WHOIS provides directory service to network users. This service is a way of finding e-mail addresses, postal addresses and telephone numbers. It may also deliver information about networks, networking organizations, domains and sites.
The main database of networking-related names (organizations, sites, networks, people, etc.) is maintained by the Internet Registration Service (InterNIC). Actually, the names of the administrative and technical contacts for registered domains are automatically entered into the database when domain or IP number applications are processed by the Internet coordination authority. Each entry of the database has a handle (a unique identifier), a name, a record type, and various other fields depending on the type of record. This database will be used as an example in the descriptions below.
Before April 1, 1993, the Network Information Center (NIC) of the Defense Data Network (DDN) was the Internet coordination authority and, therefore, maintained the database (known as the NIC database). The NIC database is now restricted to information about the .mil domain. Many documents still refer to these names.
Many academic sites maintain their own database to offer information about their staff members and students.
In its current implementation, WHOIS has some limitations which prevent it from becoming an efficient directory service for a large volume of information and numerous requests: the various WHOIS servers have no knowledge of each other, a database is maintained at each server site, and, finally, new functionalities have been implemented locally at various sites and not propagated. A new extended protocol, WHOIS++, is being specified to improve the current service. WHOIS++ will include local enhancements to the WHOIS service, an improved query syntax and its architecture will allow a real distributed directory service for the entire Internet.