Using ethtool to check and change Ethernet Card Settings

ethtool is used for querying settings of an ethernet device and changing them. ethtool is the replacement tool for mii-tool

# ethtool eth0

 As seen in the above diagram, ethtool information is very informative and helpful for diagnostic

Other useful  command includes

# ethtool -i eth0 (provide information regarding eth0 including drivers)

# ethtool -S eth0 (provide information regarding the speed and other information)

Taken from ethtool from softpanorama. You can use ethtool command to set specific parameter on the NIC

# ethtool -s eth0 speed 100 duplex full autoneg off