I capture data from telnet using tcpdump. Command:
tcpdump port http or port ftp or port smtp or port imap or port telnet -l -A | egrep -i 'pass=|pwd=|log=|login=|user=|username=|pw=|passw=|passwd=|password=|pass:|user:|username:|password:|login:|pass |user ' --color=auto --line-buffered -B20
But tcpdump doesn't capture any passwords or logins. I have a telnet server on my Fedora laptop. Does anyone know the reason why tcpdump doesn't capture it on the forums I read that it is "Here is quick example to sniff passwords using egrep"