What is IPv6?
As the Internet runs low on IPv4 address space, there's been a rapid increase in the deployment of IPv6 technologies. This shift is critical to the long-term growth and health of the Internet. At CloudFlare, we are doing our part to make it free and easy for all websites to be available on network.ipv6.
What does enabling IPv6 compatibility do?
The IPv6 gateway setting enables IPv6 on all subdomains that are on CloudFlare (marked by an orange cloud in your DNS settings). If your host provides IPv6 support, the gateway will proxy IPv6 connections through CloudFlare. We recommend keeping IPv6 Compatibility set to "On" for greater availability for your website.
Note: If you already have IPv6 records on your origin server, you must enable CloudFlare for your AAAA records on the DNS settings page.