لطفا منتظر باشید ...
Chapter 5. Name Service and Configuration
As we discussed in Chapter 2, TCP/IP networking
may rely on different schemes to convert names into addresses. The
simplest way is to use a host table stored in
/etc/hosts. This is useful only for a small LAN
that is run by a single administrator and no IP traffic with the
outside world. The format of the hosts file has
already been described in Chapter 4.
While a
hosts file approach may be appropriate on a
small network, most administrators will need to investigate a DNS
server. There are multiple services that you can use to resolve IP
addresses. The most commonly used is the
Berkeley Internet
Name Domain
service (BIND) Version 8.x. BIND v9.x has been
available for some time now and seeks to add a variety of new
features, as well as contend with security issues in BIND v8.x. The
jump from BIND 8 to BIND 9 isn't quite as
significant as was the leap from BIND 4 to 8; many of the
configuration files and options are the same. Configuring BIND can be
a real chore, but once you've done it, you can
easily make changes in the network topology. On Linux, as on many
other Unix-ish systems, BIND service is provided through a program
called named. At startup, it loads a set of
master files into its internal cache and waits for queries from
remote or local user processes. There are different ways to set up
BIND, and not all require you to run a nameserver on every host.
We
will also discuss a simpler and more secure option, djbdns, written
by David J. Bernstein. This resolver was written from scratch with
security in mind and simplifies server setup in a number of ways,
primarily by eliminating the need for multiple confusing zone files.This chapter
can do little more than give a rough sketch of how DNS works and how
to operate a nameserver. It should be sufficient for readers with a
small LAN and an Internet connection. For the most current
information, you may want to check the documentation contained in the
BIND or djbdns source packages, which supply manual pages, release
notes, and in the BIND package, the BIND
Operator's
Guide (BOG). Don't let this
name scare you off; it's actually a very useful
document. For more comprehensive coverage of DNS and associated
issues, you may find DNS
and BIND by Paul Albitz and
Cricket Liu (O'Reilly) a useful reference. DNS
questions may be answered in a newsgroup called
comp.protocols.tcp-ip.domains. For technical
details, the Domain Name System is defined by RFC numbers 1033, 1034,
and
1035
.
