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Nico Schottelius 2021-06-13 21:05:22 +02:00
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(attention, this is a test service and might not be running when you
read this article at a later time)
## IPv6 vs. IPv4
Could we have achived the same with IPv4? The answere here is "maybe":
If the kubernetes service is reachable from globally reachable
nameservers via IPv4, then the answer is yes. This could be done via
public IPv4 addresses in the kubernetes cluster, via tunnels, VPNs,
etc.
However, generally speaking, the DNS service of a
kubernetes cluster running on RFC1918 IP addresses, is probably not
reachable from globally reachable DNS servers by default.
For IPv6 the case is a bit different: we are using globally reachable
IPv6 addresses in our k8s clusters, so they can potentially be
reachable without the need of any tunnel or whatsoever. Firewalling
and network policies can obviously prevent access, but if the IP
addresses are properly routed, they will be accessible from the public
Internet.
And this makes things much easier for DNS servers, which are also
having IPv6 connectivity.
The following pictures shows the practical difference between the two
approaches:
![](/u/image/k8s-v6-v4-dns.png)
## More of this
We are discussing