E-mail Authentication Techniques: Beyond Spam Filters

Executive Summary

Ladies and gentlemen, place your bets: SPF (Sender Policy Framework) is winning the early battle between three sender authentication methods, and we expect it to retain that early lead over the next year or so. The specification's ease of deployment will let everyone publish SPF records quickly, and its record checking is supported by just about every e-mail server vendor.

Likewise, Sender ID is easy to implement and provision on both the sending and receiving sides. But it's surrounded by licensing controversy that's slowing its uptake by other vendors.

Finally, DKIM (Domain Keys Identified Mail) has value, but its complex configuration requires significant changes to both inbound and outbound e-mail software and imposes a serious performance penalty on DNS traffic between sites.

No matter which authentication method you choose, your users and the Internet community at large will come out ahead. Anything that trips up spammers is a sure winner in our book.