Any time you add a domain as hosted in some account, you normally set a pair of Name Servers to direct it to that particular service provider. On their end, 3 records are created automatically as soon as the domain name is added - one A record and two MX records. The former is a numeric address, or IP address, which “tells” the Internet domain where its website is, while the other two are alphanumeric and they show the server that deals with the e-mails for that specific Internet domain. The website and the email hosting are often considered to be one thing, while they are in fact two different services. Having separate records for them will enable you to have them with different companies if you wish. For example, some new service provider may have exceptional uptime for your site, but you might not want to switch your e-mail messages from your current host and by employing an A record to point the Internet domain to the first and MX records to have the e-mails with the second, you could get the best of both companies. These records are checked when you want to open a site or send an e-mail - in any case, the provider whose name servers are used for the domain address is going to 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 are going to see the needed site or your e-mail is going to be delivered.