Problem with DNS Client Cache CNAME TTL


Resource records that are stored in the DNS Client cache may not expire at the proper time.


This problem can occur because when a CNAME record is cached, the Windows 2000 DNS Client resolver groups the CNAME record and its associated A records as a single unit in the DNS Client resolver cache. All records in this grouping unit are assigned the Time To Live (TTL) value of the CNAME record. Because of this, if the A records have a smaller TTL than the CNAME, they will continue to be cached for the lifetime of the CNAME.


To resolve this problem, obtain the latest service pack for Windows 2000. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
260910 How to Obtain the Latest Windows 2000 Service Pack
The English version of this fix should have the following file attributes or later:

Date Time Version Size File name
5/31/2001 11:13p 5.0.2195.3663501,520 Lsasrv.dll (56-bit)
5/31/2001 03:30p 5.0.2195.3649354,576 Advapi32.dll
5/31/2001 03:31p 5.0.2195.3649135,440 Dnsapi.dll
5/31/2001 03:31p 5.0.2195.3649 94,992 Dnsrslvr.dll
5/31/2001 03:37p 5.0.2195.3649519,440 Instlsa5.dll
5/31/2001 03:31p 5.0.2195.3649142,608 Kdcsvc.dll
5/30/2001 02:55p 5.0.2195.3649209,008 Kerberos.dll
5/29/2001 09:26a 5.0.2195.3649 69,456 Ksecdd.sys
5/29/2001 09:26a 5.0.2195.3649501,520 Lsasrv.dll
5/29/2001 09:26a 5.0.2195.3649 33,552 Lsass.exe
5/31/2001 03:31p 5.0.2195.3649306,448 Netapi32.dll
5/31/2001 03:31p 5.0.2195.3649357,136 Netlogon.dll
5/31/2001 03:31p 5.0.2195.3652908,560 Ntdsa.dll
5/31/2001 03:31p 5.0.2195.3649382,736 Samsrv.dll

After this fix is successfully applied, the DNS Client resolver will use the lowest TTL returned and assign it to all RRs in that group.


Microsoft has confirmed that this is a problem in Microsoft Windows 2000. This problem was first corrected in Windows 2000 Service Pack 3.

More Information

For additional information about how to install Windows 2000 and Windows 2000 hotfixes at the same time, click the article number below to view the article in the Microsoft Knowledge Base:

249149 Installing Microsoft Windows 2000 and Windows 2000 Hotfixes

Artikelnummer: 276324 – Letzte Überarbeitung: 20.02.2007 – Revision: 1