When you add a domain name as hosted in some account, you usually set a pair of Name Servers to direct it to that specific company. On their end, 3 records are set up automatically when the Internet domain is added - one A record and two MX records. The first one is a numeric address, or IP address, that “tells” the domain where its site is, while the other two are alphanumeric and they reveal the server that deals with the emails for that specific Internet domain. The website and the email hosting are typically considered to be one thing, while they are in reality two different services. Having independent records for them will permit you to have them with different providers if you wish. For instance, some new provider could have exceptional uptime for your website, 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 emails with the latter, you will get the best of both companies. These records are checked when you want to open a site or send an e-mail - either way, the company whose name servers are used for the domain name is going to be contacted to retrieve the A and MX records and if you have set records different from their own, the correct web/mail server will then be contacted and you're going to see the needed website or your email will be delivered.