Flushing DNS

When accessing websites or mailservers, your DNS resolver caches the request so that future lookups are fast. However, sometimes when a zone on DNS is being changed while you work, you want to be able to clear the cache to force the resolver to get the latest name:IP address pair mappings. Here are some command line commands for flushing the DNS cache on your local machine: On Mac OS X Tiger:

lookupd -flushcache

On Mac OS X Leopard:

dscacheutil -flushcache

On Windows:

ipconfig /flushdns

Update: I noticed that this cache seems to survive reboots, on Leopard.