Native Cisco VPN client in Catalina broken by LuLu

[grumpybozo]

With LuLu enabled, connecting to any VPN configured using the macOS-native Cisco client (NOT AnyConnect) fails slowly after entering the password, with the error message stating that negotiation haqs failed because the server cannot be reached and advising that the name could be wrong. That implies a problem due to either outbound packets or their replies being dropped silently. .

Disabling LuLu allows the connection to be negotiated successfully. Enabling LuLu after the VPN is established does NOT disable the VPN.