Audit identifies cause of Telstra's nationwide outage

* Telstra's July 8 outage began at 2:50am following a planned NTP (Network Time Protocol) timing chassis change, according to an independent investigation into what triggered the network failure

* When the chassis came back online, its internal GPS card had reset and began sending an incorrect date - 2006 - into the network

* To prevent the issue, the GPS card required a firmware update, stipulated in bulletins sent by the supplier

* While the chassis change triggered the outage, steps leading up to it go as far back as 2020

* At its peak, the outage impacted 45 per cent of all Telstra calls and data sessions,

* Some users were unable to make or receive voice calls including Emergency Calls, send or receive messages, or access mobile data

* Telstra undertook more than 630 welfare checks on customers prevented from having triple-zero calls connected

* Alarms in Telstra's system were not recognised as signifying potential broader network issues.

*Telstra failed to recognise and prioritise network time protocols (NTP)

* The department responsible for the failure point had not sufficiently modernised and maintained adequate support for NTP in part due to budgetary constraints

* A lack of competency, curiosity and technical expertise meant problems arose, but no one investigated them

* Two engineers who were involved in the planned change were on mandatory standdown when the outage was noticed

* Despite the change associated with the outage being seen as high risk, no pre-checks of equipment and software were undertaken

*After the change, no testing was done to check key functions were working correctly