When you add a domain name as hosted in some account, you typically set a pair of Name Servers to point it to that specific provider. On their end, 3 records are set up automatically the moment the domain name is added - one A record and two MX records. The first one is a numeric address, or IP address, which “tells” the domain where its site is, while the other two are alphanumeric and they indicate the server that handles the emails for that specific Internet domain. The website and the email hosting are often regarded as one thing, when they are actually two different services. Having different records for them will permit you to have them with different companies if you'd like. As an example, some new provider may have exceptional uptime for your website, but you may not want to switch your e-mail messages from your current host and by employing an A record to point the domain address to the former and MX records to have the emails with the second, you will get the best of both providers. These records are checked when you want to open a site or send an e-mail - in either 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've set records different from their own, the right web/mail server will then be contacted and you'll see the needed site or your email will be delivered.