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Questions tagged [iperf]

42 questions
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How to perform a network loopback test using TTCP or IPERF?

The PC has two Gigabit Ethernet ports. They function as two separate network adapters. I'm trying to do a simple loopback test between the two. I've tried TTCP and IPERF. They're giving me hard time because I'm using the same physical PC. Using…
Samir
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iperf giving incorrect results

I've just had new broadband installed, and wanted to test its throughput using iperf3. However it appears to be giving considerably different results than more conventional speed tests. E:\tmp> iperf3 -c 3.testdebit.info - - - - - - - - - - - - - -…
Michael B
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iperf returning “bind failed: cannot assign requested address” in Windows XP and 7

I am trying to set up iperf on an old HP server running Windows XP Professional to test multicast, but whenever I issue the command iperf -s -u -B , it returns: bind failed: Cannot assign requested address It doesn't matter what I put…
Liesmith
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Iperf tests in reverse direction

I used iperf to measure the max throughput for TCP connection between two ubuntu machines. Both the machines were directly connected be means of a 1Gbps cable. When I performed iperf tests i obtained a bandwidth of 845 Mbps on an average. But when i…
user3226732
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Iperf for Windows - where to find newer versions?

I have just noticed that in openSuse I have iperf version 3.5, where as on Windows I cannot find anything newer then 3.1.3, which dates from June 2016! I still assume that iperf is the most recommended, cross platform, tool to measure network…
Espinosa
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How to run IPERF on DD-WRT?

I have IPERF for Windows installed on a desktop computer. Now I want to connect this computer to the router and conduct a simple throughput performance test. For that I will need IPERF running on the router. The router has the Linux based DD-WRT…
Samir
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TCP throughput much better than UDP

I'm monitoring the performances of a WAN link with iperf between two windows machines on both ends. Surprisingly (for me), TCP single session default window reaches a throughput of 12Mbps, while UDP limit (0% packet loss) is about 4Mbps. Bandwidth…
kuma
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ping works but iperf3 doesn't show any traffic for TCP

machine A has IP (eth0: 192.168.1.1, eth1: 10.10.xxx.yy) machine B has IP (eth0: 192.168.1.2) A and B are connected through RJ5 on eth0, both sides. ping works fine on both side, but when running iperf3 on a client-server mode, it doesn't show any…
iamauser
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Speed over VPN is 10x slower than connection to VPN or VPN<=>Destination

I'm trying to setup VPN for my own use. I have noticed very strange issue with speeds which I struggle to understand. Question: What is causing slow download speed from AWSFrankfurt when using VPN? Setup: [HOME] My ISP home connection with…
Yan
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Why is iPerf UDP bandwidth so much lower that iPerf TCP?

I need to perform a single direction iPerf test. Bi-directionally, using TCP, I get 25Mbps. But single direction using UDP I only get 0.7Mbps. Why is UDP rate so much lower that TCP? iPerf client setting: bin/iperf3.exe -c 10.31.186.128 -u -P 1 -i 1…
Doug Null
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Can I have server and client on the same machine and run network bandwidth test using iperf?

I have two ethernet ports (eth0 and eth1) on my system. I've tested the bandwidth with two systems and got ~940Mbit/s. If I use one of the ports as server and the other as client, I always go through the internal loopback and get really high…
tmp
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Iperf network benchmark measures under-utilized?

I am working on two embeddded high performance network routers and I have connected them point-to-point via a 10Gbit optical fibre cable. I ran iperf benchmarks on them and when I connect through an optical fibre point to point, I get slightly more…
Vigneshwaren
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Why is iperf3 faster in one direction than the other?

I've got a Windows 10 PC with Realtek RTL8125b 2.5GbE interface and I have a Debian Linux 5.10 server with an Intel I225-LM (rev 3) 2.5GbE interface. Running iperf3 -s on the server I get 1.14Gbit/s. If I use -R (reverse) option on the client I get…
Chris_F
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How does one test the LAN speed without a server?

When I need to test the intranet speed I typically use iperf3 at both ends (server and client) to check the flow rate between them. However recently when I tried some apps in the Play Store I noticed this app which claims to test the speed between…
phuclv
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Troubleshooting LAN transfer between a Windows PC and a Raspberry Pi using iPerf

I am trying to transfer GoPro files from my desktop Windows PC to a Raspberry Pi media server. Ive been using WinSCP before, and it always worked great, but in the past 6 months or so, the transfer speeds seem to have been totally throttled. When I…
Joel L
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