/INTERVAL={ INITIAL="OpenVMS_delta_time" | RETRY="OpenVMS_
       delta_time" | MAXIMUM="OpenVMS_delta_time" }

    Optional. Defaults: INITIAL=30 minutes, RETRY=60 minutes,
    MAXIMUM=3 days.

    Time intervals related to repeated attempts before delivery
    fails. Specify the value within quotation marks as follows: "dddd
    hh:mm:ss:cc." For example:

    dddd = days (0-9999)
    h    = hours (0-24)
    m    = minutes
    s    = seconds
    cc   = milliseconds

    You can modify the following options:

    o  INITIAL="OpenVMS_delta_time" is the amount of time that SMTP
       waits before making a second attempt to deliver.

    o  RETRY="OpenVMS_delta_time" is the time SMTP waits between
       retries, starting with the second attempt. (Recommended time:
       twice the initial interval.)

    o  MAXIMUM="OpenVMS_delta_time" is the maximum elapsed time that
       SMTP retries delivery.