RFC 883 (rfc883) - Page 2 of 73

Domain names: Implementation specification

RFC 883                                                    November 1983
                         Domain Names - Implementation and Specification


   Implementation components

      A host can participate in the domain name system in a number of
      ways, depending on whether the host runs programs that retrieve
      information from the domain system, name servers that answer
      queries from other hosts, or various combinations of both
      functions.  The simplest, and perhaps most typical, configuration
      is shown below:

                   Local Host                        |  Foreign   
                                                     |            
      +---------+               +----------+         |  +--------+
      |         | user queries  |          |queries  |  |        |
      |  User   |-------------->|          |---------|->|Foreign |
      | Program |               | Resolver |         |  |  Name  |
      |         |