This is a quick note on something I encountered while trying to work out why my Realtek NICs are so finicky about connecting and staying connected at gigabit speeds when running Linux.

The current hypothesis is that the r8168 driver isn't helping very much. So I uninstalled it - and ran into two problems.

Firstly

...you need to uninstall it on Ubuntu/Debian with apt-get remove --purge r8168-dkms or the config files (and it's all config files) won't be properly removed, and the module will be left installed.

Secondly

...you really need to make sure you've removed all the blacklist r8169 entries. They can be left behind if you don't purge configuration files, but I found I'd also left a few hanging around in the /etc/modprobe.d directory from earlier efforts. So a quick fgrep r8169 * would've saved me a lot of trouble and confusion as to why r8169 wasn't being automatically detected.

In my case it turned out I'd put a very official looking blacklist-networking.conf file in my modprobe.d directory. On both my machines.

Something about Realtek NICs?

If I find an answer I'll surely provide updates, but needless to say there's no rthyme or reason to when they do or do not work, other then they consistently don't work on kernel 3.11 with the r8168 driver it seems.