Comment 21 for bug 1048817

ethtool -i eth0
driver: tg3
version: 3.121
firmware-version: 6.2.1 bc 5722-v3.11
bus-info: 0000:02:00.0
supports-statistics: yes
supports-test: yes
supports-eeprom-access: yes
supports-register-dump: yes

switched to 10Mbps - not one ping
switched to 100Mbps - 3 of 10 ping pass (randomly)
switched to 1000Mbps - not one ping
the switch is some cisco GbE auto-everithing

with: ethtool -K eth0 rx off tx off - same behaviour
with: ethtool -K eth0 tso off - same behaviour
after limited testing it seems like hardware problem,
same UTP cable moved on server side to some noname USB-NIC (dm9601) and the connection works perfectly.