ETHTOOL_OPTS="autoneg off speed 100 duplex full"

This change will take effect on the next reboot or you can do the following to make it take effect immediately.

ethtool -s eth0 duplex full speed 100 autoneg off

ethtool -s eth1 duplex full speed 100 autoneg off

ifdown eth0 && ifup eth0 &

ifdown eth1 && ifup eth1 &

Please note that the last 2 lines actually restart the network interfaces. You can check and/or verify the settings by using the ethtool command. Example:

ethtool eth0