Windows only: Free application Axence NetTools is a comprehensive suite of networking tools for your PC, including a network scanner, inbound/outbound connection monitor (NetStat), port scanner, and other network and bandwidth measuring tools. NetTools is very similar in ways to previously mentioned network monitors like Look@Lan, but if you want to get elbow deep in your network, it's another great option to add to your toolbox. Axence NetTools is a free download, Windows only.