Northern ntp software

The implementation provides numerous features, including authentication, redundancy and excellent stability. The source code is open source and can be downloaded and used free of charge. The software is freely available under a BSD licence. Chrony Chronyd is a versatile implementation of a NTP client.

It was developed to run satisfactorily under a wide-range of operating conditions. It performs well on virtual machines, congested networks or systems with intermittent network connectivity. Windows Time Service — w32time The Windows Time Service w32time is the build-in client software provided by the Windows operating system. However, if domain networking is utilized, registry setting changes are required to configure the service.

The NTP project is one of the the most comprehensive client solutions available and is highly recommended. It is also available free of charge on an open source licence. Nistime is a bit client that runs in background and periodically queries a NTP server. The application is well documented by providing help links to explain various features. NTP client software is often built into firewalls, routers, IP cameras and other network devices.

Generally, configuration simply requires specifying the IP address or domain name of a NTP server for synchronization purposes. A smaller stratum number means a higher level in the hierarchy structure. On top of the hierarchy there is the daemon which has the most accurate time and therefore the smallest stratum number.

By default, a daemon's stratum level is always one level below the level of its reference time source. The top level daemon often uses a radio clock as reference time source.

By default, radio clocks have a stratum number of 0, so a daemon who uses that radio clock as reference time will be a stratum 1 time server , which has the highest priority level in the NTP hierarchy. In large networks it is a good practice to install one ore more stratum 1 time servers which make a reference time available to several server computers in each department. Thus the servers in the departments become stratum 2 time servers which can be used as reference time source for workstations and other network devices of the department.

Unlike in telecom applications where the word stratum is used e. If the time source currently selected as system peer becomes unavailable then a new system peer is determined based on this selection algorithm. The stratum level under which a daemon is visible on the network corresponds to the current system peer's stratum level plus 1. Earlier versions of NTP for Windows assumed the ntp.

In most installations the ntp. Each of those lines specifies one reference time source which can be either another computer on the network, or a radio clock connected to the local computer. Reference time sources are specified using IP addresses, or host names which can be resolved by a name server.

This IP address must not be mixed up with Most Linux distributions come with a precompiled NTP package where the parse driver has been enabled. However, NTP packages shipped with older Solaris version have been built without the parse driver.

There's also a Linux driver for Meinberg PC plug-in cards available on the Meinberg software download page. Besides ways to configure and monitor the plug-in cards this driver provides a software interface which lets NTP's parse driver read the reference time from a plug-in card rather than via a serial port under Linux.

This driver is not required for devices which are directly connected via a serial port. The configuration steps described below must be done by a user with sufficient rights on the system, e. Each symbolic link must point to a physical device which represents an existing radio clock. In most cases the physical device is a serial port at which a radio clock has been connected externally.

However, under Linux this link can also point to a device node which represents a plugin card. Each of the reference clocks must also be specified in the ntp. The pseudo IP address must be followed by a mode m parameter which specifies the type of radio clock represented by the device. The table below lists the mode values which can be used with Meinberg radio clocks:. In older versions of the driver package before 3. In the next step the file ntp.

The file should include a server line for the refclock-0 device created above. If the radio clock sends the Meinberg standard time string at baud and framing 7E2 then, as can be seen from the table above, the mode for refclock-0 must be set to 2. Also, if plug-in card is used under Linux then mode 2 must always be used: server Since the local clock is not very accurate, it should be fudged to a low stratum: server If the daemon has been shipped with the operating system then it may have support for Meinberg clocks compiled in, or not.

If the output of the command ntpq -p lists a clock labeled generic then everything is fine and the NTP daemon supports the reference clock. If the generic clock is not listed in the ntpq output then the NTP package may have been compiled without support for the parse clocks, or the NTP daemon may not have permission to access the device.

The syslog messages from the NTP daemon after startup should indicate the real reason for the problem. The permission denied problem can occur with plug-in cards under recent Linux distributions which come with AppArmor or SELinux security tools enabled. If the existing NTP daemon has been built without support for the parse clocks then the NTP package must be reconfigured and recompliled on the target platform.

This requires a compiler package installed on the target platform, and the source code of the NTP distribution. In the example below name is the base name of the NTP source package which is normally distributed as a file name. You may use the following commands: cd name. The command ntpq -p can be used to verify that the new daemon works correctly. Finally the newly compiled programs should be copied to the destination directories. The standard procedure to do that is by simply running the command make install However, care must be taken if a version of NTP had been installed previously.

The old versions of the NTP executables should be deleted or overwritten by the new programs to prevent the NTP daemon from being loaded instead of the new one when the system starts up the next time. Also, the new executables must be in the directory where they are expected by the system startup scripts.

Care must be taken especially if the NTP version changes between v3. Instead, the Meinberg driver can be used together with most internal and external Meinberg radio clocks to discipline the Windows system time. The NTP service can then be used to make the disciplined Windows system time available on the network. The NTP server is then visible as stratum 1 server on the network.

Unlike stated before on this page, the config file should not contain the line disable ntp since this may be the reason that the time server is not accepted by its clients. Also, there should be no driftfile specified, and if a file ntp. Otherwise the NTP service might try to correct the system clock drift, thus working against the radio clock driver, resulting in a poor quality of time synchronization.

Configuration Without Radio Clock Configuration of computers without external reference clock is quite simple.