Mail::MIMEDefang::Mail - Mail and SMTP related methods for email filters

Mail::MIMEDefang::Mail are a set of methods that can be called from
mimedefang-filter to send email messages or to run SMTP checks.

resend_message_one_recipient
    Method that re-sends the message as if it came from original sender
    to a single recipient.

resend_message_specifying_mode
    Method that re-sends the message as if it came from original sender
    to a list of recipients.

resend_message
    Method that re-sends the message as if it came from original sender
    to a list of recipients.

pretty_print_mail
    Method that makes a pretty-printed version of the e-mail body no
    longer than size characters.

get_smtp_return_code
    Method that reads return codes from SMTP server, returns a
    four-element list:(retval, code, dsn, text), where code is a 3-digit
    SMTP code. Retval is 'CONTINUE', 'TEMPFAIL' or 'REJECT'.

get_smtp_extensions
    Method that checks SMTP server's supported extensions. It expects
    EHLO to have been sent already (artifact of get_smtp_return_code).
    The sub returns a four-element list:(retval, code, dsn, exts)

    *   retval is 'CONTINUE', 'TEMPFAIL', or 'REJECT'.

    *   code is a 3-digit SMTP code.

    *   dsn is an extended SMTP status code

    *   exts is a hash of EXTNAME->EXTOPTS

md_check_against_smtp_server
    Method that verifies a recipient against another SMTP server by
    issuing a HELO / MAIL FROM: / RCPT TO: / QUIT sequence. The method
    returns:

    *   ('CONTINUE', "OK") if recipient is OK

    *   ('TEMPFAIL', "err") if temporary failure

    *   ('REJECT', "err") if recipient is not OK.