DKIM Checker
Enter your domain and the DKIM selector and see whether the record exists and how strong the key is.
Analysis messages from the checker are currently in Dutch.
How does it work?
DKIM signs your mail with a key whose public part is in DNS at selector._domainkey.yourdomain.com. You find the selector in the header of a sent message (s=). Microsoft 365 uses selector1 and selector2.
Frequently asked questions
Which selector should I enter?
Look at DKIM-Signature in the header of a sent message, the s= field is the selector. Microsoft 365 uses selector1 and selector2, Google often uses google.
How strong should the key be?
Use at least 2048 bits. 1024 bit keys are weak and increasingly rejected.
Why is my record not found?
Check the selector and whether the TXT or CNAME record exists under selector._domainkey.
Need help with your email security?
We set up DMARC, SPF, DKIM and MTA-STS for you and keep an eye on it, as part of Security and Monitoring.