DKIM
DomainKeys Identified Mail cryptographically signs outgoing emails so mailbox providers can verify sender identity.
Also known as: DomainKeys Identified Mail, DKIM Signature, DKIM Record
DKIM stands for DomainKeys Identified Mail. It is a technical standard that adds a cryptographic signature to outgoing emails. The receiving mail server can use a public key published in the sender domain's DNS to verify that a message really originates from the claimed sender and has not been altered in transit.
How DKIM works
The sending server signs outgoing messages with a private key. The corresponding public key is published as a TXT record in the domain's DNS, typically under a named selector like selector1._domainkey.example.com. On receipt the mail server fetches this public key, recomputes the signature and decides whether the message is authentic.
Why DKIM is central for deliverability
Without correct DKIM setup, emails land in spam folders on many providers or are rejected outright. Together with SPF and DMARC, DKIM forms the foundation of modern email authentication. A missing or wrong DKIM signature is one of the most common reasons for poor inbox placement.
DKIM management in JD Mail
In JD Mail each sender and each sending domain gets its own DKIM selector with its own key pair. Management runs centrally through the Postal backend, new domains can be set up via script in seconds and published in DNS.