Useful Information for Working with Your Web Site

SPF is Sender Policy Framework. SPF fights return-path address forgery and makes it easier to identify spoofs. Domain owners identify sending mail servers in their site's DNS. Domain names use public records (DNS) to direct requests for different services (such as the web, email,and other services) to the machines that perform those services. To receive or send email using a domain name, the domains must already have and publish email (MX) records to tell the world what machines receive mail for the domain. SPF works by domains publishing "reverse MX" records to tell the world what machines send mail from the domain. When receiving a message from a domain, the recipient can check those records to make sure mail is coming from where it should be coming from. With SPF, those "reverse MX" records are easy to publish: one line in DNS is all it takes. SMTP receivers verify the envelope sender address against this information, and can distinguish authentic messages from forgeries before any message data is transmitted.