DC Client DNS Config

Hello,

We have two buildings and two DCs in each building.

The network speed within each building, between DCs, is 10Gb.

The network speed between the buildings is 1Gb.

There is a single domain and a single AD site.

Each DC has AD integrated DNS.

What should the DNS settings be on each server?

I'm thinking..

Building 1 DC1

Building 1 DC2

Building 2 DC1

Building 2 DC2

Loopback

Building 1 DC2

Building 1 DC1

Building 2 DC1

Building 2 DC2

Loopback

Building 2 DC1

Building 2 DC2

Building 1 DC1

Building 1 DC2

Loopback

Building 2 DC2

Building 2 DC1

Building 1 DC1

Building 1 DC2

Loopback

If there were two AD sites, I'd have each site DC1 point to DC2 on the same site and itself by loopback.

I'd have DC2 point to DC1 on the same site and itself by loopback.

But with a 1Gb link between buildings, it doesn't seem necessary to have two AD sites so I have four DCs in the same AD site.

Thoughts and references if possible.

Many thanks.