Setting up a CNAME record for any one of the domain addresses or subdomains you have within a hosting account will enable you to forward it to a different domain/subdomain. The forwarded domain will lose all of its records - A, MX and so forth, and will take the records of the domain address it's being forwarded to. In this light, you simply can't create a CNAME record to direct your domain name to a third-party provider and maintain a working e-mail service with the first provider. It is also essential to know that a CNAME record is always a string of words and never a number because it is generally wrongly identified as the A record of the domain being forwarded. One of the primary uses of a CNAME record is to forward a domain name that you own through one provider to the servers of another provider assuming you have created an Internet site with the latter. In this way, the Internet site will appear under your own domain, not under some subdomain provided by the third-party provider.