DNS servers can be public or private but must be accessible from the 1st interface of the node.
IP Interface #1
IP Interface #2
IP Interface #1 - 2nd Device
IP Interface #2 - 2nd Device
This will use the same network information from Interface #2 on the first device.
Cluster IP Address
The Cluster IP must be on the same network as the IP Interface #2 interface of each device, when two interfaces are used.