Whenever you add a domain as hosted in some account, you typically set a pair of Name Servers to direct it to that specific provider. On their end, 3 records are created automatically the moment the domain address is added - one A record and two MX records. The former is a numeric address, or IP address, that “tells” the domain address where its website is, while the other two are alphanumeric and they reveal the server that manages the emails for that particular domain. The site and the email hosting are typically thought to be one thing, while they are in reality two different services. Having separate records for them will enable you to have them with different companies if you'd like. As an illustration, some new provider may have superb uptime for your website, but you might not want to switch your e-mails from your current host and by employing an A record to point the domain to the former and MX records to have the e-mails with the second, you could get the best of both companies. These records are checked whenever you want to open a website or send an email - either way, the service provider whose name servers are used for the domain will be contacted to retrieve the A and MX records and if you've set records different from their own, the right web/mail server will then be contacted and you will see the needed website or your email is going to be delivered.