Glossary: Email
What is DKIM?
A digital signature on your email that shows it came from your domain and wasn't changed on the way.
What it is
DKIM stands for DomainKeys Identified Mail. Your mail server signs each message with a private key. The matching public key sits in your DNS, so a receiving server can check the signature.
How it differs from SPF
SPF checks which server sent a message. DKIM checks the message itself, and its signature can stay valid when a message is forwarded, which often breaks SPF. You want both.
How to set it up
Your email provider generates the key and tells you which DNS record to add. Each service that sends mail for you, such as Microsoft 365 or a newsletter tool, needs its own DKIM set up.