[Dovecot] spf record

[Matt]

> But as a matter of fact, I got corrected. The major problem with even
> scoring is that the only things spammers have to do (and they really do
> it!) is to register some new domain, enter valid SPF records for it and
> then their scoring might even improve.

DKIM and domainkeys are really no better in that respect.  Spammers
typically do not go through that much effort though.

Matt