Basically: * Snow Leopard and earlier use lookupd for DNS resolving (`dscacheutil -flushcache`) * Since Lion, they switched from lookupd to mDNSResponder, pre

Basically: * Snow Leopard and earlier use lookupd for DNS resolving (`dscacheutil -flushcache`) * Since Lion, they switched from lookupd to mDNSResponder, presumably for Bonjour protocol support (`killall -HUP mDNSResponder`) * Yosemite switched to discoveryd that basically is a rewrite of mDNSResponder (`discoveryutil mdnsflushcache`) * Due to a lot of problems with discoveryd, they switched from discoveryd back to mDNSResponder since v10.10.4 (so we're back to `killall HUP mDNSResponder`) https://support.apple.com/en-us/HT202516 https://support.apple.com/en-us/HT202516