DNS (Domain Name System) is a service which translates the IP address of computers connected to the Internet into human-readable domain names & vice-versa. In environment with only a limited numbers of Linux machines, it is possible to use the /etc/hosts file for associating an IP address with a DNS name but when you have a large infrastructure with lots of systems/resources, /etc/hosts becomes easily cumbersome.
BIND or Berkeley Internet Name Domain, is an open source software that implements DNS protocols for internet. In this tutorial, we need a DNS server machine & a client machine for testing.
Requirements:
- You have an account and are logged into console.scaleway.com
- You have configured your SSH Key
- You have sudo privileges or access to the root user.
In addition, the mechanism for pointing the server to its zone data files is the configuration files. By default, four configuration files exist:
Install BIND and its related tools:
apt-get install bind9 bind9utils bind9-doc dnsutils
1 . Edit the name.conf.local file:
cd /etc/bind
nano named.conf.locale
2 . Paste the following. Make sure to edit the domain name and the IP address of the secondary machine.
//
// Do any local configuration here
//
// Consider adding the 1918 zones here, if they are not used in your
// organization
//include "/etc/bind/zones.rfc1918";
zone "scw-domain.ml" IN {
type master;
file "/etc/bind/db.scw-domain.ml";
allow-update { 51.15.250.21; };
allow-transfer { 51.15.250.21; };
notify yes;
};
3 . Create your zone file. A zone file must contain at least an SOA, a NS and a A record or CNAME.
nano db.scw-domain.ml
4 . Paste the following:
;
; BIND data file for local loopback interface
;
$TTL 10800
scw-domain.ml. IN SOA ns1.scw-domain.ml. admin.scw-domain.ml. (
2018120615 ; Serial
10800 ; Refresh
3600 ; Retry
2419200 ; Expire
604800 ) ; Negative Cache TTL
;
; Nameserver
scw-domain.ml. IN NS ns1.scw-domain.ml.
scw-domain.ml. IN NS ns2.scw-domain.ml.
ns1 86400 IN A 51.15.242.21
ns1 86400 IN AAAA 2001:bc8:4400:2c00::14:229
ns2 86400 IN A 51.15.250.21
ns2 86400 IN AAAA 2001:bc8:4400:2c00::2c:1f
www 86400 IN A 51.15.242.21
www 86400 IN AAAA 2001:bc8:4400:2c00::14:229
1 . Edit the name.conf.local file:
cd /etc/bind
nano named.conf.local
2 . Paste the following:
//
// Do any local configuration here
//
// Consider adding the 1918 zones here, if they are not used in your
// organization
//include "/etc/bind/zones.rfc1918";
zone "scw-domain.ml" IN {
type slave;
file "/etc/bind/db.scw-domain.ml";
masters { 51.15.242.21; };
allow-transfer { none; };
allow-notify { 127.0.0.1; 51.15.242.21; 51.15.250.21; 2001:bc8:4400:2c00::14:229; };
};
3 . On the primary machine, restart the service to verify that the zone replication works properly:
service bind9 restart
The following output should be displayed in the syslog file of the secondary machine
tail /var/log/syslog
Jan 11 17:24:22 bind-client named[11492]: client @0x7fa0d00c7260 51.15.242.21#42782: received notify for zone 'scw-domain.ml'
Jan 11 17:24:22 bind-client named[11492]: zone scw-domain.ml/IN: notify from 51.15.242.21#42782: zone is up to date
Jan 11 17:24:22 bind-client named[11492]: client @0x7fa0d003b900 2001:bc8:4400:2c00::14:229#53121: received notify for zone 'scw-domain.ml'
Jan 11 17:24:22 bind-client named[11492]: zone scw-domain.ml/IN: notify from 2001:bc8:4400:2c00::14:229#53121: zone is up to date
You can try to resolve hostnames on both servers by typing dig www.scw-domain.ml @ns1.scw-domain.ml & dig www.scw-domain.ml @ns2.scw-domain.ml
You should see in the answer section the following:
;; ANSWER SECTION:
www.scw-domain.ml. 86400 IN A 51.15.242.21