DKIM lookup
Find a domain's DKIM key and check the key type and length.
About this tool
DKIM signs email with a cryptographic key. The receiving server retrieves the public key from DNS and verifies that the message has not been altered in transit and that it originates from the domain.
The key is published at selector._domainkey.domain. The selector is a name chosen by the email service. You can find it after s= in the DKIM-Signature header of an email message. Leave the field blank and the tool will try twelve common selectors.
The tool shows the key type and length. 2048 bits is recommended. 1024 bits still works but is weaker, and shorter keys are rejected by many receiving servers.
Frequently asked questions
Where do I find my DKIM selector?
Open an email sent from the domain and view the full headers. In the DKIM-Signature line, the selector appears after s= and the domain after d=. The Email header tool can extract these for you.
Why can't the tool find a key?
Either the selector has a non-standard name, or DKIM is not enabled. Enter the selector in the field and check again.
How do I enable DKIM for email hosted at Admax?
Log in to webmail as an administrator and enable email signing under the domain settings. Then add the TXT record shown. The SPF, DKIM and DMARC guide walks you through the steps.