Setting up a CNAME record for any one of the domains or subdomains you have in a hosting account will permit you to redirect it to a different domain/subdomain. The forwarded domain name will lose all of its records - A, MX and so on, and will take the records of the domain name it is being redirected to. In this light, you can't set up a CNAME record to redirect your domain to a third-party provider and maintain a working e-mail service with the first hosting company. It is also essential to know that a CNAME record is always a string of words and never a number because it is generally mistaken for the A record of the Internet domain being redirected. One of the main uses of a CNAME record is to direct a domain which you own through one company to the servers of some other provider if you have created a website with the latter. That way, the Internet site will appear under your own domain address, not under some subdomain provided by the third-party company.