Setting up a CNAME record for any of the domain names or subdomains that you have in a hosting account will allow you to point it to a different domain/subdomain. The forwarded domain will lose all of its records - A, MX and so on, and will take the records of the Internet domain it is being redirected to. In this light, you cannot set up a CNAME record to point your domain to a third-party company and retain a functional email service with the first provider. Additionally, it is important to note that a CNAME record is always a string of words and never a number because it is often confused with the A record of the domain address being redirected. One of the primary uses of a CNAME record is to forward a domain name which you own through one company to the servers of some other provider in case you have created an Internet site with the latter. This way, the Internet site will appear under your own domain, not under some subdomain provided by the third-party provider.