks. NetBox was developed specifically to address the needs of network and infrastructure engineers.

Abusix - Abusix is a network security company that offers email threat protection and network abuse handling solutions to ISPs, Telcos, and Cloud/Hosting Providers to stop the rapidly growing problem of email-borne threats and other kinds of network abuse.

Opendcim - a free, web based Data Center Infrastructure Management application.