I'm working on 11.10 for few recent days, everything was working perfect until today. Updated ubuntu (some certs were updates as far as i remember) and from this time, wired network stops working randomly and systematically. (All other pcs/macs work fine)

From 192.168.0.9 icmp_seq=25 Destination Host Unreachable
From 192.168.0.9 icmp_seq=26 Destination Host Unreachable
From 192.168.0.9 icmp_seq=27 Destination Host Unreachable
From 192.168.0.9 icmp_seq=28 Destination Host Unreachable
From 192.168.0.9 icmp_seq=29 Destination Host Unreachable
From 192.168.0.9 icmp_seq=30 Destination Host Unreachable
From 192.168.0.9 icmp_seq=31 Destination Host Unreachable
64 bytes from 192.168.0.1: icmp_req=32 ttl=64 time=1003 ms
64 bytes from 192.168.0.1: icmp_req=33 ttl=64 time=0.496 ms
64 bytes from 192.168.0.1: icmp_req=34 ttl=64 time=0.576 ms
64 bytes from 192.168.0.1: icmp_req=35 ttl=64 time=0.522 ms
64 bytes from 192.168.0.1: icmp_req=36 ttl=64 time=0.624 ms
64 bytes from 192.168.0.1: icmp_req=37 ttl=64 time=0.625 ms
64 bytes from 192.168.0.1: icmp_req=38 ttl=64 time=0.555 ms

It'll work for 20 seconds then it'll stop working for 10-30sec and so on. I've tried setting my router to give static IPs, it doesn't help. NOTHING has been changed since yesterday beside the package update...

Here are other settings that may be useful:

baka@baka-PC:~/Private/projects/wduk$ lspci -nnk | grep -iA2 net
06:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller [10ec:8168] (rev 06)
Subsystem: ASUSTeK Computer Inc. P8P67 and other motherboards [1043:8432]
Kernel driver in use: r8169

baka@baka-PC:~/Private/projects/wduk$ ifconfig -a
eth0      Link encap:Ethernet  HWaddr **Removed MAC address** 
      inet addr:192.168.0.9  Bcast:192.168.0.255  Mask:255.255.255.0
      inet6 addr: fe80::ca60:ff:fe0a:85b2/64 Scope:Link
      UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
      RX packets:6400 errors:0 dropped:6400 overruns:0 frame:6400
      TX packets:7085 errors:0 dropped:107 overruns:0 carrier:0
      collisions:0 txqueuelen:1000 
      RX bytes:4191983 (4.1 MB)  TX bytes:886881 (886.8 KB)
      Interrupt:72 Base address:0x2000 

lo        Link encap:Local Loopback  
      inet addr:127.0.0.1  Mask:255.0.0.0
      inet6 addr: ::1/128 Scope:Host
      UP LOOPBACK RUNNING  MTU:16436  Metric:1
      RX packets:2522 errors:0 dropped:0 overruns:0 frame:0
      TX packets:2522 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:0 
      RX bytes:1070130 (1.0 MB)  TX bytes:1070130 (1.0 MB)

baka@baka-PC:~/Private/projects/wduk$ cat /etc/resolv.conf
# Generated by NetworkManager
nameserver 8.8.8.8

thanks for help