Any time you add a domain as hosted in some account, you typically set a pair of Name Servers to point it to that specific company. On their end, 3 records are set up 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 where its site is, while the other two are alphanumeric and they reveal the server that handles the emails for that particular domain. The website and the e-mail hosting are often regarded as one thing, while they're in reality two different services. Having independent records for them will enable you to have them with different providers if you'd like. As an illustration, some new provider can have fantastic uptime for your website, but you might not want to switch your e-mails from your current host and by using 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 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 is going to 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 will see the needed site or your email will be delivered.