Telstra has attributed last week's nationwide mobile outage to a neglected software update on a critical time-keeping system, with maintenance teams unaware of a design change that affected the reset process. Chief executive Vicki Brady appeared before a Senate inquiry on Friday, revealing that 45% of all calls and data sessions were impacted when the network went down shortly before 4:30 a.m. AEST on Wednesday.
Root Cause: A Server Reset to 2006
Brady identified the faulty server as a Microchip model SSU 2000, manufactured in 2011 and costing $30,000 to replace. Telstra operates three such servers in Sydney, Melbourne, and Perth. The issue arose during maintenance to replace faulty backup power at the Melbourne site. When the server was shut down and restarted, an underlying software configuration caused it to reboot with an incorrect date of 2006.
“Over the next few hours, the incorrect date rippled slowly across the network, causing authentication certificates in other servers to become invalid,” Telstra stated. This led to customers intermittently losing service, affecting voice calls and data usage.
Missed Software Update and Undocumented Design Change
Executives confirmed that the manufacturer had alerted Telstra in 2022 and again in January of this year about the need to update the software. Had the update been applied, the outage might have been avoided. Additionally, an intentional design change to fix an earlier fault was not properly documented, leaving maintenance workers unaware.
Gerard Tracey, Telstra's executive for end-to-end resilience, noted that investing in a new piece of hardware operating as intended could have prevented the outage. The company maintained that redundancy was not the issue; the other two NTP servers functioned correctly as backups, but the erroneous date propagated through interconnected systems.
Impact on Triple Zero and Compensation
Telstra reported that 58,835 calls to triple zero connected successfully during the outage, while 604 experienced errors. The triple-zero platform, which does not use NTP servers, remained unaffected. Fixed-line NBN callers were also not impacted.
Brady apologized, stating, “Last week, Telstra let Australians down, we let our customers down, we let the community down, and we fell short of what people rightly expect from us. For this, I am deeply sorry.” Telstra has promised compensation, with Brady expecting most customers to receive credit. As of Friday, about 8,000 claims had been received, with $100,000 already paid out.
Senate Committee Criticism
Greens senator Sarah Hanson-Young criticized Telstra's earlier “smug” attitude during hearings focused on last year's Optus outage, noting Telstra's 3,641 outages in 2024 and 5,221 in 2025, while reporting a $2.3 billion profit—a 31% increase. “You’re banking huge increases in profit [while] there are more outages, less reliability,” she said. Brady acknowledged network complexity but could not guarantee zero future outages.
