DNS – or Domain Name System – is the process of turning your domain name into language that your computer (and the internet) will understand. DNS translates each domain name into IP addresses, which allow each device to connect to the correct web server and get to the correct destination. DNS is made up of a multitude of records, all of which ensure that your website is found on the internet and that the emails you send and receive get delivered to the right place.
With incorrect DNS, a site will not resolve properly and email will be bounced back as undeliverable. Having the correct DNS for your domain name is crucial to the performance of your site.