What should I use as my ‘primary’ Common Name?
Your primary common name in a Unified Communications Certificate should be the main URL used to access the server (normally an external domain). For compatibility with older mobile devices it is recommended that you use the URL that your mobile devices connect to as the primary common name.
Note: If you are requesting a certificate for Office Communications Server 2007 then you will need to use the internal domain name for the server as your primary Common name
For more information on the Office Communications Server 2007 Certificate Wizard and installing certificates for Office Communications Server, see the deployment documentation available on the Office Communications Server 2007 Technical Library