Setting up a CNAME record for each of the domain addresses or subdomains that you've got in a hosting account will permit you to redirect it to a different domain/subdomain. The forwarded domain address will lose all its records - A, MX etc, and will take the records of the domain address it's being redirected to. In this light, you simply can't set up a CNAME record to direct your domain name to a third-party company and retain a working e-mail service with the first hosting provider. Also, it is important to note that a CNAME record is always a string of words and not a number because it is generally confused with the A record of the domain address being forwarded. One of the main uses of a CNAME record is to point a domain that you own through one company to the servers of another provider assuming you have set up a site with the latter. That way, the site will appear under your own domain address, not under some subdomain provided by the third-party company.