How to Configure BIND9 Master-Slave DNS on Linux

A master-slave BIND9 setup provides DNS redundancy — if the primary nameserver goes down, the secondary continues serving DNS queries.

Master Server Configuration

sudo nano /etc/bind/named.conf.local

zone "yourdomain.com" {
    type master;
    file "/etc/bind/zones/yourdomain.com.db";
    allow-transfer { SLAVE_IP; };
    notify yes;
};

Create Zone File

sudo mkdir /etc/bind/zones
sudo nano /etc/bind/zones/yourdomain.com.db

$TTL 86400
@ IN SOA ns1.yourdomain.com. admin.yourdomain.com. (
    2024010101 ; Serial
    3600 ; Refresh
    1800 ; Retry
    604800 ; Expire
    86400 ) ; Minimum TTL

@ IN NS ns1.yourdomain.com.
@ IN NS ns2.yourdomain.com.
@ IN A YOUR_SERVER_IP
www IN A YOUR_SERVER_IP
mail IN A YOUR_MAIL_IP
@ IN MX 10 mail.yourdomain.com.

Slave Server Configuration

zone "yourdomain.com" {
    type slave;
    file "/var/cache/bind/yourdomain.com.db";
    masters { MASTER_IP; };
};

Restart and Test

sudo systemctl restart bind9
dig @SLAVE_IP yourdomain.com SOA

Conclusion

BIND9 master-slave setup ensures DNS high availability. Our team configures redundant DNS infrastructure for production environments.