SMTP和POP3的命令集

SMTP: HELLO (HELO)
MAIL (MAIL)
RECIPIENT (RCPT)
DATA (DATA)
SEND (SEND)
RESET (RSET)
VERIFY (VRFY)
EXPAND (EXPN)
HELP (HELP)
NOOP (NOOP)
QUIT (QUIT)
TURN (TURN)
POP3:
USER
PASS
QUIT
STAT
LIST
RETR
DELE
NOOP
RSET
TOP
UIDL
APOP