Many gateways impose a limit on the maximum size message they
    will process. Because the mail server is often called upon
    to transmit large files it frequently can run afoul of such
    limitations.

    The MAXIMUM command provides a way around such limitations. When
    a maximum size is set, messages larger than that size will be
    fragmented (split) into multiple messages, each message no larger
    than the specified maximum size. The fragmentation scheme is
    compliant with the message/partial type described in RFC 2046
    (MIME, Part Two).

    The possible values for size-units are:

    BYTES  size-value specifies the maximum number of bytes allowed
           in a single message. This value includes the initial
           header attached to the message. (Note that the header
           can increase in size through the addition of header lines
           during routing.)
    BLOCKS size-value specifies the maximum number of "blocks" of
           bytes allowed in a single message. The size of a block
           is a PMDF configuration option controlled by the system
           manager with the PMDF BLOCK_SIZE option; its default value
           is 1024 bytes. As with BYTES, this value includes the
           initial header attached to the message.
    LINES  size-value specifies the maximum number of lines allowed
           in a single message. This limit is independent of the
           number of bytes or blocks. It is necessary to have an
           independent limit because some gateways limit message size
           based on both line count as well as overall size.

    The limits specified with the MAXIMUM command apply to all
    subsequent SEND commands in the same message. The imposed limits
    can be overridden with a subsequent MAXIMUM command. And, of
    course, limits you imposed in previous messages sent to the
    server have no effect on subsequent messages which you might
    send.

    Both line count and byte size limits can be simultaneously
    imposed. For instance, the two commands:

    MAXIMUM BYTES 10000
    MAXIMUM LINES 1000

    Will result in messages larger than either 10,000 bytes or 1,000
    lines being automatically fragmented into smaller messages, each
    containing fewer than 10,000 bytes and 1,000 lines.

    See the SEND command description for further information on the
    usage of this command.