====== NTP time servers ======

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**Note**\\  NTP (Network Time Protocol), is used to synchronize computer system clocks via packed based TCP/IP-Networks. For more Information on NTP see [[wp>Network_Time_Protocol|Network Time Protocol]] or [[https://www.meinbergglobal.com/english/info/ntp.htm#overview|Meinberg: information on NTP]].
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===== Time servers in DHD devices =====

An external NTP time server needs to be configured in DHD devices for having the right system time. DHD devices can work without a NTP time server configured. The following features only work with a correctly configured NTP time server:

  * **Clock elements on TFT displays**: without a correct time server the clock elements will be empty and will not show any time.

  * **System time for system state and debugging**: system time will start at January 1, 1970, 0:00am each time the system is booted. This time information is provided in any system state. This will make it hard to debug DHD systems.

  * **Clock logics**: will fall back to system time and trigger at the system time starting at January 1, 1970. 0:00am after reboot.

  * **Temporary licences (demo licences)**: will be shown in system state but they will not work without a correct time server.

===== Connect DHD device to time server =====

You can configure the connection to a time server by using [[dhdcs:v3:start|Communication Server]] (since Version 9.1) or [[tb8:maintenance:start|DHD Maintenance (MT5)]] on older versions.

To connect a time server to a DHD device using DHDCS, follow these steps:

  - Open DHDCS on a computer that is connected to the DHD network.
  - Click on the DHD device you want to connect to the time server. Then open the [[dhdcs:v3:device_menu|Device]] menu and select ''Network Config''.
  - The Network Config window opens.[{{ :installation:network_config.png?direct&400 |//Network Config window//}}]
  - In the ''Time'' area enter the IP address of the time server in the ''Primary Time Server'' box. Depending on your chosen time server you may need to enter some further settings. For that click ''Setup time zone and DST ...'' to be able to enter a general time zone offset and if necessary the settings for the daylight saving time.
  - Click ''Send'' in the ''Network Config'' window.
  - If the NTP time server is working correctly, the DHD device will sync its system time to it. 

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**Note**\\  It can take a while (up to 15 minutes) until the DHD device syncs to the NTP time server. To speed things up you can perform a ''System Reboot'' of the device via [[dhdcs:v3:start|Communication Server]] (since Version 9.1) or [[tb8:maintenance:device|Maintenance or MT5]] on older versions.
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With 52/XC2, 52/XD2, 52/XS2 cores you can define two additional time servers. If the primary time server is not available, the core will use ''Additional Time Server 1''. If ''Additional Time Server 1'' is not reachable, the core will use ''Additional Time Server 2''.

===== Configure a NTP time server on Windows =====

Although DHD audio is not responsible for your IT infrastructure, we have two suggestions to provide a time server for your DHD network.

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**Note**\\  DHD audio is not responsible for providing a correct NTP time server. When in doubt always contact your IT department first.
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==== Meinberg NTP Software ====

We recommend the ''Meinberg NTP software''. You can download it at [[https://www.meinbergglobal.com/english/sw/ntp.htm|Meinbergglobal.com]]. It is easy to configure and has proved to run very stable. Follow the installation instructions provided by Meinerg and make sure to have the required ports opened in your firewall configuration.


==== Windows Services ====

You need to configure a computer with two network interfaces. Configuration will be done in two steps:

  - Configure the first interface for the public network (e.g., office network, internet connection)
  - Configure the second interface for the DHD network

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**Note**\\  ''DHD network'' is the network where the DHD devices are connected. This network should be separated from a office network. See [[network:start|Network specifications]] for more information on network architecture recommended by DHD audio.
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=== Configure time sync for the Windows PC ===

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**Important**\\  The Windows PC has to be connected and synced to a time provider.
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  - The Windows service ''Windows Time'' must be running. It provides the NTP time for external devices.
  - Go to ''Date and Time Settings'': ''Internet time'' > ''Automatically Synchronize'' > Enter IP of network time server > ''Refresh'' (if necessary try multiple times) - Message '' Successfully synchronized [..] appears''

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**Important**\\  Make sure the UDP Port 123 is not blocked by a firewall.
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=== Configure sync for DHD ===

Now the DHD device can be configured. Follow the instructions in the section above [[installation:windows_ntp_time_server#connect_dhd_device_to_time_server|Connect DHD device to time server]].

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**Note**\\   
  * Network settings of the DHD device have to fit with the settings on the second Network adapter.
  * The IP address of the time server is the IP of the PC network adapter attached to the DHD network. This IP address needs to be entered at the DHD Maintenance ''Network Config'' page.
  * Do not forget to reboot the DHD device.
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== Trouble-shooting for time server configuration ==

  * Is the w32tm (Windows Time) service already configured as server? - Check registry key: ''HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\W32Time\TimeProviders\NtpServer\'',  key ''enabled'' DWORD must be 1 (hex).
    * If this is not correct: change to ''1'' and restart the w32tm service

  * Is the Time Server trustworthy? Check registry key: ''HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\W32Time\Config'', key ''AnnounceFlags'' is by default ''0x0a'', can be set to ''0x04''. This will make the time server always trustworthy, even if the provided time is invalid


== Check if the time server is working correctly == 

  * On your computer, go to ''Start'' and open ''cmd'' application. 
  * Use the ''w32tm /stripchart /computer:localhost'' command. This compares the system time with another time server (/computer:) in the network. 
    * example: ''w32tm /stripchart /computer:192.168.10.1'' or ''w32tm /stripchart /computer:ptbtime1.ptb.de''
  * with ''/computer:localhost'' can be checked, if the internal time server is also running. (Time difference is then 0)
  * If an error is returned, time server is not running or has configuration problems


/*

  * 1st Interface für Office Netzwerk konfigurieren (z.B. 192.168.20.5)
  * 2nd Interface für DHD Netzwerk konfigurieren (z.B. 10.5.6.42)

Sync für den PC:
  * Services "Windows Time" muss laufen
  * Datum- und Uhrzeiteinstellungen: Internetzeit > Automatisch Synchronisieren > IP des Netzwerktimeservers eintragen > Aktualisieren (ggf. zweimal versuchen, bei mir hat es immer erst beim zweiten mal geklappt)
--> Sucessfully synchronized with .... on.....

Sync für DHD
  * Netzwerkeinstellungen müssen zu den Einstellungen des zweiten Netzwerkadapter passen
  * Timeserver = IP Adresse des DHD Netzwerkinterface (2nd interface)
  * Systemreboot auf DHD um Zeitsynchronisation nach Neustart zu erzwingen, oder bis zu 15 minuten warten (zyklisches Update)
  * Auf PC darf UDP Port 123 nicht durch Firewall o.ä. geblockt sein!


** wenn es klappt ist alles gut\\
** wenn es nicht geht folgendes überprüfen:\\
+ Arbeitet der w32tm service als Server? Prüfe schlüssel: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\W32Time\TimeProviders\NtpServer\  Key "enabled" DWORD muss 1 (hex) sein.

Ggf. ändern und "Windows Time" service neu starten!

+ Versuch: Vertrauenswürdigkeit des Zeitservers auf dauerhaft "an" setzen: 
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\W32Time\Config 
Schlüssel: AnnounceFlags
Standard ist 0x0a, kann auf 0x04 gesetzt werden, dann ist der PC als Zeitgeber immer vertrauenswürdig, auch wenn seine Zeit eigentlich ungültig ist.



Also (gilt für Win 7 - 32 u 64 bit):

1. Der Windowsdienst "Windows Zeitgeber" oder "Windows Time" muss definitiv laufen.

2. Der Schlüssel HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\W32Time\TimeProviders\NtpServer\Enabled sollte auf 1 stehen - sonst wird die Zeit nicht im Netzwerk verteilt. Falls Sie diesen Wert setzten müssen, muss der Windows Zeitgeber Dienst neu gestartet werden.

Damit müsste es eigentlich funktionieren, sofern die Rechner-IP-Adresse im DHD als Time Server angegeben wurde.

Um die Funktion des rechnereigenen Zeitservers zu testen empfiehlt sich folgendes Kommando in der cmd:

w32tm /stripchart /computer:localhost
  - vergleicht die eigene Zeit mit einem beliebigen Zeitserver (/computer:) im Netzwerk.
z.B.: w32tm /stripchart /computer:192.168.10.1
z.B.: w32tm /stripchart /computer:ptbtime1.ptb.de
  - mit /computer:localhost kann geprüft werden ob, der interne Zeitserver ebenfalls läuft (Zeitdifferenz dann gleich 0)

Falls ein Error zurückgegeben wird läuft der Zeitserver nicht oder wird anderweitig behindert.  */