TCP/IPv6 Configuration and Management Manual (G06.24+)

HP NonStop TCP/IPv6 Configuration and Management Manual—524523-008
E-1
E Domain Name Server (DNS)
This appendix describes DNS 4.x on the NonStop server. Topics include:
•
DNS Overview
•
Domain Name Resolver on page E-3
For information about DNS 9.x on the NonStop server, see the DNS Configuration and
Management Manual and the BIND 9 Administrator Reference Manual.
DNS Overview
DNS serves as the yellow pages and white pages of an internet community. It provides
the translation and mapping of human-readable machine names into IP addresses.
Host table lookup routines (such as the Domain Name Resolver) work well for small
networks that include only a few machines where the organizations in the network
cooperate in maintaining the tables: a master file for the entire network can be
maintained at a central location by a few people. However, a single centralized
clearinghouse for host-name resolution does not work well for large networks which
include machines that cross organizational boundaries. The DNS allows the authority
for this information to be delegated to the organizations on the network that are
responsible for it.
The DNS, as defined in RFCs 1032, 1033, 1034, and 1035, allows a network to be
divided into a hierarchy of domains. The name space is organized as a tree structure
according to organizational or administrative boundaries. Each node (called a domain)
is given a label, and the name of the domain is derived by concatenating all the labels
of the domains from the root of the tree down to the current domain. A label need only
be unique within its domain.
The whole name space is partitioned into several areas called zones, each starting at a
domain and extending down to the leaf domains or to domains where other zones
start. Zones usually represent administrative boundaries. This example shows an
address for a host at KentComm:
guru.develop.KentComm.com
com is the top level domain for commercial organizations. KentComm is a subdomain
of com, and develop is a subdomain of KentComm. The host itself, guru, belongs to
the domain develop. Comment lines start with a semicolon (;) in the Domain Name
Server (DNS) data files.
The program file that implements the DNS is $SYSTEM.ZTCPIP.NAMED, so the DNS
is sometimes referred to as NAMED. The basic function of the DNS is to provide
information about network objects by answering queries. The information provided by
the DNS includes name-to-address mapping, address-to-name mapping, mailbox
information, and machine hardware/software information.