NIST was 5 μs off UTC after last week's power cut

Summary of Hacker News Discussion on NIST Time Server Outage

The discussion centers on a reported microsecond-level inaccuracy in NIST's time servers due to a power outage, with users debating the severity, technical alternatives, and practical applications of high-precision timekeeping. Four key themes emerge:

1. Severity and Justified Trust in NIST's Timekeeping

Most participants downplayed the 5-microsecond drift as negligible for standard internet-based NTP use, emphasizing NIST's proven reliability and redundancy. The outage's minimal impact was attributed to robust failover systems, and the incident was seen as evidence of NIST's responsible handling rather than a breach of trust.

"You still can [trust NIST]. If you're that considered about 5 microseconds: Build your own Stratum 1 time server" — evanriley
"their handling it responsibly seems like more evidence for trusting them, not less?" — ajkjk

2. Need for Redundant and Diverse Time Sources

A strong consensus stressed the importance of using multiple time sources (e.g., GPS, other NIST servers, NTP pool) to avoid single points of failure. Recommendations included configuring ≥4 diverse sources as per RFC 5905 and avoiding reliance on top-level servers like time.nist.gov directly.

"One should configure a number of different NTP sources instead of just a single host." — vel0city
"Use NTP with ≥4 diverse time sources, just as RFC 5905 suggests doing. And use GPS." — ssl-3

3. Security and Privacy Risks in Public Time Services

Some users highlighted potential privacy risks, particularly with the NTP pool, where servers (especially IPv6) could log IP addresses for malicious purposes like scanning. This underscored a broader distrust of open public time services.

"Be aware that there are members of the NTP pool with less-than-honorable intentions... they also get your IP address." — eddyg
"Is this one of those extraordinary claims that requires evidence? Or is it generally true that there are honeypots in many of these services" — edoceo

4. Applications Requiring High-Precision Time

The discussion listed domains needing microsecond-to-nanosecond accuracy (e.g., telecom, HFT, scientific instruments, distributed systems), often achieved via GPS, PTP, or atomic clocks rather than NTP. NTP's millisecond precision was deemed sufficient for most users, but specific fields like 5G, particle accelerators, and global databases (e.g., Google Spanner) demand stricter sync.

"We need nanosecond precision for trading - basically timestamping exchange/own/other events and to measure latency." — IceWreck
"All the big telecoms (Nokia, Ericsson, Cisco, etc) use Precision Time Protocol (PTP) in some capacity and all required clocks to be ns levels for accuracy." — Aromasin