On the Physical interface page, you may configure DNS Server, Static Route,Inter-Host Communication Interfaces by clicking Advanced > Other, as shown on the following page.

DNS Server: It is required when node needs to connect to the Internet to resolve domain name. For instance, DNS server should be configured when the node accesses NFS server through its domain name, synchronizes time, or sends alert email. Up to 3 DNS servers can be configured.

Inter-Host Communication Interface: It includes management interface which is used to manage nodes, and overlay network interface(VXLAN). Overlay network interface is a physical interface used for communication among virtual machines. If there are more than one physical interfaces on host, you need to specify one interface for host communication IP.

Addresses of communication interfaces should be on a same network segment.