Whenever you add a domain as hosted in some account, you normally set a pair of Name Servers to direct it to that particular provider. On their end, three records are created automatically the moment the Internet domain is added - one A record and two MX records. The former is a numeric address, or IP address, which “tells” the domain address where its site is, while the other two are alphanumeric and they show the server that handles the e-mails for that specific Internet domain. The website and the email hosting are usually thought to be one thing, when they are in fact two different services. Having different records for them will enable you to have them with different companies if you would like. For example, some new service provider could have outstanding uptime for your site, but you may 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 emails with the latter, you can get the best of both providers. These records are checked when you wish to open a website or send an email - in any case, the service provider whose name servers are used for the domain name will be contacted to retrieve the A and MX records and if you have set records different from their own, the right web/mail server will then be contacted and you're going to see the needed website or your email is going to be delivered.