This article was previously published under Q320760
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256986 Description of the Microsoft Windows Registry
If you are using Windows XP, the DNS Client service may not revert to using the first server in the DNS server list.
This behavior occurs because the Windows XP DNS Client service (Dnscache) follows a certain algorithm when it decides the order in which it uses the DNS servers configured in the TCP/IP properties. If the DNS server list is reprioritized, the Windows XP DNS Client service resets the server priority at periodic intervals. By default, the server priorities are reset every 15 minutes.
WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.
To work around this behavior, modify the registry so that the DNS server that is configured first is tried first on each query. Follow these steps, and then quit Registry Editor:
Click Start, click Run, type regedit, and then click OK.
Locate and then click the following key in the registry:
On the Edit menu, point to New, and then click REG_DWORD.
Type ServerPriorityTimeLimit, and then press ENTER.
On the Edit menu, click Modify.
Type 0, and then click OK.
When you set ServerPriorityTimeLimit to 0 (zero), the server priorities are reset before the DNS Client service decides which DNS server to use. You must restart Windows XP for these changes to take affect. Any other value used in this field will cause the default behavior.
In the ServerPriorityTimeLimit registry setting, only values of 0 change the default behavior. All other values cause the default behavior.