IPTraf, a ncurses based LAN monitor
Sometimes you just want to see what connections your machine is making to the outside world and what ports it’s using. While wireshark and tcpdump are really nice for inspecting detailed package contents. IPTraf is really about connections and interface statistics. Because iptraf is based on ncurses the program can be run from a text-console and still have a (primitive) `gui`. Navigation through the menus can be done using your arrow keys. Most of the time all the available options and their keys are shown on the bottomline of the sreen.
By default the program is not accessible by ‘normal’ users so you’ll need root access. Also iptraf can put your interfaces in promiscuous mode (this will probably show up in your logfiles as: ‘device eth0 entered promiscuous mode’). Promiscuous mode can be turned off and on in the configuration menu.