Creating a CNAME record for any of the domain addresses or subdomains you have in a hosting account will permit you to forward it to a different domain/subdomain. The forwarded domain will lose all its records - A, MX and so forth, and will take the records of the domain name it is being forwarded to. In this light, you cannot set up a CNAME record to point your domain to a third-party provider and keep a working e-mail service with the first provider. It is also important to note that a CNAME record is always a string of words and never a number because it is often mistaken for the A record of the domain being forwarded. One of the major uses of a CNAME record is to point a domain address that you own through one company to the servers of some other provider if you have created a website with the latter. In this way, the site will appear under your own domain, not under some subdomain provided by the third-party provider.