MAIL

SMTP

            HELO <SP> <domain> <CRLF>
            MAIL <SP> FROM:<reverse-path> <CRLF>
            RCPT <SP> TO:<forward-path> <CRLF>
            DATA <CRLF>
            RSET <CRLF>
            SEND <SP> FROM:<reverse-path> <CRLF>
            SOML <SP> FROM:<reverse-path> <CRLF>
            SAML <SP> FROM:<reverse-path> <CRLF>
            VRFY <SP> <string> <CRLF>
            EXPN <SP> <string> <CRLF>
            HELP [<SP> <string>] <CRLF>
            NOOP <CRLF>
            QUIT <CRLF>
            TURN <CRLF>

POP3

USER userid
PASS password
STAT
LIST
RETR msg#
DELE msg#
QUIT