Setting up a CNAME record for any of the domain addresses or subdomains you've got in a hosting account will allow you to forward 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 Internet domain it is being forwarded to. In this light, you can't set up a CNAME record to direct your domain to a third-party company and retain a functional e-mail service with the first hosting company. Additionally, it is important to note that a CNAME record is always a string of words and not a number because it is often mistaken for the A record of the domain name being forwarded. One of the major uses of a CNAME record is to direct a domain which you own through one provider to the servers of some other company 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 provider.