Você pode usar ntop :
ntop - display top network users
Além disso:
ntop shows the current network usage. It displays a list of hosts that are currently using the network and reports information concerning the (IP and non-IP) traffic generated and received by each host. ntop may operate as a front-end collector (sFlow and/or netFlow plugins) or as a stand-alone collector/display program. A web browser is needed to access the information captured by the ntop program.