I was wonder how cloud providers seemed to have a bottomless pits of IPv4 addresses and weren’t more resistant to handing them out like candy. They should be charging more for this scarce resource. AWS was, until now, the only cloud provider to not charge for static public IPv4 addresses, as long as the elastic IP is in use.

I fully expect there will be more pressure in the future to have cloud customers to use dual-stack (both IPv4 and IPv6) or IPv6 only on externally facing services and pool services behind application load-balancers or web application firewalls (WAFs). WAFs should support sending incoming IP4v and IPv6 traffic to an IPv6 only server.

Looking at Imperva’s (a WAF) documentation that should work. I haven’t tested this, so I might just have to do that.

By default Imperva handles load balancing of IPv4 and IPv6 as follows:

• IPv4 traffic is sent to all servers.
• IPv6 traffic is only sent to the servers that support IPv6.
• However, if all your servers that support IPv6 are down, then IPv6 traffic is sent to your IPv4 servers.

Imperva also enables you to configure load balancing so that IPv6 traffic is only sent to IPv6 servers and IPv4 traffic is only sent IPv4 servers. Alternatively, you can configure that Imperva sends traffic to any origin server, regardless of whether it is IPv4 or IPv6.

https://docs.imperva.com/bundle/cloud-application-security/page/more/ipv6-support.htm