Any active domain name that is added in a hosting account features a number of records that permit it to function properly. In the typical case, the name servers (NS records) show where the Internet domain is hosted and they are set on the side of the registrar company, but on the lower level there are certain records set through the hosting company such as A (IP address of the website/server), MX (e-mail server), SRV (employing a domain address for non-website purposes on a specific port number like Voice-over-IP), and many others. With access to these records and by being able to modify them, you may have your web site with company A and your e-mail messages with company B, for illustration. This gives you more overall flexibility because you can choose the best provider for every one of these services and you don't have to stick to a single company. When you select a hosting company, you have to make certain that you have access to all DNS records freely since some companies have an extra fee for this function.