Disable IPv6 from the command line on a Macbook

Run a command through the Terminal app:

• Open Launchpad.
• Search for Terminal.
• Click on the Terminal.app.
• If your active network is WiFi enter the following command:

networksetup -setv6off Wi-Fi

• If you are on Ethernet:

networksetup -setv6off Ethernet

To re-enable IPv6, you need to replace setv6off to setv6automatic for Wi-Fi or Ethernet:

networksetup -setv6automatic Wi-Fi 
networksetup -setv6automatic Ethernet