Open a Terminal session and run the “ifconfig -en1” command to obtain the network configuration of your wireless network. It should look something like this:
en1: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500 ether 60:33:4b:25:24:d0 inet6 fe80::6233:4bff:fe25:24d0%en1 prefixlen 64 scopeid 0x4 inet 192.168.1.101 netmask 0xffffff00 broadcast 192.168.1.255 media: autoselect status: active
Note the “inet6” section that assigns an IPv6 address to the en1 interface. If you want to disable IPv6 on all interfaces (except loopback), issue the following command:
$ sudo ip6 -x
Now rerun the “ifconfig -en1” command, and you should no longer see IPv6 entries. This change will survive a reboot.
$ ifconfig en1 en1: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 9000 ether 00:1c:c0:a0:5b:94 inet 192.168.1.100 netmask 0xffffff00 broadcast 192.168.1.255 media: 1000baseT <full-duplex> status: active