What are SPF, DKIM, and DMARC?

The modern email security system is built on three pillars that protect a domain from fraudsters and guarantee the deliverability of legitimate messages. The first element is SPF, which stands for Sender Policy Framework. This is a special record in the domain management panel that contains a whitelist of IP addresses and servers officially authorized to send emails on behalf of your domain. When a recipient accepts an email, their mail server checks the sender's IP against your SPF record.

The second important tool is DKIM, or DomainKeys Identified Mail. This mechanism adds a cryptographic digital signature to each outgoing message, which is signed with a private key on the sender's side. The recipient's mail service decrypts the signature using the public key published in your DNS records. If the signature matches, it proves that the email was indeed sent from your domain and its contents were not intercepted or modified by attackers during transmission.

The third level of protection is the DMARC protocol, which combines the capabilities of SPF and DKIM into a unified security policy. DMARC instructs recipients' mail servers on how to handle emails that fail SPF or DKIM checks. You can configure the policy so that suspicious messages are simply sent to spam or completely blocked by the server even before they reach the recipient's Inbox folder.

The comprehensive use of all three technologies makes it possible to completely eliminate the possibility of spoofing, i.e., falsifying the sender's address. Attackers often use unprotected domains for mass mailing of malware and phishing on behalf of well-known brands. Setting up these records in your domain's DNS is a mandatory requirement for any business that cares about its reputation and the security of its clients and partners.