The Domain Name Service ensures the determination of an IP address to a given domain name. This Domain Name Service runs on all PCs. It receives the domain name entered by a user and inquires after the corresponding IP address from a DNS Server known to it. If a DNS server cannot answer the inquiry itself, it has the possibility to inquire about the IP address from other servers.
If the Domain Name Service receives negative information from the DNS server (domain name not recognized), it can make inquiries to other DNS servers known to it or issue the user with a corresponding error message. If, on the other hand, it receives the desired IP address, the application can address the target desired by the user my means of the IP address.
The hierarchical system of DNS servers is described as the Domain Name System. The IP addresses of the DNS severs to which the Domain Name Service should make its standard inquiries are mostly delivered to the PC automatically by the Internet provider during the Internet dial-up. In local networks an assignment of addresses can also ensue via DHCP. Otherwise they have to be entered manually by the user or systems manager in the TCP/IP configuration of the PC.