Although the article says it's for Windows XP, it's still appears valid for Windows 7. However, on my own Windows 7 i noticed that ServerPriorityTimeLimit was already set to 0 http://support.microsoft.com/kb/320760/en-us If you are using Windows XP, the DNS Client service may not revert to using the first server in the DNS server list. . By default, the server priorities are reset every 15 minutes 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: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Dnscache\Parameters 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 y