Setting Up a DNS Server on Raspberry Pi with DNSmasq

Introduction

A DNS server handles translating domain names, such as pimylifeup.com, into their respective IP addresses. By setting up a DNS server on your Raspberry Pi, you can enhance the speed of DNS requests on your network by caching them locally.

Why Use DNSmasq?

DNSmasq is a lightweight and easy-to-configure DNS server, ideal for small networks, making it a perfect fit for Raspberry Pi.

Prerequisites

Ensure your Raspberry Pi is up to date by running:

sudo apt update
sudo apt upgrade

Installing DNSmasq

Install DNSmasq on your Raspberry Pi with the following command:

sudo apt install dnsmasq

Configuring DNSmasq

Modify the DNSmasq configuration by editing its config file:

sudo nano /etc/dnsmasq.conf

Key Configuration Changes

Enable domain-needed to avoid forwarding plain names:
```
domain-needed
```
Enable bogus-priv to stop local IP leakage:
```
bogus-priv
```
Disable reading of the /etc/resolv.conf file:
```
no-resolv
```
Set Google DNS as the upstream servers:
```
server=8.8.8.8
server=8.8.4.4
```
Increase cache size for improved performance:
```
cache-size=1000
```
Set a local domain:
```
domain=me.local
```

Save and exit the file by pressing <kbd>CTRL</kbd> + <kbd>X</kbd>, <kbd>Y</kbd>, and <kbd>ENTER</kbd>.

Adding Local Hosts

To add a local host such as kodi.me.local, edit the hosts file:

sudo nano /etc/hosts

Add this line:

192.168.1.17    kodi

Save and exit the file.

Restarting DNSmasq

Apply changes by restarting DNSmasq:

sudo systemctl restart dnsmasq

Check the status with:

sudo systemctl status dnsmasq

Testing Your DNS Server

Install dnsutils to test the DNS server with dig:

sudo apt install dnsutils

Run a DNS query:

dig pimylifeup.com @localhost

Repeated queries should return faster responses due to caching.

Troubleshooting: Port 53 Used by systemd-resolved

Prevent dnsmasq from starting automatically:
```
servicectl disable dnsmasq
```

Create and make executable rc.local:

#!/bin/bash
service systemd-resolved stop
service dnsmasq start

Check port 53 usage:
```
sudo ss -lp "sport = :domain"
```
Change DNSmasq's listening port if necessary:
```
listen-address=127.0.0.1#5300
```

By following these steps, you should have a fully functioning DNS server on your Raspberry Pi, offering quicker and more efficient DNS lookups for your network.