SoftPerfect Network Scanner - A free multithreaded IP,SNMP,NetBIOS scanner.
A free multi-threaded IP, SNMP and NetBIOS scanner with several advanced features. The program pings computers, scans for listening TCP ports and shows what types of resources are shared on a network (including hidden). In addition,it allows you to mount shared resources as network drives, browse them, filter the results list and more. The scanner can also check for a user-defined port, resolve host names and auto-detect your local IP range.