Dns Resolver is used to queries DNS servers for host information and programmatically query DNS servers for information, without having to worry about complex packet parsing. It easily returns information in a humanly readable form. It allows you to programmatically perform DNS record lookups.It can be used from ASP.NET web pages, to windows forms, to web services.
The Domain Name System or DNS is a system that stores information about host names and domain names in a kind of distributed database on networks, such as the Internet. Most importantly, it provides an IP address for each host name, and lists the mail exchange servers accepting e-mail for each domain.

The DNS provides a vital service on the Internet, because while computers and network hardware work with IP addresses to perform tasks such as addressing and routing, humans generally find it easier to work with host names and domain names, for example in URLs and e-mail addresses. The DNS therefore mediates between the needs and preferences of wetware and of software.