Possible missing firmware fix
Error Possible missing firmware /lib/firmware/rtl_nic/rtl8411-2.fw for module r8169 Possible missing firmware /lib/firmware/rtl_nic/rtl8411-1.fw for module r8169 Possible missing firmware /lib/firmware/rtl_nic/rtl8402-1.fw for module r8169 Possible missing firmware /lib/firmware/rtl_nic/rtl8168f-2.fw for module r816
Fix
sudo apt-get install firmware-realtek