DNS Cache

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When a Windows XP or Windows 2000 machine queries a DNS server, the response is either positive (a match was found) or negative (no match was found). The OS stores these results in a local DNS cache so that local clients don't repeatedly query the DNS server for the same address. These DNS cache entries are known as DNS Resource Records (RR), and the DNS resolver always checks the local cache before it queries the DNS server.

To view the current DNS resolver cache content and the entries preloaded from the Hosts file, go to the command prompt and type

C:\> ipconfig /displaydns

Each entry shows the remaining Time to Live (TTL) in seconds. To clear the cache, go to the command prompt and type

C:\> ipconfig /flushdns

Flushing the DNS cache clears all entries and reloads the entries from the Hosts file.

Stop XP from displaying the time on the desktop

To stop XP from displaying the time on the desktop in the notification area, perform the following steps:

1. Start a registry editor (e.g., regedit.exe).

2. Navigate to the HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer

registry subkey to hide the time for the current user or to the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer

registry subkey to hide the time for all users.

3. From the Edit menu, select New, DWORD Value.

4. Enter the name HideClock, then press Enter.

5. Double-click the new value, set it to 1, then click OK.

6. Close the registry editor.

7. Log off or restart the machine for the change to take effect.