Question regarding Blacklist: SPF Checking option

[wickedmx]

I would like to enable this option but just wanted to check one thing prior to doing so.

I am assuming that this rule only applies to domains that actually have an SPF record setup, and any domain that does not have an SPF record will have mail delivered as normal. Am I correct in this presumption?

Thanks in advance.

[PenguinInternet]

Yes, that is correct. Many people have not implemented SPF yet and so otherwise their mail would be rejected therefore only SPF mismatches are rejected.