Zabbix - Track, record, alert and visualize performance and availability of IT resources
FastNetMon - FastNetMon is a very fast DDoS analyzer with sflow/netflow/mirror support.
Arbor - Easily manage product development
Nfsen - NfSen is a graphical web based front end for the nfdump netflow tools that allows you to:
nfsen-ng - nfsen-ng aims to be an in-place replacement for the ageing nfsen.
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.