What is a DKIM “selector”?
A selector is added to the domain name, used to find DKIM public key information. It is specified as an attribute for a DKIM signature, and is recorded in the DKIM-Signature header field. Validation uses the selector as an additional name component, to give differential DNS query names. There are different DKIM DNS records associated with different selectors, under the same domain name. For example: jun2005.eng._domainkey.example.com Hence, selectors are used to permit multiple keys under the same organization’s domain name. This can be used to give separate signatory controls among departments, date ranges, or third parties acting on behalf of the domain name owner.. • How is a DKIM signature recorded in a message A DKIM signature is recorded as an RFC2822 header field for the signed message.
