If you have tried to validate your DKIM record with DKIM record lookup, you need to specify your DKIM selector. In this blog we will discuss the various ways for how to find it for your domain. DKIM, or DomainKeys Identified Mail is your standard email authentication protocol that makes use of cryptography to authenticate your messages. DKIM exists in your DNS as a DNS TXT record that you can easily generate using our free DKIM record generator, and subsequently published in your domain’s DNS to configure the protocol for your domain.
What is a DKIM Selector?
You can spot the DKIM selector for your domain as an “s=” tag in your DKIM signature header. It is a string variable that helps in pointing towards the DKIM public key in your domain’s DNS while authenticating your messages using DKIM authentication protocol. The receiving MTA authenticates your outbound messages by matching the private key assigned to your email, against the public key in your DNS to check for the legitimacy of the email.
Your selector is a unique identifier and has to be different for different email exchange services or vendors you are using.
How to Find DKIM Selector using Test Mail?
You can find your selector using the following 3 steps:
1) Send a test mail to your gmail account
2) Click on the 3 dots next to the email in your gmail inbox
3) Select “show original”
4) On the “Original Message” page navigate to the bottom of the page to the DKIM signature section and try to locate the “s=” tag, the value of this tag is your DKIM selector.
In the above example, s1 is my DKIM selector. This is one of the methods you can use to identify and locate yours.
DKIM Selector Examples
If your Hostname is s1._domainkey.domain.com (i.e. your record is published on this subdomain), s1 is your selector. You can configure any selector of your choice, it can be an alphanumeric value, and may contain hyphens where the hyphen cannont be the first character. Here are a few DKIM selector examples:
How to Find DKIM Selector with PowerDMARC
Alternatively, you can sign up with PowerDMARC to be on your free DMARC analyzer trial and enable DMARC reporting for your domain. Here you can easily locate and identify the DKIM selectors for each of your sending sources in the DMARC aggregate reports view. This way you no longer have to manually send yourself test mails to search for it every time.
1) On the PowerDMARC control panel, go to DMARC aggregate reports and your desired view. For this example I am working with the “Per sending source” view
2) Cascade the row of the sending source for which you want to view your DKIM selector
3) Cascade the row of the sender hostname
4) You will now be able to find the selector under the DKIM verification box, as shown below:
Once you have found out your DKIM selector you can freely perform DKIM record check to configure errors in your DKIM record and resolve issues. Hope this blog helped you find your DKIM selector. Get your free DMARC analyzer today to implement error-free SPF, DKIM and DMARC for your domain!