Flush DNS cache
Windows
The following command flushes the DNS cache.
IPCONFIG /FLUSHDNS
Mac OSX 10.10 (Yosemite)
The following commands flushes multicast- and unicast DNS cache.
sudo discoveryutil mdnsflushcache
sudo discoveryutil udnsflushcaches
Max OSX 10.7/8/9/ (Lion, Mountain Lion, Mavericks)
The following command flushes the DNS cache.
sudo killall -HUP mDNSResponder