SPF record (SPF_HELO_PASS rule) This option is available through menu Anti Spam > Setup. An SPF record is a type of Domain Name Service (DNS) record that identifies which mail servers are permitted to send email on behalf of your domain. The purpose of an SPF record is to prevent spammers from sending messages with forged From addresses at your domain. Recipients can refer to the SPF record to determine whether a message that is intended to be from your domain comes from an authorized mail server. You can enable this option to increase trust in mail messages with a valid SPF record. In this case, a score of 10 is deducted from the total Anti Spam score.When this option is , the risk of false negatives grows (spam messages not caught by the Anti Spam filter).