The Anti-Spam feature examines transmitted messages and decides which are spam and which are not. When the device detects a message deemed to be spam, it either tags the message field with a preprogrammed string, or it drops the message. Anti-Spam uses a constantly-updated IPbased spam blocking service that uses information gathered worldwide. Because this service is robust and yields very few false positives, it is not mandatory to tune or configure blacklists. However, the administrator has the option of adding specific domains and IPs to local whitelists or blacklists, which the device can enforce locally.