Default

    preprocessor SMTP: \
        ports { 25 } \
        inspection_type stateful \
        normalize cmds \
        normalize_cmds { EXPN VRFY RCPT } \
        alt_max_command_line_len 260 { MAIL } \
        alt_max_command_line_len 300 { RCPT } \
        alt_max_command_line_len 500 { HELP HELO ETRN } \
        alt_max_command_line_len 255 { EXPN VRFY }