Fail Closed Mechanism
A general problem with VPNs is that connections often fail to remain open. This means the VPN connection suddenly closes, leaving the user directly connected to the Internet (without first tunneling through the VPN). This is not a Whonix-specific problem. VPN servers and software can occasionally fail without prior notice. Therefore, if the VPN is unreachable or the connection breaks down for whatever reason, in most cases the user will continue to connect to the Internet without the VPN.
One of the key benefits of Whonix is that when a VPN connection fails, protection is still provided by the Tor process. In this instance, the Whonix-Workstation will seamlessly continue to make "direct" connections through Tor. Failure of the VPN tunnel may be inconsequential if a VPN is only used to circumvent Tor censorship. On the other hand, if VPN use is intended to improve security, then it must be configured so that if/when the VPN connection fails, all connections between the outside world and the computer are halted.