- Q: How do I reset the DNS cache in OS X?
A: The classic method of clearing the DNS cache is to run the following command in the Terminal:
% /usr/bin/sudo /usr/bin/dscacheutil -flushcache
In OS X 10.7 (Lion) and 10.8 (Mountain Lion) use:
% /usr/bin/sudo /usr/bin/killall -HUP mDNSResponder
Apple has recently outlined in a small knowledge base article how to reset the DNS cache, since the methods for doing this have changed in recent releases of OS X.