Solution for VPN client not working after upgraded to Mac 10.10 Yosemite

Source: http://apple.stackexchange.com/questions/151345/vpn-client-is-not-working-after-yosemite-update-enforce-firewall-policy-fail

Solution: put computer into kext developer mode (-> 10.9 behavior)
   sudo nvram boot-args="kext-dev-mode=1"

To change back to 10.10 behavior (VPN client will not work)
   sudo nvram -d boot-args


After the change, you need to reboot the computer