--- title: "How to find a DKIM selector for your domain? | DuoCircle" description: "How to find the DKIM selector for your domain so you can verify your DKIM record." image: "https://www.duocircle.com/images/og-default.png" canonical: "https://www.duocircle.com/blog/email-security/how-to-find-a-dkim-selector-for-your-domain/" --- Quick Answer A DKIM selector is the identifier that tells a receiver which public key to use when verifying a DKIM signature. It appears as the s= tag in the DKIM-Signature header and combines with \_domainkey and your domain to form the full DNS query, for example selector.\_domainkey.example.com. Selectors are alphanumeric, may contain hyphens (not as the first character), and you choose them when configuring DKIM. To find an existing selector: send yourself a test message, open it in your mail client and select View Source or Show Original to see the headers, locate the DKIM-Signature header, and read the s= value. With multiple DKIM-Signature headers, identify the one whose d= tag matches your domain. Verify the selector by performing a DNS TXT lookup at selector.\_domainkey.yourdomain.com and confirming a public key is published. Different selectors per service or department let you rotate keys without disrupting other senders. How to find a DKIM selector for your domain? Your browser does not support the audio element. [ Download episode](https://media.mailhop.org/duocircle/images/2024/07/How-to-find-a-DKIM-selector-for-your-domain%5F.mp3) Share [ ](https://www.linkedin.com/sharing/share-offsite/?url=undefined%2Fblog%2Femail-security%2Fhow-to-find-a-dkim-selector-for-your-domain%2F "Share on LinkedIn") [ ](https://twitter.com/intent/tweet?text=How%20to%20find%20a%20DKIM%20selector%20for%20your%20domain%3F&url=undefined%2Fblog%2Femail-security%2Fhow-to-find-a-dkim-selector-for-your-domain%2F "Share on X/Twitter") [ ](https://www.facebook.com/sharer/sharer.php?u=undefined%2Fblog%2Femail-security%2Fhow-to-find-a-dkim-selector-for-your-domain%2F "Share on Facebook") [ ](https://reddit.com/submit?url=undefined%2Fblog%2Femail-security%2Fhow-to-find-a-dkim-selector-for-your-domain%2F&title=How%20to%20find%20a%20DKIM%20selector%20for%20your%20domain%3F "Share on Reddit") [ ](mailto:?subject=How%20to%20find%20a%20DKIM%20selector%20for%20your%20domain%3F&body=Check out this article: undefined%2Fblog%2Femail-security%2Fhow-to-find-a-dkim-selector-for-your-domain%2F "Share via Email") ![DKIM(DomainKeys Identified Mail) selector](https://media.mailhop.org/duocircle/images/2024/07/email-sending-services-5924.jpg) The risk of [cybercriminals](https://edition.cnn.com/2024/07/19/politics/us-sanctions-alleged-russian-hackers/index.html) intercepting your emails and tampering with them is perpetual. But there’s a way to mitigate this risk and make sure that your emails are **delivered unaltered** without any [malicious interference](https://www.standard.net.au/story/8580005/malicious-interference-led-to-12-hours-of-radio-silence/). Implementing [DKIM](/resources/what-is-dkim) or DomainKeys Identified Mail is your masterstroke against email tampering and [spoofing](https://securityintelligence.com/x-force/phishing-kit-trends-top-10-spoofed-brands-2023/). _It relies on cryptographic techniques to sign your emails, allowing recipients to verify that they truly originate from your domain and have not been messed with_. For this email authentication protocol to work, it is imperative that you have a configured DKIM selector. A DKIM selector is like a **unique identifier** that helps locate the public key in your [DNS records](/data-privacy/dns-record-types-defined-and-explained/). Not sure where to find the [DKIM selector](/resources/what-is-dkim-selector) for your domain? In this article, we’ll take you through everything you need to know about DKIM selectors, what they are, how they work, and **where to find them**. ## What is a DKIM selector? _A DKIM selector is certainly one of the **most important constituents** of the [email authentication](/resources/email-authentication) protocol for DomainKeys Identified Mail. It identifies and retrieves the corresponding public key from the DNS record of a domain._ For every email sent out, a DKIM signature with the selector is added to the [email header](/email-services/learning-to-trace-back-emails-to-their-source-ip-addresses/), which tells the recipient’s email server **which public key to use** in the sender’s DNS for verification of the authenticity of the email. The selector combined with a domain forms a complete [DNS TXT record](https://www.cloudflare.com/learning/dns/dns-records/dns-txt-record/), which retrieves the public key used in verification. _It is the flexibility offered by the DKIM selector that **allows you to rotate multiple DKIM keys** without changing the configuration of the domain._ So, if your organization uses different email services or servers, you can assign a different DKIM selector for each server. Doing this can help you ensure that all parts of your email system remain secure and trustworthy, preventing [unauthorized access](https://thehackernews.com/2024/06/ai-company-hugging-face-notifies-users.html) and tampering. ## How does a DKIM selector work? As you already know, a DKIM selector is an **integral aspect** of implementing the DKIM protocol, let us take a look at how it works to enhance [email security](/). When you send an email from your domain, your sending server adds a DKIM signature to the email header. This signature includes the selector indicated by the **“s=” tag**, which helps identify the public key in the Domain Name System (DNS) and should be used to verify the email’s authenticity. Now, when the email reaches its intended recipient, its server uses the selector along with the domain to form a [DNS query](https://bunny.net/academy/dns/what-is-a-dns-and-recursive-query/), which **retrieves the corresponding public key**. The key then verifies if the email is really from the domain it claims to be and that it hasn’t been tampered with along the way. [![How DKIM Works](https://media.mailhop.org/duocircle/images/2024/07/office-365-tenant-migration-tool-3.jpg)](https://media.mailhop.org/duocircle/images/2024/07/office-365-tenant-migration-tool-3.jpg) ## What does a DKIM selector look like? To be able to find a DKIM selector, you should know what it looks like. Let us explain this with a simple example. For instance, if your hostname is **s1.\_domainkey.example.com**, s1 is your selector. A selector is typically an **alphanumeric string** and can include hyphens, though the hyphen cannot be the first character. Moreover, you can **configure any selector** of your choice to suit your needs. Here are a few examples of DKIM selectors. **mail1.\_domainkey.example.com**, then mail1 is your selector. Similarly, in **authkey.\_domainkey.example.com**, authkey is the selector. ## How do you find a DKIM selector? _When you [set up DKIM](/resources/dkim-bluehost) for your domain, it inevitably creates a **public and a private key**, along with specifying a DKIM selector._ This selector is included in the DKIM signature of your email. While the process of locating the selector might vary depending on the email service provider (ESP) or email client you are using, here’s a brief overview of how you should go about it: ### Analyze the DKIM signature in the header First of all, you should start by inspecting the DKIM signature in the header of the email. To do so, you can send yourself a test email, and once you open the email, click on the “**View Source**” or “Show Original” option in your email client. Here, you will find all the information about the email headers and [source code](https://myemma.com/blog/what-is-email-source-code-and-why-should-i-care/), along with other technical information like the DKIM signature. In the header section, **look for the “DKIM-Signature” field**, which contains several tags that provide information about the email’s authentication. ### Identify the DKIM selector Now that you know what a DKIM selector looks like, it should be easy to identify it. _To reiterate, all DKIM selectors have the [“s=” tag](/email-security/dkim-syntax-guide-create-your-dkim-record-for-free/) in the DKIM signature_. This tag is followed by a string that represents the selector. In some cases of multiple signature headers, you might come across multiple selectors; you must identify the one that includes the domain. ### Verify the selector Once you have identified the selector, it is important that you verify it. Verifying the selector ensures that it is correctly set up and associated with the appropriate [public key for your domain](https://www.techtarget.com/searchsecurity/definition/public-key). [![DKIM configuration](https://media.mailhop.org/duocircle/images/2024/07/email-smtp-service-7824.jpg)](https://media.mailhop.org/duocircle/images/2024/07/email-smtp-service-7824.jpg) ## What if you’re unable to find the DKIM signature header? If you are unable to find the DKIM signature header matching the specified domain, chances are that you have some issues with your [DKIM configuration](/email-security/configuring-dkim-sign-mail-from-your-microsoft-365-domain/). In this case, it is recommended that you **troubleshoot the settings**, ensuring the selector and key are correctly set in your DNS records. After completing the process, send another test email and then check the headers for the DKIM signature. ## DKIM implementation made easy with DuoCircle Let’s face it: configuring DKIM is no easy feat, especially considering the complexities involved. But with a few simple steps, such as using selectors, periodically rotating the key, and using strict (difficult to decode) [private keys](https://www.1kosmos.com/authentication/private-key/), you can significantly enhance your email security. These simple yet effective efforts will not only safeguard your [outbound emails](/content/outbound-email) but also reinforce the **trust and reliability** of your communication. Need help deploying DKIM and other authentication protocols for your domain? Our experts at **DuoCircle** are here to your help! [Get in touch](/get-a-quote) with us to gain insights into our services. ## Topics DKIMemail securityUpdates ![Brad Slavin](https://media.mailhop.org/dmarcreport/images/team/brad-slavin.jpg) Brad Slavin General Manager General Manager at DuoCircle. Product strategy and commercial lead across the email security portfolio. ## Secure your email infrastructure Protect, authenticate, and deliver. Contact our team to find the right solution. [Contact Sales](/contact/) [Explore Products](/products/) ## Related Articles [ Email Security 8m Configuring DKIM to sign mail from your Microsoft 365 domain Jun 27, 2024 ](/blog/email-security/configuring-dkim-sign-mail-from-your-microsoft-365-domain/)[ Email Security 6m How to fix “Your DKIM signature is not valid” error Jun 28, 2024 ](/blog/email-security/fixing-your-dkim-signature-is-not-valid-error/)[ Email Security 3m Learning to perform SPF delegation for enhanced email delivery Jul 24, 2024 ](/blog/email-security/learning-to-perform-spf-delegation-for-enhanced-email-delivery/)[ Email Security 4m Preventing DKIM replay attacks Jul 19, 2024 ](/blog/email-security/preventing-dkim-replay-attacks/) ```json {"@context":"https://schema.org","@type":"Organization","name":"DuoCircle LLC","url":"https://www.duocircle.com","logo":{"@type":"ImageObject","url":"https://www.duocircle.com/images/duocircle-logo.png"},"description":"DuoCircle is a portfolio of specialized email products covering protection, authentication, delivery, and routing. 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