I am getting used to Ubiquiti, and recently added a VPN Client to cover one of my VLANs. Am I correct in my understanding that having no Fallback option is essentiall a Kill switch that will not allow traffic to pass outside of the VPN in the event it goes down?
I believe a fallback VPN would allow for a secondary connection in the event the primary goes down. If you have the networking configured to only route over the VPN and the connection goes down that network will not be able to route traffic until the connection is reestablished.
yes, that's what it means, but to be sure you must remove the default GW of your PCs routing table (which it may get via DHCP) and add a route only for the VPN server to go through the address that your default GW was. That way all connections trying to use something else will fail with a "no route to host" error.