Each registered domain name has a minimum of 2 Name Server records that show where it is hosted i.e. by using these records you direct your Internet domain to the servers of a certain hosting company. In this way, you have got both your site and your e-mails managed by the same service provider. On the lower level of the Domain Name System (DNS), nevertheless, there is a variety of other records, for example A and MX. The first one shows which server deals with the site for a given domain name and is always an IP address (18.104.22.168), while the second one shows which server deals with the e-mails and is always an alphanumeric string (mx1.domain.com). For instance, whenever you type a domain address in your Internet 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 forwarded to the servers of a different provider in case you have set an IP address of the latter as an A record for your domain. Having separate records for the website and the e-mails means you could have your website and your e-mails with two different companies if you wish.