SPF, or Sender Policy Framework, is an email authentication protocol designed to prevent email spoofing. Email spoofing occurs when someone sends an email that appears to be from a specific domain but is actually sent from a different source. SPF helps verify the authenticity of the sender’s domain by allowing domain owners to specify which mail servers are authorized to send emails on their behalf. This is done by adding TXT record into the DNS of your domain.
SPF Record Example:
example.com. IN TXT "v=spf1 ip4:192.168.1.1 include:_spf.example.net -all"
In this example, the SPF record for “example.com” specifies that the mail server with the IP address 192.168.1.1 and the servers listed in the “_spf.example.net” include mechanism are authorized to send emails on behalf of “example.com.”
SPF Authentication Process
When an email is received, the recipient’s mail server performs SPF authentication to verify if the sending server is authorized. The SPF authentication process involves checking the sending server’s IP address against the list of authorized servers in the SPF record.
Click here to check you SPF record against your domain.
Here’s how SPF works:
- Sender Specifies Authorized Mail Servers: The owner of a domain publishes SPF records in the domain’s DNS (Domain Name System) records. These records contain information about the mail servers that are authorized to send emails on behalf of that domain.
- Receiving Mail Server Checks SPF Records: When an email is received, the recipient’s mail server checks the SPF records of the sender’s domain. It identifies the IP addresses of the servers that are allowed to send emails on behalf of that domain.
- Verification: The receiving mail server compares the IP address of the sending server with the list of authorized servers in the SPF records. If the IP address matches, the email is considered authentic. If there is no match, the email may be flagged as suspicious or treated as potential phishing.
SPF helps in reducing the likelihood of spam and phishing attacks that involve forging the sender’s address. However, it’s worth noting that SPF alone may not provide complete protection against email fraud. For a more comprehensive solution, SPF is often used in conjunction with DKIM (DomainKeys Identified Mail) and DMARC (Domain-based Message Authentication, Reporting, and Conformance).