Microsoft's daylight- saving time (DST) patch - - Does it matter to AD? I wonder if the United States Congress and Canadian Parliament had any idea that expanding the dates of daylight.. By submitting your email address, you agree to receive emails regarding relevant topic offers from Tech. Target and its partners. You can withdraw your consent at any time. Update for Windows Server 2003 (KB931836) Select Language: Download. View account Order tracking Retail store locations Returns. DST patch for Outlook- Apply to every profile ever to connect to Exchange???? Last Modified: 2012-05-05. The Outlook 2000, 2002,2003,2007 Daylight Savings. Contact Tech. Target at 2. Grove Street, Newton, MA. You also agree that your personal information may be transferred and processed in the United States, and that you have read and agree to the Terms of Use and the Privacy Policy. The table here shows the previous dates for DST changes (2. Year. Spring time change. Fall time change. April 2. 02: 0. 0 Oct. March 1. 10. 2: 0. Nov 4. Microsoft has released KB 9. DST hotfix to address this issue. If you are in a time zone outside the U. Cisco is proactive in its approach to comply with the new daylight saving time (DST) changes and wants to ensure that Cisco products in our customer's networks continue to operate without impact through the DST. Microsoft Security Bulletin Summary for March 2015 Published: March 10, 2015. Windows Server 2012 and Windows Server 2012 R2. Microsoft Office 2013 and Microsoft Office 2013 RT. System Center 2012 R2; Microsoft SQL Server 2014 SP1. Non-Microsoft Products. For DST 2007 information about some of the third-party products that are often used with Exchange Server, see the following third. S. But does it really affect domain controllers if the DST is incorrect? Further more, if you have DCs in Atlanta, Seattle, Sydney and London, all in different time zones with various DST settings, how can they all stay within five minutes of each other? How Windows time service works. To better understand this issue, let's review some basics on Windows Time Services. Windows 2. 00. 3 relies on the NTP (Network Time Protocol) to synchronize clocks across a network. NTP is much more accurate than the Simple Network Time Protocol (SMTP) used in Windows 2. SMTP is still available in Windows 2. In order to synchronize all clocks on the network, NTP needs a . In order to eliminate the confusion caused by the many time zones in the world, (such as those shown in Figure 2), NTP uses Coordinated Universal Time (UTC) as the standard. UTC is a standard time that everyone agrees on, regardless of time zones. It is generally considered synonymous with GMT (Greenwich Mean Time). However, don't confuse GMT with British Standard Time. Bottom line, all computers use UTC to synchronize clocks. Regardless of what the time in the Notification Area says, the computer knows the UTC. Dst Patch 2012 Microsoft CertificationSo, even though a client computer in Atlanta says it's 1. Seattle says it's 1. UTC on both is 2. Microsoft could have made things simple and just had all computers report the UTC time and be done with it, but they decided to make it user- friendly and built a utility to convert UTC to . While using UTC time may make it easier when comparing logs from two machines in different time zones, it would render things such as calendar functions useless. For more information on time services in Windows, check out Microsoft's article How Windows Time Service Works. It doesn't answer all questions, but it addresses a lot of them. Many admins have probably dealt with a time sync problem at one time or another where they have users that try to log in and get time synchronization errors. Or, they may get AD replication errors saying . You can fix that by changing the clock in the UI to the correct time. For instance, say the UTC/GMT time was 1. If you were in Atlanta at GMT- 5 your local time would be 0. However, if you set your local time to be 0. UTC/GMT would put your clock at 1. This would put your clock an hour off, and trying to authenticate with a DC that has correct UTC time would fail. It is easy for computers to get out of sync if they are on a VPN or an otherwise unreliable network link. Microsoft's nifty tool, called W3. While I don't have space to go into details about W3. I'll do that in a future article), it is important to note that this tool is available in Windows 2. But the options are completely different. To sync an XP or Windows Server 2.
In Windows 2. 00. Make sure you study the online help for the command when you use it. So, here is what we know: Windows computers use NTP to stay synchronized. NTP uses UTC as a reference time, ignoring time zones. The . For example, if you have your laptop in Atlanta (Eastern U. S. Time Zone) and go to Dallas (Central U. S. Also, remember that the computer doesn't really know where you are, so you can change the time zone without moving and it will still work. You can have DCs, servers and clients in different time zones and they will still authenticate - - assuming they all see the correct UTC time (i. You can force clock synchronization by using the w. What about DST adjustment? OK, so now that we have all our clocks synchronized, along comes a daylight- saving time change (called . How does the DST adjustment affect all this? A utility called tzchange. HKEY. This is detailed nicely in Microsoft's article, KB 9. This is loaded on each computer when the operating system is installed, and if the check box . Then, when the appointed date arrives for the daylight- saving time change, the clock moves ahead (spring) or behind (fall) by one hour. When this happens, all workstations, servers and DCs are affected and their clocks (local time) are adjusted. It is critical to note that, like the time zone change, the DST change only modifies the time setting you see in the notification area and does not affect the computer's UTC time or time zone. This is readily seen with a simple test: Double- click on the clock in the notification area of your screen to bring up the Date and Time properties UI. Change the time zone and click apply. Notice the new local time is adjusted, which does not affect the computer's UTC time. If it did, the offset of the change would alter the computer's UTC time and the local time would remain the same. Now it's time to test the DST change. To see this, you need to move to a different time zone that has DST. In Figure 1, the time zone has been changed from Eastern U. S. The local time now shows 1: 4. Canberra is on DST now, so if you checked the DST box and clicked apply, as in Figure 2, the time then shows the DST adjustment to be 2: 4. Note that if you select a time zone that does not use DST, such as Saskatchewan, Canada, the DST check box does not appear. Figure 1. Figure 2. The question is - - does it really matter to AD? So now we can finally answer the question about how it all affects Active Directory. In regard to the DTC patch from Microsoft, will replication and authentication fail? The answer is no, since changing the time zone or the DST adjustment does not change the computer's UTC time that is used for clock synchronization. As mentioned at the start of the article, it does matter to applications like Outlook. So, from that standpoint, the patch is important. Of course these scenarios are for a mental exercise in time services only. Don't start telling everyone that Gary Olsen said you don't need to apply the DST patch. What about Windows 2. Here is the rub for legacy systems running Windows 2. Unless you have an extended support agreement with Microsoft, you can't get this hotfix, KB9. Sorry about that, but this hotfix is just like any other hotfix, and the policy is clear. However, Microsoft did throw you a rope (just don't hang yourself with it). KB 9. 14. 38. 7 provides some workarounds that allow you to implement the change without the hotfix. You can use the tzedit. You can also manually configure one machine with all the proper new settings, then export the registry key and ship it out to all the other machines via a login script, provided in the KB. Note that Vista has the changes built in, so there is no need to worry about Vista clients. Obviously there are many issues involving time services in terms of configuration, security, authentication and troubleshooting synchronization problems. Other articles in the near future will cover these issues. Here are the important things to take away from this article: Changing a computer's time zone does not affect its UTC time. Thus, it will have no ill effects on authentication or NTP synchronization. The same goes for changing the DST setting. Changing the time using the Date and Time Properties UI will change the computer's UTC and will affect authentication and NTP synchronization. Changing the time zone or DTC properties will affect applications like Outlook. Joe Richards, Microsoft MVP for Windows Server Directory Services, contributed to this article. Gary Olsen is a systems software engineer for Hewlett- Packard in Global Solutions Engineering. He authored Windows 2. Active Directory Design and Deployment and co- authored Windows Server 2. HP Pro. Liant Servers. Gary is a Microsoft MVP for Window Server- File Systems.
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