Network configuration for the NTP server

VLAN choice

• Management VLAN: the NTP server must be reachable for WinDiscovery (UDP 3030 + 5353)
• NTP VLAN for clocks: a separate VLAN for clock traffic shrinks the broadcast domain
• Trunk to core switch: for multi-VLAN deployments

IP configuration

• Static IP recommended for the NTP server itself (not via DHCP)
• DHCP option 42 in the client DHCP config ensures clients automatically receive the NTP server IP
• IPv4 and IPv6 dual-stack supported on the NTP100 series

Firewall rules

Minimum ports open FROM clients TO NTP server:

• UDP 123: NTP protocol
• UDP 67/68: DHCP relay (if DHCP clients)

For management FROM the IT workstation TO the NTP server:

• TCP 22 or 443: SSH or HTTPS administration
• UDP 161/162: SNMP (if monitored)
• UDP 3030, 5353: WinDiscovery + mDNS

DNS

• A-record for `ntp.yourcompany.lan` → IP of the NTP server (simplifies client configuration)
• With dual NTP servers: pool-style DNS (round-robin) for automatic failover

WinDiscovery test

After the initial install: start WinDiscovery on a Windows laptop on the management VLAN. The NTP server must appear within 5 seconds. If it does not appear, check:

1. Clock powered on?
2. On the same VLAN as the laptop?
3. Firewall blocking mDNS?

Delivery by Daylight

We can perform the WinDiscovery test remotely if you set up a TeamViewer/AnyDesk session. Saves a lot of travel.

Contact: Daylight bv.