The purpose of this filter is to detect forged senders. Whenever an email is received, a check is made to see if the server which sent it is allowed to send emails on behalf of the sender's domain. The Sender Policy Framework (SPF) is a community-based effort, which requires senders to publish their mail servers in an SPF record. The order in which the various modules scan an email is configurable and can be altered from the MailEssentials Configuration > Anti-Spam > Filter Priority. This filter is part of the Anti-Spam Engine (ASE) chain as shown in the illustration below. SPF is a community-based effort, which requires that the senders publish the IP addresses of their mail servers in an SPF record. The Sender Policy Framework filter uses SPF records to stop email sent from forged IP addresses by identifying if the sender IP address is authorized. This article describes how the filter can be used to effectively identify and block emails originating from forged senders. The Sender Policy Framework (SPF) filter identifies and blocks spam with forged senders.
