SCL - Spam Confidence Level

Exchange anti-spam as mentioned in my post about detection techniques, uses specific methods to calculate a SCL (Spam Confidence Level.) On a scale of 1 to 10 - 1 being almost certainly not spam and 10 being all certianly spam.

Dependent on what SCL score the message is assigned will depend on what will happen to the message, for example:

Score of 10: Message deleted, no NDR sent to sender.
Score of 9: Message rejected, NDR sent to recipient.
Score of 8: Message quarantined - so Exchange admin can decide whether it's spam or not.
Score of 7: Message goes to recipients spam folder.
Score of 6 or below: Goes directly to recipients inbox.