Router(config)#interface fastEthernet 0/0
Router(config-if)#ip nat outside
Router(config)#access-list 10 permit 192.168.0.0 0.0.0.255
Router(config)#access-list 10 permit 192.168.10.0 0.0.0.255
Router(config)#access-list 10 permit 192.168.20.0 0.0.0.255
Router(config)#ip nat inside source list 10 interface fastEthernet 0/0 overload
Router(config-if)#ip nat outside
Router(config)#access-list 20 permit 192.168.10.0 0.0.0.255
Router(config)#access-list 20 permit 192.168.20.0 0.0.0.255
Router(config)#access-list 20 permit 192.168.0.0 0.0.0.255
Router(config)#ip nat inside source list 20 interface fastEthernet 0/0 overload
Router(config-if)#exit
Router(config)#end
%SYS-5-CONFIG_I: Configured from console by console
Router#