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The TCP/IP Guide  9  TCP/IP Application Layer Protocols, Services and Applications (OSI Layers 5, 6 and 7)       9  Name Systems and TCP/IP Name Registration and Name Resolution            9  TCP/IP Name Systems: Host Tables and Domain Name System (DNS)                 9  TCP/IP Domain Name System (DNS)                      9  DNS Overview, Functions and Characteristics

DNS Overview, Functions and Characteristics 1 2 3 DNS Design Goals, Objectives and Assumptions

Standardization of DNS and Initial Defining Standards

The documents above were discussed frequently over the months that followed, and the basic DNS mechanism revised many times. Several subsequent RFCs were published, updating the DNS cut-over plan and schedule. Finally, in November 1987, agreement on the operation of the system was finalized and a “quartet” of new RFCs were published that formalized the DNS system for the first time. These standards are RFCs 1032 through 1035, shown in Table 163.

These last two documents, RFCs 1034 and 1035, are considered the definitive original specification for the operation of the Domain Name System. While they are now many years old, they still provide the essential description of how DNS works.

DNS has quickly become a very important part of how both the Internet and TCP/IP work. As the Internet has grown to include thousands and then millions of sites, the importance of DNS has grown as well. Today, most people use DNS almost every time they use TCP/IP to access the Internet. It has gone from an alternative form of addressing for applications to one that is preferred by most users. It is an important building block of the more complete “application layer addressing” scheme developed for TCP/IP: Uniform Resource Identifiers (URIs).

The hierarchical nature of the DNS name space is the only thing that has allowed the Internet to grow while making the assignment and mapping of names manageable. The authority structure is also hierarchical, giving local administrators control over the names of devices they manage while ensuring name consistency across the hierarchy as a whole. The distribution of data using many name servers and a standardized resolution technique following a standard message protocol provides efficiency and reliability. These concepts will become more clear as we explore DNS more completely in later topics.

DNS Overview, Functions and Characteristics 1 2 3 DNS Design Goals, Objectives and Assumptions