DNS riêng tư với AdGuard Home và Unbound

# 01 Cài Unbound làm máy phân giải đệ quy

Bind it to localhost on a non-standard port so AdGuard Home can take 53.

apt install -y unbound
cat >/etc/unbound/unbound.conf.d/local.conf <<'EOF'
server:
  interface: 127.0.0.1@5335
  do-ip6: yes
  prefetch: yes
  hide-identity: yes
  hide-version: yes
  qname-minimisation: yes
EOF
systemctl restart unbound

# 02 Cài đặt AdGuard Home

The installer sets up a systemd unit and a web interface on port 3000 for initial configuration.

curl -sSL https://raw.githubusercontent.com/AdguardTeam/AdGuardHome/master/scripts/install.sh | sh -s -- -v

# 03 Trỏ AdGuard vào Unbound

In Settings → DNS, set the upstream to 127.0.0.1:5335 and disable all other upstreams. Full recursion means no third party sees your queries at all.

# 04 Bật DNS-over-HTTPS

Get a certificate with Certbot, then enable DoH on 443 and DoT on 853 in the encryption settings. Clients then reach the resolver privately in transit as well as at rest.

certbot certonly --standalone -d dns.example.com

# 05 Khóa chặt nó lại

Restrict access by client IP, or require DoH with a secret path. An open resolver is recruited into DNS amplification attacks within days and will be null-routed.