1. Installing and enabling DNS server

Step 1.1: Install BIND9 Packages

sudo apt install bind9 bind9-utils -y

Step 1.2: Enable and Start the named Service


sudo systemctl enable named
sudo systemctl start named

Step 1.3: Verify Service Status

Confirm the service is active and running:

sudo systemctl status named

2. Configuring the DNS server

Step 2.1: Configure Forwarders

Edit the BIND options file:

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

Modify the options block:


EX:
    forwarders {
        10.0.10.100;
        8.8.8.8;
    };

    recursion yes;
    allow-query { any; };
};



    
    
        Step 2.2: Create Forward Lookup Zone

        Edit the local zones file:
        sudo nano /etc/bind/named.conf.local

        Add the zone definition:

zone "lab.local" {
    type master;
    file "/etc/bind/db.lab.local";
};


        Screenshot:
        
    

    
    
        Step 2.3: Create Zone File

        Copy the default template:
        sudo cp /etc/bind/db.local /etc/bind/db.lab.local

        Edit the new zone file:
        sudo nano /etc/bind/db.lab.local

$TTL    604800
@       IN      SOA     ns1.lab.local. admin.lab.local. (
                             2026021101 ; Serial
                             604800     ; Refresh
                             86400      ; Retry
                             2419200    ; Expire
                             604800 )   ; Negative Cache TTL

@       IN      NS      ns1.lab.local.

ns1     IN      A       192.168.1.10
server1 IN      A       192.168.1.20


        Important: Increment the serial number anytime the file is modified.

    

 
           
            3. Configuring UFW
        


    
    
        Step 3.1: Configure UFW Firewall

        Check UFW status:
        sudo ufw status

        Allow DNS traffic (TCP and UDP port 53):
        
sudo ufw allow 53/udp
sudo ufw allow 53/tcp
sudo ufw reload
        

        Screenshot:
        
    

    
    
        Step 3.2: Verify BIND is Listening

        sudo ss -tulnp | grep :53

        Confirm that bind9 (named) is listening on TCP and UDP port 53.

        Screenshot:
        
    


           
            4. Test DNS Resolution
        

    
    
        Step 4.1: Test Local DNS Resolution

        dig @localhost ns1.lab.local

        Expected Result: A valid A record is returned.

        Screenshot:
        
    

    
    
        Step 4.2: Test from Another Machine

        From a second machine:
        dig @<DNS_SERVER_IP> server1.lab.local

        Or using nslookup:
        nslookup server1.lab.local

        Expected Result: The correct IP address is returned.

        Screenshot: