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How Many DKIM Records Can I Have? Revealing the Limits and Leveraging Email Authenticity

At the heart of email authentication’s intricate system lies DKIM (DomainKeys Identified Mail), a mechanism that stands guard, ensuring your emails are genuine and unaltered in transit. But here’s where it gets tricky – the concept of multiple DKIM records. How many can you have? Why would you need more than one?

And how do you set them up without tripping over technical hurdles? This article unravels these questions, shedding light on the limits of DKIM records and how leveraging them correctly can significantly bolster your email authentication framework, keeping your email communications secure and trusted.

Note: Check if your DKIM records are properly published today. Use our DKIM record checker tool to confirm that your DKIM record is configured properly and that your domain’s DKIM selector is pointing to the correct DKIM key. 

 

What is DKIM?

DomainKeys Identified Mail (DKIM) is a robust email authentication method that enables the receiver to check that an email was actually sent by the domain it claims to be sent from, and that it hasn’t been altered in transit. It employs a form of public key cryptography to ensure the integrity and authenticity of the email messages.

Here’s a breakdown of how DKIM operates:

Signature Creation and Verification

When an email is sent, the sending mail server generates a unique signature for the email using a private key, covering various parts of the email including the headers and the body. This signature is then attached to the email and sent to the recipient. Upon receipt, the recipient’s mail server retrieves the public key from the DNS records of the sender’s domain, which is stored in a DKIM record, to verify the signature, ensuring the email’s authenticity and integrity.

Authentication

If the signature verification is successful, it confirms that the email has not been tampered with during transit and indeed originates from the claimed domain. This process significantly helps in reducing email spoofing and phishing attacks.

Alignment with DMARC

DKIM works in conjunction with Domain-based Message Authentication, Reporting, and Conformance (DMARC) and Sender Policy Framework (SPF) to provide a more comprehensive email authentication framework. While SPF verifies the sending IP address, and DMARC sets the policy for message validation, DKIM ensures the message integrity.

The beauty of DKIM lies in its ability to remain intact even if the email passes through several mail servers along its journey, which is a common occurrence. This enduring nature of DKIM signatures ensures that the email authentication remains robust, providing a significant layer of trust and security in email communication.

Understanding DKIM Record Structure:

A DKIM record is a snippet of text that is added to your domain’s DNS records. It comprises three main components: the selector, the domain, and the public key. Let’s break down these components:

  • Selector: The selector is a unique string of characters that helps identify the DKIM record. When you have multiple DKIM records on a single domain, each record must have a unique selector. This is crucial for differentiating between the various DKIM records, especially when you are utilizing multiple email sending services.

  • Domain: The domain is your website’s address. It’s where the DKIM record is published and where receiving email servers will look to find your public key for verifying your email’s signature.

  • Public Key: The public key is a part of the key pair used in the DKIM signature process. It’s published in the DKIM record on your domain’s DNS and is used by receiving email servers to verify the signature on your emails.

Here’s an example of what a DKIM record might look like:

selector._domainkey.yourdomain.com IN TXT “v=DKIM1; k=rsa; p=MIGfM…”

In this example:

  • selector is the unique string you choose.

  • _domainkey is a fixed part of the DKIM record structure.

  • yourdomain.com is your domain.

  • v=DKIM1 specifies the version of DKIM being used.

  • k=rsa specifies the key type.

  • p=MIGfM… is the public key.

Understanding the structure of a DKIM record is the foundation for setting up and managing multiple DKIM records on your domain. It’s the first step towards leveraging DKIM for enhanced email authentication and deliverability.

How Many DKIM Records Can I Have?

The number of DKIM (DomainKeys Identified Mail) records you can have on your domain largely hinges on the specifications and allowances set by your DNS (Domain Name System) provider. The architecture of DKIM is designed to accommodate multiple records on a single domain, each associated with a unique selector. This setup is particularly beneficial when a domain utilizes various external email providers for different types of email communications, as each provider can have its own unique selector and corresponding public-private key pair for DKIM signature verification.

The architecture of DKIM is designed in such a way that it allows you to create multiple DKIM records on a single domain, each associated with a unique selector. This is particularly useful in scenarios where a domain utilizes various external email providers for different types of email communications. Each of these email providers can have its own unique selector and corresponding public-private key pair for DKIM signature verification. The unique selectors are crucial as they enable the receiving mail servers to fetch the correct public key from the sender’s DNS records, ensuring the integrity and authenticity of the email.

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What Is The Limit Of DKIM Records?

Some DNS providers might have restrictions on the total number of TXT or CNAME records you can create, which in turn, affects the number of DKIM records you can have. It’s advisable to consult with your DNS provider to understand their specific limitations and guidelines regarding the creation of as many DKIM records on your domain.

While there isn’t a strict limit on the number of DKIM records a domain can have, effective management of these records is paramount to avoid any potential complications or misconfigurations.

Each DKIM record should be associated with a unique selector to ensure accurate matching and verification of email signatures. The organization and management of multiple DKIM records require a structured approach to ensure that each email-sending service or server has its correct DKIM setup.

This structured approach not only facilitates a streamlined email authentication process but also significantly contributes to reducing email spoofing and phishing attempts, thereby enhancing the domain’s overall email deliverability and trustworthiness.

Why Would You Need Multiple DKIM Records?

When a domain engages with various external email providers for different types of email communications, each of these providers necessitates its own unique DKIM setup for email authentication. Each email provider or server can have its own unique selector and corresponding public-private key pair, which are crucial for the DKIM signature verification process. This setup enables the domain to maintain a high level of email authentication and integrity across different email communications, ensuring that the emails are indeed sent from the claimed domain and have not been altered in transit.

Moreover, the process of setting up multiple DKIM records is facilitated by the flexibility inherent in the DKIM architecture. Creating additional DKIM records involves designating unique selectors for each record and publishing them in the domain’s DNS. This organized approach allows for a streamlined management of multiple email sending sources, each with its own DKIM record, enhancing the domain’s email authentication framework.

How to Set Up Multiple DKIM Records?

Setting up multiple DKIM records is a structured process that requires a meticulous approach to ensure accurate email authentication. The primary step involves generating unique DKIM keys for each email sending service or server you intend to use. Each set of keys will consist of a private key, which remains on your email server, and a public key, which will be published in your domain’s DNS records. Using a DKIM generator tool can simplify the process of creating multiple DKIM records. Once you’ve designated a unique selector for your record, such as “s1” or “s2”, you’re ready to move on to the next step.

The subsequent step involves publishing the DKIM records in your domain’s DNS. This can be done by creating different TXT/CNAME records for each sending source and pasting them on your DNS for the same domain. Using a different DKIM selector each time you generate a record is crucial to avoid any clashes with the selectors used in your previous records.

DKIM keys and TXT records are instrumental in safeguarding against email spoofing, phishing, and aiding in preventing emails from being flagged as spam. Typically, a DNS TXT record can accommodate up to 255 characters.

Reach out to your domain host to check if they support TXT records exceeding 255 characters. If supported, you can update your DNS record with a 2048-bit DKIM key as per the provided steps in the Admin console. It’s advisable to limit the number of TXT records to 49 as this is the maximum number most domain providers can support.

Wrapping Up: Harnessing Multiple DKIM Records for Enhanced Email Authentication

With a clear understanding of DKIM and its multifaceted setup, you’re already leaps ahead in ensuring a secure email communication channel. The ability to add multiple DKIM records is not just a technical luxury, but a practical necessity for many organizations juggling various email sending services. 

The steps towards setting up multiple DKIM records, as outlined in this guide, provide a structured pathway to bolster your domain’s email authentication framework. By meticulously following the setup process and effectively managing your DKIM records, you’re not only enhancing the email deliverability but also building a fortress of trust around your domain.