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How to set up Port Forwarding and bypass CGNAT

Last Updated: Sunday 13 Aug 2023

Does Aussie broadband use CGNAT? 

Yes – CGNAT (Carrier-Grade Network Address Translation) is used on our broadband services and is typically enabled by default. This means that your public-facing IP address is often shared with other users, which is necessary to avoid running out of limited IPv4 addresses.  

Most of the time, this isn’t an issue! But problems can arise when trying to set up port forwarding or other network utilities. The good news is that you can opt out of this on request at no additional cost to your plan. 

How to opt-out of CGNAT 

If your service has a static IP address on it, your service will automatically be opted out of CGNAT and no further action is needed from you. 

If you don’t have a static IP address, you can have CGNAT disabled on your Aussie Broadband internet service by request.  

All you’ll need to do is give our friendly Australian-based Customer Service team a call on 1300 880 905 to ask for this. The change should be applied straight away, and you should only need to power cycle your modem or router after your call.  

 

Tips for setting up port forwarding  

The first thing you need to enable port forwarding is to start with configuring some settings in your router or gateway. Please note that the following instructions are general advice and the steps may vary depending on your hardware, so it might be best to check your router guide or reach out directly to the manufacturer for more detailed steps or troubleshooting. 

  1. Obtain the IP address and MAC address of the device you wish to open and paste into an empty text document for later reference. 

  2. Login to the settings of your network’s router or gateway. 

  3. Look for the page where you may configure port forwarding settings. Sometimes, this might be categorised under ‘LAN’. 

  4. Add a new ‘rule’ and fill out the form fields as required by your router/gateway. What you should enter in those fields can be found in the documentation for the application or service you wish to run.   
    Typically, the fields in your settings can include:  

    • Device IP address -  copy this from the text document used in step 1. 

    • Incoming Port  

    • Outgoing  

    • Protocol (TCP or UDP)  

  5. Save the changes to your router or gateway’s settings. 

  6. Enable or start the application, service, or server. You can refer to a third-party listening tool, such as canyouseeme.org to determine if the port has successfully been opened. 

Can CGNAT affect Port Forwarding? 

Because of the way CGNAT ‘shares’ and cycles your public-facing IP address, devices trying to connect to a port in your network can’t locate your desired destination. This becomes an issue because the routers on our network won't know which device is yours or direct traffic in this specific way. 

Which ports are blocked by Aussie Broadband? 

For more information about open mail relay, see Can I send emails via an open relay?  

Blocked Outbound Ports 

  • TCP/25 (Except to our mail servers) 

Blocked Inbound Ports 

  • TCP/80 

  • TCP/443 

  • TCP/25 

  • UDP/135 

  • UDP/137-139 

  • TCP/UDP 11211 

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