Invalid bandwidth

[ipetrushin]

• Hardware:

• Operating system (and distribution, if any):
  Linux srv1c 2.6.32-504.23.4.el6.centos.plus.x86_64 setting of window size should be explicit #1 SMP Wed Jun 10 13:09:42 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux
  CentOS 6

iperf version 2.0.5 (08 Jul 2010) pthreads

iperf -c iperf.mts-nn.ru -t 60 -i 1 -p 5201
gives abnormal speed:

Client connecting to iperf.mts-nn.ru, TCP port 5201
TCP window size: 19.3 KByte (default)

[ 3] local 192.168.0.10 port 58702 connected with 213.177.97.66 port 5201
[ ID] Interval Transfer Bandwidth
[ 3] 0.0- 1.0 sec 18014398509481962 KBytes 18014398509481962 KBytes/sec
[ 3] 1.0- 2.0 sec 18014398509481918 KBytes 18014398509481918 KBytes/sec
[ 3] 2.0- 3.0 sec 18014398509481916 KBytes 18014398509481916 KBytes/sec
[ 3] 3.0- 4.0 sec 18014398509481916 KBytes 18014398509481916 KBytes/sec
[ 3] 4.0- 5.0 sec 18014398509481918 KBytes 18014398509481918 KBytes/sec
[ 3] 5.0- 6.0 sec 18014398509481916 KBytes 18014398509481916 KBytes/sec
[ 3] 6.0- 7.0 sec 18014398509481916 KBytes 18014398509481916 KBytes/sec

This occurs only with given server, but from differetn machine everything goes OK:
Ubuntu 16.04, Linux teacher-MS-7A74 4.13.0-41-generic #46~16.04.1-Ubuntu SMP Thu May 3 10:06:43 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

iperf version 2.0.10 (11 Aug 2017) pthreads
iperf -c iperf.mts-nn.ru -t 60 -i 1 -p 5201

Client connecting to iperf.mts-nn.ru, TCP port 5201
TCP window size: 85.0 KByte (default)

[ 3] local 194.176.114.13 port 52156 connected with 213.177.97.66 port 5201
[ ID] Interval Transfer Bandwidth
[ 3] 0.0- 1.0 sec 1.25 MBytes 10.5 Mbits/sec
[ 3] 1.0- 2.0 sec 1.38 MBytes 11.5 Mbits/sec
[ 3] 2.0- 3.0 sec 1.62 MBytes 13.6 Mbits/sec
[ 3] 3.0- 4.0 sec 1.88 MBytes 15.7 Mbits/sec
[ 3] 4.0- 5.0 sec 1.88 MBytes 15.7 Mbits/sec
[ 3] 5.0- 6.0 sec 2.00 MBytes 16.8 Mbits/sec
[ 3] 6.0- 7.0 sec 1.12 MBytes 9.44 Mbits/sec
[ 3] 7.0- 8.0 sec 1.25 MBytes 10.5 Mbits/sec

[FuzzyStatic]

@ipetrushin this repo supports iperf3, it looks like you are using iperf2. Typically the binary name for iperf2 is iperf where the binary name for iperf3 (https://github.com/esnet/iperf) is iperf3.

Can you try installing iperf3 and running your tests again?