Email authentication protocols, such as SPF, DKIM, and DMARC, act as a multi-layer defence against phishing attacks and unauthorised emails. They verify the sender’s identity and message integrity to ensure email security.

Email, a vital communication tool for companies, has now become an easy target for phishing. Moreover, phishing emails are no longer the obvious scams they once were. Today, they’re drafted to appear as trusted messages from authentic organisations, making them harder to spot and dangerous than ever. This leads us to an important question- how can one differentiate between real and fake emails?

This is where email authentication protocols are beneficial. SPF, DKIM, and DMARC authentication protocols verify whether a message actually comes from the sender it claims to be.

In this guide, we’ll explain what these protocols are and how they help with phishing prevention and email security.

E-mail Authentication Protocols Explained

A majority of cyberattacks start with a phishing email and can cause significant financial and reputational damage to organisations.

Also Read: Top Domain Add-Ons to Safeguard Against Phishing and Typosquatting

To contradict these attacks, email authentication methods such as SPF, DKIM, and DMARC have been developed. Let us understand how these help with email security.

SPF, DKIM, and DMARC are three essential email authentication methods that every company should utilise to protect its domain against phishing attacks fully.

Pro Tip: Domain owners should configure their SPF, DKIM, and DMARC records to prevent spam emails from being sent through their domain and prevent legitimate emails from being marked as spam.

Sender Policy Framework (SPF)

In this email authentication method, domain owners post a list of trusted email servers or SPF records in their Domain Name System, which are permitted to send email.

SPF Works as Follows:

  • The server checks the domain’s SPF record from which the mail is being sent and makes sure it is coming from a valid source. This authentication is done before the email reaches the receiver’s inbox.
  • It does not allow unauthenticated IPs to send emails using your domain, thereby reducing the threat of email spoofing.

SPF is compatible with all inbox providers to prevent direct spoofing of your domain. However, SPF is one of the earliest protocols and is not a complete solution for email security.

  • SPF doesn’t work during mail forwarding, as the IP of the forwarding server may not be present in the SPF records.
  • Updating the SPF records can be tough for organisations with complex email infrastructure.
  • It only authenticates the sender’s IP address.

However, SPF is important as it sets the foundation by authenticating ownership of a domain, and DMARC and DKIM act upon it further.

DomainKeys Identified Mail (DKIM)

DKIM is an email authentication system that digitally signs outgoing mail using cryptographic keys. The receiving server verifies the signature according to the public key implemented in the domain’s DNS records.

DKIM works as follows:

  • DKIM utilises public key cryptography. The private key is kept secret by the sender and used later to sign the email header. There is a DKIM record that keeps the public key of the domain, which is made accessible as a DNS record of the domain.
  • Mail servers that receive the mail then verify the sender’s private key using the public key for comparison.

DKIM may fail, however, due to inconsistent signatures, if the DKIM private key is misplaced, or when a mail forwarding service that alters the email headers is used. This is where DMARC is used.

Domain-based Message Authentication Reporting and Conformance (DMARC)

DMARC instructs a receiving mail server to act on its findings of DKIM and SPF testing

  • One can configure the DMARC policy for a domain, instructing mail servers to quarantine (sending emails to the spam folder) those that don’t pass SPF or DKIM (or both), reject them (not delivering the mail to the inbox), or deliver them as usual.
  • DMARC policies are stored in DMARC records. A DMARC record instructs domain administrators to report to them which emails are passing and failing these tests.
  • DMARC reports provide administrators with feedback on crafting their DMARC policies.
Pro Tip: Browser extensions or SIEM can automate email protocol validation.

How to Verify the Authenticity of an Email?

  • Email clients have an option to display the complete email, including the header, where you can observe the output of email authentication protocols.
  • Type “Ctrl+F” or “Command+F” in the browser and enter “SPF”, “DKIM”, or “DMARC” to check the results.
  • For example, spf=pass means that the mail came from a valid server whose IP address is included in the domain’s SPF record.

If the email cleared all three protocols, then the mail server can confirm that the email was from a valid domain.

Also Read: Domain Phishing Attacks: Have You Been Targeted?

Importance of Email Authentication Protocols

Email authentication protocols are critical for an organisation’s email security. Phishing is becoming increasingly difficult to identify, but employing email authentication such as SPF, DKIM, and DMARC provides a three-step protection against spoofing and phishing.

Attackers will sign up for lookalike or deceptive domains in an effort to deceive individuals into thinking they are authentic domains. The best option for phishing prevention is ensuring the safety of your domain online.

That is where reliable service providers, such as CrazyDomains, can help by registering your domain name and its variations, and controlling DNS settings, so that email authentication protocols can be configured appropriately.

Sign up with CrazyDomains today to take advantage of their services.