Caller ID for E-Mail: The Next Step to Deterring Spam

Caller ID for E-Mail Technical Specification:
"'Caller ID for E-Mail: The Next Step to Deterring Spam' is the Microsoft draft specification to address the widespread problem of domain spoofing. Domain spoofing refers specifically to the use of someone else's domain name when sending a message, and is part of the larger spoofing problem, the practice of forging the sender's address on e-mail messages.

Caller ID for e-mail would verify that each e-mail message originates from the Internet domain it claims to come from. Eliminating domain spoofing will help legitimate senders protect their domain names and reputations, and help recipients more effectively identify and filter junk e-mail.…"

http://www.microsoft.com/mscorp/twc/privacy/spam_callerid.mspx