Sendio I.C.E. Box anti-spam appliance review
...spam appliance brings an assortment of weapons to do battle with the evil spammers of the world, including challenge-response (Sender Address Verification (SAV)), silverlisting, SPF, Domain Keys and Sender Policy Framework (SPF) with detailed SMTP protocol checks, and finally blacklisting by domain name or email address on a system-wide or...
