A chronological documentation test project, nothing serious, really!

19 Jan 2010 Change ethernet settings using ethtool

Force network speed on a network card to 100 MBit Full Duplex and in the same time disable auto negotiation

# ethtool -s eth0 speed 100 duplex full autoneg off

These settings are active until you reboot the machine or restart the network.

In order to keep this change on each system reboot, append the following line in the following Redhat file /etc/sysconfig/network-scripts/ifcfg-eth0

ETHTOOL_OPTS="speed 100 duplex full autoneg off"

An alternative tool to use to change the settings is mii-tool.

Tags: ,

Posted by

02 Mar 2008 Determine which interface is eth0

It can sometimes be difficult to determine which networcard is eth0, eth1 and so on. A easy way to determine it is to use the ethtool command

ethtool -p eth0 10

This makes the network cards LED blink for 10 seconds, and this happens without interrupting the network traffic.
You do offcourse need physical access to the server to actually see that the LEDs blink :)

To install this tool in Debian you have to run the command

apt-get install ethtool


Posted by