Windows
CMD as admin
ipconfig /flushdns
MacOS
Applications> Utilities > Terminal
10.7, 10.8, and 10.9 10.10.4 and above – sudo killall -HUP mDNSResponder
10.10.1, 10.10.2, and 10.10.3 – sudo discoveryutil mdnsflushcache
10.5 and 10.6 – sudo dscacheutil -flushcache
Enter mac login password (requires admin)
Linux
Check if service is running – sudo systemctl is-active systemd-resolved.service
sudo systemd-resolve –flush-caches