Required, User-defined
A Domain Name Server (DNS) is an essential part of any internet application. It translates internet domain names to their corresponding IP addresses. These IP addresses are the actual, low-level network addresses used for referring to other email servers, mail relays and network time servers and for resolving email address domains.
The Domain Name Server(s) parameter value is a string of IP addresses, separated by commas. Enter at least one DNS address in the Domain Name Server(s) text box. If you define two or more DNS entries, they will be searched in the order that you type them whenever a domain name needs to be resolved.