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DKIM Lookup
Check the DKIM record for email digital signatures
usage:
dkim-lookup --domain --selector What is DKIM Lookup?
DKIM Lookup verifies the DKIM (DomainKeys Identified Mail) record of a domain, an authentication system that adds a cryptographic digital signature to outgoing emails. The receiving server uses the public key in DNS to verify that the message was not altered during transit.
Frequently Asked Questions
What is DKIM and how does it work? +
DKIM adds a digital signature in the email header using a private key. The recipient verifies the signature with the public key published in the sender domain's DNS, ensuring integrity and authenticity.
What is a DKIM selector? +
The selector is an identifier that allows having multiple DKIM keys for the same domain. The record is found at selector._domainkey.domain.com. Each email service can use a different selector.
How do I find my domain's DKIM selector? +
Check the headers of an email sent from your domain: look for the DKIM-Signature field and the s= parameter that contains the selector. Common selectors: google, default, selector1.
Does DKIM affect deliverability? +
Yes, significantly. Emails with a valid DKIM signature are more likely to reach the inbox. Gmail, Outlook, and other providers penalize emails without DKIM.
What size should the DKIM key be? +
At least 2048 bits is recommended. 1024-bit keys are considered weak. Some providers support keys up to 4096 bits for greater security.
Can I have multiple DKIM records? +
Yes, you can have multiple DKIM records with different selectors. This is useful when you use multiple services to send email (e.g., Google Workspace + Mailchimp), each with its own selector.