Change Speed & Duplex settings of LAN card

To check the Speed & Duplex settings of your lan card use the command

• mii-tool or mii-tool eth0
• ethtool eth0

Now to change the Speed & the Duplex settings

• ethtool -s eth0 speed 100 duplex full
• ethtool -s eth0 speed 10 duplex half
• mii-tool -F 100baseTx-FD (to force a particular speed and duplex settings)

OR

• Go to this file /etc/sysconfig/network-scripts/ifcfg-eth0 & then and put this entry in the file
  
• ETHTOOL_OPTS="speed 100 duplex full autoneg off"

Once it is done do this

service network restart