Configuring Dynamic DNS on OPNsense

These steps are based on the guide configuration shared in the OPNsense Reddit Community.

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Cloudflare Configuration

1. Create an API Token: Go to My Profile > API Tokens and click Create Token.
2. Select Template: Locate Edit zone DNS and click Use template.
3. Name the Token: Change the token name if desired (e.g., OPNsense DDNS).
4. Set Permissions: Set permissions to Zone > DNS > Edit.
5. Set Zone Resources: Set to Include > Specific zone > [Select the zone you want OPNsense to update].
6. Review Summary: Leave the remaining settings at their defaults and click Continue to summary.
7. Generate Token: If the configuration looks correct, click Create Token.
8. Test (Optional): Copy the provided test code and paste it into your terminal to verify the setup if desired.
9. Save the Token: Copy the generated token and save it securely (e.g., in a password manager), as this is the only time it will be visible.

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OPNsense Configuration

General Settings

1. Navigate to Services > Dynamic DNS > Settings > General settings.
2. Check the box to Enable.
3. Set the Interval (e.g., 360 seconds for 10 updates per hour).
4. Set the Backend to ddclient.
   • Note: If this backend option is missing, navigate to System > Firmware > Plugins and install os-ddclient by clicking the + icon.

Account Settings

1. Click the Accounts tab at the top and click the orange + icon to create a new account.
2. Configure the entry with the following details:
   • Enabled: Check this box
   • Description: Enter an identifying name (e.g., Cloudflare)
   • Service: Select Cloudflare
   • Username: Leave blank
   • Password: Paste your Cloudflare API token
   • Zone: Enter your domain zone (must match the zone configured in Cloudflare, e.g., domain.com)
   • Hostname(s): Enter the specific domain or subdomain to update (e.g., subdomain.domain.com)
   • Check IP Method: Set to Interface
   • Interface to Monitor: Set to WAN
   • Force SSL: Check this box
3. Click Save to apply the configuration.