Soft Maximum - best free downloads
spf

MDaemon
... Program supports multi-threading/multi-CPU capabilities, SPF (Sender Policy Framework), mailing lists, remote control, strong ... domain support. MDaemon 7.10 added features include SPF (Sender Policy Framework) support, easier spam filter white listing ...

SurgeMail Mail Server
... feature rich, with integrated WebMail software. Enhanced SPF mode which stops most spam early. Runs on your platform of choice (Windows, ... each other. Features include: Enhanced SPF mode which stops most spam early. Integrated WebMail software. Easy and ...

NoSPAMProxy
NoSPAMProxy is the first Windows Solution supporting SPF and CallerID. Other solutions initially scan all incoming mails before ...

1