"DomainKeys is an anti-spam software application in development at Yahoo that uses a form of public key cryptography to authenticate the sender's domain. dkfilter is an SMTP-proxy designed for Postfix. It implements DomainKeys message signing and verification. It comprises two separate filters, an 'outbound' filter for signing outgoing email on port 587, and an 'inbound' filter for verifying signatures of incoming email on port 25. This document is to describe step by step how to install dkfilter for postfix to deploy domainkeys signing and verification..."
