N-View

From Wolfgang Ullrich:

N-View is a network monitor for small and medium-sized networks. It features automatic scanning of subnets for host addresses, monitoring of ICMP responses from all hosts, signalling of timeouts and delays in the GUI and by mail, a portscanner, an SNMP client (MIB browser and trap receiver), a graphical display of network traffic for network interfaces, connectivity to hosts by telnet, HTTP browser, or an arbitrary external program (such as ssh), printing of network diagrams, automatic generation of HTML pages, and more.