How to start iperf3 server in UDP mode?

Question

I would like to test UDP connectivity with iperf3 but do not know how to start it in UDP server mode.

iperf3 -s only opens a TCP socket:

root@srv ~# lsof -i -P | grep iperf3
iperf3    21030            root    3u  IPv4 15606995      0t0  TCP *:5201 (LISTEN)

score 12 · Accepted Answer · edited Jan 20 '25 at 18:54

12

The syntax is a bit different for iperf3. Example 1Mbps udp test:

server side:

iperf3 --server

client side:

iperf3 --udp --client <server ip address> --bitrate 1M

What I find really interesting is the server-side doesn't start listening on the udp port until it receives the first incoming udp packet. This is weirdly unintuitive.

edited Jan 20 '25 at 18:54

Fidel

434

answered Oct 16 '19 at 15:52

hank

136

score 3 · Answer 2 · edited Oct 04 '19 at 13:05

3

You can open UDP socket in the port 5003 using the below command.

iperf3 -s -p 5003

edited Oct 04 '19 at 13:05

RalfFriedl

3,258

answered Oct 04 '19 at 11:58

Preash

31

score 1 · Answer 3 · answered Jul 29 '24 at 05:55

1

iperf3 -s -p port

it opens UDP socket as well.

answered Jul 29 '24 at 05:55

deokyong song

33

How to start iperf3 server in UDP mode?

3 Answers3