MAC OS X (beginning with 10.5) requires no changes. IPv6 works out of the box.
Note: If IPv6 is turned off (disabled), change the Configure IPv6 drop-down box from Off to Automatically.
Note: Typically, en0 is the wired connection and en1 is the wireless connection.
computer$ ifconfig en0 en0: flags=8863 mtu 1500 inet6 fe80::217:f2ff:fec9:94c3%en0 prefixlen 64 scopeid 0x6 inet6 2607:ea00:101:2032:217:f2ff:fec9:94c3 prefixlen 64 autoconf inet 22.214.171.124 netmask 0xffffff00 broadcast 126.96.36.199 ether 00:17:f2:c9:94:c3