35Figure 9 RADIUS SettingsAuthentication RADIUS ServerThis is for RADIUS authentication. It can communicate with RADIUS through IP Address, Port andShared Secret.IP Address: Enter the IP address of the Radius Server;Port: Enter the port number of the Radius Server;Shared Secret: This secret, which is composed of no more than 31 characters, is shared by theIEEE 802.11n Wireless Customer Premises Equipment and RADIUS during authentication.Global-Key Update:Check this option and specify the time interval between two global-key updates.Firewall FilteringThe firewall is a system or group of systems that enforce an access control policy between twonetworks. It may also be defined as a mechanism used to protect a trusted network from anun-trusted network. IEEE 802.11n Wireless Customer Premises Equipment has capabilities of SourceIP Filtering, Destination IP Filtering, Source Port Filtering, Destination Port Filtering, Port Forwardingas well as DMZ. This is available only under Router Mode.To make the Firewall Filtering page show up, select Router from System > Network Settings and itwill appear under System menu. Tick Enable Firewall Filtering to enable firewall functions.