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I used to be able to connect to wireless networks and wired networks (although my wireless network had problems; see my other question). Then, one day, the section Wired Networks just disappeared! And when I plugin a cable, nothing happens! Why?

Despite having worked a while, the answer below seems to have stopped working for me. Therefore, my question is still active, and I anxiously await any replies.

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Can you add some hardware information to your question?… – Jorge Castro Dec 26 '10 at 22:31
Any specifics? I'm not sure where to start, as I don't know what has changed in the meantime. – Lyrositor Jan 1 '11 at 2:03
Anything in those log files that mention networking stuff, like the kind of hardware the network card is, etc. – Jorge Castro Jan 25 '11 at 13:16
up vote 1 down vote accepted

Edit /etc/network/interfaces and make sure it looks like this:

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto eth0

It sounds like it's blocking network-manager from configuring the interface.

share|improve this answer
Perfect! That worked! Thanks a lot! – Lyrositor Oct 24 '10 at 17:09
No, wait, it only worked a few hours and a few restarts. Four hours later, I booted up my computer to see that it was as before, and worse: this time, when I checked the file, auto eth0 was still there! So that means the problem lies elsewhere. – Lyrositor Oct 24 '10 at 21:14
Hold on... It's back again. What the... – Lyrositor Oct 25 '10 at 1:31
when i input the code it says permission denied – user11417 Feb 24 '11 at 17:35
You have to have admin rights to edit the file. Use something like gksudo gedit /etc/network/interfaces – Jonathon Feb 26 '11 at 11:20

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