If your Turbo NAS is located behind a router, please check the following settings on your router:
- Port forwarding. Your router must be set up to forward VPN-related protocols. Please refer to the “Setup port forwarding on your router” section of this tutorial: How to set up a QNAP NAS as a VPN server?
- VPN or NAT passthrough. If NAT is enabled on the router, you must enable “NAT passthrough” for VPN-related protocols (this is known as “VPN passthrough” on some routers). See your router’s manual for details.
Note: If your router does not support NAT passthrough, you will not be able to establish a VPN connection to your Turbo NAS through the router.
Other known issues:
When using the L2TP/IPSec VPN Service, if there is a mobile device connected to the Turbo NAS VPN server with WiFi, other devices in the same subnet might not be able to connect to the NAS VPN server. The problem can be resolved by connecting the devices to different subnets.