Questions tagged [iperf]
The iperf tag has no usage guidance.
0
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1answer
18 views
Issues with Cisco IPSec VPN speed. Fast uploads, slow downloads from external to internal servers
We are using a Cisco ASA5516, configured with a IPsec (IKEv1) split tunnel VPN.
When uploading files to a server behind the firewall, the transfer speeds are normal (up to 10mbps).
When downloading ...
2
votes
1answer
55 views
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....
1
vote
1answer
341 views
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 ...
0
votes
1answer
184 views
iperf3 UDP not reliable with iptables drop random
I'm performing some local test on my network with iperf3 using UDP connections between 2 Ubuntu 18.04 hosts. But it seems that the UDP iperf3 connections it is not robust to support a random packet ...
0
votes
1answer
187 views
Low bandwidth when Iperfing data thorugh IPSEC tunnel
We have two server connected next to each other. When we're iperfing each other through 'simple' physical interaces - we're getting ~5GB/S of bandwidth. But when im sending traffic through tunneled (...
0
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1answer
269 views
How can I use an iperf output and only grep Interval and Bandwidth?
I am trying to get the output from the command
iperf -c 10.0.0.1 -t 3600 -i 2
And only need the Interval and bandwidth fields listed for the entire hour of logging.
I haven't used grep or awk in ...
0
votes
0answers
262 views
How test OpenVPN speed using iPerf on Ubuntu
I try to load test my server with OpenVPN for determine maximum speed. To remove all network limitation i want to use iPerf on local network connection. Im install on Ubuntu 16.04 openvpn server and ...
0
votes
2answers
530 views
Undefined iperf3 ports?
I am trying to identify all of the ports affiliated with an iperf3 UDP session and am noticing that the TCP handshaking uses an undefined(?) port on the iperf3 server.
Is there a way to specify all ...
0
votes
1answer
87 views
Iperf2 capture received promiscous mode traffic Not Multicast
I want to capture all traffic in my Iperf server that I listen for promiscously, even if I am not the intended IP.
I know you can do this with Multicast addresses, but I do not want to follow that ...
1
vote
1answer
385 views
The FastNetMon client why not show the Incoming and Outgoing traffic?
I use VMWare created two VMs on my Windows Server.
two VM all are CentOS-7.2.
My FastNetMon version is bellow:
/opt/fastnetmon/fastnetmon --version
Version: 1.1.3 master git-...
1
vote
0answers
201 views
I test the Iperf failed
In my Server(CentOS7.2, address is 103.193.202.2), I run the iperf server:
# iperf -u -s
------------------------------------------------------------
Server listening on UDP port 5001
Receiving 1470 ...
0
votes
1answer
145 views
ieprf vs iperf3 metrics does not match
I am not a network expert but I was measuring the network between to physical hosts using iperf and I got different results depending of the version I was using.
Server configuration:
CPU:
...
1
vote
2answers
225 views
How to measure bandwidth per cpu utilization [closed]
I'm trying to measure efficiency of the networking system and looking for a tool that either allows to limit max bandwidth for each test or, ideally, limit cpu utilization. At the end I need to have ...
0
votes
1answer
47 views
Can ARP expire mid iperf connection?
If one runs an iperf connection between a node 'A' and a node 'B' is it possible that the arp entry expires from one of the nodes. [I have a simple mininet topology and while running an iperf ...
0
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0answers
427 views
What is happening if I am running iperf without a specified iperf server running?
I occasionally run iperf on my network, with only the -c pointing to an interface IP address, but no server running anywhere. What is happening when I run this? I can see network bandwidth increase to ...
0
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0answers
266 views
UDP traffic loss on all interfaces
I've encountered a problem UDP traffic loss in between two servers.
Host A hardware is:Supermicro X11SSL-F v1.01
Intel(R) Xeon(R) CPU E3-1270 v5 @ 3.60GHz
32GiB DIMM DDR4 Synchronous 2400 MHz
...
0
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0answers
391 views
Low network speed with small packets
Using iperf3 to test the network with --length 1000 --no-delay:
iperf3 --interval 1 --time 3 --no-delay --length 1000 --parallel 100 --client 10.0.0.3
Result:
[SUM] 0.00-3.00 sec 835 MBytes ...
0
votes
2answers
175 views
iperf bandwidth less than interface speed
I used linux bonding driver to bond 2 NICs in mode 6 in client PC.
ethtool ethX shows speed =1000
ethtool bond0 shows speed =2000
but when i use iperf
bandwidth of eth0 = 934Mbps
bandwidth of eth1 ...
0
votes
1answer
2k views
How to increase bandwidth of bonding interface in mode 6?
I am new to Linux Bonding Driver. I have configured a bond in mode 6 which combines 2 ethernet interfaces. Their individual bandwidth is 937Mbps and 700 Mbps. But when both the interfaces are up, the ...
0
votes
2answers
414 views
What's the operation about iperf udp
I'm trying to doing some bandwidth test by run iperf on my device,
My Network Max Bandwith is 100 Mbps
(test by speed test CLI - https://github.com/sivel/speedtest-cli)
And I ran the iperf UDP ...
6
votes
0answers
649 views
Why multicast UDP can be slower than unicast UDP?
I have two machines (with Centos 7.3 on both) connected via 1G switch.
When I measure UDP thoughput between macines with iperf it gives about 850 Mbit/s.
However when I measure multicast UDP thoughput ...
0
votes
1answer
274 views
LACP bond work intermittently on Cisco N5000
Our clients are using Centos 7.1 and 7.3. They are two 10GB card bonded to make a 20GB link. Each of the network card is connected to a pair of Cisco N5000 switch. While running cp or iperf, I can see ...
1
vote
0answers
98 views
What network setting could impact iperf3 results?
I am making some bandwidth tests to set a baseline for some other tests and I have a behaviour I cannot understand. The tests are done with iperf3 on Linux (with and without -R to get both up- and ...
3
votes
0answers
48 views
Measuring effectiveness of qdisc
I am trying to set the incoming and outgoing bandwidth of a particular interface. I set the outgoing bandwidth in the following way.
sudo tc qdisc add dev f30e888e9a857_c handle 1: root htb default ...
1
vote
0answers
120 views
slow single connection between two otherwise fast machines
I'm having trouble with larger file transfers from one of our virtual servers to our office network. The virtual server acts as a VPN server, therefore we call it "VPN", but the usage of VPN is not of ...
1
vote
2answers
10k views
How to set the UDP Packet Size with iperf3?
How to set the UDP Packet Size with iperf3?
The flag "-M" does not work with iperf3. Is there an alternative?
0
votes
3answers
2k views
IPERF 2.0.8/2.0.9 in Windows - "connect failed: Connection refused
I've been using iperf for some time but at present day i need to use the birectional test using -d or -r in the iperf command. The thing is that i always have "Connect failed: Connection refused" when ...
1
vote
1answer
1k views
Why the bandwidth is not ~10G?
I originally posted on "Network Engineering", but I was told to ask here.
I have 2 servers connected with 10G cable between them directly. I need to know that the connection is good and it has indeed ...
1
vote
2answers
6k views
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 --...
1
vote
1answer
3k views
What's the default TCP window size of iperf3?
Does anyone know what's the default TCP window size for iperf3? It is not mentioned in the manual and I also can't find it in the output, when running a test.
0
votes
1answer
591 views
Iperf3 keeps hanging when running UDP test
I wrote a Python program that runs iperf3 in a for loop with different datagram sizes. I am using Python's subprocess.call function to run iperf3 like this:
iperf3 -u -c 185.82.21.60 -b 100M -t 5 -l ...
4
votes
1answer
441 views
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 ...
7
votes
1answer
411 views
Right way of measuring overlay network performance
I am currently examining the performance (especially UDP throughput) of different Docker overlay networks. I do this by creating point-to-point connections between two hosts that are connected with a ...
1
vote
0answers
196 views
iperf actual send rate always lower than the expected target bandwidth until some equilibrium reached. Why?
I did an UDP iperf 2.0.5-Ubuntu test between two VMs on the same hypervisor. As can be seen in the iperf output below I started my first test with "-b 686M" flag. However, iperf reported that it was ...
0
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0answers
1k views
How slow can be a QCOW2 vm disk (proxmox/KVM) over NFS (dedicated 1Gbit)?
I'm running 3 proxmox 3.4 nodes using NFS shared storage with a dedicated 1GB network switch.
root@lnxvt10:~# pveversion
pve-manager/3.4-11/6502936f (running kernel: 2.6.32-43-pve)
root@lnxvt10:~# ...
1
vote
0answers
1k views
Strange iperf3 behaviour with UDP streams
I am using iperf3 verson 3.0.11 to measure the throughput of a UDP stream between two virtual machines. The virtual machines are deployed via OpenStack. Of the physical hosts, one is located in ...
1
vote
3answers
12k views
No package iperf3 available CentOS
I'm trying to install iperf3 on a server to run some tests...
Unfortunately I cannot. What do I need to do? Enable a repo or download a rpm file with wget?
[root@localhost hodor]# yum install iperf3
...
1
vote
0answers
88 views
Iperf Tcp Client and Server
I'd really like to know why the bandwith in the client is higher than the server, i can´t find the answer explaining why this happens.
Thank you,
Tiago Melancia
Values of the bandwidth:
Client
...
0
votes
1answer
165 views
Why is Apache2 serving as an iperf server?
My Question:
Does anybody know why an apache2 server can act as an iperf server? I thought that an apache2 server does only answer HTTP requests.
My Situation:
I accidentally realized that an apache2 ...
1
vote
0answers
110 views
Network Traffic fluctuating, even with loopback
I am using iperf tool to benchmark my network interfaces on two identical machines (Dell Blade Server M620). Both have given different results.
On 1st machine, I ran server and clients as:
Server ==>...
1
vote
0answers
161 views
iperf shows 200Mb when host is the client, but 900Mb when it is the server
On host 'abc' I run:
iperf -s -w 256k
On host 'xyz' I run:
iperf -c -w 256k
And I get 900Mb. When I reverse the commands, making 'abc' the client, I get 200Mb. This means that abc's upload speed ...
1
vote
2answers
2k views
Is iperf valid to measure network performance?
We are investigating performance issues in one of our software deployment between our application servers (Windows) and our Redis instances (Linux).
On a 10 Gbits/s link single TCP connections can ...
1
vote
0answers
634 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 ...
1
vote
1answer
191 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 ...
10
votes
2answers
20k 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 ...
0
votes
1answer
140 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
156 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 ...
-2
votes
2answers
478 views
Is it possible to test throughput without server cooperation?
To measure throughput between two points in a network using iperf, you have to run iperf at one point in server mode. My question is, is there a tool I can use to measure this bandwidth without ...
0
votes
1answer
416 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 iperf -...
0
votes
0answers
5k 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
-----------------------------------------------------------...
