Setting up a CNAME record for any one of the domain addresses or subdomains that you've got in a hosting account will allow you to point it to a different domain/subdomain. The forwarded Internet domain will lose all its records - A, MX etc, and will take the records of the domain name it's being redirected to. In this light, you can't set up a CNAME record to redirect your domain to a third-party company and maintain a working e-mail service with the first hosting provider. Additionally, it is very important to know that a CNAME record is always a string of words and never a number as it is generally confused with the A record of the domain name being redirected. One of the major uses of a CNAME record is to forward a domain address that you own through one provider to the servers of another company when you have created an Internet site with the latter. In this way, the site will appear under your own domain name, not under some subdomain provided by the third-party company.