In one embodiment, the present invention sends SNMP queries to sets and/or ranges of IP numbers to determine whether a network device exists at each IP number and whether the network device has IP forwarding capabilities. The set of IP numbers searched may be specified by specifying ranges or subnets or by providing a list of discrete IP numbers. When a new network device with IP forwarding capabilities is discovered, that network device is added to a list of discovered network devices. The list is displayed to the network manager. In one embodiment, in addition to discovering newly added devices via IP number polling, the invention also discovers newly added devices from SNMP messages ("traps") broadcast by a newly added device. In one embodiment, each network device discovered as a result of a SNMP trap is added to the newly discovered device list.