charles@hawk:~$ apt-file search rtl_nic/rtl8168g-2.fw firmware-realtek: /lib/firmware/rtl_nic/rtl8168g-2.fw charles@hawk:~$ You should do similarly. If the log shows that the driver wants firmware but can't find it, you may need to install the appropriate firmware package. I understand that some hardware will work without the firmware blob, but work much better with it. This may be one of those situations.
I remember reading somewhere (while researching to buy my hardware) that they had to remove firmware to make the NIC work. So, I thought I should not install any binary firmware. Now that I hear that you are using the firmware, I am going to try adding it to see if that changes anything. Let us hope it is just this.
Regards Ramesh