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 company. On their end, three records are set up automatically as soon as the domain is added - one A record and two MX records. The former is a numeric address, or IP address, that “tells” the Internet domain where its site is, while the other two are alphanumeric and they reveal the server that handles the emails for that particular Internet domain. The website and the email hosting are usually thought to be one thing, while they are actually two different services. Having separate records for them will permit you to have them with different providers if you would like. As an illustration, some new provider may have exceptional uptime for your site, but you may not want to switch your e-mails from your current host and by using an A record to point the Internet domain to the first and MX records to have the e-mails with the latter, you can get the best of both companies. These records are checked when you wish to open a site or send an e-mail - 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've set records different from their own, the right web/mail server will then be contacted and you will see the needed website or your email will be delivered.
