./iperf_2.0.5-2_amd64 -c 10.5.0.35 -r -u
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Client connecting to 10.5.0.35, UDP port 5001
Sending 1470 byte datagrams
UDP buffer size:  124 KByte (default)
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[  3] local 10.5.0.113 port 34961 connected with 10.5.0.35 port 5001
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Server listening on UDP port 5001
Receiving 1470 byte datagrams
UDP buffer size:  124 KByte (default)
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[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-10.0 sec  1.23 MBytes  1.03 Mbits/sec
[  3] Sent 893 datagrams
read failed: Connection refused
[  3] WARNING: did not receive ack of last datagram after 5 tries.