DomainKeys Identified Mail (DKIM) is an anti-tamper protocol that keeps your emails secure in transit. DKIM uses digital signatures to check that the email was sent by a specific domain.
Setting up DKIM on Fastmail is very simple and requires you to follow a few simple steps.
Fastmail uses three different CNAME records to sign your outbound emails with DKIM.
The records are shown below with {mydomain.com} to represent your domain name.
Login to your DNS management console and publish these three CNAME records correctly and wait for 24-48 hours for the changes to take effect.
After they have been verified, check your DKIM record using our free DKIM validator tool.