Simple Cloudflare DDNS

中文版本 / Chinese Version

A minimal Cloudflare Dynamic DNS client written in Go. No dependencies, single binary, configured entirely via environment variables.

How it works: Detect public IP → Compare with Cloudflare DNS → Update if changed

Features

• Auto-selects IP detection service based on record type (IPv4 or IPv6 endpoints of icanhazip / ifconfig.co / ipify)
• Remembers the last successful service to minimize latency
• Only calls Cloudflare API when IP actually changes
• IPv4 (A) and IPv6 (AAAA) support
• Single-run mode for cron jobs

Requirements

• Go 1.18+ (or use Docker )
• Access to Cloudflare API

Configuration

All configuration is done via environment variables:

Variable	Required	Description
CF_API_TOKEN	✅	Cloudflare API token (DNS edit permission)
CF_ZONE_ID	✅	Cloudflare Zone ID
CF_RECORD_NAME	✅	DNS record to update, e.g. home.example.com
CF_RECORD_TYPE	✅	A (IPv4) or AAAA (IPv6)
CF_CHECK_INTERVAL	—	Check interval in seconds (default: 300)
CF_TTL	—	DNS TTL in seconds (default: inherits existing record)
CF_PROXIED	—	true or false (default: inherits existing record)
CF_IP_URLS	—	Comma-separated IP detection service URLs (default: built-in list, auto-selected based on CF_RECORD_TYPE)

Quick Start

Run directly

export CF_API_TOKEN=your-token
export CF_ZONE_ID=your-zone-id
export CF_RECORD_NAME=home.example.com
export CF_RECORD_TYPE=A

go run main.go

Compile and run

go build -o scfddns .
./scfddns

Run once (for cron)

./scfddns -once

Docker

If using a proxy, add *.ipify.org, ifconfig.co, *.icanhazip.com to your bypass list.

Docker run

docker run -d \
  --name cloudflare-ddns \
  --restart unless-stopped \
  -e CF_API_TOKEN=your-token \
  -e CF_ZONE_ID=your-zone-id \
  -e CF_RECORD_NAME=home.example.com \
  -e CF_RECORD_TYPE=A \
  betterlmy/simple-cloudflare-ddns:latest

Docker Compose

Create a .env file:

CF_API_TOKEN=your-token
CF_ZONE_ID=your-zone-id
CF_RECORD_NAME=home.example.com
CF_RECORD_TYPE=A

Then run:

docker-compose up -d

Build your own image

git clone https://github.com/betterlmy/simple-cloudflare-ddns.git
cd simple-cloudflare-ddns
docker build -t simple-cloudflare-ddns:latest .

Docker image features

• Runs as non-root user
• Multi-arch: AMD64 and ARM64
• Alpine-based (~20MB)

Command Line Arguments

Flag	Description
-once	Run once and exit (suitable for cron)

How to Get Cloudflare Credentials

API Token

1. Go to Cloudflare API Tokens
2. Click "Create Token" → "Edit zone DNS" → "Use template"
3. Set permissions: Zone:DNS:Edit, select your zone
4. Copy the generated token

Zone ID

1. Go to Cloudflare Dashboard
2. Select your domain
3. Find "Zone ID" in the bottom-right of the Overview page

FAQ

Can't get public IP?

• The program tries multiple services automatically
• If all fail, check your network connection or proxy bypass list
• Restart the program to retry

DNS update not taking effect?

• Verify CF_ZONE_ID, CF_RECORD_NAME, and CF_RECORD_TYPE are correct
• Check that the API token has DNS edit permission
• Make sure there's no conflicting record of a different type in Cloudflare

Updates too frequent?

• Increase CF_CHECK_INTERVAL (recommended: 300–600 seconds for home users)

License

MIT License

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