Ultimate DNS Shield — Self-hosted recursive DNS with Pi-hole + Unbound + Docker

#privacy #linux #raspberrypi #docker

Every domain you resolve goes through a DNS resolver. By default, that's Google (8.8.8.8), Cloudflare (1.1.1.1), or your ISP (all of which log your queries). Your browsing history is essentially visible to them.

Ultimate DNS Shield breaks that dependency entirely. Unbound resolves domains by querying root nameservers directly. Pi-hole drops ad and tracker domains before they reach the network stack. No third-party resolver ever sees your queries.

This is not about hiding from law enforcement; it's about reducing unnecessary data exposure to commercial entities and your ISP.

Architecture

Three layers, all containerised on an isolated Docker bridge network (dns-net). Unbound is never exposed to the LAN (only Pi-hole can reach it).

LAN devices ──► Pi-hole :53 (172.20.0.3)
                    │
                    └──► Unbound :5335 (172.20.0.2) (internal only)
                                │
                                └──► Root nameservers (a-m.root-servers.net)

networks:
  dns-net:
    driver: bridge
    ipam:
      config:
        - subnet: 172.20.0.0/24

services:
  unbound:
    image: mvance/unbound:latest
    networks:
      dns-net:
        ipv4_address: 172.20.0.2

  pihole:
    image: pihole/pihole:latest
    networks:
      dns-net:
        ipv4_address: 172.20.0.3
    ports:
      - "53:53/tcp"
      - "53:53/udp"
      - "80:80/tcp"

Pi-hole forwards unblocked queries to Unbound via PIHOLE_DNS_=172.20.0.2#5335 (not a public resolver).

Prerequisites

Raspberry Pi 4 (2 GB RAM minimum)
Raspberry Pi OS Lite 64-bit
Static LAN IP on the Pi
Docker + Docker Compose installed
Port 53 free on the host

Watch out: systemd-resolved occupies port 53 by default on Ubuntu/Pi OS. Disable it first: sudo systemctl disable --now systemd-resolved

Installation

git clone https://github.com/cherifon/Ultimate-DNS-Shield.git
cd Ultimate-DNS-Shield

Edit config/docker-compose.yml:

environment:
  TZ: Europe/Paris
  WEBPASSWORD: your_password
volumes:
  - /home/pi/pihole:/etc/pihole
  - /home/pi/dnsmasq:/etc/dnsmasq.d

# Preview (no changes applied)
sudo bash scripts/install.sh --dry-run

# Full install
sudo bash scripts/install.sh

Point your router's DHCP DNS to the Pi's LAN IP (every device is covered automatically).

Security hardening

sudo bash scripts/security.sh

UFW (port 53 and 80 from LAN only; everything else denied)
Fail2Ban (rate-limits DNS floods and web UI brute-force)
DNSSEC (enforced in Unbound; invalid signatures rejected)
Unbound isolation (bound to 172.20.0.2 only; unreachable from outside Docker's bridge)

Verification

# Normal resolution (answered by your Pi)
dig github.com @<PI_IP>

# Ad blocking (returns 0.0.0.0)
dig doubleclick.net @<PI_IP>

# DNSSEC (invalid signature correctly rejected)
dig sigfail.verteiltesysteme.net @<PI_IP>