Package ethtool

Settings tool for Ethernet NICs

http://ftp.kernel.org/pub/software/network/ethtool/

This utility allows querying and changing settings such as speed,
port, auto-negotiation, PCI locations and checksum offload on many
network devices, especially of Ethernet devices.

System Administration (Section 8)
ethtool
ethtool is used to query and control network device driver and hardware settings, particularly for wired Ethernet devices. devname is the name of the network...