Local Area Network (LAN) Bandwidth Speed Test

If you want to test the network speed between computers on the same local area network, you can use the iperf3 tool. Think of this as using Speedtest.net, but instead of measuring your Internet speed, you’re measuring the speed within your local network (intranet).

For example, suppose you have a MacBook connected via Wi-Fi and a Windows PC connected via wired LAN. You want to see how fast file transfers are within your LAN. For this tutorial, let’s assume the macOS IP address is 192.168.1.10 and the Windows PC is 192.168.1.2.

Installing iperf3

The first thing we need to do is to install iperf3 on every machine we want to test.

Install iperf3 on macOS

On macOS, you can install it with Homebrew:

brew install iperf3

Install iperf3 on Windows

On Windows, you can install it with Scoop:

scoop install iperf3

Alternatively, you can also install it with winget on Windows:

winget install ar51an.iPerf3

Install iperf3 on Debian-based Linux

If you’re using a Debian-based Linux distribution, you can install iperf3 with:

sudo apt install iperf3

Starting iperf3 Test

Next, start iperf3 in server mode on one of the machines. In this example, start it on the Windows PC:

$ iperf3 -s
-----------------------------------------------------------
Server listening on 5201 (test #1)
-----------------------------------------------------------

Then, from the other machine (the MacBook in this case), run iperf3 in client mode to test the bandwidth speed. Use the command iperf3 -c $IP_ADDRESS. Since the server is on Windows, run iperf3 -c 192.168.1.2.

$ iperf3 -c 192.168.1.2
Connecting to host 192.168.1.2, port 5201
[  5] local 192.168.1.10 port 53766 connected to 192.168.1.2 port 5201
[ ID] Interval           Transfer     Bitrate
[  5]   0.00-1.01   sec  17.1 MBytes   143 Mbits/sec
[  5]   1.01-2.01   sec  17.6 MBytes   148 Mbits/sec
[  5]   2.01-3.01   sec  17.1 MBytes   144 Mbits/sec
[  5]   3.01-4.00   sec  17.9 MBytes   150 Mbits/sec
[  5]   4.00-5.00   sec  17.5 MBytes   147 Mbits/sec
[  5]   5.00-6.00   sec  17.9 MBytes   150 Mbits/sec
[  5]   6.00-7.01   sec  17.5 MBytes   146 Mbits/sec
[  5]   7.01-8.00   sec  17.6 MBytes   148 Mbits/sec
[  5]   8.00-9.00   sec  17.8 MBytes   149 Mbits/sec
[  5]   9.00-10.00  sec  17.4 MBytes   145 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate
[  5]   0.00-10.00  sec   175 MBytes   147 Mbits/sec                  sender
[  5]   0.00-10.02  sec   175 MBytes   147 Mbits/sec                  receiver

iperf Done.

Once the test is complete, you can see a summary of the network speed between the computers.

That’s it! Thanks for reading.

Video

References

• iPerf - The TCP, UDP and SCTP network bandwidth measurement tool