It is recommended to run these commands in a screen (remote management module console) session as you will likely lose the SSH connection as soon as the new settings are applied
Important: Ensure that Ethtool is installed on your operating system before proceeding further.
Open the file:
# vi /etc/sysconfig/network-scripts/ifcfg-eth0
Append following line directly beneath the ‘DEVICE’ line:
ETHTOOL_OPTS="speed 100 duplex full autoneg off"
You can simply restart networking to change the port settings of your network interface. WARNING: This will terminate your SSH connection.