The virtual interface IP address (IPv4 or IPv6) is used only in communications between the controller and wireless clients. It serves as the redirect address for the web authentication login page. It is recommended that you configure a nonroutable IP address for the virtual interface, ideally not overlapping with the network infrastructure addresses. Use one of the options proposed in RFC 5737, for example, 192.0.2.0/24, 198.51.100.0/24, and 203.0.113.0/24 networks.