paulgorman.org

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Fri Jun 5 10:12:56 EDT 2015 Slept well. Supposed to be another hot day today. Goals: Work: - Work on network cabling book A little. - Write a work order for trash flapper Done. Home: - Work on Traveller character generator - Read more of the Traveller Book Questions: - How do Windows clients in a domain find their time server (i.e. discovery)? https://technet.microsoft.com/en-us/library/cc773013%28WS.10%29.aspx?f=255&MSPPError=-2147217396 "Although the Windows Time service is not an exact implementation of the Network Time Protocol (NTP), it uses the complex suite of algorithms that is defined in the NTP specifications to ensure that clocks on computers throughout a network are as accurate as possible. Ideally, all computer clocks in an AD DS domain are synchronized with the time of an authoritative computer." "Every computer that is running the Windows Time service uses the service to maintain the most accurate time. In most cases, it is not necessary to configure the Windows Time service. Computers that are members of a domain act as a time client by default." "The Windows Time service uses the Network Time Protocol (NTP) to help synchronize time across a network. NTP is an Internet time protocol that includes the discipline algorithms necessary for synchronizing clocks. NTP is a more accurate time protocol than the Simple Network Time Protocol (SNTP) that is used in some versions of Windows; however W32Time continues to support SNTP to enable backward compatibility with computers running SNTP-based time services, such as Windows 2000." "As part of the time convergence process, domain members attempt to synchronize time with any domain controller located in the same domain. If the computer is a domain controller, it attempts to synchronize with a more authoritative domain controller." "Synchronization that is based on a domain hierarchy uses the AD DS domain hierarchy to find a reliable source with which to synchronize time. Based on domain hierarchy, the Windows Time service determines the accuracy of each time server. In a Windows Server 2003 forest, the computer that holds the primary domain controller (PDC) emulator operations master role, located in the forest root domain, holds the position of best time source, unless another reliable time source has been configured." So, I'm still not totally sure if it's doing any sort of low-level NTP autodiscovery (e.g. broadcast/multicast), but any Windows client in a domain (which by default run the ntp-client-like w32time service) should choose time sources among domain controllers. (The question was initially inspired by whether Windows clients might get time servers via DHCP, which I'm pretty sure at this point they do not.)

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