How to Configure BIND9 as a Secondary DNS Server on Ubuntu 20.04
The secondary DNS server works for fault tolerance. If the primary one stops working for some reason, the secondary one will ensure the functionality of the website and other resources specified in it.
First, you need to install and make a basic configuration of the BIND9 DNS server.
Initial settings
- Primary DNS server IP - 10.1.1.9
- Secondary DNS server IP - 10.1.1.10
- Example domain name - domain-name.com
Additional settings for the primary DNS server BIND9
If you configured the primary DNS server according to our instructions, you can skip this step.
We must allow the primary DNS server to transmit DNS zone data to the secondary server. Open the BIND9 configuration file.
sudo nano /etc/bind/named.conf.localAdd the following 2 parameters to the zone settings: allow-transfer and also-notify, substituting the IP address of the secondary server in them. The result will be something like this.
zone "domain-name.com" {
type master;
file "/etc/bind/db.domain-name.com";
allow-transfer { 10.1.1.10; };
also-notify { 10.1.1.10; };
};Save this file and reload BIND9.
sudo systemctl reload bind9Configuring BIND9 as a secondary DNS Server
Open the BIND9 configuration file.
sudo nano /etc/bind/named.conf.localAdd the following directive to it.
zone "domain-name.com" {
type slave;
file "db.domain-name.com";
masters { 10.1.1.9; };
};The masters parameter must contain the IP address of the primary DNS server. Save the file and reload BIND9.
sudo systemctl reload bind9To check if the secondary DNS server is working correctly, use the command on any remote computer:
nslookup domain-name.com 10.1.1.10Use your FQDN instead of domain-name.com and the IP address of your secondary DNS server instead of 10.1.1.10.
Output
Server: 10.1.1.10
Address: 10.1.1.10#53
Name: domain-name.com
Address: 10.1.1.10
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