Any active domain that is added in a hosting account features a variety of records which allow it to work properly. In the typical case, the name servers (NS records) show where the domain name is hosted and they're set on the side of the registrar company, but on the lower level there are particular records set through the hosting company such as A (IP address of the website/server), MX (email server), SRV (employing a domain name for non-website purposes on a specific port number like Voice-over-IP), and so on. Having access to these records and by being able to edit them, you may have your web site with company A and your e-mail messages with company B, for instance. This offers you more overall flexibility because you can select the best provider for every one of these services and you don't have to stick to only one company. Whenever you pick 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.