ntop is a network traffic probe that shows the network usage, similar to what the popular top Unix command does for CPU usage of a system. ntop is based on libpcap and it has been written in a portable way in order to virtually run on every Unix platform and on Win32 as well.

ntop now fully supports IPv6, thanks to the effort of INRIA within the WP6 framework of the 6NET project. ntop can collect and make stats available on IPv6 flows and hosts in the network. Moreover, IPv6 flows can be exported with netflow v9 from with the nProbe feature, merged with the ntop tool. ntop can also act as a netflow v9 collector for IPv6 flows exported from other equipment (eg. a CISCO router or another ntop application)