telnet 25/110测试mail服务器

telnet test.com 25
R: 220 SU-SCORE.ARPA Simple Mail Transfer Service Ready
S: HELO MIT-MC.ARPA
R: 250 SU-SCORE.ARPA
S: VRFY Crispin
R: 250 Mark Crispin
S: SEND FROM:
R: 250 OK
S: RCPT TO:
R: 250 OK

S: DATA
R: 354 Start mail input; end with .
S: Blah blah blah...
S: ...etc. etc. etc.
S: .
R: 250 OK
S: QUIT
R: 221 SU-SCORE.ARPA Service closing transmission channel


telnet test.com 110
POP3 Commands:

USER name valid in the AUTHORIZATION state
PASS string
QUIT

STAT valid in the TRANSACTION state
LIST [msg]
RETR msg
DELE msg
NOOP
RSET
QUIT

Optional POP3 Commands:

APOP name digest valid in the AUTHORIZATION state

TOP msg n valid in the TRANSACTION state
UIDL [msg]

POP3 Replies:
+OK
-ERR

More Details
http://www.ietf.org/rfc/rfc1939.txt
http://www.ietf.org/rfc/rfc0821.txt