What does the result "Received-SPF: Neutral" in an email exchange indicate?

The result "Received-SPF: Neutral" in an email exchange indicates that the sender’s IP address is neither authorized nor restricted to send emails on behalf of the domain in question. This typically means that the Sender Policy Framework (SPF) record for the domain does not explicitly state whether the IP address is permitted to send email for that domain.

In this context, SPF is a mechanism designed to prevent spoofing by allowing domain owners to specify which IP addresses are authorized to send emails using their domain. When an incoming email is analyzed and results in a "Neutral" status, it suggests that the domain owner has not made a definitive declaration about the IP address's permission to send emails. Therefore, recipients and their email systems must exercise caution, as there is ambiguity regarding the legitimacy of the email source.

The other possible interpretations of SPF results do not apply in this case: an indication that an IP address is authorized or restricted would have provided a much clearer signal to email systems regarding whether the email is likely legitimate or not. Consequently, the "Neutral" result does not suggest potential phishing, but rather reflects uncertainty about the authorization status of the sender's IP address.