Information Technology Reference
In-Depth Information
The Network Information Service (NIS)
➤
The Network Information Service Plus (NIS+)
➤
The Federated Naming Service (FNS), which conforms to the X/Open
Federated Naming Specification (XFN)
➤
The
/etc files
, NIS, and NIS+ are considered enterprise-level naming
services. That is, they work adequately within an intranet environment, but
are not scalable to the global level (Internet environment). To address this
scaling issue, FNS can be used to
federate
or link NIS and NIS+ with a glob-
al-level naming service such as X.500 via the Lightweight Directory Protocol
(LDAP) or DNS. By linking these naming services, the information man-
aged by the enterprise-level name service is accessible globally.
Of these naming services, NIS and NIS+ are covered in the most detail on the exam.
The
/etc
files and DNS are covered briefly. FNS will probably not be mentioned. But
be sure to understand the significance of enterprise-level (NIS and NIS+) versus
global-level (DNS and LDAP) naming services.
Domain Name System (DNS)
DNS is part of the TCP/IP protocol suite and is the name service used by
the Internet. It provides hostname-to-IP-address resolution as well as IP-
address-to-hostname resolution. The DNS namespace is divided into
domains that in turn are divided into subdomains (or zones). One or more
DNS servers can be responsible for (is
authoritative
over) a zone. All the
DNS servers work together to provide name-resolution services across the
entire namespace.
The DNS server provided with Solaris 9 is a version of the Berkeley Internet
Name Domain (BIND) program that is referred to as the
Internet name dae-
mon
(
in.named
).
Information on the namespace is stored in text files using a predefined syn-
tax known as a
record
. The
in.named
program uses the following data files:
➤
/etc/named.conf
—The
BIND
configuration file that identifies zones over
which the DNS server is authoritative and the associated data files.
➤
/etc/resolv.conf
—When configured as a DNS client, a file that identi-
fies the DNS server that should be used for name resolution. This file is
actually used by the resolver libraries (of the DNS client), and not the
DNS server.
➤
named.ca
—The names and IP addresses of the Internet root DNS
servers.
