How Does DKIM Improve Deliverability? | EasyDMARC

How Does DKIM Improve Deliverability?

7 Min Read
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If you’re aiming to learn how to improve email deliverability, you need to understand how email filters work. They’re the first line of defense in any inbox, promptly blocking messages that appear to be fake or spam. 

Unfortunately, there’s no secret code to bypass email filters. Each email service provider (ESP) uses different settings. But it’s not only the filters that hinder your deliverability rates. Domain reputation, content quality, and other factors play major roles too. 

We’ll leave all other factors aside and focus on email authentication for improving deliverability of emails. We’ve already talked about SPF as the first step toward DMARC compliance. Now it’s time to dive into DKIM (DomainKeys Identified Mail).

So, What’s the Problem with Deliverability?

There are plenty of issues plaguing your deliverability rates. Emails get lost in transit or end up in the lonely “Spam” folder all the time. You can build up an incredible mail list database, but if you don’t send emails frequently, your messages could be diverted by spam blockers. Other notable challenges that may affect deliverability rates include the following:

  • A single opt-in system is also problematic since your messages can be flagged as erroneous signups or spambots.
  • Sending a massive email campaign from a free domain is likely to enable spam filters.
  • Using spam flagging subject lines can divert all your messages to the spam folder or block them immediately.
  • ESPs can also flag messages with a heavy load of HTML resources, such as images and links. It’s why most commercial emails use a single template, including everything they have to say. 
  • URL shorteners are a big no-no since ESPs can flag these shortened links as malicious. 
  • Making opt-out difficult can cause people to manually flag your emails for being problematic.

Implementing DMARC is the best way to protect your domain and ensure better deliverability rates. It’s an email authentication standard that essentially tells recipient mail servers to block any emails from sources you haven’t authorized. As such, spam, spoof, and phishing emails using your company’s domain name aren’t delivered, and only legitimate emails are.

Without email authentication, you can’t prove that your emails are genuine so spam filters can block them. Fraudulent emails might also go through, which isn’t good for your company’s domain reputation. But to implement DMARC, you need to properly configure SPF and DKIM first.

DKIM and SPF are separate authentication protocols used together with DMARC to help recipient servers validate and authenticate emails.

The difference between DKIM vs. SPF lies in its function and purpose. DKIM uses a cryptographic key pair, one public and one private, to link an email to its domain and ensure a message wasn’t altered in transit. 

Conversely, the SPF (Sender Policy Framework) protocol allows you to define precisely which sending sources are authorized to send emails from your domain.

Why Email Authentication is a Reliable Way to Improve Deliverability

If we have to explain the advantages of email authentication in a nutshell, it would be with a single word: visibility. By adding a DKIM record to your DNS, your recipients know your messages originate from you and haven’t been tampered with during transit. This verifies every single email you send, lowering the chances of being blocked by email filters. Once you configure a DKIM signature for your domain, you’ll see how quickly DKIM can improve deliverability rates.

The verification standard used by many big companies to authenticate messages is known as DMARC (short for Domain-Based Message Authentication, Reporting, & Conformance). DMARC vs. DKIM enhances and builds upon the protection and authentication offered by both DKIM and SPF.s. 

DKIM verifies the authenticity of an email. SPF allows you to define the authorized IP addresses permitted to send messages from a particular domain.

Both systems work in tandem to prevent anyone from spoofing your domain. DMARC effectively blocks bad actors from delivering spoofed, spam, or phishing emails to unsuspecting recipients using your domain or company’s name… 

As you take further steps to learn how to improve email deliverability, you’ll realize that email authentication does wonders to prove that you are who you say you are online. ESPs will know you’re a legitimate sender and your emails will have a higher chance of landing in your recipients’ inboxes.

Remember, deliverability rates depend on various factors, so email best practices are still vital.

Still, if you want to improve email deliverability while protecting your domain, DMARC implementation is a must, requiring proper SPF and DKIM configuration. With DMARC in place, ESPs will know instantly you’re a trusted sender. 

DKIM is mandatory for many companies such as Yahoo! and Google because of their feedback loop policies. These policies keep track of spam complaints, and their algorithm is fed each time someone flags a message as spam. 

Without DKIM, you can’t keep track of spam complaints at such companies and spam emails can’t be automatically blocked. This could, in turn, lead to your domain being blocked or blacklisted by email service providers…

What Does DKIM Add to Improving Email Deliverability?

The road to improving email deliverability requires DKIM. While it’s not the only protocol you’ll need, it’s a solid step in the right direction. It’s a critical standard on the way to full DMARC compliance, which requires SPF setup as well.

While it’s not the only protocol to consider, DKIM adds a lot of value to your email infrastructure. DKIM informs every email service provider you’re sending legitimate messages. This happens because of the digital signature imprinted in the header of all your messages. 

As mentioned, DKIM uses a pair of cryptographic keys. The public key is published in the DKIM record while the private key is used to generate an encrypted digital signature for each email sent from your domain. 

ESPs validate the signature against the public key found in your domain’s DNS records. You can easily publish your key in a TXT record using EasyDMARC’s DKIM record generator tool. If you’re unsure whether you have a DKIM record, you can always use EasyDMARC’s DKIM lookup tool.

Once you’ve made sure DKIM is properly configured, any message you send generates a unique signature. Inbound mail servers use the public key to decrypt and compare the signature. If the values match, the message proves authentic and unaltered. This guarantees a soft landing without issues. 

The process is relatively easy to manage, but it still needs fine-tuning for all DMARC policies and tags to work correctly. Remember that an exemplary DMARC configuration will issue reports indicating the status of every message sent and if it passed verification. These reports also indicate the performance of DKIM signatures. You’ll see if they pass, fail, or are rejected based on another issue.

Final Thoughts

So, does DKIM improve deliverability? The final answer is yes, but it takes effort to get to the perfect point where email service providers verify all your messages. DKIM alone doesn’t do all the work, but it handles a lot of heavy lifting in the verification process. 

DKIM is important for DMARC authentication, along with SPF.

Once you implement DMARC, you can evaluate the performance of your email authentication measures. This will help you make any necessary changes to improve email deliverability rates. Rest assured, once you add a DKIM record to your DNS, you’ll be one step closer to DMARC compliance.

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


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