Every domain that is registered and hosted has a great deal of DNS records - some of them are created automatically when you host a domain, others can be set up by hand if necessary. For example, the A record of a domain address is its IP address i.e. this record reveals where the web site is located; the MX records show where the emails are managed, while through an SRV record you can use a domain address for unconventional purposes, like a Voice-over-IP service. The ability to set up and modify specific records enables you to have different services with different providers if, for illustration, your present host provides stable web hosting, but has difficulties with the email service, or you simply prefer to get a specific service from a particular company. While you must be able to create and edit these records freely and with no restrictions as you own a given domain address, some companies charge extra to give you this option.