Greylisting valid SPF domains
Starting with firmware 47.0 the Protector will automatically whitelist all the sender domains with valid SPF records. This feature has been built to avoid that the Grey Listing Filter blocks such domains even if they are entitled to be whitelisted thanks to the SPF compliance. It is possible however to disable this feature by unchecking the checkbox Grey List SPF Pass in the Grey Listing page. The page is available through menu Anti Spam > Listings.