Pi-hole Network Ad Blocking

Overview

This project documents the setup of a Pi-hole instance on a Raspberry Pi Zero 2 W to provide network-wide ad blocking.

The goal is to understand how DNS-based filtering works and how such a system can be deployed in a real home network environment.

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Introduction

Pi-hole is a DNS sinkhole that blocks advertisements and tracking domains at the network level.
Instead of blocking ads on individual devices, all DNS queries are filtered centrally.

This approach provides:

• Network-wide ad blocking
• Reduced tracking
• Improved performance and bandwidth usage
• Visibility into DNS requests

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Objectives

• Deploy Pi-hole on a Raspberry Pi Zero 2 W
• Configure remote access via SSH
• Integrate the device into the local network
• Understand DNS-based filtering in practice
• Prepare for network-wide deployment

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Environment

• Raspberry Pi Zero 2 W
• Raspberry Pi OS Lite (64-bit)
• Local home network (router-managed DHCP)
• SSH access via PuTTY

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Setup

1. Install Operating System

Raspberry Pi OS Lite (64-bit) was installed on the SD card. I’d recommend using the Raspberry Pi Imager, which is simple and straightforward.

During setup:

• Wi-Fi was configured
• SSH was enabled

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2. Network Configuration

After connecting the Raspberry Pi to the network, the router configuration was adjusted:

• A static IP address was assigned to the Raspberry Pi

This ensures consistent access to the Pi-hole interface and prevents IP changes after reboot.

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3. Initial Access via SSH

The Raspberry Pi was accessed remotely using PuTTY via static ip:

Or use any OS and conect via ssh:

ssh pihole@192.168.2.123

This allows full control of the system without requiring a monitor or keyboard.

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4. Install Pi-hole

Pi-hole was installed using the official installation script:

curl -sSL https://install.pi-hole.net | bash

You will be thoroughly guided through the installation process.

At the end you’ll get your admin login password. I changed it right after finishing the installation to a secure one.

sudo pihole setpassword

All done for now - close PuTTY here.

During the installation process:

• Default network interface was selected
• DNS provider was chosen
• Web interface was enabled

Check the official Pi-hole documentation here: https://docs.pi-hole.net/main/basic-install/

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5. First Login

After the installation I could access the Pi-hole dashboard via browser:

192.168.2.123/admin/login

The first login confirmed that the installation was successful.

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6. Configure DNS on Router

To integrate your Pi-hole in your network, configure its IP as your primary (and only, except you have a second Pi-hole) DNS server on your router. The configuration might be different on every router!

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7. Pi-Hole dashboard check

Now check your Pi-hole dashboard if there are queries and also blocked queries - congratulations! It works!

Here are two examples of websites before and after enabling the Pi-hole:

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Security Relevance

While Pi-hole is commonly used for ad blocking, it also provides valuable security benefits at the network level.

By filtering DNS requests, it can:

• Block known malicious domains (e.g. malware, phishing, tracking infrastructure)
• Reduce exposure to drive-by downloads and malicious advertising
• Provide visibility into DNS queries across the network
• Help identify unusual or suspicious traffic patterns

From a defensive perspective, Pi-hole can act as a lightweight first layer of protection by preventing communication with known harmful domains.

It also introduces important limitations:

• DNS-based filtering can be bypassed (e.g. DNS over HTTPS)
• It does not inspect encrypted traffic
• Effectiveness depends on the quality of blocklists

This makes Pi-hole a useful supporting control, but not a replacement for dedicated security solutions.