Problem

After configuring NTP, Niagara still shows unsynced time, or history/alarm timestamps don't match other systems.

Root Cause

Misconfigured NTP properties, unreachable server, blocked UDP 123, or misunderstanding of how long sync takes.

Solution

Troubleshooting Checklist

Step 1: Confirm NTP Server Is Reachable

• Ping/traceroute from OS level or out-of-band test
• Verify server is responding to NTP requests

Step 2: Check Niagara NTP Configuration

• Ensure NtpPlatformService is enabled
• Verify correct server address
• Confirm time zone is set correctly
• Check sync interval is appropriate

Step 3: Verify Network Settings

• JACE/Supervisor must have working gateway and DNS
• Required to reach external NTP hosts

Step 4: Check Firewall/Router Rules

• Outbound UDP 123 must be allowed from the BAS VLAN
• Some corporate firewalls block this by default

Step 5: Reboot and Verify

• After changes, reboot the station
• Allow time for initial synchronization
• Verify logs or time status

Common NTP Issues

Symptom	Likely Cause	Fix
Time drifts slowly	NTP enabled but not syncing	Check firewall for UDP 123
Time jumps randomly	Multiple NTP sources	Use single authoritative source
Can't reach NTP server	No gateway/DNS	Configure network settings
Sync fails silently	Pre-4.9 NTP bugs	Upgrade Niagara version