NAT64 and DNS64 a simple walk through!

I was working on the IPv6, and translation from IPv4 to IPv6 (vice versa) for DNS64 and NAT64, so wanted to share this post with audiences.

I configured the DNS64 with NAT64 on the Viprion (f5 DUT).

Before starting one thing i want to clear about NAT64 and DNS64 that both are kind of independent, and you don't even need DNS64 if the client (or workstation) knows about the destination address. But in the real life no client really knows the server address so you have to resolve it first thats when DNS64 comes into picture.

Here is the basic logical architecture of the NAT64 and DNS64.

DNS64:

First DNS64 resolves the ip-address of the server in ipv4, DUT convert it into (AAAA) ipv6 resolution.

Then client sent the request to the resolved ipv6 address and DUT again convert the destination address into the ( A type) ipv4 form.

NAT64:

Once the DNS is resolved rest of the NATing from V6 to V4 is done by DUT to forward the inward and outward traffic. each time a request is sent to the V6 address before travelling to outside world, DUT convert the IP format to V4 from V6 similarly each time any request is processes from the real server it is converted to V6 form from V4 to reach the IPv6 client sitting behind the V6 virtual server.

                                                                            -------------diagram courtesy F5 devcentral and F5 site.

It will be very interesting to see how L2 and L3 DSRs works in combination with DNS64 and NAT64

For the F5 like devices you can even map an IPv6 Pool to the IPv4 type VIP, so if anybody is testing only NAT64 you don't have to exercise DNS64 that will give far better performances because DNS resolution definitely eat up lots of performances. 

Although i faced the following problem while using DNS64.

The problem I am facing is what should be the DNS server address to use the load balancer. Once I configure DNS server to give the ip-adderss of the http-server address it uses only 1 ip on the pool and but I cant use more than 1 ip  on the server with one GET command, so I have to put multiple GET with different server names which I think is not a good idea.

So basically for the GET command I can’t use the conventions F5 load balancing mechanism.

Any idea in this regard will be highly appreciable friends.