Revert "Merge pull request #591 from pinwing/ipv6"

You reverted one part of this pull request in 780c48007970e2cc5f6953d89d0a7b51dce3dca6. This is the leftover part that has not been reverted.

At first glance, I don't see a proper way to re-apply #591 which wouldn't become a maintenance burden due to the extensive changes Asus has done.

I also don't want to apply any changes without properly understanding what Asus did or without checking if they are still needed.