At times it may be necessary to clear your browser and DNS resolver cache, especially if a site was visited prior to Parental Controls being enabled. You can clear your cache in the advanced settings menu of most web browsers. You can also clear your local DNS cache separately by running the following from the command line:
The local resolver cache can be cleared by running the following commands from the command prompt
Windows Computers
ipconfig /flushdns
Apple Computers
Tiger:
lookupd -flushcache
Leopard:
dscacheutil -flushcache