Setup os-ddclient for when external IP address changes

Here's a step-by-step guide in English on how to configure os-ddclient in OPNsense to automatically update your Cloudflare DNS records when your external IP address changes (e.g., from your ISP).

Prerequisites

Before you begin:

You need a Cloudflare account.
You need a domain managed by Cloudflare.
You should have your Cloudflare API token or API key (Token is preferred for security).
os-ddclient must be installed and enabled in OPNsense (System > Firmware > Plugins > install os-ddclient).

Step-by-step Configuration

1. Enable os-ddclient

Go to:

Services > Dynamic DNS > Settings
Check Enable
Click Save

2. Add a Dynamic DNS Account

Go to:

Services > Dynamic DNS > Accounts
Click ➕ Add

Now fill in the required fields:

General Settings

Enabled: ✅
Description: e.g., Cloudflare mydomain.com
Service: cloudflare
Protocol: namecheap (even though it's Cloudflare, this is used internally for IP updates)

Cloudflare API Credentials

You have two options: API Token (preferred) or Global API Key.

If you're using an API Token:

Username / Email: leave blank
Password: paste your API Token
Make sure your API token has permission to:
- Zone: DNS → Edit
- Zone: Zone → Read

I Made a new API token. When logged in on Cloudflare, go to the top right and click on Profile . Then go to {} API Tokens and add a new token for "Edit zone DNS". Save the token on a safe place.

If you're using a Global API Key:

Username / Email: your Cloudflare account email
Password: your Global API Key

The use of the Global API key for this is not recommended!

Hostname Details

Zone: your domain name (e.g., example.com)
Hostname: the DNS record you want to update (e.g., home.example.com)
Wildcard: usually unchecked unless you want *.home.example.com updated too
MX: leave empty (unless you're setting an MX record)
Back MX: leave empty
Offline: leave unchecked

IP Settings

Check IP Method: Interface (or use Web for online IP detection)
Interface to monitor: WAN
Force SSL: (recommended)

Click Save, then Apply.

Test the Setup

After saving, go to the Services > Dynamic DNS > Log File.
Click Run now next to your entry to test it.
Check the log to see if the IP update succeeded.

Done!

Your OPNsense box will now monitor your WAN IP and automatically update your Cloudflare DNS A or AAAA record whenever your public IP changes.