Cloudflare IP Updater

Overview

The Cloudflare IP Updater is a Go-based application that updates Cloudflare DNS A records whenever your public IP address changes. This ensures that your domain always points to your current IP address. The updater runs as a background process, checking your IP address every 2 minutes.

TL;DR: Open home server to internet without static ip

Features

• Periodically checks your public IP address.
• Updates Cloudflare DNS A records if the IP address has changed.
• Runs as a lightweight service.
• Can be deployed using Docker.

Prerequisites

• Go 1.21.4 or later (for building from source).
• Docker (for containerized deployment).
• Cloudflare account with API key and appropriate permissions.

Adding {filter} in Comment of DNS Record

To ensure the application can identify and update the correct Cloudflare DNS A records, include the {filter} value in the comment of each DNS record you want to be updated. Follow these steps:

1. Log in to your Cloudflare account.

2. Navigate to the DNS settings of your domain.

3. Locate the A records you want the application to update.

4. Edit the A records:

   • Click on the edit button next to the A record.
   • Add the {filter} value in the comment section of the DNS record. For example, if your filter value is self_managed, your comment should include self_managed.
   • 

5. Save the changes to the DNS records.

By adding the {filter} value to the comments of the DNS records, the application can accurately identify which records to update based on the filter you provide when running the application.

Generating Access Keys from Cloudflare

To use the Cloudflare IP Updater, you need to generate an API token with the necessary permissions. Follow these steps to create an API token:

1. Log in to your Cloudflare account.

2. Go to the API Tokens page:

   • Click on your profile icon in the top right corner.
   • Select My Profile from the dropdown menu.
   • Navigate to the API Tokens tab.

3. Create a new API token:

   • Click on Create Token.

4. Configure the API token:

   • Under Custom Token, click on Get started.

5. Set up permissions:

   • Zone Resources:
     • Zone: Include All Zones or Specific Zone based on your requirement.
     • DNS: Select Edit permission.
   • 

6. Specify the zone resources:

   • Choose All Zones if you want the token to have access to all your zones.
   • Otherwise, select Specific Zone and specify the zone you want to manage.

7. Complete the setup:

   • Give your token a descriptive name.
   • Optionally, set an expiration date for the token.

8. Create and save the token:

   • Click on Continue to summary.
   • Review the token settings.
   • Click on Create Token.
   • Copy the generated API token and store it securely. You will need this token to authenticate the Cloudflare IP Updater.

By following these steps, you will have a Cloudflare API token with the necessary permissions to update DNS records. Use this token as the auth_key when running the Cloudflare IP Updater.

Getting the Zone Identifier from Cloudflare

The Zone Identifier (Zone ID) is a unique identifier for your domain in Cloudflare. You need this ID to configure the Cloudflare IP Updater. Follow these steps to obtain the Zone Identifier:

1. Log in to your Cloudflare account.

2. Select the domain for which you need the Zone Identifier:

   • From the Cloudflare dashboard, click on the domain name in the list of your sites.

3. Find the Zone Identifier:

   • Once you are on the Overview page for your domain, scroll down to the API section on the right-hand side.
   • Here, you will see the Zone ID.

4. Copy the Zone Identifier:

   • Click on the Copy button next to the Zone ID to copy it to your clipboard.

You will use this Zone Identifier as the zone_identifier parameter when running the Cloudflare IP Updater.

Installation

Build from Source

1. Clone the repository:

   git clone https://github.com/your-repo/cloudflare-ip-updater.git
   cd cloudflare-ip-updater

2. Build the application:

   go build -o cloudflare-ip-updater

3. Run the application:

   ./cloudflare-ip-updater -zone_identifier your_zone_id -auth_key your_auth_key -filter your_filter

Using Docker

Build Docker Image

1. Clone the repository:

   git clone https://github.com/your-repo/cloudflare-ip-updater.git
   cd cloudflare-ip-updater

2. Build the Docker image:

   docker build -t cloudflare-ip-updater:latest .

3. Run the Docker container:

   docker run -d --name cloudflare-ip-updater \
     cloudflare-ip-updater:latest \
     -zone_identifier your_zone_id -auth_key your_auth_key -filter your_filter

Using Docker Compose

1. Clone the repository:

   git clone https://github.com/your-repo/cloudflare-ip-updater.git
   cd cloudflare-ip-updater

2. Create a .env file with your configuration:

   ZONE_IDENTIFIER=your_zone_id
   AUTH_KEY=your_auth_key
   FILTER=your_filter

3. Run the application using Docker Compose:

   docker-compose up -d

Usage

Command Line Arguments

• -zone_identifier: Cloudflare Zone Identifier (required)
• -filter: Cloudflare A record filter (required)
• -auth_key: Cloudflare Authentication Key (required)

Example

./cloudflare-ip-updater -zone_identifier your_zone_id -auth_key your_auth_key -filter your_filter

Docker Example

docker run -d --name cloudflare-ip-updater \
  cloudflare-ip-updater:latest \
  -zone_identifier your_zone_id -auth_key your_auth_key -filter your_filter

Docker Compose Example

Create a .env file with your configuration values. Then, run:

docker-compose up -d

Implementation Details

Main Program Flow

1. The application reads the required flags (zone_identifier, filter, and auth_key).
2. It validates the presence of required flags.
3. It initializes a CloudflareService instance.
4. A Goroutine checks the current IP address every 2 minutes.
5. If the IP address has changed, it updates the Cloudflare DNS A records.

Functions

• main(): The entry point of the application.
• checkRequiredFlags(): Validates the presence of required flags.

Contributing

Feel free to submit issues, fork the repository, and send pull requests.

License

This project is licensed under the MIT License. See the LICENSE file for details.