What is the function of authenticating SMTP sessions using client certificates?

Users must configure a mail client to send messages through a secure SSL connection and accept a server certificate from the appliance.

If the certificate is valid, the Secure Email Gateway allows an SMTP connection from the mail client over TLS.

If the Secure Email Gateway is configured to require users to provide a certificate when sending mail, no exceptions are allowed for any users.

The Secure Email Gateway requests a client certificate from a user ' s mail client during connection to the appliance.