NTP
How to verify NTP stratum and offset on a LAN
Check reachability, LOCK, stratum/offset, then size clients with datasheet Performance (Up to) and N=⌊η×R/f_poll⌋—do not mistake switch or overload issues for a bad time server.
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.
NTP throughput: Up to 3840 NTP requests per second (sustained 3840; LOCKED, lab full load 24 h). Do not treat short peaks as the specification during bring-up.
Planning: N=⌊η×R/f_poll⌋ (SY-1231 R=3840). Leave headroom for jitter and export/scan limits.
Port scans or large Web exports can rate-limit replies—do not mix that with capacity conclusions during bring-up.
If an NTP source ACL is enabled, allowlist client IPs or you will see “reachable but not syncing”.