Add Split Tunneling for L2TP/PPTP/SSTP VPN Clients.
This will allow clients to receive routes through the tunnel.
Some VPN clients like Windows L2TP VPN client can generate a DHCPINFORM message after connection to receive routes.
https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2003/cc779919(v=ws.10)?redirectedfrom=MSDN#split-tunneling
This feature can allow using L2TP/PPTP/SSTP protocol with different subnets on the local side and VPN client side (without transferring Internet traffic through VPN)