Curious tale of broken VPNs, the Year 2038, and certs that expired 100 years ago
Had an NTP client been used to discipline the clock from different redundant sources, instead of resetting the time periodically from a single source, the wild server would be safely ignored as a false ticker and this issue in a comercial VPN service would have never happened. And, no, it was not any problem with NTP, but with the system engineering.