How to Check DNS Cache Details in OS X Yosemite

If you are changing or are going to change DNS, and you want to see some details about what is currently cached.

Step 1. Open Terminal.app

Step 2. To get UDNS cache statistics insert this command to terminal

sudo discoveryutil udnscachestats

Hit return and enter the admin password when requested.

 

Step 3. To get MDNS cache statistics insert this command to terminal

sudo discoveryutil mdnscachestats

Hit return and enter the admin password when requested.

Both of these will offer details as to the number of DNS entries are cached, offering a report that should look like this:

UDNS Cache Stats: Cached 507 of 5000

MDNS Cache Stats: en0: Cached 11 of 7500

If you run those commands before and after running the flushcache variations, you’ll find they should be reset to 0 entries cache, like so:

UDNS Cache Stats: Cached 0 of 5000

MDNS Cache Stats: lo0: Cached 0 of 7500