DKIM Selectors: Step-by-Step Guide on How to Find DKIM Selectors
Inna Sabada
by Inna Sabada
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DKIM Selectors: Step-by-Step Guide on How to Find DKIM Selectors

Email authentication is a critical aspect of modern email marketing and communication. 

 

DomainKeys Identified Mail (DKIM) is a widely used email authentication method that allows email recipients to verify the authenticity of incoming emails. DKIM selectors are an important component of DKIM, as they help recipients identify which public key to use for verifying the DKIM signature in an email. 

 

In this blog post, we will explore what DKIM selectors are, why they are important, and how to find DKIM selectors using step-by-step examples.

 

 

What are DKIM Selectors?

 

DKIM selectors are strings of text that are added to the DKIM signature in the header of an email. They are used to specify which public key should be used by the recipient to verify the DKIM signature. 

 

DKIM selectors are unique to each domain and can be any string of characters chosen by the domain owner. They are typically added as a subdomain to the domain name in the DKIM signature.

 

 

Why are DKIM Selectors Important?

 

DKIM selectors are crucial for email authentication as they help recipients verify the authenticity of incoming emails. By using DKIM selectors, the recipient can ensure that the DKIM signature in an email has been generated by the legitimate sender and has not been tampered with during transit.

 

DKIM selectors also allow domain owners to rotate their public keys without affecting the verification of previously sent emails. This makes DKIM selectors an essential component of email security and sender reputation management.

 

 

How to Find DKIM Selectors:

 

Finding DKIM selectors involves a few steps that may vary depending on the email service provider (ESP) or email client you are using. 

 

Here is a step-by-step guide on how to find DKIM selectors with examples:

 

 

Step 1: Check the DKIM Signature in the Email Header

 

To find the DKIM selector, you need to inspect the DKIM signature in the header of the email. 

 

You can usually do this by viewing the email source or header information, which is typically accessible through the "View Source" or "Show Original" option in your email client. Once you have accessed the email source or header, look for the "DKIM-Signature" field, which contains the DKIM signature.

 

Example DKIM-Signature field in an email header:

 

DKIM-Signature:

v=1;

a=rsa-sha256;

d=mydomain.com;

s=myselector;

c=relaxed/simple;

q=dns/txt;

h=From:Date:Subject:Message-ID:To:Content-Type;

bh=XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX;

b=XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

 

In this example, "myselector" is the DKIM selector used by the domain "mydomain.com".

 

 

Step 2: Identify the DKIM Selector

 

Once you have located the DKIM-Signature field in the email header, you need to identify the DKIM selector. The DKIM selector is typically indicated by the "s=" tag followed by the selector string. 

 

In the example above, "s=myselector" indicates the DKIM selector used by the domain.

 

 

Step 3: Verify the DKIM Selector with the Domain Owner

 

After identifying the DKIM selector, it is important to verify it with the domain owner. The domain owner is responsible for generating and managing DKIM selectors for their domain. You can contact the domain owner or check their domain's DNS records to confirm the DKIM selector.

 

 

Step 4: Use the DKIM Selector for Email Authentication

 

Once you have confirmed the DKIM selector, you can use it for email authentication. 

 

DKIM selectors are typically used in combination with the domain name and the public key to verify the DKIM signature of incoming emails. The recipient's email server retrieves the public key associated with the DKIM selector from the domain's DNS records and uses it to verify the DKIM signature in the email header. 

 

If the DKIM signature is valid, it indicates that the email has not been tampered with during transit and was indeed sent by the legitimate sender.

 

 

🔹 Conclusion:

 

In conclusion, learning about DKIM Selectors and how to find them is an essential part of running a successful email marketing campaign. 

 

Setting up your emails with the correct DKIM Selectors will ensure that your emails reach the inboxes of your intended receivers and that any bounce backs or incorrect filters can be avoided. 

 

It’s also important to remember to keep your domain DNS updated periodically, as domain-based filtering requires consistently updated information. Navigating the world of DKIM Selectors can seem daunting at first, but using this step-by-step guide should make the process much simpler for anyone managing emails for their business. 

 

With a few simple steps, you’ll be one step closer to having a successful, effective email marketing strategy!

 

 

📜 Related articles:

 

◾ Why Do You Need to Configure SPF, DKIM, DMARC and How To Set Them

◾ A Guide to Implementing DKIM in Office 365 for Custom Domains

◾ The benefits of SendGrid SPF Record and SendGrid DKIM Record