思科ASA8.4（2）防火墙vlan 第三个dmz怎么创建

已然

默认vlan1为inside，vlan2为outside，现在想创建vlan3为dmz，可是遇到问题

iscoasa(config)#int vlan 3

ciscoasa(config-if)#nameif dmz

ERROR: This license does not allow configuring more than 2 interfaces with nameif and without a "no forward" command on this interface or on 1 interface(s) with nameif already configured.

应该怎么做？