Is there a way to set a spf filter on an exchange server 2013 so we only are checking for a valid SPF on our domain only? E.g. our domain is @widgets.com and I want to allow all people with no spf through provided they aren't from our own domain? We get a lot of fake emails from many public IPs that are from lets say info22@widgets.com - there is no one internally with that email address but the end users will open it thinking it is valid.