Setting up Tailscale on OPNSense in 2025

Prep

Please ensure you are running atleast OPNSense 25.1.1

Install

1. Navigate to System > Firmware > Plugins
2. Install the os-tailscale Plugin (If plugins do not load Navigate to status and select check for updates)

Tailscale setup

1. Naviate to Tailscale Admin Dashboard
2. Select Genereate auth key
3. Select Generate Key
4. Copy your Auth Key
5. Navigate to VPN > Tailscale > Authentication on your firewall
6. Paste your Auth key into Pre-authentication Key and select Apply
7. Navigate to VPN > Tailscale > Settings
8. Select Enabled and click Apply

Interface Setup

1. Navigate to Interfaces > Assignments
2. Add the Tailscale Interface
3. Open the interface you just added
4. Select Enable Interface
5. Add the Description Tailscale
6. Select Save

Firewall Rule Setup

1. Navigate to Firewall > Rules > Tailscale
2. Select the Oragen + Icon
3. Select Save