What is OpManager?

OpManager is a complete, efficient network and operations management software that offers comprehensive fault and performance management across WAN, Servers, Applications and all other IT infrastructure. OpManager offers a host of intuitive driven designs and easy-to-use functionalities that automate several network and datacenter monitoring capabilities and removes the complexities associated with IT management.

Opmanager, this is another good one network monitoring suite. The good thing is, if you run a small network, they offering a free lincense for limited 10 server :D