mail_dkim_selector

Name: DKIM Selector Type: String Default: (empty)

The DKIM selector: the label that identifies which public key is used, published in DNS as <selector>._domainkey.<domain>.

mail_dkim_selector is required for DKIM signing. It is passed to PHPMailer by core/src/Revolution/Mail/modMail.php.

DKIM (DomainKeys Identified Mail) lets the receiving mail server verify that a message was sent by your domain and was not modified in transit. MODX passes these values to PHPMailer, which signs outgoing mail; you also need a matching public key in DNS at <selector>._domainkey.<domain>.

See also: mail_dkim_domain, mail_dkim_privatekeyfile, mail_dkim_privatekeystring.