The CONFIRM command is used to confirm for MAILSERV the execution
    of a command from a previous message.

    That is, for security your system administrators might have
    configured MAILSERV to require confirmation of certain commands.
    If you receive a message from MAILSERV saying that you need to
    send a

    CONFIRM cookie-string

    message back to MAILSERV in order for it to perform some
    particular command you previously requested, then if you want
    that command executed you must send back exactly

    CONFIRM cookie-string

    where COOKIE-STRING is the exact string MAILSERV tells you to
    send for that command.

    Note that you should send a new message back to MAILSERV
    containing the required CONFIRM command, rather than simply
    resending or bouncing MAILSERV's own message back to MAILSERV (to
    ensure that you hear about any errors in processing your CONFIRM
    command).

    Note that if you receive a message from MAILSERV talking about
    confirming a command that you did not send yourself, then that
    might mean that someone is attempting masquerade as you in
    e-mail and you might want to take this up with your system
    administrators.