Netlimiter
2 Monitor displays all open processes and
applications on the system, showing incoming and outgoing
bandwidth along with ports, IP addresses and process numbers. A useful extra is the history function which applications connected to the Internet before on your system – you can use this to check whether an application is new to the list.
There’s the free version, and a Pro version which adds some usfeull functions like
Traffic Shaping, Network support, and useful network tools like Whois and
Traceroute