Symantec Brightmail Gateway includes pre-installed certificates for the most common Certificate Authority vendors. Add a CA certificate if the CA issues you an SMTP/TLS or HTTPS certificate that is not already in the Control Center. Another reason to add a CA certificate is if your certificate requires an intermediate CA certificate. When you add a CA certificate, you complete the certificate chain to permit authentication of the new certificate. All of your configured Scanners can access the CA certificates in the Control Center for SMTP/TLS and HTTPS authentication.
Ensure that you have the CA certificate before you proceed. The CA certificate may have been included when you received the certificate from the CA. Alternatively, you may be able to download the CA certificate from the Certificate Authority's Web site. The file that contains the CA certificate must be in PEM format.
See About certificates.
To add a CA certificate bundle