denke, das ist es! ist zwar doch der cache, aber mit dem 0 setzen von negativen antworten sollte es funktionieren (entspricht auch dem link von overload), sollte doch noch jemand was besseres finden, bin ich für Hinweise dankbar.
It might be useful not to store any negative responses at all. For example, your ISP's DNS cache might produce a lookup failure due to a temporary server problem (network path congested). By default, you'd have to wait at least 5 minutes before Windows XP would do a new DNS lookup on the server. Until then Windows XP will just return the invalid cached info (giving you that lovely "Cannot find server or DNS Error" in Internet Explorer). To change this:
1. Start the Registry Editor
2. Go to HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Services \ Dnscache \ Parameters
3. From the Edit menu select New > DWORD value
4. Enter the name MaxCacheEntryTtlLimit to change the positive cache period or the name NegativeCacheTime to change the negative cache period
5. Double-click the new value, set it to the desired number of seconds, choosing Decimal as Base (see picture below)
6. To stop Windows XP from caching negative responses set the value of NegativeCacheTime to 0
7. Close the registry editor and flush the DNS cache (see above for instructions) for the changes to take effect
Preventing the Resolver from accepting responses from nonqueried servers