NBN Self-Diagnostic Tool
The NBN Diagnostics tool gives you the freedom to run tests when you need them

Why Run Tests?

If an active service is not performing within expected boundaries, you should investigate what the problems are and their possible causes. Once these are known, actions can then be taken to resolve them.
If an End-User is having connection issues on their service, these can sometimes be resolved by running a Port or NTD Reset diagnostic.
Diagnosing the issue/s is a necessary step prior to submitting a trouble ticket. NBN can/will reject any trouble ticket without the proper tests being done. A Trouble Ticket submitted to NBN may require the Service Health Report ID and/or the Diagnostic Test ID values as proof that the issue exists.

How to Access

To access the NBN Diagnostics Tool, you first need to navigate to a NBN TC4 Service. Once you are viewing your service you will see the Diagnostics tool button.
Diagnostics Tool

Types of Tests

The types of tests vary depending on the access technology. The tests are separated into two categories, “Non-Service Impacting” and “Service Impacting”
Service Impacting are tests that will cause the connection to become unstable and can affect the user on the end of the line. Some Service Impacting tests can take up to 15 mins to complete.
Service Type/s
Loopback Test
Service Impacting
Sends small amount of data between us and you (and back again) to test that data is getting through in both directions.
Line State
Service Impacting
The Line State test is a snapshot test of the operational state of the DSLAM port, including line rates, VDSL2 speed and Stability profiles, DSL statistics such as bitrates/SNRs/signal attenuation, and a 24-hour/10-day historical service stability report in graphical format. The CPE modem must be in sync for the results to be meaningful.
Line Quality Diagnostic
Non Service Impacting
The Line Quality Diagnosis test is a longer running version of the Line State test that automatically takes a series of observations at 20 second granularity and displays them as a trend over time. It reports the same basic measures as Line State but is useful for detecting intermittent or variable conditions. It also includes an extensive graphical report of each DSL parameter, graphed over time to allow variations to be easily detected. Can also determine “fine grained” imperfections affecting a service with potential impact to performance or stability, for example the use of untwisted pair cabling, interference from switch mode power supplies, unfiltered CPE etc. Modem must be in sync for test results to be meaningful.
Single End Line Test
Service Impacting
Long-running test of copper line from one end only. This test that can detect relatively “coarse grained” line conditions such as breaks (open circuit condition) and bridge taps which can cause performance degradation. It will also quantify line bitrate capacity which can be used as a speed profile upgrade predictor. It must be run with all CPE physically disconnected from the line for the results to be accurate and meaningful.
DSL Port Reset
Service Impacting
Forces a lock/unlock of the NBN DSLAM port. Identifies if the modem is connected to correct port (dataflow issues). Resets to original settings
Metallic Line Test
FTTN, FTTP (if using UNI-V port)
Service Impacting
MLT (metallic line test) runs a DC electrical test from the DSLAM port towards the Premises. A range of tests to assess passive copper electrical characteristics including any CPE connected at the time
NCD UNI-D Status
Non Service Impacting
Check the current operational status of the UNI-D port. If the NCD UNI-D port is operationally up and there is still no data, perform a 'NCD Port Reset'. Wait for 2 minutes and retest.
NCD Reset
Service Impacting
Forced reset and then resynchronise the NCD
NCD Port Reset
Service Impacting
Forces a lock/unlock of the port to allow the modem to attempt a reconnection. May resolve some dataflow issues
DPU Status
Non Service Impacting
Checks that the equipment in the pit outside your property is online.
DPU Port Status
Non Service Impacting
Checks that the Port on equipment in the pit outside your property is receiving power from your nbn™ Box. Also shows the connected data rate.
DPU Port Reset
Service Impacting
Resets the port on the equipment in the pit that your nbn™ Box connects to.
NTD Status
Non Service Impacting
Perform an NTD Status test. If the NTD Status test Fails, ensure that the NTD is powered on and repeat Basic Troubleshooting.
NTD Reset
Service Impacting
Resets the NTD and then checks NTD Status
UNI-D Status
Non Service Impacting
Check the current operational status of the UNI-D port. If the NCD UNI-D port is operationally up and there is still no data, perform a “Port Reset’. Wait for 2 minutes and retest.
Port Reset
Service Impacting
Forces a lock/unlock of the port. Identifies if the modem is connected to correct port (dataflow issues)
FTTP Tests
FTTN Tests
HFC Tests

Performing a test

Before performing a test the system will display a description of the test you are about to perform, as well as a confirmation or cancel
NTD Status Test
A service impacting test will inform you if the test will impact users on the line.
Metallic Line Test
Each test varies in time to complete, the page will refresh after 15 seconds but you may need to refresh the page after a few minutes to get the results.
Test in progress

Test Results

Most tests will only have a single result, and the majority of those will have a Passed result. Some tests, like the Loopback test or a port reset, only list whether the test Passed or Failed.
If the diagnostic test has any measurements and values included in the result, they will be displayed in tables in the relevant result card. Some test types will have several measurement types, each with their listed table of values.
Should the test complete successfully but have a Failed result there will often be a table of the errors detected during the test. The reasons provided may include information as to how to go about resolving the issue, or the next steps to take.
Once a test has been completed you can see a list of tests that have been performed as well as a detailed breakdown of the most recent test on the right.
By clicking on the NBN Ref # you will be displayed the details of that test that has been returned. You can also use this number in reference to a ticket to help assist in troubleshooting issues with the connection that aren’t resolved with tests within the diagnostics system.
When lodging a fault, NBN can see the tests performed below.
Results from the tests
Each test has a “Status” and a “Results” column. The status is whether the test was able to be executed. The Result is the outcome of the test that is being performed.
The level of detail returned differs from each test. Since some tests performed may test the device on the other end, frequency or noise, the test results will vary.
Results from NTD Status test