interface FastEthernet0
ip address dhcp
ip nat outside
ip virtual-reassembly
!
interface FastEthernet1
no ip address
pppoe enable
no cdp enable
!
interface FastEthernet2
no cdp enable
!
!
interface Vlan1
description LAN Interface
ip address 192.168.108.1 255.255.255.0
ip nat inside
ip virtual-reassembly
ip tcp adjust-mss 1452
!---Define LAN-facing interfaces with "ip nat inside".
!
!
Interface Dialer 0
description PPPoX dialer
ip address negotiated
ip nat outside
ip virtual-reassembly
ip tcp adjust-mss
!---Define ISP-facing interfaces with "ip nat outside".
!
ip route 0.0.0.0 0.0.0.0 dialer 0 track 123
!
!
ip nat inside source route-map fixed-nat interface Dialer0 overload
ip nat inside source route-map dhcp-nat interface FastEthernet0 overload
!
!--- Configure NAT overload (PAT) in order to use route-maps.
!
access-list 110 permit ip 192.168.108.0 0.0.0.255 any
!
!--- Define ACLs for traffic that are NATed to !--- the ISP connections.
!
route-map fixed-nat permit 10
match ip address 110
match interface Dialer0
!
route-map dhcp-nat permit 10
match ip address 110
match interface FastEthernet0
參考
[Cisco] IOS NAT Load-Balancing for Two ISP Connections