Whenever 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 the moment the Internet domain is added - one A record and two MX records. The first one is a numeric address, or IP address, which “tells” the Internet domain where its website is, while the other two are alphanumeric and they reveal the server that manages the emails for that specific domain address. The site and the email hosting are often thought to be one thing, when they're in fact two different services. Having separate records for them will enable you to have them with different companies if you wish. As an example, some new company might have superb 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 domain name 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 site or send an email - in any case, the service 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're going to see the needed site or your email will be delivered.