Does an spf record check sending mail server

An SPF (Sender Policy Framework) record does not directly check the sending mail server. Instead, it helps to verify the authenticity of the sender's domain by specifying which mail servers are authorized to send emails on behalf of that domain.

Here's how it works:

  1. When an email is sent, the sending mail server includes a "MAIL FROM" or "HELO" command in the SMTP conversation.
  2. The receiving mail server looks up the SPF record for the sender's domain (the domain specified in the "MAIL FROM" command).
  3. The SPF record specifies a list of IP addresses or networks that are authorized to send emails on behalf of the domain.
  4. The receiving mail server checks if the IP address of the sending mail server is included in the list of authorized IP addresses or networks specified in the SPF record.
  5. If the IP address is authorized, the receiving mail server considers the email to be authentic and proceeds with the delivery process.
  6. If the IP address is not authorized, the receiving mail server may reject the email or mark it as spam.

SPF records do not check the sending mail server's configuration, such as its DNS settings or mail server software. They only verify that the sending mail server is authorized to send emails on behalf of the sender's domain.

It's worth noting that SPF is just one part of the overall email authentication process. Other authentication mechanisms, such as DKIM (DomainKeys Identified Mail) and DMARC (Domain-based Message Authentication, Reporting, and Conformance), can also help to verify the authenticity of emails.