router#sh ru
Building configuration...

Current configuration : 1841 bytes
!
version 12.1
!
!
interface FastEthernet0/0
 no ip address
 no ip mroute-cache
 speed auto
 full-duplex
!
interface FastEthernet0/0.1
 encapsulation dot1Q 1
 ip address 172.16.0.0 255.255.0.0
 ip nat inside
!
interface FastEthernet0/0.2
 encapsulation dot1Q 2
 ip address 172.18.0.0 255.255.0.0
 ip nat inside
!
interface FastEthernet0/0.3
 encapsulation dot1Q 3
 ip address 172.20.0.0 255.255.255.0
!
interface FastEthernet0/0.10
 encapsulation dot1Q 10
 ip address 10.64.0.0 255.192.0.0
 ip nat outside
!
interface Serial0/0
 no ip address
 no ip mroute-cache
 shutdown
!
interface FastEthernet0/1
 no ip address
 no ip mroute-cache
 shutdown
 duplex auto
 speed auto
!
ip nat inside source list nat interface FastEthernet0/0.10 overload
!
ip access-list extended nat
 deny ip any 10.64.0.0 0.63.255.255
 permit ip 172.16.0.0 0.0.255.255 any
 permit ip 172.18.0.0 0.0.255.255 any
!