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Questions tagged [iperf]

128 questions
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Segmentation fault when running nuttcp inside Docker

I am measuring the UDP throughput between two Docker containers that are connected by Docker's native overlay network. I already used iperf but also want to measure the throughput with nuttcp. But when I am starting the server instance and then…
arne.z
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Is it reasonably safe to host a publicly accessible iperf3 server?

CentOS 6.x An IT team member would like run iperf3 on a publicly accessible server for the purpose of running on-demand connectivity checks from anywhere (no restrictions on remote source IP). Does this present any major security concerns? The…
Mike B
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Why is UDP slower than TCP on Ubuntu Server?

I transfer data between two Ubuntu Servers (12.04) via iperf on 1Gb LAN. iperf -s <-> iperf -c -n2G TCP speed = 925 Mbits/sec iperf -su <-> iperf -uc -b1G -n2G UDP speed = 810 Mbits/sec Jitter = 0.016 ms Lost = 0 ..…
Rom098
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Different versions of iperf for windows give totally different results

Measuring TCP output from a Windows client to Solaris server: WXP SP3 with iperf 1.7.0 --> returns an average around 90Mbit Same client, same server but iperf 2.0.5 for windows --> returns an average of 8.5 Mbit Similar discrepancies have been…
Albert Mata
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using random ports with iperf/iperf3

I am using Iperf/iperf3 -c remotehost which is iPerf3 is a tool for active measurements of the maximum achievable bandwidth on IP networks. It supports tuning of various parameters related to timing, buffers and protocols (TCP, UDP, SCTP with…
USER
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iperf3 error - unable to create a new stream: permission denied

I am new to using iperf but others in my company use it but today it is acting strangely. From the server: iperf3 -s which results in cmd showing: Server listening on 5201. From the client: iperf3 --format k --length 1 -t 10 -b 1K -i 1 -c…
tmwoods
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Difference in iperf output between client and server

Been playing with iperf for the last 4 hours and I'm unable to understand why the results are different in client and server. Consider the following iperf output on client : iperf -c 91.121.112.163 -p…
Eric MORAND
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How does iperf calculate throughput and jitter?

I've read that iperf basically tries to send as much information down a connection as quickly as possible reporting on the throughput achieved. This tool is especially useful in determining the volume of data that links between two machines can…
Varda Elentári
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iperf-like bidirectional bandwidth measurement through NAT

I am using iperf to measure my uplink speed between my home PC behind NAT and a fully accessible root server. It does so using a TCP connection. For whatever reason it seems that iperf can only measure client to server speed, where client is the one…
Paul
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iperf 2.0.5 on Windows 7: degraded/inaccurate throughput

Was testing out some wireless equipment today using iperf on (at first) two Windows XP workstations. Throughput testing was fairly consistent at around 18Mbps. Moved equipment around (outside), tested again this time with a Windows 7 laptop and one…
gravyface
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AMD EPYC 7413 slow down to arround 400mhz when running iperf

we are trying to setup a 40gbit connection between two servers and get weird cpu behaviour when using iperf. It is also only using around 10Gbit/s of the possible 40. Server specs: AMD EPYC 7413 8x MultiBitECC 3200 MHz 16384 MB Memory Supermicro…
Flaep
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using Iperf3 to test upload and download

How to use Ipfer3 to test upload and download speed or in other words which data of the output given below represents upload and download speed ? Iperf3 output
USER
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socat tun device very low throughput

I was tinkering around with socat and tried to use socat for creating a TUN device for tunneling between two debian stretch servers. However, throughput seemed very low and comparing with iperf against TCP/TCP-Listen on localhost, TUN has about 5…
1gd_1bs37coua9dd
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Why am I only achieving 2.5Gbps over a 10Gbe direct connection between 2 machines?

I have 2 machines directly connected to each other with a 7 foot Cat6a ethernet cable (included in the box of the NIC cards). The PCIe x4 NIC I bought and in both machines is this: https://www.amazon.com/gp/product/B07CW2C2J1 I'm trying to debug why…
Mike
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How can iperf reporting packet loss in udp

Iperf is the well known tool to calculate throughput. When i tried udp throughput using iperf on my linuxpc, It reported that 10% of packet loss. In UDP protocol, data gram did not receice any acknowledgements. But, in what way iperf is reporting or…
Vijay Kalyanam
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