The Telstra outage is a stark reminder of the widespread effects of single system failures

The nearly five-hour Telstra outage appears to have been caused by an issue with time-keeping servers. Photograph: George Chan/AAP View image in fullscreen The nearly five-hour Telstra outage appears to have been caused by an issue with time-keeping servers. Photograph: George Chan/AAP Analysis The Telstra outage is a stark reminder of the widespread effects of single system failures Josh Taylor The network disruption – which brought trains, traffic lights and Eftpos payments to a halt – raises questions about the resilience of services Follow our Australia news live blog for latest updates Get our breaking news email , free app or daily news podcast Wednesday’s national Telstra mobile outage serves as another stark reminder of how reliant on connectivity Australia now is, and how single points of failure can have widespread consequences across the country. The nearly five-hour outage – which brought train lines to a halt, affected traffic lights, stopped Eftpos payments and even people being able to charge their electric vehicles – was caused by what Telstra chief financial officer Michael Ackland said was time-keeping servers that feed out up-to-date information to the rest of the network. When the time appears out of sync across the systems, it creates problems. Telstra outage: Telco apologises for major time-keeping issue that hit mobiles, trains and triple-zero calls Read more “Lots of computer systems, they have to synchronise time. It’s one of the ways that you authenticate what’s going on in the network and the time synchronisation in those nodes, wasn’t wasn’t working as it should,” Ackland said at a press conference on Wednesday morning. “We don’t know why yet.” While Telstra says, as of Wednesday afternoon, that the root cause of the outage remains unknown, it appears to be yet another example of a single issue at one company causing massive disruption in Australia. As we saw in the 2024 global outage caused by Crowdstrike , the Optus 2023 national outage , and the 2025 Optus triple zero outage , single system problems can have cascading effects across not just their own systems, but across the economy. Outages are not uncommon elsewhere in the world, but in Australia they seem to hit with greater impact. When it comes to mobile outages, it is hard not to see this as an issue with having just three mobile network operators in the market – Telstra, Optus, and Vodafone. When one falls over, the impacts are widespread – particularly for Telstra, which has the lion’s share of customers and whose network is used by numerous smaller mobile companies. Customers who left Optus after the incidents of recent years learned today that it’s not just an Optus issue. It also raises questions around resilience of services – both of the telcos and also businesses and organisations that use their services. The processes for governments to deal with these outages appears to have improved since the 2023 national Optus outage. On Wednesday, the federal gov