Quick Ping Monitor 

A powerful simultaneous ip monitor tool . It is able to monitor thousands of IP equipments simultaneously and send message and mail when states of some equipments change , it could also adopt necessary steps to deal with troubles.
ping monitor monitor ping ip monitor network monitor server monitor line monitor ping trace monitor lan monitor host monitor network lan

Essential NetTools 

Essential NetTools is a useful tool for diagnosing networks and monitoring your computer's network connections. It's a Swiss Army knife for everyone interested in a set of powerful network tools for everyday use.
network monitoring netstat ping ip portscan snmp audit utility

NetInfo 

NetInfo is a collection of 15 different state-of-the-art network tools on a single, easy-to-use interface.
network utilities network tools network scanner ping lookup finger whois