Why is my network connection dropping in Ubuntu 12.04?

Question

ubuntu

Hello!
Recently (a couple of weeks ago) there was a problem with a wired connection in Ubuntu 12.04: skype, ssh clients fall off, pings fail.
Screenshot from a Wirth machine running on a problem computer (in the Ubuntu terminal, the moments when the network falls off are not clear):

Before that, everything worked fine for more than 2 years.
Initially, I sinned on the operator, then on the router, on the cable ... but it's not about them.
For example, I ping the router from 2 computers: from the problematic one and another one (works on win7). At a time when pings disappear on the problem computer, everything is stable on the other computer (router pings are coming, the Internet is working).
I plugged the cable of the problematic router into the socket of another computer in the router - the problem remained.
Replaced the cable - the problem remained.
Thus, the problem is not in the router, not in the cable and not in the provider.
Yes, the network is completely unloaded, there is no load on the problem computer, on the router.
Can you tell me how to identify the problem? How to understand whether software or hardware is crooked?

Answer 1

In ubuntu, during the problem, dmesg does not write anything?