CNames map subdomains to domain names. You can point MAIL.domain.com to the Gmail portal for your company, or SALES.domain.com to SalesForce.com. This allows you to use an easy to remember naming strategy for users to access different web services.
Subdomains are prefixes to domain names that allow administrators to provide different web services to users, but do so using the same namespace so that it is easier to remember. Such as MAIL.failednormal.com, WWW.failednormal.com, VPN.failednormal.com… […]