Rui CarmoSender Policy Framework, one of the many DNS-based anti-Spam initiatives making the rounds these days.
(It uses DNS TXT records as a sort of "reverse MX", identifying which machines are allowed to send mail from a given domain.)
Sender Policy Framework, one of the many DNS-based anti-Spam initiatives making the rounds these days.
(It uses DNS TXT records as a sort of "reverse MX", identifying which machines are allowed to send mail from a given domain.)