means feature present means feature not present means not applicable Management Features

Master-Slave-Client hierarchy								1
On-demand install/upgrade/remove on remote machines		2	2	2	2		2	2
Batch/background remote install/upgrade/remove
Remotely monitor and configure Windows Time via GUI
Change timezones on remote machines
Automatic network-wide sync trigger
On-demand network-wide sync trigger
On-demand sync trigger for individual remote machines
Centralized control of clock training
Remote control panel viewing and control
Remote realtime log viewing
Configurable installation defaults for mass rollouts
Failover of Master settings to Slaves
Multiple, configurable broadcast subnets
Configuration changes require admin rights
Server can control client schedules and target accuracies
Diagnostic reports of all network time sources and clients
Individual machine historical statistics								3
Network historical statistics
Network variance reports for machines with or without time clients
Test and graph clock stability, accuracy and network latency
Report of installed machines, versions, and platforms
Report of license status for all installed machines
Monitor with real-time and email alerts
Audit records acceptable for OATS/FDA CFR 21 part 11 certification
Graphical server/client multiprotocol test utility

¹ Supports a pre-defined three- or four-tier hierarchy, but members of the intermediate tiers are Win2000 DCs that serve the time. They are not true Slaves because they do not take over for the Master automatically, replicate its settings, or have redundancy checks and tighter sync requirements than clients.
² If PCAnywhere, Terminal Services, or other remote-control software is installed, pretty much anything can be installed remotely. However, Domain Time II has native support for click-and-install without having to view the remote computer's desktop or install remote-control software first.
³ Error information is available in the event log
⁴ Supports NT5DC-based discovery, but not DHCP or other mechanisms

means feature present means feature not present means not applicable Server Features

NT/2K/XP/2003/Vista/2008 Intel Server								1
Native support for 64-bit Windows
Server runs as a native NT service in system context
Serves and obtains time-zone independent time
Control panel applet
System tray applet, with visual/audio sync feedback
Activity monitor		2	2
Real-time drift data graphs
Configuration changes require admin rights
Logged-on user requires time-change rights to set time		3	3
Works without batch files or scheduled jobs
Supports remote control/install/upgrade/remove
LAN/WAN latency compensation
Clock correction by slewing					5
Clock training over time					6
Clock-change monitor to reverse unauthorized time changes
Max variance limits								7
Can check the time at fixed intervals
Can adjust check intervals to maintain specified variance								8
Denial of Service (DoS/flooding) protection
Configurable IP access ranges
Multiple, configurable broadcast subnets
Test mode available								9
Automatic rejection of invalid timestamps								10
Supports NTP/SNTP
Supports NTP broadcast
Supports TIME/ITP via UDP
Supports TIME/ITP via TCP
Supports Domain Time I
Supports Domain Time II
Supports Domain Time over HTTP
Supports high-accuracy protocols through HTTP proxies
Supports high-accuracy protocols through SOCKS proxies

¹ Only Win2K/XP/2003/Vista/2008 supported by the Windows Time service
² Foreground program blinks to indicate client accesses
³ Only if installed as an NT service (optional)
⁵ Maximum slew is limited to 499 milliseconds in most implementations
⁶ Only when using 1PPS time source
⁷ Only when using SNTP, and limited only by SNTP valid timestamp limits
⁸ Target is set to 2 seconds and is not configurable
⁹ Only with the w32tm command-line tool
¹⁰ Rejects anything more than 12 hours off from current time; requires manual clock-setting to correct

means feature present means feature not present means not applicable Client Features

Win95/98/ME Client			1
Win95/98/ME Client runs as a Win9x service
NT/2K/XP/2003/Vista/2008 Client								2
Native support for 64-bit Windows
NT/2K/XP/2003/Vista/2008 Client runs as a native NT service
Windows for Workgroups Client
Solaris SPARC and Intel Clients
Linux Clients		3
FreeBSD Client
On-demand client available								4
Win9x/NT/2K/XP/2003/Vista/2008 Clients are time-zone independent		5	5					6
Control panel applet		7
System tray applet, with visual/audio sync feedback
Activity monitor
Real-time drift data graphs
Configuration changes require admin rights
Sets time without logged-on user having time-change rights		7	7
Works without batch files or scheduled jobs
Client supports remote control/install/upgrade/remove
Auto-sync on detection of dial-up connection
Auto-discovery of servers						8		9
Time servers can be specified using DHCP
Auto-discovery of protocols
LAN/WAN latency compensation
Clock correction by slewing on NT/2K/XP		17
Clock training over time					11
Clock-change monitor to reverse unauthorized time changes
Max variance limits
Can check the time at fixed intervals							12
Can adjust check intervals to maintain specified variance								13
Denial of Service (DoS/flooding) protection
Configurable IP access ranges
Multiple, configurable broadcast subnets
Test mode available						14
Automatic rejection of invalid timestamps							15	15
Supports NTP/SNTP
Supports NTP broadcast
Supports TIME/ITP via UDP
Supports TIME/ITP via TCP
Supports Domain Time I
Supports Domain Time II (TCP & UDP)
Supports Domain Time over HTTP
Supports high-accuracy protocols through HTTP proxies
Supports high-accuracy protocols through SOCKS proxies

¹ No support for Win95
² Only Win2K/XP/2003/Vista/2008 supported by the Windows Time service
³ Only NTP broadcast listener provided
⁴ The W32tm.exe command-line program may be used (a) with SNTP if the Windows Time service isn't running, or (b) if not using SNTP
⁵ Supports query of a web server's HTTP headers, which may or may not include time zone information, and may or may not use UTC
⁶ Only Win2K/XP/2003/Vista/2008 supported by the Windows Time service
⁷ Only when installed as an NT service
⁸ Examines the browse list to discover machines with the TimeSource bit set, and uses the first server found (if any); will not proceed to next server if first fails
⁹ Only when a member of a Windows Domain using NT5DS mode. No auto-discovery of non-Windows sources (see Q224799 for details)
¹¹ Only when using 1PPS time source
¹² Can be set to x times per day
¹³ Target is set to 2 seconds and is not configurable
¹⁴ NET TIME without the /set parameter can report the time (to the nearest second) on a remote machine
¹⁵ Rejects anything more than 12 hours off from current time; requires manual clock-setting to correct
¹⁸ K9 (but not Tardis itself) can slew variances of up to two seconds

means feature present means feature not present means not applicable Audit Server Features

Collects network time sync data centrally in detailed audit records
Audit Domain Time, Windows Time, & NTP machines
Collects sync logs from multiple machines into a central folder
Keep records of who exactly synched with whom, when
Graphically display clock drift data from any time period
Generate alerts if machines not synched or audited
Automatically add machines to be audited

Information Sources Information on this page was gathered from the public web pages listed below. In addition, Microsoft provided significant help in our documentation of the W32Time (a.k.a. Windows Time) service and the w32tm command-line utility. If you discover any inaccuracies on this page, please contact us.
Tardis2000 and K9:	HC Mingham-Smith Ltd.
YATS32:	Dillobits
Dimension 4:	Thinking Man Software
Net Time:	Microsoft
TimeServ:	Doug Hogarth and Microsoft
More info on Windows Time/W32Time "W32Time meets the requirements specified by the Kerberos authentication protocol to provide clock values that are 'loosely synchronized' across a network. This service is not designed for use by applications that require greater precision." -- From The Windows Time Service, Microsoft, April 2001. This white paper provides some of the best documentation available on the philosophy, goals, and implementation of Windows Time. Article Q246145 explains about the "other W32Time" product from Microsoft. Officially called "W32Time Network Time Service for Windows NT 4.0," and documented in w32time.doc, the other W32Time is a cross between an early version of Windows Time and a late version of TimeServ, and is part of the NT4 Resource Kit. When we talk about W32Time and Windows Time on this page, we are referring to the Windows 2000/XP/2003/Vista/2008 product, not the earlier W32Time. Other interesting articles include How to configure an authoritative time server in Windows Server 2003 How to configure an authoritative time server in Windows 2000 How to configure an authoritative time server in Windows XP Q224799: Basic Operation of the Windows Time Service Q247321: W32tm Command Generates Error Messages When Run on a Windows 2000 Domain Controller Q257187: RPC Error Messages Returned for Active Directory Replication When Time Is Out of Synchronization Q258059: How to Synchronize the Time on a Windows 2000-Based Computer in a Windows NT 4.0 Domain Q285641: W32Time Client Does Not Fail Over to Secondary NTP Servers by FQDN Q223184: Registry Entries for the W32Time Service