Cisco Defense Orchestrator (CDO) will discover a site-to-site VPN tunnel when one of the peers is onboarded. If the second peer is not managed by CDO, you can filter the list of VPN tunnels to find the unmanaged device and onboard it:
- In the main navigation bar, select VPN > Site-to-Site VPN to open the VPN page.
- Select Table View.
- Open the filter panel by clicking .
- Check Unmanaged.
- Select the unmanaged device from the results.
- In the Peers pane on the right, click Onboard Device and follow the instructions on the screen.