Domain Name Service (DNS) is an Internet service that maps IP addresses and fully qualified domain names (FQDN) to one another. In this way, DNS alleviates the need to remember IP addresses. Computers that run DNS are called name servers. Ubuntu ships with BIND (Berkley Internet Naming daemon), the most common program used for maintaining a name server on Linux.
Installation
At a terminal prompt, enter the following command to install dns:
sudo apt-get install bind
Configuration
The DNS configuration files are stored in the /etc/bind directory. The primary configuration file is
/etc/bind/named.conf. The content of the default configuration file is shown below:
// This is the primary configuration file for the BIND DNS server named.
//
// Please read /usr/share/doc/bind/README.Debian for information on the
// structure of BIND configuration files in Debian for BIND versions 8.2.1
// and later, *BEFORE* you customize this configuration file.
//
include "/etc/bind/named.conf.options";
// reduce log verbosity on issues outside our control
logging {
category lame-servers { null; };
category cname { null; };
};
// prime the server with knowledge of the root servers
zone "." {
type hint;
file "/etc/bind/db.root";
};
// be authoritative for the localhost forward and reverse zones, and for
// broadcast zones as per RFC 1912
zone "localhost" {
type master;
file "/etc/bind/db.local";
};
zone "127.in-addr.arpa" {
type master;
file "/etc/bind/db.127";
};
zone "0.in-addr.arpa" {
type master;
file "/etc/bind/db.0";
};
zone "255.in-addr.arpa" {
type master;
file "/etc/bind/db.255";
};
// add local zone definitions here
include "/etc/bind/named.conf.local";
The include line specifies the filename which contains the DNS options. The directory line in the
options file tells DNS where to look for files. All files BIND uses will be relative to this directory.
The file named /etc/bind/db.root describes the root name servers in the world. The servers change over time, so the /etc/bind/db.root file must be maintained now and then.
The zone section defines a master server, and it is stored in a file mentioned against file tag. Every zone file contains 3 resource records (RRs): an SOA RR, an NS RR and a PTR RR. SOA is short of Start of Authority. The "@" is a special notation meaning the origin. NS is the Name Server RR. PTR is Domain Name Pointer. To start the DNS server, run the following command from a terminal prompt:
sudo /etc/init.d/bind start