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I let my laptop upgrade to 12.04. And have no network afterwards. I went through all the articles I could find in google.

Right now, I can ping google, and yahoo, but not for example or anything else. Firefox says it can't reach or (or anything, not even IP.


dns-nameservers                       <<<<<added
auto lo
iface lo inet loopback


#prepend domain-name-servers,;
prepend domain-name-servers;                 <<<<< tried both

/etc/NetworkManager/NetworkManager.conf with and without dns=dnsmasq commented out.

I can ping my wireless router and connect to it just fine.

Have tried proxy/noproxy.

This looks like After Upgrade to 12.04 - cannot connect to network but no answer there.

I would hate to do a fresh install. Any assistance appreciated.

share|improve this question

I had the same issue. No more cable network after upgrade !!! The only solution I found is to remove the network manager and manually edit my /etc/network/interfaces file to have network using cable working;

Unfortunately, this solution has the drawback than nothing is display in notification area.

For information, a fresh install didn't solve the issue for me, so I guess there is some bug somewhere with the network manager.

to remove network-manager

sudo apt-get remove network-manager

A reboot may be required ...

edit the /etc/network/interfaces file

sudo gedit /etc/network/interfaces

and add the following lines depending on the network connexion you want to use (eth0, th1, etc ...)

auto eth1
iface eth1 inet dhcp
share|improve this answer
How do you remove the network manager? – Reg Sep 3 '12 at 20:40
I edited the answer to answer. – Manuel Selva Sep 3 '12 at 21:17
I tried the interfaces modification, after that reboot I could not use nm-tool. Removed the eth1 entry (which happens to be my wireless), rebooted and still says connect: Network is unreachable. Seriously, a OS update should not leave you in a mess like this. – Reg Sep 3 '12 at 22:53
So, I am back to a stage where I can ping all sorts of websites. but browsers still don't work. I do not have firestarter, so no idea why my connections get refused. – Reg Sep 5 '12 at 3:41

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