Every single registered domain has at least 2 Name Server records that show where it is hosted i.e. by using these records you point your Internet domain to the servers of a certain website hosting company. In this way, you have got both your site and your emails managed by the exact same company. On the lower level of the Domain Name System (DNS), nevertheless, there are a number of other records, such as A and MX. The first one shows which server handles the website for a given domain name and is always an IP address (188.8.131.52), while the latter indicates which server deals with the emails and is always an alphanumeric string (mx1.domain.com). As an example, any time you enter a domain address in your web browser, your request is directed through the global DNS system to the provider whose NS records the domain uses and from there you may be directed to the servers of another service provider if you have set an IP address of the latter as an A record for your Internet domain. Having separate records for the website and the emails means that you can have your website and your emails with two different providers if you would like.