DNS Client is a client machine configured to send name resolution queries to a DNS server.
What is DNS client?
DNS Client is a client machine configured to send name resolution queries to a DNS server. A DNS client is also called a resolver. When a client needs to resolve a remote host’s name into its IP address, it sends a request to the DNS server, which returns the IP address of the remote host. DNS client software, which is built into most machines that have TCP/IP installed, enables the machines to issue DNS queries to name servers.

For example, on Microsoft Windows platforms, the DNS client software makes possible the use of DNS names for browsing the Internet using Microsoft Internet Explorer.
Configuring TCP/IP property
In Windows operating systems, you must configure the IP address of the DNS server in the client’s TCP/IP property sheet in order for the DNS client software to work properly. With dial-up networking connections to the Internet, this information can be communicated to the client machine during negotiation of the Point-to-Point Protocol (PPP) connection with the Internet service provider (ISP).