Router(config)#access-list 10 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)#ip nat pool lsp 12.12.12.2 12.12.12.2 netmask 255.255.255.252
Router(config)#ip nat inside source list 10 pool lsp overload
Router(config)#ip nat inside source list 20 pool lsp overload
Router(config)#int gig0/0
Router(config-if)#ip nat outside
Router(config)#int f0/0.10
Router(config-subif)#ip nat inside
Router(config-subif)#int f0/0.20
Router(config-subif)#ip nat inside
Router#debug ip nat