Flush DNS in OS X

flushdns

#!/bin/bash
#
# flushdns
# This script will flush your DNS cache on Mac OS X 10.1 - 13.x
# The method for doing this chages it seems in every version of OS X,
# and I can never remember the correct command, so I wrote this script
# and gave it a name I could remeber.  
#
# v.2022-11-03 by bill@wellingtonnet.net
# https://gist.github.com/thewellington/6736175

OSX_VERSION=`sw_vers -productVersion`

echo "Attempting to flush DNS cache"

case $OSX_VERSION in
    # OS X 10.1 - 10.4 (Puma, Jaguar, Panther, and Tiger )
    10\.[1-4]*)
        lookupd -flushcache
        ;;
    # OS X 10.5 & 10.6 (Leopard and Snow Leopard)
    10\.[56]*)
        dscacheutil -flushcache
        ;;
    # OS X 10.7 & 10.8 (Lion and Mountain Lion)
    10\.[78]*)
        killall -HUP mDNSResponder
        ;;
    # OS X 10.9 (Mavericks)
    10\.9*)
        dscacheutil -flushcache
        sudo killall -HUP mDNSResponder
        ;;
    # OS X 10.10 - 10.10.3 - the crappy times (Yosemite, part 1 )
    10\.10|10\.10\.[1-3])
        sudo discoveryutil mdnsflushcache
        sudo discoveryutil udnsflushcache
        ;;
    # OS X 10.10.4 and up -- long live mDNSResponder! (Yosemite, part 2 )
    10\.10\.[4-5])
        dscacheutil -flushcache
        sudo killall -HUP mDNSResponder
        ;;
    # OS X 10.11 - 10.12.2 -- El Capitan, and Sierra
    10\.11|10\.12|10\.12.[1-2]*)
        dscacheutil -flushcache
        sudo killall -HUP mDNSResponder
        ;;
    # OS X 10.12.3 - 10.15 -- Sierra, High Sierra, Mojave, and Catalina
    10\.12.[3-6]*|10\.1[3-5]*)
        sudo killall -HUP mDNSResponder
        sudo killall mDNSResponderHelper
        dscacheutil -flushcache
        ;;
    # OS X 11.0 -- Big Sur and Monterey, when in compatibility mode show up as "10.16". (SYSTEM_VERSION_COMPAT=1)
    10\.16*)
        sudo killall -HUP mDNSResponder
        sudo killall mDNSResponderHelper
        dscacheutil -flushcache
        ;;
    # OS X 11.0 12.x -- Big Sur, Monterey, and Ventura
    11\.*|12\.*|13\.*)
        sudo killall -HUP mDNSResponder
        sudo killall mDNSResponderHelper
        dscacheutil -flushcache
        ;;
    # Catch anything else...
    *)
        echo "Sorry, this script is not prepared to handle your version of OS X."
        exit 1
esac

echo "DNS cache flushed."

exit 0

Updated because Apple brought back the mDNSResponder!

Updated again for El Capitan through Monterey - Big Sur and Monterey include compatibility mode recognition too. (10.16)

I have been maintaining this script for some time, but I have been forgetting to update the gist. I have included the gist in the comments near the version, so that in the future, I will hopefully remember to update the gist when incrementing the version.

Updated to include Ventura

Look at that, including the link to the gist last year made me remember to update the gist this year!