sniffing program what familiar is wireshark (formerly "ethereal") you can download it at www.wireshark.org. but in this explanation we use a new version, it's 0.99.4 version.
for using wireshark, firstly you mas choose ethernet card what will be done for sniffing through capture menu then option or press Ctr-OK. After choosing ethernet card , you can determine that option "capture packets in promiseuous mode" is activate, if you don't active it, so just package to and from your computer what will be catched by sniffer. after all of the configuration are finishing, press star for beginning sniffing action.
when sniffing action is runing , you can see total of packages what through ethernet card what you have choosed, wireshark will show total of packages for each protocol. after you feel enough press stop. all of the packages will be showed.
this packages are showed based on time list, so sometime it be difficult to know the communication what's happening, but wireshark can compare all of datas to be one unit. for trying click right on mouse and choose follow tcp stream menu. all of communication datas will compare and showed in new window, beside that just data content from packages will be compared where header of package will be throwed cause it's not useful for you.
by this ways, don't be wonder if password, email and all of your activities can be plowed without touching and attacking your computer.
