Telnet is a wonderful legacy, now totally insecure and replaced by SSH etc. but there
are plenty of interesting things to learn:
telnet www.yahoo.com 80
HEAD / HTTP/1.1
telnet www.yahoo.com 80
GET / HTTP/1.1
telnet ipchicken.com 80 //gets your external ip address! =)
GET / HTTP/1.1
telnet pop.mail.yahoo.com 110
user username
from the microsoft cmd prompt telnet ? //help with commands set ? //help with what options you can set set localecho o 192.168.1.4 25 //open a connection to cpu w/ ip address on port 25 ehlo domain.com //shows the info of that domain mail from:test@test.com //create an email from test rcpt to:user@faraway.com //recipient should be user@faraway.com
550 5.7.1 Unable to relay for ... //not an open relay (but emails can still be sent to local recipients)
telnet mail.YourServer.com 25
EXAMPLE: IT WILL LOOK LIKE THIS
220 mailserver 959 ready at Fri, 25 Jan 2008 11:43:22 +0000 ehlo 250-mailserver Hello [127.0.0.1] 250-TURN 250-SIZE 250-ETRN 250-DSN 250-ENHANCEDSTATUSCODES 250-8bitmime 250-BINARYMIME 250-VRFY 250-X-EXPS GSSAPI NTLM LOGIN 250-X-EXPS=LOGIN 250-AUTH GSSAPI NTLM LOGIN 250-AUTH=LOGIN 250-X-LINK2STATE 250 OK
mail from:john@domain.com
250 2.1.0 john@domain.com.com....Sender OK
rcpt to: test@domain.com
250 2.1.5 test@domain.com
data //sometimes should be DATA?
354 Start mail input; end with
.
250 2.6.0
At the very end, credit goes to: http://usertools.plus.net/tutorials/id/21 http://www.ietf.org/rfc/rfc1939.txt //pop3