Sur Online, ça semble plus stable :
iperf3 -c ping.online.net --get-server-output -R -p 5205 -6 -t 20
Connecting to host ping.online.net, port 5205
Reverse mode, remote host ping.online.net is sending
[ 7] local 192.168.200.115 port 50677 connected to 62.210.18.40 port 5205
[ ID] Interval Transfer Bitrate
[ 7] 0.00-1.00 sec 143 MBytes 1.20 Gbits/sec
[ 7] 1.00-2.00 sec 160 MBytes 1.35 Gbits/sec
[ 7] 2.00-3.00 sec 160 MBytes 1.34 Gbits/sec
[ 7] 3.00-4.00 sec 162 MBytes 1.36 Gbits/sec
[ 7] 4.00-5.00 sec 160 MBytes 1.34 Gbits/sec
[ 7] 5.00-6.00 sec 162 MBytes 1.36 Gbits/sec
[ 7] 6.00-7.00 sec 161 MBytes 1.35 Gbits/sec
[ 7] 7.00-8.00 sec 158 MBytes 1.32 Gbits/sec
[ 7] 8.00-9.00 sec 160 MBytes 1.35 Gbits/sec
[ 7] 9.00-10.00 sec 160 MBytes 1.35 Gbits/sec
[ 7] 10.00-11.00 sec 160 MBytes 1.34 Gbits/sec
[ 7] 11.00-12.00 sec 160 MBytes 1.34 Gbits/sec
[ 7] 12.00-13.00 sec 162 MBytes 1.36 Gbits/sec
[ 7] 13.00-14.00 sec 160 MBytes 1.34 Gbits/sec
[ 7] 14.00-15.00 sec 161 MBytes 1.35 Gbits/sec
[ 7] 15.00-16.00 sec 160 MBytes 1.34 Gbits/sec
[ 7] 16.00-17.00 sec 160 MBytes 1.34 Gbits/sec
[ 7] 17.00-18.00 sec 160 MBytes 1.35 Gbits/sec
[ 7] 18.00-19.00 sec 160 MBytes 1.34 Gbits/sec
[ 7] 19.00-20.00 sec 162 MBytes 1.36 Gbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bitrate Retr
[ 7] 0.00-20.00 sec 3.13 GBytes 1.35 Gbits/sec 0 sender
[ 7] 0.00-20.00 sec 3.12 GBytes 1.34 Gbits/sec receiver
Server output:
iperf 3.1.3
Linux ping 4.15.0-47-generic #50-Ubuntu SMP Wed Mar 13 10:44:52 UTC 2019 x86_64
-----------------------------------------------------------
Server listening on 5205
-----------------------------------------------------------
Time: Thu, 09 Jan 2020 18:22:29 GMT
Accepted connection from xxx, port 50676
Cookie: piwaxi5xlrwe5jxom6rr2s7hqnypg7bduwrc
TCP MSS: 1448 (default)
[ 5] local 62.210.18.40 port 5205 connected to xxx port 50677
Starting Test: protocol: TCP, 1 streams, 131072 byte blocks, omitting 0 seconds, 20 second test
[ ID] Interval Transfer Bandwidth Retr Cwnd
[ 5] 0.00-2.00 sec 318 MBytes 1.33 Gbits/sec 0 4.00 MBytes
[ 5] 2.00-4.00 sec 322 MBytes 1.35 Gbits/sec 0 4.00 MBytes
[ 5] 4.00-6.00 sec 322 MBytes 1.35 Gbits/sec 0 4.00 MBytes
[ 5] 6.00-8.00 sec 318 MBytes 1.33 Gbits/sec 0 4.00 MBytes
[ 5] 8.00-10.00 sec 321 MBytes 1.35 Gbits/sec 0 4.00 MBytes
[ 5] 10.00-12.00 sec 320 MBytes 1.34 Gbits/sec 0 4.00 MBytes
[ 5] 12.00-14.00 sec 321 MBytes 1.35 Gbits/sec 0 4.00 MBytes
[ 5] 14.00-16.00 sec 322 MBytes 1.35 Gbits/sec 0 4.00 MBytes
[ 5] 16.00-18.00 sec 320 MBytes 1.34 Gbits/sec 0 4.00 MBytes
[ 5] 18.00-20.00 sec 322 MBytes 1.35 Gbits/sec 0 4.00 MBytes
[ 5] 20.00-20.01 sec 1.25 MBytes 799 Mbits/sec 0 4.00 MBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
Test Complete. Summary Results:
[ ID] Interval Transfer Bandwidth Retr
[ 5] 0.00-20.01 sec 3.13 GBytes 1.35 Gbits/sec 0 sender
[ 5] 0.00-20.01 sec 0.00 Bytes 0.00 bits/sec receiver
CPU Utilization: local/sender 2.6% (0.0%u/2.6%s), remote/receiver 9.3% (1.7%u/7.8%s)
iperf Done.