If you’re a systems administrator or a web developer, chances are you’ll have to flush your DNS cache every once in a while to get things straightened out serverside. Flushing your DNS cache in Mac OS X is actually really easy, and there are two different commands to use, one for Leopard and for Tiger. Depending on your version of OS X, open your Terminal and follow the appropriate directions below:

Flush DNS Cache in Mac OS X 10.5, Mac OS X 10.6, or OS X 10.7 Lion

Launch Terminal and issue the following command:

dscacheutil -flushcache

All done, your DNS has been flushed. On a side note, the dscacheutil is interesting in general and worth taking a look at, try the -statistics flag instead for some stats.

Flush your DNS Cache in Mac OS X 10.4 Tiger

Type the following command in the Terminal:

lookupd -flushcache

That’s it, that’s all there is to it. Now your DNS settings should be as you intended them to be.