Windows 2000/XP caches both successful ("positive") and unsuccessful ("negative") DNS lookups locally. When Windows 2000/XP cached an unsuccessful DNS lookups, problems occur, such as failed connections and timeouts.

The registry script W2KWXPDNSfix.reg disables the caching of unsuccessful ("negative") DNS lookups.

Turning off unsuccessful ("negative") DNS caching:

1. Download the registry script W2KWXPDNSfix.reg
2. Save W2KWXPDNSfix.reg to your desktop
3. Double-click on W2KWXPDNSfix.reg
4. Click Yes, when you get "Are you sure you want to add the information..." dialog box
5. Click OK
6. Delete W2KWXPDNSfix.reg
7. Reboot your computer

Disabled negative DNS caching on the following workstations/laptops:

• windows lab in henn203b
• jmolnar's laptop
• ugradsec - mabel's workstation - 20070109
• tfelton's workstation - 20070109
• kotlicki's workstation - 20070110
• headsec - janie's workstation - 20070111
• eagle - bill mc's workstation - 20070111
• mshop2 shared workstation - 20070115
• clerk3 - eileen's workstation - 20070115

Reference(s):
How to keep DNS Errors from slowing you down!