Whenever you add a domain name as hosted in some account, you normally set a pair of Name Servers to direct it to that specific service provider. On their end, three records are created automatically right after 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 name where its site is, while the other two are alphanumeric and they indicate the server that deals with the e-mails for that specific domain name. The website and the e-mail hosting are typically thought to be one thing, while they're in reality two different services. Having different records for them will allow you to have them with different companies if you want. For instance, some new service provider can 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 domain name to the first and MX records to have the e-mails with the second, you will get the best of both companies. These records are checked whenever you want to open a website or send an email - in any case, the company whose name servers are used for the Internet domain 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 will be delivered.