Greetings!

This PC has Ubuntu 12.04 and kernel 3.5

After recent, small updates to the OS and some additional packages, I suddenly cannot access to internet: "Server Not Found".
It worked for years.

The PC is wired-connected on ETH1. I can ping the gateway successfully, as well as 127.0.0.1 and 8.8.8.8 (which I do not know what they are).

It all behaves the same if I try via WLAN instead of ETH.

The file /etc/resolv.conf contains:

nameserver 192.168.7.2
nameserver 192.168.1.241
search eng.myemployer.com

Ping to any of these fails totally.

I have another PC wire-connected and tablet/phones WiFi connected. All works just fine. Tha problem is only on this Ubuntu PC.

Can anyone help, please?

This tells me that you HAD a local DNS server at 192.168.1.241, and another in a different subnet at 192.168.7.1. Since those are non-routable addresses, they were NOT out on the internet. Since you HAVE network and can ping an external DNS server (8.8.8.8) we know you have a proper route to the world. IT is as if your local DNS servers are down, or you can no longer reach them.

Do this, make the first entry on your /etc/resolv.conf file read so you can resolve public names. That will get you some action while you investigate what happened to your local name servers.

PS: 127.0.0.1 is your loopback address. IT is generally registered as the LO (not ETHx) interface, and provides a way to test that your networking system is running. Since it is your own machine, it gives no information about your external connections.

1 members found this post helpful.

It works. Thank You. But... how should I investigate "what happened to your local name servers" ?

It all started after having installed some VPN packages to ssh-access (succesfully) to "eng.myemployer.com". Now of course I cannot access anything at all.

Among the running processes I see [/usr/sbin/sshd -D] and [/usr/bin/ssh-agent ......]

Not sure if this helps.
Thanks again.

pps. if you can ping public servers (8.8.8.8 is one) then you have internet. what you have not is name resolution (dns services) working.

Need a lot more information from you to answer that. Those DNS servers are non-standard. You, or somebody else, had to manually configure them somewhere. The question is why? Were there ever machines at those IPs? What happened to them? What does your network look like? And why did you feel it necessary to install VPN in order to SSH somewhere? Those are two completely different protocols.