SPF vs DKIM vs DMARC. Why Are They Important?

Email deliverability requires email authentication, and there are three ways to do so. Read our SPF vs DKIM vs DMARC study to see which works for you!
Email deliverability has never been as important as it is today.

To protect users, email servers employ a variety of authentication methods to ensure that no spam or malware emails enter inboxes.

But they’re not always the best at it.

For salespeople, this means that sometimes that perfectly crafted and relevant cold email may not make it through due to technicalities.

To avoid ending up in your prospect’s spam, one thing you need to do is make sure that your email is authenticated as well.

And there are three ways you can do this.

What is SPF?

SPF, or Sender Policy Framework, is an email authentication protocol that helps prevent email fraud and phishing.

Essentially, SPF allows email domain owners to designate which mail servers are authorized to send emails on behalf of their domain.

Here's how it works:

When an email is sent, the receiving email server can consult the SPF record for the sending domain to determine whether the email is legitimate or fraudulent. If the email comes from a server that isn't listed in the SPF record, it's likely to be marked as spam or rejected outright.

Thanks to it, companies can help protect themselves and their email recipients from becoming victims of email-based scams.

Advantages of SPF

Prevents Email Fraud & Phishing

By verifying that the email message was sent from an authorized server, SPF helps protect email recipients from receiving spam or malicious emails that attempt to impersonate legitimate sources.

Implementing it in your email infrastructure is essential for ensuring the security and integrity of your email communications.

Increases Email Deliverability

By implementing the Sender Policy Framework (SPF), you can improve your email deliverability and reduce the chances of your legitimate emails getting marked as spam or an email bounced back by the recipient's email server.

Emails sent from authorized servers have a higher chance of reaching their intended destination.

Enhances Brand Reputation

By implementing Sender Policy Framework (SPF), you can add an extra layer of protection to your domain and prevent spammers from using it to send out phishing or fraudulent emails.

As a result, you can maintain the trust of your customers and partners who receive emails from your domain.

Provides Visibility & Control

SPF empowers domain owners to monitor and control who can send emails on behalf of their domain.

This is crucial in keeping your domain safe from potential malicious attacks.
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What is DKIM?

DKIM, or DomainKeys Identified Mail, is an email authentication protocol that helps ensure the legitimacy of your email messages.

Basically, it adds a digital signature to the email header that can be used to verify that an authorized sender sent the message and has not been tampered with in transit.

Here's how it works:

When an email is sent, the sender's domain generates a digital signature using a private key. The recipient's email server can then use the corresponding public key, published in the sender's DNS records, to verify the digital signature and confirm the message's authenticity.

When implemented correctly, it can help improve email delivery and deliverability and reduce the risk of phishing attacks.

Advantages of DKIM

Provides Protection Against Message Tampering

Email tampering can be a severe issue, compromising security and trust. While SPF helps to verify the sender's identity, DKIM provides even more robust protection against message tampering.

Unlike SPF, which only checks the sending server's IP address, DKIM verifies the integrity of the message itself. This means that it ensures the email has not been altered in transit, providing an added layer of security.

Authentication of Message Header

When it comes to email security, it's not just about the sender's domain being verified. The message header contains crucial details such as the subject line and recipient email addresses, and it's important to ensure that these details are also authenticated.

This is where DKIM comes in, verifying the message header along with the rest of the message content.

By authenticating the entire message, not just the envelope sender, DKIM provides healthier security for email communication.

No DNS Lookup Limitations

While SPF may be restricted in its ability to perform DNS lookups for a message, DKIM offers more flexibility and effectiveness.

This is because DKIM doesn't have a limit on DNS lookups, making it the optimal choice for authentication in situations where multiple keys are needed for a single domain.

Widely Supported

DKIM authentication is a widely supported method trusted by email clients, servers, and major service providers such as Google, Yahoo, and Microsoft.

This reliable and effective authentication method ensures that your emails are delivered safely and securely.

What is DMARC?

DMARC is an email authentication protocol that enhances email security with its Domain-based Message Authentication, Reporting, and Conformance system.

It is built upon the existing authentication protocols SPF and DKIM and provides a comprehensive solution for email security.

With DMARC, domain owners decide which authentication methods (SPF, DKIM, or both) should be used to verify incoming messages.

Additionally, it provides a mechanism to instruct email receivers on handling messages that fail authentication and allows domain owners to receive reports on how their emails are being addressed.

When an email receiver receives a message that fails authentication, it can check the DMARC policy for the sender's domain to decide how to handle the message. The policy can instruct the receiver to reject, quarantine, or allow the message to be delivered. It can also specify how to run messages that pass authentication.

Advantages of DMARC

Enables Domain Owners to Monitor Email Activity

DMARC offers domain owners a straightforward way to receive reports from email receivers on how their emails are processed.

This gives domain owners greater visibility into their email information and empowers them to monitor for any signs of unauthorized use of their domain.

Helps Reduce Email Fraud & Impersonation

DMARC is an essential tool that empowers email receivers to authenticate messages and reject those that fail verification, thus curbing impostors and phishing scams.

Only authorized emails reach their intended recipients, ensuring adequate protection against fraudulent activities.

Supports Email Forwarding

DMARC provides secure email forwarding with authentication. This ensures that forwarded messages remain authentic even when shared with multiple recipients.

Improves Email Deliverability

Using DMARC, domain owners can improve email deliverability by ensuring their emails are correctly authenticated.

This helps to prevent incorrect flagging as spam or rejection by email receivers.
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Without SPF, there is no DMARC.

If you can only do one of the three, SPF is by far the easiest to have ready. However, it can cause issues as it is not as perfect without DMARC.

DMARC uses SPF and DKIM to validate email addresses, making it much faster and more trustworthy to your prospect’s servers when receiving emails. You can also lose this validity with SPF if it is forwarded.

And you are losing out on more responses if you only have SPF and an email fails to be verified by a prospect’s inbox.

DMARC provides a reporting system that helps those receiving your emails take specific actions if, for some reason, your messages do not pass the verification requirements.


There are two main differences between the two:

First, SPF relies on IP addresses for anti-spoofing and determining which addresses can send mail from a particular domain. DKIM’s approach is more sophisticated and safe, as it instead relies on an encryption algorithm to create electronic keys that are tied to a digital signature.

Second, DKIM uses the signature to validate trust. Because this information is found in the header, it is preserved when forwarding. SPF, instead, will lose the information tied to its trustworthiness when forwarding, as it is found in the message envelope.

While both methods can work independently of each other, it is best when used together to make up for each other’s flaws.


The comparison between DMARC and DKIM is similar to SPF and DMARC.

DMARC needs both DKIM and SPF to work, while neither needs something else to be set up previously.

But because DMARC makes use of both authentication methods, your prospect’s inboxes are far more likely to accept your emails a lot quicker as it is a faster verification process.

What DMARC does offer is that neither DKIM nor SPF does the possibility of your prospect’s inbox to decide what to do with your email if, for some reason, it fails the verification checks.

Based on your prospect’s DNS settings, there is a far greater chance that your email will still make it through. After all, if you have taken the time to make your email safe and secure yourself, it means you send safe and secure messages that are good to receive.


Email deliverability is the concern of sales and marketing, not IT.

As such, it is up to us as salespeople and marketing professionals to check that our emails are set up correctly to arrive at our prospect’s inboxes.

Preparing and verifying your DNS settings is an essential step in this process. This article has outlined the three authentication methods you can take to make this happen, although using the three together is by far the most successful.
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