The fix worked for me with an RTL8111/8168B on an ASRock GM31 motherboard.
A quick note for users, when kernel updates automatically via Ubuntu update you need to repeat steps:
04 - $ cd /usr/src/r8168-8.005.00
05 - $ sudo make clean modules
06 - $ sudo make install
07 - $ sudo depmod -a
08 - $ sudo insmod ./src/r8168.ko
The fix worked for me with an RTL8111/8168B on an ASRock GM31 motherboard.
A quick note for users, when kernel updates automatically via Ubuntu update you need to repeat steps: r8168-8. 005.00
04 - $ cd /usr/src/
05 - $ sudo make clean modules
06 - $ sudo make install
07 - $ sudo depmod -a
08 - $ sudo insmod ./src/r8168.ko