+---------+               +----------+         |  +--------+
      |         | user queries  |          |queries  |  |        |
      |  User   |-------------->|          |---------|->|Foreign |
      | Program |               | Resolver |         |  |  Name  |
      |         |<--------------|          |<--------|--| Server |
      |         | user responses|          |responses|  |        |
      +---------+               +----------+         |  +--------+
                                  |     A            |            
                  cache additions |     | references |            
                                  V     |            |            
                                +----------+         |            
                                |  Shared  |         |            
                                | database |         |            
                                +----------+         |            
                                  A     |            |            
        +---------+     refreshes |     | references |            
       /         /|               |     V            |            
      +---------+ |             +----------+         |  +--------+
      |         | |             |          |responses|  |        |
      |         | |             |   Name   |---------|->|Foreign |
      |  Master |-------------->|  Server  |         |  |Resolver|
      |  files  | |             |          |<--------|--|        |
      |         |/              |          | queries |  +--------+
      +---------+               +----------+         |            
                                  A     |maintenance |  +--------+
                                  |     \------------|->|        |
                                  |      queries     |  |Foreign |
                                  |                  |  |  Name  |
                                  \------------------|--| Server |
                               maintenance responses |  +--------+

      The shared database holds domain space data for the local name
      server and resolver.  The contents of the shared database will
      typically be a mixture of authoritative data maintained by the
      periodic refresh operations of the name server and cached data
      from previous resolver requests.  The structure of the domain data
      and the necessity for synchronization between name servers and
      resolvers imply the general characteristics of this database, but
      the actual format is up to the local implementer.  This memo
      suggests a multiple tree format.







 

RFC 883                                                    November 1983
                         Domain Names - Implementation and Specification


      This memo divides the implementation discussion into sections:

         NAME SERVER TRANSACTIONS, which discusses the formats for name
         servers queries and the corresponding responses.

         NAME SERVER MAINTENANCE, which discusses strategies,
         algorithms, and formats for maintaining the data residing in
         name servers.  These services periodically refresh the local
         copies of zones that originate in other hosts.

         RESOLVER ALGORITHMS, which discusses the internal structure of
         resolvers.  This section also discusses data base sharing
         between a name server and a resolver on the same host.

         DOMAIN SUPPORT FOR MAIL, which discusses the use of the domain
         system to support mail transfer.