NTP
How to verify NTP stratum and offset on a LAN
Check reachability, LOCK, stratum, and offset so you do not mistake switch issues for a bad time server.
Updated 2026-08-22
Decision
Prove UDP 123 + LOCK first, then accept stratum/offset on the NIC.
Notes
Confirm L3 reachability and that UDP 123 is allowed. SY-1231 factory default IP is 192.168.1.123 unless changed.
Ping the server and open its Web UI. Confirm GNSS LOCK and the NTP serve policy; warm-up may temporarily reply Stratum 2.
On Linux, use chronyc tracking / ntpq -p (or OS tools) to read reach, offset, and stratum. Accept per lab/contract method—do not accept against GNSS nanosecond figures.
Planning cap defaults to 60; compute client count from the datasheet formula. Design reply capacity ≈ 1800 req/s (16 sources). Port scans or large Web exports can rate-limit replies.
If an NTP source ACL is enabled, allowlist client IPs or you will see “reachable but not syncing”.
FAQ
- What is the decision?
- Prove UDP 123 + LOCK first, then accept stratum/offset on the NIC.
- What are the key points?
- Check reachability, LOCK, stratum, and offset so you do not mistake switch issues for a bad time server.