A Cisco Secure Email Gateway administrator must provide outbound email authenticity and configures a DKIM...

To use DKIM for outbound email, the administrator must export the DNS TXT record from the Cisco Secure Email Gateway and provide it to the DNS registrar of the domain. This will allow the recipient servers to verify the DKIM signature of the email by querying the DNS record of the sender domain. References: [Cisco Secure Email Gateway Administrator Guide - Configuring DKIM Signing]