How to set up a DNS server on Ubuntu Server

This guide will use Bind9 as the DNS server software.

Software used in this guide

• Nala - A faster frontend for APT
• Bind9 - DNS server software
• Nano - A command line text editor

Replacement values

• Replace [INITIALS] with your initials.
• Replace [SURNAME] with your surname.
• Replace [HOSTNAME] with the output of the hostname -f command.

Install requirements

Network adapter settings

Ensure that your ubuntu server virtual machine is running on one network adapter in NAT mode.

1. Install nala (optional)

apt install nala

2. Install Bind9 and its utilities

nala install bind9 bind9utils

Configuring the network

Network adapter settings

Ensure that your ubuntu server virtual machine is running on one network adapter in internal-network mode, with the promiscuous mode set to Allow All.

1. Configure a static IP address for your server.

sudo ip addr add 10.80.80.1/24 dev enp0s3
sudo ip link set enp0s3 up

2. Verify the IP address

ip a

You should see the IP address 10.80.80.1 assigned to the enp0s3 adapter.

3. Edit the hosts file, run sudo nano /etc/hosts, then change the first two lines to:

127.0.0.1       localhost
127.0.0.1       [HOSTNAME].[SURNAME].local   [HOSTNAME]

4. Stop the systemd-resolved service to prevent conflicts with Bind9.

sudo systemctl stop systemd-resolved
sudo systemctl disable systemd-resolved

5. Edit the resolv.conf file to use the local DNS server. Run sudo nano /etc/resolv.conf, remove everything from the file and add:

nameserver 127.0.0.1
search [SURNAME].local

Configuring Bind9

1. Edit the name configuration file. Run sudo nano /etc/bind/named.conf.options, erase everything in the file and add:

options {
        directory "/var/cache/bind";
        forwarders {
                10.1.1.30;
        };
        dnssec-validation auto;
        listen-on { any; };
};

2. Create a new zone configuration file. Run sudo nano /etc/bind/named.conf.local, erase everything in the file and add:

zone "[SURNAME].local" IN {
        type master;
        file "/etc/bind/zones/db.[SURNAME].local";
};
zone "80.80.10.in-addr.arpa" {
        type master;
        file "/etc/bind/zones/db.10.80.80";
};

3. Create the IP databases
   1. Run sudo nano /etc/bind/db.[SURNAME].local and add:

    $TTL    604800
    @       IN      SOA     [HOSTNAME].[SURNAME].local. root.[SURNAME].local. (
                                2         ; Serial
                            604800         ; Refresh
                            86400         ; Retry
                            2419200         ; Expire
                            604800 )       ; Negative Cache TTL
    ;
    @       IN      NS      [HOSTNAME].[SURNAME].local.
    [HOSTNAME]   IN      A       10.80.80.1

   2. Run sudo nano /etc/bind/db.10.80.80 and add:

   $TTL    604800
   @       IN      SOA     [SURNAME].local. root.[SURNAME].local. (
                               1         ; Serial
                           604800         ; Refresh
                           86400         ; Retry
                           2419200         ; Expire
                           604800 )       ; Negative Cache TTL
   ;
   @       IN      NS      [HOSTNAME].[SURNAME].local.
   10.80.80.1       IN      PTR     [HOSTNAME].[SURNAME].local.

Check the configuration locally

1. Check the Bind9 configuration for errors

sudo named-checkconf

If there are no errors, the command will return nothing. 2. Check the zone files for errors

sudo named-checkzone [SURNAME].local /etc/bind/db.[SURNAME].local
sudo named-checkzone 80.80.10.in-addr.arpa /etc/bind/db.10.80.80

If there are no errors, the command will return something like:

zone [SURNAME].local/IN: loaded serial 2
OK
zone 80.80.10.in-addr.arpa/IN: loaded serial 2
OK

3. Restart Bind9 to apply the changes

sudo systemctl restart bind9

4. Check the status of Bind9 to ensure it is running

sudo systemctl status bind9

You should see active (running) in green text.

Testing the DNS server

1. Ubuntu server
   1. Test the DNS server using dig

   dig [HOSTNAME].[SURNAME].local

2. Windows client
   1. Go to the network adapter settings in virtualbox settings for the machine, make sure there is only ONE adapter set to internal network, with the promiscuous mode set to Allow All.
      
   2. After that is done, power on the machine, open the control panel, go to Network and Internet > Network and Sharing Center > Change adapter settings, right click on the network adapter and select properties. Select Internet Protocol Version 4 (TCP/IPv4) and click properties. Set the preferred DNS server to 10.80.80.1.
   3. Open a command prompt and run:

   nslookup [HOSTNAME].[SURNAME].local

Done! You have successfully set up a DNS server on Ubuntu Server using Bind9.