Sender Policy Framework (SPF)
The Sender Policy Framework (SPF) is an authentication method which, in combination with DMARC, is effective in preventing email spoofing.
Email spoofing is used to mislead the recipient into thinking an email is from a different sender, usually a sender that the user will trust. It is a malicious practice common in phishing and email spam.
To use the SPF Generator, simply enter your domain, set the appropriate toggles and pick your 'fail authentication' setting. You also have the option to include any Domains/IP addresses that send mail on your behalf.
You can choose from A-Record, MX-Record, IPV4 or IPV6. Then copy the SPF record and enter it on your domain's DNS record. You can choose from 'SPF Record', 'SPF Record using Bind' or 'SPF Record using TinyDNS'.
Once you add the newly generated SPF record, you'll be one step closer to preventing malicious use or spoofing of your mail server.
SPF Record using Bind
SPF Record using TinyDNS