Graylisting and methods for making decisions

Graylisting

Graylisting is a way to automatically block spam. It is based on the fact that the behavior of spam software is often different from that of ordinary e-mail servers. If the recipient’s e-mail server refuses to accept the e-mail and signals a temporary error, the sending server must wait and try again later. Spamming applications, however, are usually unwilling to do so.

How can I avoid being graylisted?

• Maintain the good reputation of your IP address
• Use a reliable domain
• Sign your mails with a real name
• Allow immediate unsubscribing
• Format your e-mails correctly (follow the RFC 5322 and HTML standards)
• Don’t use stop words (“Click/Buy/Download”)