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 6 · Accepted Answer · edited Oct 17 '19 at 01:29

6

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

server side:

iperf3 -s

client side:

iperf3 -u -c client.ip.address -b 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 Oct 17 '19 at 01:29

WoJ

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answered Oct 16 '19 at 15:52

hank

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score 1 · Answer 2 · edited Oct 04 '19 at 13:05

1

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

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answered Oct 04 '19 at 11:58

Preash

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This is the same command I used in my question. This said, I checked a client with `-u` and the UDP connection is successful. It means that both TCP and UDP ports are opened automatically. – WoJ Oct 04 '19 at 13:31

How to start iperf3 server in UDP mode?

2 Answers2