A speed test seems simple, but results are often misleading due to Wi-Fi interference or CPU limits of the testing device. To determine if your connection actually performs according to specifications, you must conduct the test in an environment with as less external influences as possible.

Crucial for an accurate measurement:
  • Always test wired: Connect your laptop or PC via an Ethernet cable directly to the router/CPE port where the signetbreedband connection is delivered. Wi-Fi is unreliable for bandwidth measurements. Ideally, no other devices should be connected to the delivery point during the test.
  • Disable Wi-Fi: Ensure your testing device is not connected via Wi-Fi.
  • Stop other traffic: Turn off downloads, cloud backups, streaming services, and VPNs during the test.

Method 1: Speedtest.net (Quick and easy)

Speedtest.net by Ookla is the standard for a quick check of your internet speed. For the most accurate results, measure the speed within the signetbreedband network to exclude external bottlenecks on the public internet.

  1. Go to Speedtest.net.
  2. Click on 'Change Server'.
  3. Type signetbreedband in the search bar.
  4. Select the available signetbreedband server.
  5. Click 'GO' to start the measurement.

Why the signetbreedband server?
By testing against our own server, you measure the performance of your line directly into our core network. This is the most reliable way to verify if the delivered bandwidth on the physical connection is correct. If the speed test results are insufficient or inconsistent, please execute a test with iperf3, as described in Method 2.

Method 2: iperf3 (do a technical deep-dive analysis)

For IT administrators who require an analysis without the overhead of a web browser (which is often limited by the browser engine or CPU), iperf3 is the best tool. iperf3 generates synthetic TCP or UDP streams to measure raw throughput.

Installation

  • Windows: Download the binary from iperf.fr
  • Linux:
    sudo apt install iperf3


  • macOS:
    brew install iperf3


Running the test

To obtain a pure measurement, you need a server. You can use public iperf3 servers in the Netherlands. Run the following command in your terminal or command prompt:

iperf3 -c nl.iperf.014.fr -P 8 -t 10


Parameter explanation:

  • -c [server-address]: Starts the client and connects to the specified server.
  • -P 8: Uses 8 parallel streams. This is essential for high bandwidths (Gigabit+) to bypass TCP windowing issues and single-core CPU bottlenecks.
  • -t 10: The test duration is 10 seconds.

Public servers in NL: Public servers can occasionally be overloaded. If you see unexpectedly low values, please try a different server.
The full updated server list can be found at iperf.fr/iperf-servers.php.


Interpreting results

If the results do not match your contract, go through this checklist before opening a support ticket:

  • Is the network interface card (NIC) of the testing device capable of the speed? (e.g., a 1Gbps port for a 1Gbps connection).
  • Is the Ethernet cable used at least Cat5e or Cat6?
  • Are there security suites or firewalls running on the device that limit throughput?

Sources