How to Check Network Interface Speed on Linux Print

Checking the network interface speed of a Linux server can help confirm whether the server is connected at 1Gbps, 10Gbps or another network speed.

This guide explains how to check network interface speed on Ubuntu and Debian using ethtool and other Linux tools.

Find Your Network Interface

First, list the available network interfaces:

ip link

You may see interface names such as:

eth0
ens3
ens18
enp1s0

You can also display IP addresses associated with each interface:

ip addr

Install ethtool

On Ubuntu or Debian:

sudo apt update
sudo apt install ethtool -y

Check Network Interface Speed

Run:

sudo ethtool eth0

Replace eth0 with your actual network interface.

Look for:

Speed: 1000Mb/s
Duplex: Full
Link detected: yes

This indicates a 1Gbps network connection.

For a 10Gbps interface, you may see:

Speed: 10000Mb/s
Duplex: Full
Link detected: yes

Display Only the Interface Speed

To display only the speed:

sudo ethtool eth0 | grep Speed

Example:

Speed: 10000Mb/s

Check Link Status

To verify whether the network link is detected:

sudo ethtool eth0 | grep "Link detected"

A working physical link normally displays:

Link detected: yes

Check Duplex Mode

Run:

sudo ethtool eth0 | grep Duplex

You will commonly see:

Duplex: Full

Full duplex allows simultaneous transmission and reception.

Check Interface Statistics

To inspect network interface statistics:

ip -s link show eth0

Look for increasing values under:

errors
dropped
overruns

Unexpected errors or dropped packets can indicate a network, driver or interface problem.

Check Driver Information

To see which network driver is being used:

sudo ethtool -i eth0

This can display information such as:

driver
version
firmware-version
bus-info

This information can be useful when troubleshooting physical dedicated servers.

Virtual Servers and VPS

On virtual machines, ethtool may not always report the actual physical port speed.

For example, a virtual network interface may display an unexpected value or may not expose link speed information at all.

This is normal in many virtualized environments.

The speed reported inside a VPS does not necessarily represent the actual bandwidth limit assigned by the hosting provider.

Interface Speed Is Not Internet Speed

A network interface showing:

Speed: 10000Mb/s

does not guarantee 10Gbps of Internet throughput.

The actual network performance can also depend on:

• Server bandwidth limits
• Upstream network capacity
• Routing
• Peering
• Network congestion
• CPU performance
• Virtualization
• Traffic shaping
• Remote server capacity

The interface speed only shows the link capability.

Test Actual Network Throughput

To measure real throughput between two servers, use iperf3.

Install it:

sudo apt install iperf3 -y

Then test against an iperf3 server you control:

iperf3 -c SERVER-IP

For high-speed connections, multiple parallel streams can also be tested:

iperf3 -c SERVER-IP -P 8 -t 30

Do not rely on a single destination when evaluating overall network performance.

1Gbps vs 10Gbps

A 1Gbps interface has a theoretical link rate of:

1000 Mbps

A 10Gbps interface has a theoretical link rate of:

10000 Mbps

Actual application throughput will normally be lower because of protocol overhead and other network factors.

Troubleshooting Slow Network Performance

If your network performance is lower than expected, check:

Interface speed

sudo ethtool eth0

Interface errors

ip -s link show eth0

Routing

ip route

Packet loss

mtr -n -rw -c 100 DESTINATION-IP

Throughput

iperf3 -c SERVER-IP

Combining these tests can help identify whether the limitation is related to the server, interface, routing or network path.

IDONCLOUD Network Infrastructure

IDONCLOUD provides VPS and Dedicated Server infrastructure with IPv4, IPv6 and high-bandwidth connectivity options.

Dedicated infrastructure with 1Gbps and multi-gigabit connectivity is available for workloads requiring consistent network performance.

Visit idoncloud.com to explore IDONCLOUD infrastructure.

Related Guides

• How to Test Network Speed on a Linux Server with iperf3
• How to Diagnose Packet Loss with MTR on Linux
• How to Use Traceroute on Linux
• How to Check Open Ports on a Linux Server
• 1Gbps vs 10Gbps Dedicated Server