Question 1

What is DKIM?

Accepted Answer

DKIM (DomainKeys Identified Mail) is an email authentication method that adds a digital signature to outgoing emails. Recipients can verify the signature using the public key published in your DNS records.

Question 2

What is a DKIM selector?

Accepted Answer

A DKIM selector is a string used to identify the specific DKIM key. It forms part of the DNS record name: selector._domainkey.yourdomain.com. Common selectors include default, google, s1, s2.

Question 3

How do I get my DKIM public key?

Accepted Answer

Your email service provider (like Google Workspace, SendGrid, Mailgun) generates the DKIM key pair. They provide the public key to add to DNS. Alternatively, you can generate your own key pair using OpenSSL.

Question 4

What key size should I use for DKIM?

Accepted Answer

RSA 2048-bit is recommended for new deployments. RSA 1024-bit is still supported but considered less secure. Some DNS providers have record length limits that may require 1024-bit keys.