Troubleshooting NBN HFC for Dropouts

This article will guide you through the troubleshooting for connection dropouts on an NBN™ HFC service.

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

  • Your internet connection will stop and start – it may drop out for short or long periods of time, either randomly or around the same time each day. However, your connection will always return. If your connection drops out and stays out, please see troubleshooting no connection instead.
  • You experience dropouts on all computers or devices in your home, not just a single device or only devices that are connected to the WiFi.
  • The lights on the front of your NBN™ Connection Box may indicate a problem. See this article for more information.


Potential cause Try this:
Incorrect power supply Make sure your NBN™ Connection Box is plugged directly into an electrical outlet. A double adapter or faulty power board may be causing an inconsistent power supply.
Loose or damaged cables Check that all cables are in good condition and plugged in securely. In particular, the coaxial cable that connects your NBN™ Connection Box to the wall socket must be screwed on securely at both ends.
WiFi issues Test your connection on a computer connected to your modem with an Ethernet cable to confirm that the issue isn’t just WiFi dropouts.
Data congestion To rule out the possibility of data congestion, reduce the number of devices connected to your home network.
Network congestion Keep note of the times when your internet connect drops out, particularly if it only seems to happen around 5-8PM, which is a time when network congestion commonly occurs.


  1. Locate your NBN™ Connection Box. This will be connected to a wall socket inside your premises.
  2. Unplug any additional WiFi routers from the NBN™ Connection Box.
  3. Using an Ethernet cable, connect a computer directly to the yellow Ethernet port on the back of your NBN™ Connection Box.
  4. Leave your modem plugged in like this for at least 24 hours or however long it typically takes the dropouts to occur, making a note of the time any dropouts occur, and how long they last.

    Important: When the connection drops out, you should see the lights on your NBN™ Connection Box turn off, particularly the ONLINE, DOWNSTREAM and UPSTREAM lights (see this guide for details). If these lights do not change, it's unlikely that the issue lies with the NBN™ service. Please check the connections between your NBN™ Connection Box and computers/devices and try troubleshooting WiFi dropouts.

  5. If possible, try using different Ethernet cables to connect you computer to the NBN™ Connection Box, and to connect your NBN™ Connection Box to any WiFi routers. An old or damaged cable may be interfering with the connection.
  6. If you still experience dropouts, please call us on 13 22 58 for further assistance. We'll need to confirm your NBN™ Connection Box's Serial Number and CMAC number - you can find these details printed on a sticker on the base of the modem as shown below. You may wish to write them down for easy reference.