Configuring and Managing MPE/iX Internet Services (MPE/iX 6.5)

116 Chapter8
DNS BIND/iX
Introduction
Introduction
This section of the Configuring and Managing MPE/iX Internet
Services manual assumes that the reader has prior experience with
DNS BIND as implemented on other operating systems, or has
familiarity with the concepts involved. There are a number of good
textbooks available on this subject to which the reader is recommended
— the following is a brief overview of a sophisticated system.
The Domain Name System is a distributed and structured directory of
information. One of its more frequent uses is the naming of host
machines. A DNS host name will consist of several fields separated by
dots, for example:
quasar.india.hp.com.
The host quasar exists in the domain india, which itself is a
subdomain of hp, which is a subdomain of com, which is a subdomain of
the root domain (identified as “.”).
With this structured naming convention, the responsibility for
maintaining accurate database information for a name domain can be
delegated to a server which is managed by the organization who owns
that domain. for example, DNS server hosts within HP maintain
information about hp.com. Queries for names inside the domain hp.com
will be referred to that server by servers in other domains. Within HP,
the responsibility for india.hp.com can also be delegated to another
local DNS server.
Before MPE/iX 6.0, hosts running MPE/iX were able to make DNS
queries of servers running on other machines and operating systems.
Now a full implementation of the server code has been introduced.
DNS BIND/iX will enable your MPE/iX host to act as a DNS server,
both responding to queries (from clients and other servers) as well as
communicating with other DNS servers on the local network and the
Internet.
The way this information is accessed is through client programs or code
routines called “resolvers”. When a program on a client host needs to
obtain information about a domain, it will send a message to the local
DNS server host. If the local server has this information, it will send
back a reply immediately. If the local server does not have this
information, it will research by sending queries to other servers,
following the Domain Name System structure. Once the local server
has found an answer for the client, it will then reply, but will also cache
what it has learned in order to respond more speedily to subsequent
queries.
DNS BIND/iX on MPE/iX 6.0 is an implementation of BIND
version 8.1.1, which has introduced many new features since the more