Grey List

A Grey List is a mechanism used by email servers to evaluate whether incoming emails are legitimate or potentially spam. When an email is received from a new sender, the server temporarily postpones accepting it, asking the sender to try again later. If the same sender repeatedly attempts to send email, they are more likely to be trusted, and future messages are accepted more quickly. This process helps prevent spam and malicious messages by filtering out one-time or suspicious senders, improving overall email security without blocking legitimate contacts.