How to Disable IPv6 in MacOS Sierra

If you wish to turn off the IPv6 network protocol on in MacOS Sierra, follow these steps.

1. From the Finder, select “Go” > “Utilities” > “Terminal“.
2. Enable the “Off” option in Network Preferences for IPv6 by typing the following and pressing “Enter“:
   networksetup -setv6off Wi-Fi
3. Provide admin credentials if prompted.
4. Close Terminal, then go to the Finder and select the “Apple Menu” > “System Preferences…“.
5. Open “Network“.
6. Select the “Advanced…” button.
7. Select the “TCP/IP” button.
8. Ensure the “Configure IP6” option is set to “Off“.