[Cisco] IOS NAT Load-Balancing for Two ISP Connections

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

啟用Load balancing

conf t

no ip cef

啟用端口追蹤

conf t

# 設定sla偵測方式
ip sla 100
icmp-echo dest-ip source-ip local-ip
frequency 5
timeout 5000
threshhold 5000

#啟用此sla偵測，不啟用無法偵測
ip sla schechdule 100 start-time now

#將sla偵測套用至追蹤動作
track 105 ip sla 100 reachability

#在路由設定上，將IP追蹤加入
ip route 0.0.0.0 0.0.0.0 e0/0 100.100.100.1 track 105

靜態one-to-one source NAT

ip nat inside source static inside-local-ip inside-global-ip