nanodns 0.3.3

A lightweight, JSON-configurable DNS server for internal networks

NanoDNS

A lightweight, zero-dependency DNS server for internal networks — configured with a single JSON file.

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Features

• 🚀 Zero dependencies — pure Python standard library only
• 📝 JSON config — human-readable, hot-reloadable configuration
• 🔄 Upstream forwarding — forwards unknown queries to public DNS
• 💾 LRU Cache — configurable in-memory response cache with TTL
• 🌐 Record types — A, AAAA, CNAME, MX, TXT, PTR, NS, SOA
• 🃏 Wildcard records — *.example.internal support
• 🚫 Rewrites / blocking — NXDOMAIN any domain instantly
• ♻️ Hot reload — config changes applied without restart
• ⚡ Async — built on Python asyncio
• 🐳 Docker — multi-platform OCI image (amd64 + arm64)
• 🔏 Signed — cosign keyless signatures via Sigstore

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Installation

pip

pip install nanodns

Docker

# Docker Hub
docker pull iyuangang/nanodns:latest

# GitHub Container Registry
docker pull ghcr.io/iyuangang/nanodns:latest

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Quick Start

pip

# 1. Generate an example config
nanodns init

# 2. Edit nanodns.json to your needs

# 3. Validate config
nanodns check nanodns.json

# 4. Start (high port — no admin rights needed)
nanodns start --config nanodns.json --port 5353

# 5. Start on port 53 (requires root / Administrator)
sudo nanodns start --config nanodns.json

Docker

# Generate a config first
nanodns init nanodns.json

# Run with Docker
docker run -d \
  --name nanodns \
  -p 53:53/udp \
  -v $(pwd)/nanodns.json:/etc/nanodns/nanodns.json:ro \
  --cap-add NET_BIND_SERVICE \
  iyuangang/nanodns:latest

# Run with Docker Compose
docker compose up -d

Verify it works

# Linux / macOS
dig @127.0.0.1 -p 5353 web.internal.lan A

# Windows
nslookup web.internal.lan 127.0.0.1

# PowerShell
Resolve-DnsName -Name web.internal.lan -Server 127.0.0.1 -Type A

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Configuration

{
  "server": {
    "host": "0.0.0.0",
    "port": 53,
    "upstream": ["8.8.8.8", "1.1.1.1"],
    "upstream_timeout": 3,
    "upstream_port": 53,
    "cache_enabled": true,
    "cache_ttl": 300,
    "cache_size": 1000,
    "log_level": "INFO",
    "log_queries": true,
    "hot_reload": true
  },
  "zones": {
    "internal.lan": {
      "soa": {
        "mname": "ns1.internal.lan",
        "rname": "admin.internal.lan",
        "serial": 2024010101,
        "refresh": 3600,
        "retry": 900,
        "expire": 604800,
        "minimum": 300
      },
      "ns": ["ns1.internal.lan"]
    }
  },
  "records": [
    { "name": "ns1.internal.lan",  "type": "A",     "value": "192.168.1.10",  "ttl": 3600 },
    { "name": "web.internal.lan",  "type": "A",     "value": "192.168.1.100", "ttl": 300  },
    { "name": "db.internal.lan",   "type": "A",     "value": "192.168.1.101", "ttl": 300  },
    { "name": "api.internal.lan",  "type": "CNAME", "value": "web.internal.lan"            },
    { "name": "ipv6.internal.lan", "type": "AAAA",  "value": "fd00::1",       "ttl": 300  },
    { "name": "internal.lan",      "type": "MX",    "value": "mail.internal.lan", "priority": 10 },
    { "name": "internal.lan",      "type": "TXT",   "value": "v=spf1 ip4:192.168.1.0/24 ~all" },
    {
      "name": "app.internal.lan",
      "type": "A",
      "value": "192.168.1.200",
      "wildcard": true,
      "comment": "Matches *.app.internal.lan"
    }
  ],
  "rewrites": [
    { "match": "ads.doubleclick.net", "action": "nxdomain" },
    { "match": "*.tracker.example",   "action": "nxdomain" }
  ]
}

See USAGE.md for the full configuration reference.

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CLI Reference

nanodns start  --config FILE  [--host HOST] [--port PORT] [--log-level LEVEL] [--no-cache]
nanodns init   [OUTPUT]       Generate an example config file
nanodns check  CONFIG         Validate a config file and print a summary
nanodns --version

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Record Types

Type	value	Extra fields
A	IPv4 address	—
AAAA	IPv6 address	—
CNAME	Target hostname	—
MX	Mail server hostname	priority (int)
TXT	Text string	—
PTR	Pointer hostname	—
NS	Nameserver hostname	—

All records support: ttl (default 300), wildcard (bool), comment (string).

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Docker

Images

Registry	Image
Docker Hub	iyuangang/nanodns
GHCR	ghcr.io/iyuangang/nanodns

Tags

Tag	Description
latest	Latest stable release
1.2.3	Exact version
1.2	Minor version
1	Major version
sha-a1b2c3	Specific commit

Platforms

linux/amd64 · linux/arm64 (Raspberry Pi, Apple Silicon)

docker-compose.yml

services:
  nanodns:
    image: iyuangang/nanodns:latest
    container_name: nanodns
    restart: unless-stopped
    ports:
      - "53:53/udp"
    volumes:
      - ./nanodns.json:/etc/nanodns/nanodns.json:ro
    cap_add:
      - NET_BIND_SERVICE
    read_only: true

OCI Compliance

Images follow the OCI Image Spec with standard annotations:

# Inspect OCI annotations
docker inspect iyuangang/nanodns:latest \
  --format '{{json .Config.Labels}}' | python3 -m json.tool

# Verify cosign signature (keyless / Sigstore)
cosign verify \
  --certificate-identity-regexp="https://github.com/iyuangang/nanodns/*" \
  --certificate-oidc-issuer="https://token.actions.githubusercontent.com" \
  iyuangang/nanodns:latest

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Deployment

Linux — systemd

# /etc/systemd/system/nanodns.service
[Unit]
Description=NanoDNS Server
After=network.target

[Service]
ExecStart=/usr/local/bin/nanodns start --config /etc/nanodns/nanodns.json
Restart=on-failure

[Install]
WantedBy=multi-user.target

sudo systemctl enable --now nanodns

Windows — NSSM

nssm install NanoDNS "C:\Python\Scripts\nanodns.exe"
nssm set NanoDNS AppParameters "start --config C:\dns\nanodns.json"
nssm start NanoDNS

High Port (No Root Required)

nanodns start --config nanodns.json --port 5353

# Redirect port 53 → 5353 with iptables
sudo iptables -t nat -A PREROUTING -p udp --dport 53 -j REDIRECT --to-port 5353

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CI / CD

Workflow	Trigger	Description
release.yml	v* tag	Run tests → build wheel → GitHub Release → publish PyPI
docker.yml	v* tag / main	Build multi-platform OCI image → push GHCR + Docker Hub → cosign sign

Release a new version

# 1. Bump version in pyproject.toml
# 2. Commit and tag
git add pyproject.toml
git commit -m "chore: bump version to 0.2.0"
git tag v0.2.0
git push origin main --tags

Both PyPI and Docker Hub are published automatically.

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License

MIT