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8
votes
2answers
369 views

Extreme UDP packet loss at 300Mbit (14%), but TCP > 800Mbit w/o retransmits

I have a linux box I use as the iperf3 client, testing 2 identically equipped Windows 2012 R2 server boxes with Broadcom BCM5721, 1Gb adapters (2 ports, but only 1 used for the test). All machines are ...
7
votes
1answer
2k views

iperf max udp multicast performance peaking at 10Mbit/s?

I'm trying to test UDP multicast throughput via iperf but it seems like it's not sending more than 10Mbit/s from my dev machine: C:\> iperf -c 224.0.166.111 -u -T 1 -t 100 -i 1 -b 1000000000 ...
6
votes
3answers
11k views

Pre-compiled Iperf 2.x binary for win32?

I'd like to do some network testing on Windows using Iperf. The latest on sourceforge appears to be 2.0.4. However, it's only available as source to be compiled. I attempted to do some google ...
6
votes
4answers
7k views

Packet loss rate with iperf and tcpdump

I tested a line for its link quality with iperf. The measured speed (UDP port 9005) was 96Mbps, which is fine, because both servers are connected with 100Mbps to the internet. On the other hand the ...
6
votes
1answer
4k views

Increasing the number of outbound TCP connections

I am developing a small test client for websockets. I am using Ubuntu 11.04 . I have read http://stackoverflow.com/questions/410616/increasing-the-maximum-number-of-tcp-ip-connections-in-linux and I ...
5
votes
1answer
8k views

ESXi 5.5, slow network speed when writing to guests

This is an issue that has been bugging me for a lot time with ESXi. I had the issue with my old Dell server (ESXi 5.0 and 5.5) and even with my new Dell T20 (ESXi 5.5). For the current issue at hand I ...
4
votes
3answers
2k views

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 ...
3
votes
4answers
4k views

Iperf CSV output format

If I use iperf with -y C and -r arguments to test bidirectional transfer and export it as a CSV. I get some output but the problem is that I don't know what the column names are. For example it shows ...
3
votes
1answer
1k views

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 ...
3
votes
1answer
242 views

Bandwidth Throttling using tc qdiscs

I am trying to limit the bandwidth between a simple iperf server and client, using a third, passive machine acting as a bridge. With no interference, iperf returns a bandwidth of ~90 Mbits/sec. My ...
3
votes
1answer
2k views

IPerf - Reverse test

I'm trying to perform a test using IPerf but in a special case. Usually iperf client send data to iperf server, what I need in this case is the server send data back to the client in the same ...
3
votes
1answer
1k views

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), ...
2
votes
2answers
431 views

Interconnected switches Slow throughput

I am in charge of a network of which a portion of it looks like this: One DLink DGS-1210-24 (1) as the main switch. One DLink DGS-1210-16 (2) connected with cat5e 250 feet away connected on (1) One ...
2
votes
2answers
347 views

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). ...
2
votes
1answer
2k views

SSH tunnel speed is very slow

I have remote server with Ubuntu Linux and I want to establish SSH tunnel with this server from Windows machine using PuTTY(plink). I have to use this method for getting access to some service on this ...
2
votes
1answer
4k views

Iperf from one interface to another on the same computer?

I need to test network throughput of a server to/from itself (it's a lonnnng story!). I love Iperf and use it across the network, but, I just can't figure out how to bind it to a single interface and ...
2
votes
1answer
3k views

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 ...
2
votes
2answers
223 views

tcpreplay throughput on eth0 well below (iperf confirmed) max

I'm trying to replay captured UDP multicast packets at a rate of a couple of hundreds of Mbps, but it maxes out at about 86 Mbps. (For some strange reason, at other times during the day it ...
2
votes
1answer
140 views

Poor network performance on Server 2008 machines

I have a network consisting of about 40 Windows 7 machines (physical) and 2 servers (Virtual, ESX) which are Server 2008 Std ed (one is a SBS 2008 but they're the same 'under the hood'). Network is a ...
2
votes
2answers
127 views

File transfer - Bandwidth flickering for no reason

We are experiencing file transfer issues. I try to troubleshoot this problem but it is really hard. Here is a screenshot I took while transferring a file from my workstation to another server. The ...
2
votes
1answer
1k views

Measuring network performance between Windows and Linux

I'm using iperf to estimate network performance between Windows and Linux. For TCP iperf shows 312 Mbits/sec from a Linux server to a Windows client, but it shows only 160 Mbits/sec from a Windows ...
1
vote
3answers
6k views

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 <addr> -n2G TCP speed = 925 Mbits/sec iperf -su <-> iperf ...
1
vote
1answer
526 views

iperf installation and use

I would like to use iperf to test my WAN bandwidth connection. However, I can't find a good method to install and administer it. I'm a Windows guy and don't know much about Linux, and googling iperf ...
1
vote
2answers
3k views

Testing download speed using iperf

I am using iperf to test my bandwidth. But I am not getting whether it is showing my upload or download speed. Say, I have two PCs A and B. If I want to test how fast I can download a file to A from ...
1
vote
1answer
95 views

Network connection slow to server, only from one device

I have looked around, but there doesn't seem to be anyone with the same problem. I am getting almost no connection from my console (laptop) to one of my servers (Raspberry Pi 2 B) . All other ...
1
vote
2answers
348 views

Slow local area network speeds

Updated on 2014-10-09 Disclaimer This question is similar to Unexplained slow gigabit network speeds but because the latter is still unanswered after 5 years, and that I think I'm able to add more ...
1
vote
1answer
1k views

Iperf bidirectional bandwidth measurement

Server side: # iperf -s ------------------------------------------------------------ Server listening on TCP port 5001 TCP window size: 85.3 KByte (default) ...
1
vote
1answer
1k views

Iperf udp test show only 50 % of bandwidth

I test bandwith with iperf. I set up UDP protocol. I'm trying to setup limit from 10 to 100 megabit/s. Until 90 megabit max speed is correct. When I write -b 100m or don't write this speed become ...
1
vote
1answer
1k views

Throughput tool with decent graphing [closed]

I've been looking through some of the tools available for generating traffic to measure maximum network throughput, namely iperf, bwping, ttcp, etc. I am planning on doing throughput tests over a long ...
1
vote
0answers
274 views

Network Performance / SMB-CIFS / Guidance

I'm an IT professional working out of my home office. I'm having some performance problems (NAS file copies) which I'm trying to isolate, using iperf. My question is on iperf. Infrastructure - ...
1
vote
0answers
215 views

Iperf multiple streams

I need to test my network between two sites using iperf. I'd like to open parallel streams sending data on different (let's say 5 defined) ports, with random length from 10-1000, with random 1-2 ...
1
vote
0answers
543 views

iperf - first packet loss and acceptable jitter

I'm using iperf to test the bandwidth on my network. I have a few questions: 1. I'm running this command on the client: "iperft -c -u -b 400m" and it successfully runs. I'm running the command ...
1
vote
1answer
840 views

benchmark tcp: ab or iperf like tool to send hex/binary/pcap data?

I have written a server in Twisted for a current project I'm working on, and now I need to test it. It receives TCP packets, with the payload consisting of just a serialised binary string. I want to ...
0
votes
2answers
16k views

iperf connect failed: Connection refused

iperf -c 192.168.3.2 -i 2 connect failed: Connection refused 3.2 is another machine. I think the port might be blocked. How can I make this work?
0
votes
1answer
909 views

Can I pull data from server to client with Iperf?

To test bandwidth, I just can push data from client to server with iperf. But can i pull data from server to client ? that is like webserver, the client request data, then server give data to client?
0
votes
2answers
2k views

Command line based IP traffic generator

Does anyone know of a command line based traffic generator which can produce IP traffic so that we cant test QOS feature on DSL modem . It would be good if we can set the dscp marking in the IP ...
0
votes
3answers
8k views

WARNING: did not receive ack of last datagram after 10 tries

I use iperf to test bandwidth, if i set large test bandwidth, it gives me "WARNING: did not receive ack of last datagram after 10 tries" and there is no report, i want to know what does this mean? ...
0
votes
3answers
2k views

Can software traffic generator generate 100 Mbps traffic?

Can software traffic generators like iperf etc can generate 100mbps traffic? else is there any software generators which can produce such high rates ? Regards, Mithun
0
votes
1answer
316 views

iperf udp sequence number wireshark

I'm using iperf for generating udp traffic and my objective is to measure paquet loss. I wanted to know if the first 4 Bytes of Iperf Data are currently the sequence number.
0
votes
2answers
235 views

Debugging slow transfer rate from server [duplicate]

I'm trying to explain this as simple but documented as possible. This is not exclusive to this server or my current ISP. I've seen the same exact issue over the years while being with different ISPs ...
0
votes
0answers
15 views

How to route multicast traffic under Ubutun 14.04

I am trying to achieve a very simple goal here, which is to set up a iperf server on my desktop machine to receive any incoming traffic, joe@longbeach:~$ iperf -s -u -B 224.0.0.1 -i 1 ...
0
votes
0answers
40 views

How to fix the amount of bandwidth of iperf in tcp mode?

I'm working on some experiments about my master's degree project. I'm studying some load-balancers (I'm not supposed to cite them here) and the aim is to get for each bandwidth the cpu % usage of a ...
0
votes
1answer
38 views

Troubleshooting poor point to point (over internet) bandwidth between two machines

My problem started out as poor bandwidth between a 64 bit Win 7 Home OpenVPN server in location A (Northern Europe) and a Win 7 or Linux Client in location B (Southern Europe). Location A has FTTC ...
0
votes
1answer
60 views

Simulation of TX/RX Drop

I'm trying to get the "TX/RX Drop" values to increase. I've tried dropping packets using both iperf and iptables but the statistics aren't increasing even when packets are being dropped. Is there a ...
0
votes
1answer
161 views

Teaming two NIC: iperf shows 200MB/s downloads but only 100MB/s upload

I have: One client with two 1000Mbps NICs, teamed using round-robin method One master with a 10Gbps NIC They are connected with a Huawei 10G switch (S5700). Then I ran iperf -s on master and ...
0
votes
0answers
769 views

my iperf connection test client side keeps showing connection refused

I am trying to setup an iperf test but the client side keeps getting connection refused message. Server side: ubuntu@webserver1:~$ iperf -s ...
0
votes
0answers
120 views

Network connectivity (reachability) between nodes located in the same LAN using iperf

I am trying to get network related data from more than 2 machines within a LAN using iperf. I run a node(Node-1) in server mode & trying to start other node(Node-2) in client mode here i am ...
0
votes
0answers
41 views

There's huge gap between two results for iperf

I used iperf -c FOO_NODE -t 120 -i 10 to test the network with the other node FOO_NODE, sometimes I get the result like: [ ID] Interval Transfer Bandwidth [ 3] 0.0-10.0 sec 3.75 MBytes ...
0
votes
0answers
236 views

Iperf UDP listening on used port

I get WARNING[9157] chan_sip.c: Retransmission timeout reached on transmission error on asterisk and trying to troubleshoot the problem. Now asterisk is listening on 5060 port: udp 0 0 ...
0
votes
1answer
528 views

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 ...