Troubleshooting NBN FTTC for Speed Issues

This article will guide you through the troubleshooting for speed issues on an NBN™ Fibre to the Curb (FTTC) service.

There are several factors that can affect your NBN™ speed which are explained in more detail here but they can include:

  • The speed capabilities of your computer and/or devices
  • The speed capabilities of your wireless router (if used)
  • Data or Network congestion

Select one of the links below to jump to a query:

  • When running a speed test on an Ethernet cable-connected computer, your results are significantly slower than usual
  • These slow speeds occur on all connected computers/devices, not just one
  • Files take a long time to download despite being small in size


Potential cause
Try this:
Weak WiFi signal To rule out a weak WiFi signal, you should test your speed on a computer connected to your modem with an Ethernet cable.
Damaged or loose cables Check that all cables are in good condition and plugged in securely.
Virus or malware infection Run an antivirus/anti-malware scan using your antivirus software. If you need a hand with this, please contact your security software’s Customer Support.
Firewalls or other antivirus software settings Test your speed while firewalls/antivirus software is temporarily disabled. Please contact your security software’s Customer Support if you need a hand with this.
Data congestion To rule out data congestion, reduce the number of connected devices on your home network.
Network congestion Test your speed at different times of the day, especially if your slow speeds only seem to occur around 5-8PM, which is a typical time for network congestion to occur.


  1. If you've had a licensed cabler install internal network wiring in your home (aka "smart wiring), make sure your modem is plugged directly into the NBN™ Connection Box (NCD), not via any cables that are running through walls.

    If you have speed issues while the modem is connected to the NCD via internal network cabling but not when it's connected directly to the NCD, then you'll need to contact an electrician who is registered with an ACMA-accredited registrar (this means that they are properly licensed to work on communications cables) to investigate.
  2. Using an Ethernet cable, connect one computer directly to a LAN port on your modem. If you have any other computers cable-connected to your modem, unplug their Ethernet cables.

    Note: There are different kinds of Ethernet cables. We recommend using a Cat 6 or Cat 5e cable. While a Cat 5 cable will work, it may not support the speeds of your NBN™ service.

  3. Turn off or disconnect any computers or devices connected to your WiFi network. Alternatively, your modem has a Wireless on/off button you can use to temporarily disable your WiFi network.
  4. Run another speed test. If your speeds are faster now, it's likely that the issue was data congestion.
  5. If possible, try using different Ethernet cables to connect your modem to the NBN™ Connection Box, and to connect your computer to the modem.
  6. Run another speed test. If your speed are faster now, it's likely that an old or damaged Ethernet cable was interfering with your connection.
  7. If you continue to experience slow speeds, please call us on 13 22 58 for further assistance.