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Email Authentication Checker

Check SPF, DKIM and DMARC: the records inboxes use to decide whether your mail is genuine, and whether they are strict enough to stop spoofing.

Enter a domain or hostname. Pasted URLs and internationalized names work too.

Find it as s= in the DKIM-Signature header of a sent message. Up to 5, separated by commas. Leave empty to try common ones.

Checking github.com

Looking up MX records…