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When presented with the choice of DKIM vs. SPF, it’s nearly impossible to tell whether one is more important than the other. After COVID-19 fundamentally changed how companies operate, email communications have gained a high profile in many industries. 

Long gone are the days of closed meetings and long calls. Everything from logisitics to liaison can be handled by email to save time while increasing efficiency and productivity. 

The problem with such a drastic change is that emails are still pretty vulnerable withoutDMARC in place. Fraudsters and bad actors have noticed how profitable it is to spoof a company’s identity online. 

DMARC is an email security protocol that combines the strengths of SPF and DKIM to authenticate your messages and protect your domain from malicious exploits. 

The big discussion isn’t about choosing SPF, DKIM, or DMARC; it’s about how to implement all three policies together to protect your domain. 

Without DMARC in place, your company can be impersonated by anyone online. The consequences can affect your brand’s reputation. You can face liability by having customer data exposed via business email compromise, lose credibility due to phishing attacks, and even end up in legal trouble, facing potential lawsuits and the scrutiny of regulatory entities. 

Fortunately, email authentication protocols like DKIM, SPF, and DMARC can help keep the fraudsters at bay, protect your domain, and ensure only legitimate and authorized messages make it to your recipients. 

In this blog post, we’ll discuss the importance of DKIM and SPF and why both are necessary to achieve the best security for your domain.

What is DKIM and How Does it Work?

So, what is DKIM? The term DKIM is short for Domainkeys Identified Mail. It’s a security measure that uses public and private cryptographic keys to authenticate and validate each email you send. 

A DKIM signature is included in every email created using the private key. Recipient servers then retrieve the public key, published when you create a DKIM record. If the private and public key values match, the email passes authentication.

DKIM uses asymmetric encryption on all your emails to stamp every outgoing message sent from your domain with a digital signature. This allows receiving providers to confirm that your message has been sent without changes or tampering mid-traffic. 

To validate the signature, ESPs retrieve the public key in your DKIM record.

When SMTP servers get an email with a DKIM signature, they take action by fetching the public key published in the DKIM TXT record contained in the DNS. 

Once the verification process is done, the receiving server takes action according to the results. If the check fails or the signature is not found, the receiving ESP can flag the email as spam or block it altogether.

What is SPF and How Does it Work?

SPF is short for Sender Policy Framework. It’s a security protocol that allows you to present a list of authorized senders or IP addresses in your DNS. These sending sources are the only ones who can deliver emails on your domain’s behalf. 

Any emails from unauthorized sources are blocked instantly. SPF allows you to compile a safelist, signaling to other ESPs that your domain is trustworthy. SPF has to be included as a TXT record in your DNS, similar to how it’s done with DKIM.

When you create an SPF record, you can stipulate specific IPs and third-party senders authorized to send emails on your company’s behalf.

After that, all you need to do is publish this record in your DNS. You can always check what servers are authorized to send emails from your domain by using our free SPF record checker tool.

When an email is sent claiming to come from your domain, all receiving servers retrieve your SPF record to determine whether the sender’s IP address is listed. If so, the email passes SPF authentication.

If the check-up fails, the message fails authentication, and the email is sent to the spam folder or discarded.

Is SPF vs. DKIM Better?

When it’s time to compare DKIM vs. SPF, you can’t go wrong with either. These protocols aren’t mutually exclusive. They’re rather complementary to each other and required for full DMARC compliance.

Each SPF vs. DKIM protocol deals with integral but separate issues related to email security. 

SPF verifies email senders according to your list of authorized sources in your SPF record.. DKIM, on the other hand, places a digital signature on each of your emails as a unique identifier validated by matching it with the public key in your DKIM record.  DKIM also verifies your emails haven’t tampered with mid-traffic. 

Both components are integral to making DMARC work at its best.  

SPF uses an authorized senders list, while DKIM uses an encrypted signature. You can technically implement DKIM without SPF, but that defeats the purpose of complete DMARC compliance. 

You can still be held accountable if your client receives a spoofed message that prompts a phishing attack. A team of auditors can easily find out if there was no SPF  or DKIM record in your domain when the spoofed email reached the affected party. 

Having SPF, DKIM, and DMARC in place can also improve the success of your email marketing campaigns. Email service providers can verify your messages without issues, significantly increasing the chances of them landing in the recipient’s inbox. You won’t have to waste time and money sending emails asking your customer base to safelist your email address.

What’s the Difference Between DKIM and SPF?

To understand the differences between DKIM vs. SPF, it’s best to analyze what each one of them does. SPF essentially offers a way for you to specify email senders you’ve authorized.. DKIM, on the other hand, allows you to sign all of your emails with an encrypted digital signature.

SPF lets receiving servers know the sending sources permitted to send email messages on your domain’s behalf. DKIM tells receiving servers that incoming messages purporting to come from your domain/organization must have a digital signature that matches the public key in your DKIM record.

What Does DMARC Add to the Equation?

You can configure DKIM without SPF, but that won’t guarantee DMARC compliance. DMARC is essentially the system bringing email security to a whole new level. 

Domain-based Message Authentication, Reporting & Conformance is a standard security protocol applied by reputed organizations to protect their domains from spoofing and phishing attacks.

DMARC takes email authentication a step further by verifying the visible address in the “header from” against the address in the “return-path” (for SPF) and the DKIM signature (for DKIM). This way, cybercriminals can no longer spoof the “header from” address and trick unsuspecting recipients. 

DMARC also allows you to instruct email servers on how to handle emails when they pass or fail DMARC authentication. 

DMARC relies on three basic policies to sort and handle messages. They need to be appropriately configured and adjusted over time until you reach the best rate of deliverability. These policies are:

  • p=none: No action is taken by the receiver regardless of whether the email passes or fails DMARC authentication; the email is delivered as usual. It’s the basic setup of DMARC, typically used for monitoring in the very first stages of DMARC implementation.
  • p=quarantine: Blocks messages based on how SPF and DKIM have been set up. Any messages failing DMARC authentication are sent to spam folders. 
  • p=reject: Blocks messages which fail DMARC authentication.

With DMARC in place, you can also get reports detailing delivered, failed, and rejected emails. The reports give you more control over your stream of messages letting you see what’s working, what’s not, and whether bad actors are trying to spoof your domain—all in real time.

DMARC nurtures more trust in your company, as your communications have more value and are deemed trustworthy by your receivers.

Final Thoughts

By now, it’s easy to see why there’s no reason to choose between SPF, DKIM, or DMARC. You need all three to have a fully protected domain. Successful DMARC implementation relies on slowly ramping up to the p=quarantine policy. You must also analyze your DMARC reports frequently to understand your email infrastructure better.

At EasyDMARC, we’re happy to help you implement SPF, DKIM, and DMARC the easiest and most efficient way possible.

You can get started with our dedicated DKIM lookup tool. We also have similar utilities for SPF and DMARC. 

With EasyDMARC, you can generate your SPF, DKIM, or DMARC records easily with our suite of free tools. If you need help setting them up properly, contact us.

We’re here to help you achieve the best security for your domain while making your communications safer.

Various authors from EasyDMARC teams have contributed to our blog during company's lifetime. This author brings everyone together.


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