how to enable to work both at same time LAN and internet network cards on ubintu 14.04 LTS

Solution

Normally ifplugd is active and will autoswitch between wireless and wired (disabling the other interface in the process). Priority is given to wired.

Normally ifplugd is active and will autoswitch between wireless and wired (disabling the other interface in the process). Priority is given to wired.
 
Solution