Are you running also an iperf3 server? iperf2 and iperf3 are not compatible, so each should use its own server.

If this is not the problem, do you have an output from the server? That might help to understand what the problem is.

Another reason may be related to ports that are closed in the firewall (but per the error I don't think this is the reason).

Are you running also an iperf3 server? iperf2 and iperf3 are not compatible, so each should use its own server.

If this is not the problem, do you have an output from the server? That might help to understand what the problem is.

Another reason may be related to ports that are closed in the firewall. Can you also show the iperf2 command you used successfully?

No, I don't use a iperf3-server? I have a problem with the speed from the Linux-PC to the NAS (Nfs4). So I was looking for iperf to measure the speed. The iperf2 command is the last one above in my first post.

I have this server-output (192.168.0.2 is the Linux-PC):

Nov 27 08:04:36 xigmanas64fu lighttpd: (h1.c.413) oversized request-header -> sending Status 431
Nov 27 08:07:10 xigmanas64fu kernel: Limiting closed port RST response from 242 to 209 packets/sec
Nov 27 08:07:11 xigmanas64fu kernel: Limiting closed port RST response from 277 to 203 packets/sec
Nov 27 08:07:12 xigmanas64fu nfsd: accept failed: Software caused connection abort
Nov 27 08:07:13 xigmanas64fu kernel: Limiting closed port RST response from 290 to 197 packets/sec
Nov 27 08:07:15 xigmanas64fu kernel: Limiting closed port RST response from 289 to 185 packets/sec
Nov 27 08:07:16 xigmanas64fu kernel: Limiting closed port RST response from 217 to 195 packets/sec
Nov 27 08:09:02 xigmanas64fu lighttpd: (h1.c.413) oversized request-header -> sending Status 431
Nov 27 08:44:26 xigmanas64fu root: AUTH: admin logged in from IP address 192.168.0.2
Nov 27 10:21:07 xigmanas64fu root: AUTH: admin logged in from IP address 192.168.0.2
Nov 27 10:51:36 xigmanas64fu lighttpd: (h1.c.413) oversized request-header -> sending Status 431
Nov 27 10:52:14 xigmanas64fu lighttpd: (h1.c.413) oversized request-header -> sending Status 431
Nov 27 10:56:54 xigmanas64fu lighttpd: (h1.c.413) oversized request-header -> sending Status 431
Nov 27 11:23:15 xigmanas64fu root: AUTH: admin logged in from IP address 192.168.0.2

These ports are open at 192.168.0.43 (NAS):

Port Status Dienst
22/tcp open ssh
80/tcp open http
111/tcp open rpcbind
139/tcp open netbios-ssn
445/tcp open microsoft-ds
2049/tcp open nfs

As I wrote, you cannot use ipef3 client with iperf (iperf2) server. Since you are using iperf server, and as you wrote the iperf test is successful, I am not sure what is the problem.

I the problem is that you want to use iperf3 instead, you must run iperf3 server.

I don't understand you. I have only both iperf-versions installed on my PC from which I try to measure the conncection to the NAS. I don't know anything about iperf-server. I think I am missing something to know...? :-)

iperf (all versions) are testing the connection throughput, etc. using client-server interface. In your case, iperf server is running on 192.168.0.43 machine and is using port 2049. Since 192.168.x.x is a local address, I assume you can find the machine and what is running on it.

To understand this better, try the following in your PC:

1. In one window run iperf3 server by: iperf3 -s
2. In a second window run iperf3 client that is connecting to the server you run: iperf3 -c localhost

You should see the test results output from both the client and the server.

Note that the default port used is 5201. If there is a problem with this port, you can try using another port using the -p option (for both the server and the client).

Awesome! Thank you! First I did it with success on the PC with 2 terminals open.

I found that on den XigmaNAS iperf3 is still installed! I didn't know this. Now I did this:

In the server terminal: iperf3 -s
PC: iperf3 -c 192.168.0.43

I got an answer and a middle Bitrate about 50 Mbits/sec. Do I right now? This Bitrate is still low. But it is not on iperf3...

Looks good!

Thank you very much!