Network: Speed Test

In this tutorial, we test TCP WireGuard tunnel performance with the iperf3 tool.

iperf3 measures network throughput (maximum bits per second).

Install iperf3

Install an iperf3 implementation on both the WireGuard server and client.

Linux Debian Buster: sudo apt install iperf3 --assume-yes
macOS: brew install iperf3
Windows: TODO
iOS: install the app
Android: install the app

Test

Run iperf3 Server

The iperf3 server listens for incoming iperf3 client requests.

Run iperf3 in server mode on the WireGuard server. This is a blocking process; use ctrl-C to terminate the server.

$ iperf3 --server
-----------------------------------------------------------
Server listening on 5201
-----------------------------------------------------------

Test from macOS or Linux Client

With the WireGuard tunnel active, test the network speed. In this example:

--client 10.0.2.1 test against the WireGuard server via the tunnel
--omit 1 the first sample is omitted from the summary
--parallel 2 two network streams are run concurrently
--time 5 test is run for 5 seconds
--reverse we’re testing download (leave this out to test upload)
resulting average download speed is about 30 megabits per second

$ iperf3 --client 10.0.2.1 --omit 1 --parallel 2 --time 10 --reverse
Connecting to host 10.0.2.1, port 5201
Reverse mode, remote host 10.0.2.1 is sending
[  5] local 10.0.2.2 port 55507 connected to 10.0.2.1 port 5201
[  7] local 10.0.2.2 port 55508 connected to 10.0.2.1 port 5201
[ ID] Interval           Transfer     Bitrate
[  5]   0.00-1.00   sec   383 KBytes  3.14 Mbits/sec                  (omitted)
[  7]   0.00-1.00   sec   394 KBytes  3.23 Mbits/sec                  (omitted)
[SUM]   0.00-1.00   sec   778 KBytes  6.37 Mbits/sec                  (omitted)
- - - - - - - - - - - - - - - - - - - - - - - - -
[  5]   0.00-1.00   sec   898 KBytes  7.35 Mbits/sec
[  7]   0.00-1.00   sec  1002 KBytes  8.21 Mbits/sec
[SUM]   0.00-1.00   sec  1.86 MBytes  15.6 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
...
- - - - - - - - - - - - - - - - - - - - - - - - -
[  5]   9.00-10.00  sec   919 KBytes  7.52 Mbits/sec
[  7]   9.00-10.00  sec   882 KBytes  7.22 Mbits/sec
[SUM]   9.00-10.00  sec  1.76 MBytes  14.7 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.04  sec  18.6 MBytes  15.5 Mbits/sec    8             sender
[  5]   0.00-10.00  sec  18.2 MBytes  15.3 Mbits/sec                  receiver
[  7]   0.00-10.04  sec  17.6 MBytes  14.7 Mbits/sec    6             sender
[  7]   0.00-10.00  sec  17.0 MBytes  14.3 Mbits/sec                  receiver
[SUM]   0.00-10.04  sec  36.2 MBytes  30.2 Mbits/sec   14             sender
[SUM]   0.00-10.00  sec  35.2 MBytes  29.6 Mbits/sec                  receiver

iperf Done.

Keep the iperf3 Service Running in the Background

It is convenient to keep iperf3 always running on the WireGuard server.

Create a systemd unit configuration file at /etc/systemd/system/iperf3.service. (Use a command like sudo nano /etc/systemd/system/iperf3.service.)

[Unit]
Description=iperf3

[Service]
ExecStart=/usr/bin/iperf3 --server

[Install]
WantedBy=multi-user.target

Start the systemd unit and “enable” it so that it starts on boot.

$ sudo systemctl start iperf3
$ sudo systemctl enable iperf3
Created symlink /etc/systemd/system/multi-user.target.wants/iperf3.service → /etc/systemd/system/iperf3.service.

With iperf3 running as a systemd service, the STDOUT logs are written to log files instead of to the console. To view the logs, use journalctl.

$ sudo journalctl --follow --identifier iperf3 --output cat