How does the Gray List technology work at fighting SPAM?
The Gray List feature depends on increasing the cost of junkmail mail delivery by taking advantage of the current behavior of most “junkmail servers” in that they don’t retry delivery of messages to servers that refuse the connection. Each time a particular sender attempts delivery to a particular recipient from a particular IP address range, Office-Logic InterChange looks for the “triplet” of information in its database. If it is the first attempt, it will be added to the database and the sending server will be given a “451 Server busy. Please try again later.” message and the attempt terminated. On the second attempt, if it is found to fall within the time window (i.e., more than 59 seconds and less than 4 hours) the message will be delivered. If it tries too quickly (i.e., less than 59 seconds) it will be again rejected as “early” or too late (i.e., more than 4 hours) it will be rejected as “late”. Once the triplet is allowed to deliver a message, it will continue to be allowed unle
