Setting up a CNAME record for any one of the domain names or subdomains that you've got in a hosting account will permit you to point it to a different domain/subdomain. The forwarded domain will lose all of its records - A, MX etc, and will take the records of the domain it is being redirected to. In this light, you can't set up a CNAME record to redirect your domain name to a third-party provider and maintain a working e-mail service with the first hosting company. Also, it is essential to know that a CNAME record is always a string of words rather than a number as it's commonly confused with the A record of the domain being forwarded. One of the major uses of a CNAME record is to forward a domain address you own through one company to the servers of another company if you have created an Internet site with the latter. That way, the Internet site will appear under your own domain, not under some subdomain provided by the third-party provider.