Device Level L2TP VPN: Using VPN Rule Configuration Overview
After you have configured the VPN on each device you want to include in the VPN, you can add a VPN rule to a security policy:
For policy-based VPNs, you must add a VPN rule to create the VPN tunnel.
For route-based VPNs, the VPN tunnel is already in place. However, you might want to add a VPN rule to control traffic through the tunnel.
For details on adding VPN rules to a security policy, see Adding VPN Rules to a Security Policy Overview.