Host names

A host, or Web site, on the Internet is identified by a host name, such as www.example.com. Host names are sometimes called domain names. Host names are mapped to IP addresses, but there is not a one-to-one relationship between a host name and an IP address.

A host name is used when a Web client makes an HTTP request to a host. It is possible for the user making the request to specify the IP address of the server rather than the host name, but that is now unusual on the Internet. Host names are more convenient for users than numeric IP addresses. Companies, organizations and individuals frequently choose host names for their Web sites that can be easily remembered by users.

More importantly in modern HTTP implementations, the use of host names in HTTP requests means that:
  • Services in the name of one host can be provided by many servers, which have different IP addresses.
  • One server, with one IP address, can provide services in the name of many hosts. This is known as virtual hosting. Virtual hosting explains this process.

Host names are mapped to IP addresses by a server known as a DNS server, or domain name server. DNS stands for Domain Name Service. In a large network, many DNS servers may collaborate to provide the mapping between host names and IP addresses.


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Timestamp icon Last updated: Wednesday, 31 May 2017


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