Linux change the speed and duplex settings of an Ethernet card

To change the speed and duplex settings of an Ethernet card on a Linux system, you can use the ethtool command.

Here's an example of how to use ethtool to set the speed and duplex of the Ethernet interface eth0:

$ sudo ethtool -s eth0 speed 100 duplex full autoneg off

The above command sets the speed of the interface to 100 Mbps and the duplex to full. The autoneg option disables auto-negotiation, which allows the interface to negotiate the best possible speed and duplex settings with the connected device.

You can also use ethtool to display the current speed and duplex settings of an Ethernet interface:

$ ethtool eth0

Note: You will need to have the necessary privileges to run the sudo command.

It's also important to note that the specific options and syntax for the ethtool command may vary depending on your Linux distribution and version. Consult the ethtool man page or documentation for your system for more information.