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 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 address where its website is, while the other two are alphanumeric and they reveal the server that manages the e-mails for that particular domain address. The website and the email hosting are often regarded as one thing, while they're in fact two different services. Having separate records for them will enable you to have them with different companies if you wish. For instance, some new service provider can have outstanding 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 to the former and MX records to have the e-mails with the second, you will get the best of both providers. These records are checked when you wish to open a website or send an e-mail - either way, the company whose name servers are used for the Internet domain is going to be contacted to retrieve the A and MX records and if you've set records different from their own, the correct web/mail server will then be contacted and you will see the needed website or your email will be delivered.