[12] WHAT ARE THE LIMITS ON SENDING EMAIL FROM SDF?

    There are no limits on the number of messages you can send from SDF
    as long as it falls within the guildelines of the AUP.  That basically
    boils down to:  Send messages to your friends all you'd like, but
    under no circumstances use the SDF mail server to send retaliatory or
    bulk/spam email.  If you do this, you will lose your account ASAP.

    MESSAGE SIZE:  Approximately 100MB, total size (header/body/attachments)

    This has changed (increased) over the years and probably will continue
    to increase as pipes fatten and disk prices drop.   Historically it
    has been as low as 1MB during the early to mid 1990s.  It has increased
    over the past few years from 5mb, 8mb, 10mb, 16mb, 20mb and 30mb.

    MAX NUMBER OF RECIPIENTS:  20 addresses.

    This is the number of people in the To:, Cc: and Bcc: lines in your
    header that can receive a single piece of email from you.  If you are
    going to send email to so many people on a regular basis, we suggest
    the MLIST membership.

    Some server info:

    MAX NUMBER OF SERVERS:  128

    We currently allow up to 128 simultaneous server connections.  The
    average number of active connections we have at the time of writing
    this is less than 50.  What this means is that, there would have to
    be over 128 connections before the server begins denying connections.
    Those incoming emails would not be lost, but deferred for when the
    email flood dies down.  For more information about how SMTP works,
    see the previous entry for this FAQ.

    QUEUE RUN:  60 minutes

    When an outgoing email it deferred, it remains in the mailq queue for
    up to 5 days before being returned to sender.  Every message in the
    queue is retried every 60 minutes or roughly 120 times before it is
    returned to you.  For more information about how SMTP works, see the
    previous entry for this FAQ.