This speedtest server is located at the MIRhosting DataCenter1, AS52000 and is running on a 20GE connection.

MIRhosting speedtest servers in DataCenter1 DataCenter3

Test with IPERF

Iperf software and manuals you can find on official home page https://iperf.fr
You can find TCP Throughput calculator here.
For a more correct test, use the command like: 
iperf -c speedtest.nl1.mirhosting.net -p 5000-5010 -P 10 (for IPv4)
iperf -c speedtest.nl1.mirhosting.net -p 5000-5010 -V -P 10 (for IPv6)
Also you can use IPERFv3 (client sends, server receives) 
iperf3 -c speedtest.nl1.mirhosting.net -p 5200-5210 -P 10 -4 (for IPv4)
iperf3 -c speedtest.nl1.mirhosting.net -p 5200-5210 -P 10 -6 (for IPv6)
( -R reverse mode (server sends, client receives) 
iperf3 -c speedtest.nl1.mirhosting.net -p 5200-5210 -P 10 -4 -R  (for IPv4)
iperf3 -c speedtest.nl1.mirhosting.net -p 5200-5210 -P 10 -6 -R  (for IPv6)

Test with download files from HTTP and HTTPs

This archive is available over HTTP and HTTPs on both IPv4 and IPv6.

10mb.bin, 100mb.bin, 1000mb.bin, 2000mb.bin, 5000mb.bin, 10000mb.bin
For a more correct test, use the command like: 
wget -4 -O /dev/null http://speedtest.nl1.mirhosting.net/2000mb.bin (for IPv4)
wget -6 -O /dev/null http://speedtest.nl1.mirhosting.net/2000mb.bin (for IPv6)