DNS Multiple entries (Set DNS to use configuration)

Summary

I have tried to put space or comma but only one DNS is used which is obviously too low.

This improvement concerns

What is the current behavior?

Not possible to set more than one DNS server

Setting more than one more server is failing back to '9.9.9.9"

What is the improved behavior?

Adding one more server to failover to a secondary server should be possible

Option to set two IP servers (IPv4 or IPv6 or a mix)

What does it bring?

Resilient and failover

Should be the default behavior like most / all network based solution propose.

Adding something like: "A.A.A.A,B.B.B.B"

Check IPv4/v6 validity