Flush DNS on Mac OSX

OSX 10.4

lookupd -flushcache

OSX 10.5-10.6

sudo dscacheutil -flushcache

OSX 10.6-10.8

sudo killall -HUP mDNSResponder

OSX 10.9

dscacheutil -flushcache; sudo killall -HUP mDNSResponder

OSX 10.10

sudo discoveryutil udnsflushcaches