kernel

r8169: rtl_nic/rtl8168f-2.fw, rtl_nic/rtl8168f-1.fw, rtl_nic/rtl8105e-1.fw, rtl_nic/rtl8168e-3.fw, rtl_nic/rtl8168e-2.fw, rtl_nic/rtl8168e-1.fw,     │
  │ rtl_nic/rtl8168d-2.fw, rtl_nic/rtl8168d-1.fw                                                                                                         │
  │                                                                                                                                                      │
  │ Most firmware files are not included in the system because they do not conform to the Debian Free Software Guidelines. You may need to reconfigure   │
  │ the package manager to include the contrib and non-free sections of the package archive before you can install these firmware files.