Wired network for Lenovo S540 on Ubuntu 14.04

Installed Ubuntu 14.04 on a Lenovo S540 ultrabook. Wireless work fine, but had problems with the wired network!

Fix turned out to be upgrading drivers for the Realtek rtl8111/8168/8411 card. Use lspci | grep net to find what network card you have.

New drivers can be downloaded from Realtek:http://www.realtek.com/downloads/downloadsView.aspx?Langid=1&PNid=5&PFid=5&Level=5&Conn=4&DownTypeID=3&GetDown=false#RTL8111B/RTL8168B/RTL8111/RTL8168%3Cbr%3ERTL8111C/RTL8111CP/RTL8111D%28L%29%3Cbr%3ERTL8168C/RTL8111DP/RTL8111E%3Cbr%3ERTL8168E/RTL8111F/RTL8411%3Cbr%3ERTL8111G/RTL8111GUS

Source: https://www.mail-archive.com/kernel-packages@lists.launchpad.net/msg49591.html