Updating ethernet driver
Like other hardware devices in your computer, the network adapter may require you to install updated drivers for better performance.However every time I run "apt-get upgrade", the driver I have downgraded gets updated.While simply reinstalling the old driver fixes the issue, it's quite annoying. The driver that works is "r8168" and the newer driver that doesn't work is "r8169".Some people say the r8168 driver from Realtek works better than the r8169 driver from the Linux kernel.
If I'm right, then you're installing a kernel module on top of the drivers installed by the linux-image-* package from apt.
You can download these drivers from the network adapter’s manufacturer website.