Recently I updated to ubuntu 11.10 – for no good reason. Now I think about it, the reason should be I forgot the golden maxima “don’t ‘fix’ it unless it is broken”.

After getting lost and tortured by the fancy interface, and found there was no way to roll back by package uninstallation. I reinstalled the system, and during various configurations later, BTW, I screwed up my Python installation and resintalled the os one more time. One thing especially lucky is I have my /home directory on a different hard disk sector – thank God I did that!

However, today after booting my ubuntu, I found I could no longer connect to the internet – although it was supposed to (I can connect from my Windows 7), many googling on my phone brought me the following solution.

sudo vi /etc/network/interfaces
# add the following two lines
auto eth0
iface eth0 inet dhcp
# quit vi and…
sudo /etc/init.d/networking restart

You can check the following reference for more explanation
http://lotphelp.com/lotp/ubuntu-network-suddenly-becomes-unreachable

And one more time, remember that:
don’t ‘fix’ it unless it is broken