Setting up a CNAME record for any of the domain addresses or subdomains you've got within a hosting account allows you to point it to a different domain/subdomain. The forwarded Internet domain will lose all of its records - A, MX etc, and will take the records of the Internet domain it's being redirected to. In this light, you cannot create a CNAME record to point your domain name to a third-party provider and maintain a functional e-mail service with the first provider. It's also essential to know that a CNAME record is always a string of words and never a number because it is frequently confused with the A record of the domain being forwarded. One of the main uses of a CNAME record is to direct a domain name which you own through one provider to the servers of some other company in case you have set up a site with the latter. By doing this, the website will appear under your own domain, not under some subdomain provided by the third-party company.