DomainKeys Identified Mail (DKIM) is an email authentication method that ensures emails are genuinely from the sender they claim to be.
In an era where phishing and spam are rampant, DKIM acts as a digital signature, adding a layer of trust and security to email communications.
By attaching this digital signature, DKIM helps email providers verify that the content of a message hasn’t been tampered with during transit - playing a crucial role in combating email spoofing, protecting brands, and improving inbox placement rates.
Implementing DKIM helps safeguard your reputation, ensures reliable email delivery, and reduces the chances of emails being flagged as spam.
In this article, we’re going to look at the different parts of a DKIM record, the tools you can use to check DKIM settings, how to set up a DKIM record with a DKIM generator, and how to amend a DKIM record for your domain.
We’ll also explain how Simplelists can help streamline DKIM implementation for your email marketing needs.
What are the different parts of a DKIM record?
A DKIM record is made up of several key parts that work together to authenticate outgoing emails.
Let’s break down the different parts of a DKIM record:
DKIM selector
The selector is a string of text that identifies which DKIM key is being used to sign an email. It allows domain owners to manage multiple DKIM keys for different purposes, such as transactional emails or newsletters, without any kind of conflict.
Selectors are added as a prefix to the domain name in the DKIM signature.
This allows receiving email servers to find the correct DKIM record in the domain’s DNS settings.
A DKIM selector example might be:
- transactional._domainkey.simplelists.com
- newsletter._domainkey.simplelists.com
Using clear and descriptive selectors can help with easier management and troubleshooting.
Public key
The public key is stored in the domain’s DNS records and is used by email providers to verify the authenticity of the message.
When an email is sent, the public key decrypts the digital signature created by the private key (which we’ll cover in the next section).
If the decrypted signature matches the email content, the message is confirmed as authentic.
Here’s an example of a public key:
v=DKIM1;k=rsa;p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDTHx1H+O3Xz4t4m1tEgUKtR+C2tI8dCdZ13+nksZnIsx+DzqkX5n5B5N5efIw5D5MyCnJtegpt2fC27b/vvjI1n/fMScU6VQ2oKL+bw6hc1U6+hnE7VZbIlJvH7VWc9XVmY7OImyxsYi/S7p3q3/RrpO7M1F6AGxvRiQIDAQAB
The “v=” and “k=” tags specify the version and key type, making the DKIM record complete and functional.
Private key
Unlike the public key, the private key is stored securely and should never be shared or exposed.
Most email platforms generate and manage private keys internally, reducing the risk of mismanagement.
How to check DKIM records
It’s crucial to regularly check your DKIM records are set up correctly and remain valid. This ensures email authentication is working as expected, reducing the risk of messages being flagged as spam or failing delivery.
To check DKIM records, you’ll need to know your DKIM selector, which can usually be found in the DNS settings of your domain.
Once you have the DKIM selector, several online tools make the process simple:
DNSchecker.org
DNSchecker.org offers a free, user-friendly tool for checking DKIM records. By entering your domain name and DKIM selector, you can quickly confirm if your DKIM records are configured correctly.
Courier.com
While Courier is primarily an API tool for developers managing customer notifications, it also provides free DKIM checking tools. These tools are easy to use, even for non-technical users, making them a convenient option for validating your DKIM setup.
EasyDMARC
EasyDMARC specializes in email security and offers tools to improve email deliverability. Their free tool to check DKIM helps validate records, while their premium features start at £35.99 per month for advanced monitoring and reporting.
PowerDMARC
PowerDMARC provides real-time monitoring of email authentication protocols, making sure your emails meet DKIM standards. Their basic tool to check DKIM is free, and you’re able to monitor it with their real-time solutions from $8 per month.
MX Toolbox
MX Toolbox offers a comprehensive suite of email troubleshooting tools, including a free DKIM checker. And if you need more advanced diagnostics and monitoring, premium plans start at $129 per month.
When you use a tool to check DKIM regularly, you can help identify potential issues early, ensuring your emails consistently reach your recipients’ inboxes.
How to add or amend a DKIM record
Setting up or tweaking a DKIM record might sound complicated, but it’s actually quite manageable if you have the right tools and access.
Before getting started, here’s what you’ll need:
- Access to your DNS settings: You’ll make changes to your domain’s DNS records, which you can find through your domain registrar or hosting provider.
- Admin access to your email service provider: You’ll usually adjust DKIM settings through the control panel of your email platform.
Once you’re ready, here’s how to get the job done:
Decide on a DKIM selector
The first step is picking a DKIM selector. Think of the selector as a unique identifier for your DKIM key.
Each domain can have multiple selectors for different email purposes, like marketing campaigns or transaction receipts.
We can refer back to our previous example to illustrate:
- transactional._domainkey.simplelists.com
- newsletter._domainkey.simplelists.com
Using clear names like these makes managing multiple DKIM records easier later on.
Generate your DKIM records
Next, you’ll need to generate your DKIM records.
These include both a public key and a private key.
The easiest way to do this is by using a DKIM generator tool, such as the one available at EasyDMARC.
This DKIM generator tool will provide the keys you need, ready to copy and paste into the right places.
Add your public key to your DNS records
Once your DKIM generator has given you what you need, take your public key and add it to your domain’s DNS records.
This is the part email providers use to verify your messages. Make sure the record includes the required tags like v=DKIM1 and k=rsa.
Add your private key to your email provider
Your private key stays with your email service provider—it’s used to create the digital signatures for your messages.
Most platforms have simple options to enable DKIM, where you just input your selector and public key.
If you’re unsure, your email provider likely has a guide to help you enable DKIM step by step.
Enabling DKIM within Simplelists
If you’re using Simplelists for your email marketing, you’re in luck - setting up DKIM is straightforward.
If you have a Simplelists multiple lists account, you can send emails from your own domain while ensuring they’re properly authenticated with DKIM.
Here’s how Simplelists makes DKIM easy:
- Full support for DKIM and SPF: Simplelists fully supports email authentication protocols, ensuring your emails are verified and less likely to land in spam folders.
- Tutorials and resources: Need help? Simplelists provides clear, step-by-step tutorials.
By enabling DKIM within Simplelists, you not only protect your brand reputation but also improve your email deliverability.
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