[CentOS] Using tcpdump to sniff telnet password

Hi all,
As long as I can remember reading various articles/docs, they all say that 
telnet is not secure because all traffic is in clear text. Well, out of 
boredom, I try to sniff username and password from a telnet session.

The command I use: tcpdump tcp port 23 -vvv -w test.txt
Then I read the result: strings test.txt 
|`D 
|fD 
|fD 
38400,38400
Red Hat Enterprise Linux ESD 
Ologin: D 
5eE 
LsE 
_tE 
Password: F 
[aG 
|hG 
jaH 
Last login: Wed Feb  6 15:53:3H 
]0;test4 at server:~
GV{

But it succeeds with FTP.
strings test.txt 
<.9@
4.:@
220 (vsFTPd 2.0.1)
4.;@
@.<@
USER test4
331 Please specify the passwor
4.=@
B.>@
PASS secret
230 Login successful.
4.?@
:.@@
SYST
215 UNIX Type: L8
4.A@


Did I miss something? How do we capture telnet password using tcpdump?
Thank you.
-- 
Fajar Priyanto | Reg'd Linux User #327841 | Linux tutorial 
http://linux2.arinet.org
15:51:58 up 8:16, 2.6.22-14-generic GNU/Linux 
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