Network tests

To diagnose a network problem, it may be interesting to perform various tests.

MTR test

A MTR test combines the functions of traceroute and ping on all points between two machines.

If you are requested to do a MTR test, it is important to do it always in both directions:

  • From the server to the IP of your connection
  • From your connection to the server

On Linux

You have to check that the packet mtr is installed.

sudo apt-get install mtr

or

sudo yum install mtr

On Windows

You have to install WinMTR on your server: http://winmtr.net/download-winmtr/

Once you have downloaded it, extract the archive and run the executable.

Enter the target (IP) of your test in the Host textbox, then click on Start. Wait one or two minutes before you stop the test. You can then make a screenshot or export the result with the functions of the software.

Example of MTR between a Online.net server and free.fr:

root@163-172-30-2:~# mtr --report free.fr
Start: Sun May  1 16:23:57 2016
HOST: 163-172-30-2                Loss%   Snt   Last   Avg  Best  Wrst StDev
1.|-- 163-172-30-1.rev.poneytel  0.0%    10    0.5   0.5   0.4   0.5   0.0
2.|-- 195.154.1.248              0.0%    10    1.6   1.0   0.9   1.6   0.0
3.|-- 195.154.1.254              0.0%    10    1.2   1.4   1.2   2.6   0.3
4.|-- th2-crs16-1-be1503-t.intf  0.0%    10    1.3   1.3   1.1   1.4   0.0
5.|-- p11-crs16-1-be1001.intf.r  0.0%    10    4.5   3.0   1.4   4.5   0.7
6.|-- p11-9k-1-be1000.intf.rout  0.0%    10    1.5   2.1   1.4   3.5   0.6
7.|-- bzn-9k-2-sys-be2001.intf.  0.0%    10    1.7   1.8   1.6   2.8   0.0
8.|-- www.free.fr                0.0%    10    1.2   1.2   1.2   1.2   0.0

The results we can see are in detail :

  • Loss%: The percentage of lost packets
  • Snt: The number of packets sent during the test (here 10)
  • Last: The latency of the last packet sent between two points
  • Avg: Average latency for all packets sent between two points
  • Best: Latency of the best result
  • Wrst: Latency of the worst result

IPERF test

With an IPERF test you can check the available bandwidth of your server.

On Linux

If iperf is not yet installed on your server, you can install it with the following command:

sudo apt-get install iperf3

or

yum apt-get install iperf3

Then launch the test:

root@163-172-30-2:~# iperf3 -c ping.online.net -R
------------------------------------------------------------
Client connecting to ping.online.net, TCP port 5001
TCP window size: 85.0 KByte (default)
------------------------------------------------------------
[  3] local 163.172.30.2 port 36490 connected with 62.210.18.40 port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-10.0 sec  1.10 GBytes   943 Mbits/sec

If your server is located at Amsterdam execute: root@163-172-30-2:~# iperf3 -c ping-ams1.online.net -R

On Windows

You have to download the tool at: https://iperf.fr/iperf-download.php#windows

Choose the latest 3.x version and download the file.

It will download an archive, extract it.

Then open a console with the command cmd:

Now go to the folder to which you have extracted the archive (with CD) and run the command:

The results we get are:

  • Interval: Sampling interval in seconds
  • Transfer : Amount of data transferred during the test
  • Bandwidth : Available bandwidth of your server