# cp -p /etc/hosts /etc/hosts.disableipv6
# sed -i 's/^[[:space:]]*::/#::/' /etc/hosts
Optionally to prevent rpc.nfsd setting up IPv6 sockets while NFS server is running, edit /etc/netconfig for the lines starting with udp6 and tcp6; change the "v" in the third column to "-"(hyphen/dash)
Reboot the system to disable IPv6 support.
Note: The solution above only disables(unhooks all of the calls) the ipv6 module, but doesn't prevent it from loading. Unloading the module isn't recommended due to the dependency factors it has with other modules(for example: bonding) and services. To prevent the module from loading, modify/etc/modprobe.d/ipv6.conf with the following only: