What this is and isn't.
DNS is is the Domain Name System. DNS converts machine names to
the IP addresses that all machines on the net have. It maps from name
to address and from address to name, and some other things. This
HOWTO documents how to define such mappings using a Linux system. A
mapping is simply a association between two things, in this case a
machine name, like ftp.linux.org, and the machines IP number (or
address) 199.249.150.4.
DNS is, to the uninitiated (you ;-), one of the more opaque areas of network administration. This HOWTO will try to make a few things clearer. It describes how to set up a simple DNS name server. Starting with a caching only server and going on to setting up a primary DNS server for a domain. For more complex setups you can check the QnA section of this document. If it's not described there you will need to read the Real Documentation. I'll get back to what this Real Documentation consists of in the last chapter.
Before you start on this you should configure your machine so that
you can telnet in and out of it, and successfully make all kinds of
connections to the net, and you should especially be able to do
telnet 127.0.0.1 and get your own machine (test it now!). You
also need a good /etc/nsswitch.conf (or
/etc/host.conf), /etc/resolv.conf and
/etc/hosts files as a starting point, since I will not
explain their function here. If you don't already have all this set
up and working the NET-3-HOWTO and/or the PPP-HOWTO explains how to
set it up. Read them.
When I say `your machine' I mean the machine you are trying to set up DNS on. Not any other machine you might have that's involved in your networking effort.
I assume you're not behind any kind of firewall that blocks name queries. If you are you will need a special configuration, see the section on QnA.
Name serving on Unix is done by a program called named. This
is a part of the ``bind'' package which is coordinated by Paul Vixie
for The Internet Software Consortium. Named is included in most
Linux distributions and is usually installed as
/usr/sbin/named. If you have a named you can probably use
it; if you don't have one you can get a binary off a Linux ftp site,
or get the latest and greatest source from
ftp.isc.org:/isc/bind/src/cur/bind-8/. This HOWTO is about
bind version 8. The old version of the HOWTO, about bind 4 is still
available at
http://www.math.uio.no/~janl/DNS/ in case you use bind 4. If
the named man page talks about (at the very end, the FILES section)
named.conf you have bind 8, if it talks about named.boot you
have bind 4. If you have 4 and are security conscious you really
ought to upgrade to a recent 8.
DNS is a net-wide database. Take care about what you put into it. If you put junk into it, you, and others will get junk out of it. Keep your DNS tidy and consistent and you will get good service from it. Learn to use it, admin it, debug it and you will be another good admin keeping the net from falling to it's knees by mismanagement.
In this document I state flatly a couple of things that are not completely true (they are at least half truths though). All in the interest of simplification. Things will (probably ;-) work if you believe what I say.
Tip: Make backup copies of all the files I instruct you to change if you already have them, so if after going through this nothing works you can get it back to your old, working state.