Email from known spam sources is blocked so that it never appears in your mailbox. This service uses published lists from a vendor to identify such mail, which is then blocked. Blocked mail is rejected and not accepted for delivery. You can turn off use of the Do Not Spam List if you wish, but we do not recommend that. How the Do Not Spam List Works ITS uses several spam-blocking lists for its Do Not Spam List service to reduce unwanted email for your