How To Check Ethernet Connection Speed in Linux

In this article I will show How To Check Ethernet Connection Speed in Linux using 3 different ways.

Ethtool Show Speed

ethtool is powerful utility for query or control network driver and hardware settings for wired Ethernet devices.

To determine link connection speed using ethtool command type:

# ethtool eth0

example output:

ethtool command check eth speed

or if you want see brief report only about connection speed and nothing else:

# ethtool eth0 | grep Speed

Check Ethernet Connection Speed using mii-tool command

mii-tool utility checks or sets the status of a network interface’s Media Independent Interface (MII) unit. Most fast ethernet adapters use an MII to autonegotiate link speed and duplex setting.

# mii-tool eth0

Example output:

eth0: negotiated 1000baseT-FD flow-control, link ok

possible outputs for different connections:

1000baseTx-HD, 1000baseTx-FD,
100baseT4, 100baseTx-FD, 100baseTx-HD,
10baseT-FD, 10baseT-HD,
(to advertise both HD and FD) 1000baseTx, 100baseTx, 10baseT

View Interface Speed From Kernel

We can also ‘cat’ kernel files to check Ethernet connection speed:

# cat /sys/class/net/eth0/speed /sys/class/net/eth0/duplex

Example output:

Ethernet Connection Speed


You just learn How to Check Ethernet Connection Speed in Linux using ethtool, mii-tool, and kernel files.

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