Telstra outage traced to a GPS week rollover and an NTP timing loop

Sources: primary, discussion
Summary: Telstra commissioned an independent review from Technology Audit Partners, which attributes the 2026-07-08 outage to one GPS receiver that had not been patched for the GPS week rollover and so set its time to 2006, and to an NTP timing loop that carried that time into the network. The review finds that two changes made five years apart, each defensible on its own, had removed both of NTP's defences against a single bad time source. Netnod summarises that report in a blog post, which is where these findings surfaced.
Why it matters: A national mobile network took its clock from one unpatched receiver, which puts the control in the sanity checks around a time source rather than in the receiver itself.