Every registered domain has a minimum of 2 Name Server records that show where it is hosted i.e. by using these records you direct your domain to the servers of a particular web hosting company. This way, you have got both your website and your e-mails managed by the very same provider. On the lower level of the Domain Name System (DNS), however, there are a number of other records, for instance A and MX. The first one reveals which server manages the site for a given domain and is always an IP address (18.104.22.168), while the latter indicates which server handles the emails and is always an alphanumeric string (mx1.domain.com). As an example, whenever you type a domain address in your browser, your request is sent through the global DNS system to the company whose NS records the domain uses and from there you may be sent 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 different records for the site and the e-mails suggests that you may have your website and your emails with 2 different providers if you wish.