so i just started using bt3 and im having trouble
i want to monitor my network so ive been using ettercap, driftnet and urlsnarf
but i don't know if anything is working correctly
for driftnet and urlsnarf when i enter the code and push enter i get

"urlsnarf: SIOCGIFHWADDR: No such device" and

"driftnet: pcap_open_live: SIOCGIFHWADDR: No such device"

and when i use ettercap it seems to work and i get 4 hosts, but when i actually try it, like on the same computer putting in a username and password to something nothing happens, same thing when i use a different computer on the same network and sing into a website it doesn't show anything up on there

thanks for any help ahead of time