Creating a CNAME record for any of the domain addresses or subdomains you have in a hosting account will allow you to forward 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 domain address it's being directed to. In this light, you can't set up a CNAME record to point your domain name to a third-party company and keep 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 commonly wrongly identified as the A record of the domain name being forwarded. One of the primary uses of a CNAME record is to point a domain address you own through one company to the servers of another provider when you have set up a site with the latter. This way, the site will appear under your own domain name, not under some subdomain provided by the third-party provider.