I have internet via ethernet cable plugged in directly into my desktop machine; windows and ubuntu on the same machine.

The problem is that after loggin in internet is working (though the speed is less than on Windows) for about 10 mins, after which connection disappears: cannot ping anything, nslookup is not responding too. Then after about 10 mins connection is back.

I'm not much familiar with Ubuntu, sorry if some info is missing. I have

Ubuntu version: 10.04.4 LTS

Codename: lucid

(for some reason I have to stay on 10.04 and cannot upgrade to a newer version now)

Network interfaces:

~$ cat /etc/network/interfaces

auto lo

iface lo inet loopback

Ethernet controller:

~$lspci -v

...

07:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 06)

        Subsystem: ASUSTeK Computer Inc. Device 8432

        Flags: bus master, fast devsel, latency 0, IRQ 31

        I/O ports at d000 [size=256]

        Memory at f2104000 (64-bit, prefetchable) [size=4K]

        Memory at f2100000 (64-bit, prefetchable) [size=16K]

        Capabilities: <access denied>

        Kernel driver in use: r8169

        Kernel modules: r8169

...