What Is DKIM Record? Learn Why It’s So Important.
- Lucas H.
- May 16, 2022
- 4 min read
Updated: May 30, 2022
DomainKeys Identified Mail, or DKIM record in short, is an email security standard created to ensure messages are not altered in transition between the sending and receiver servers.
It uses public-key cryptography to sign email using a private key as it renders a sending host. The receiver’s servers then use a public key published to a domain name’s DNS to validate the source of the message, also that the body of the message hasn’t altered during transit.
When the signature is verified with the recipient host’s public key, the message passes DKIM and is considered authentic.
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Why Is A DKIM Record Essential?
While DKIM isn’t required, having emails signed with DKIM appears more legitimate to your recipients and therefore are not as likely to visit Junk or Spam folders. Spoofing email from trusted domain names is a popular method for malicious spam and spam campaigns, and DKIM makes it more difficult to spoof emails from domains that have it.
DKIM can work with existing email infrastructure and functions with SPF and DMARC to create multiple security layers for domain names sending emails. Mail servers that don’t encourage DKIM signatures are still able to receive signed messages without any difficulties. It’s an optional safety protocol, and DKIM is not a universally adopted standard.
How Does It Work?
DKIM uses two actions to confirm your messages. The first action occurs on a server sending DKIM signed emails, while the second happens on a receiver server verifying DKIM signatures on incoming information. The entire process is possible because of a set of private & public keys. Your private key is kept confidential and safe (either on your server or with your ESP), along with the public key, which is added to the DNS records for your domain name (to announce it to the world) to help verify your messages.
Even though it’s not mandatory, we advise that you incorporate a DKIM record to your DNS whenever possible to authenticate email from the domain name. ISPs such as Yahoo, AOL, and Gmail use it to check incoming messages. We have completed testing that proved messages are more likely to be delivered when they use these security protocols.
Since you send good quality emails and improve your delivery methods (low spam and bounce rate, great engagement), you help your domain build a great sending standing with ISPs, enhancing deliverability.
While it’s essential to understand what DKIM does, it’s crucial to clarify what it doesn’t solve. Employing DKIM will ensure that your message hasn’t been altered, but it will not encrypt the message’s contents. Most ESPs use opportunistic TLS to encrypt messages as they transfer between recipients and sender. However, it is still possible to send unencrypted messages if an email server fails a TLS connection.
Now that we’ve explained what DKIM does let’s jump on to how it guards your domain email.
How Can DKIM Improve Deliverability?
Our tests have discovered that using email authentication methods like SPF and DKIM is critical to good deliverability.
While DKIM guarantees messages aren’t changed in transit between the sending and receiver servers, SPF verifies that the sending server is permitted to transfer messages using a domain in the first place.
DMARC gives domain owners a means for communicating how they’d like unauthenticated messages to be dealt with by recipients. It utilizes DKIM and SPF to determine if a message is legitimate and whether it ought to be delivered to the recipient or obstructed.
How Can DKIM Prevent Domain Spoofing?
DKIM alone doesn’t prevent domain spoofing. It is possible to sign a message using a DKIM key linked to another domain other than the one defined in the “From” header.
But in case you’ve got a DMARC policy set to your domain name, the receiving mail server will check the DKIM key used to sign the message matches the From domain name when deciding DMARC compliance.
How Can I Set A DKIM Record On My Own?
It’s not important which ESP or mail server you use. The overall setup for DKIM is identical. You want a private key stored somewhere safe, and you need to share a public key on your domain’s DNS records. Very similar to SPF, DKIM additionally uses DNS TXT records using a particular format.
Almost all email service providers make this step really easy, as they generate these records automatically.
I. e. with MailerLite you can do this very quickly with only a few mouse clicks. Head to ‘Domains’ section, click ‘authenticate’.
Then you will see all your NAME and VALUE records. Just copy them and update your DNS records.
The DKIM standard advises rotating your keys each quarter, and it also suggests you revoke your old DKIM keys as part of the rotation. The most reliable way to manage this is by adding your new keys and removing your old keys' DNS records for your domain name a few days later. You can read more about DKIM here.
We made a few reviews about the ESPs who make it easy to set up all email authentication:
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