Word of the Day : Vouch by Reference (VBR)

Vouch by Reference (VBR)

Vouch by Reference (VBR) is an e-mail header tagging mechanism whereby senders can list third parties, known as domain certification services, that will attest to their integrity and good standing in the Internet community. When a sender includes a vouch-by-reference (VBR) list in an e-mail header, recipients (or intermediate servers) can look up VBR vouchers through the domain name service (DNS), to determine whether trusted third parties find the sender to be reputable. VBR makes it possible to bypass spam filtering, assuming that the recipient is willing to take the word of the voucher that the sender is legitimate.

Vouch by reference uses the domain name in the sender's e-mail address (the part that follows the "at symbol") to determine the sender's domain of origin. To avoid spoofing or prevent forgery, VBR relies upon sender authentication schemes such as DomainKeys Identified Mail (DKIM), the Sender Policy Framework (SPF) or Sender ID to prove that claimed identity and actual identity match.