R1 R2 R6组成外网使用ospf协议，R6回环口1.1.1.1

R3为出口路由器f0/0 和f1/0都可以访问到1.1.1.1

R4 R5充当PC机器

R6:配置

interface Loopback0

ip address 1.1.1.1 255.255.255.255

!

interface FastEthernet0/0

ip address 16.1.1.6 255.255.255.0

duplex auto

speed auto

!

interface FastEthernet1/0

ip address 26.1.1.6 255.255.255.0

duplex auto

speed auto

!

router ospf 1

log-adjacency-changes

network 1.1.1.1 0.0.0.0 area 0

network 16.1.1.0 0.0.0.255 area 0

network 26.1.1.0 0.0.0.255 area 0

!

R5 配置

interface FastEthernet0/0

ip address 192.168.2.2 255.255.255.0

no ip route-cache

duplex auto

speed auto

!

ip default-gateway 192.168.2.1

R4配置

interface FastEthernet0/0

ip address 192.168.1.2 255.255.255.0

no ip route-cache

duplex auto

speed auto

!

ip default-gateway 192.168.1.1

R3配置

SLA配置

ip sla monitor 1

type echo protocol ipIcmpEcho 13.1.1.1

ip sla monitor schedule 1 life forever start-time now

ip sla monitor 2

type echo protocol ipIcmpEcho 23.1.1.2

timeout 60000 这里我延迟一分钟切换

ip sla monitor schedule 2 life forever start-time now

定义跟踪

track 123 rtr 1 reachability

track 124 rtr 2 reachability

interface FastEthernet0/0

ip address 13.1.1.3 255.255.255.0

ip nat outside

ip virtual-reassembly

duplex auto

speed auto

!

interface FastEthernet1/0

ip address 23.1.1.3 255.255.255.0

ip nat outside

ip virtual-reassembly

duplex auto

speed auto

!

interface FastEthernet2/0

ip address 192.168.1.1 255.255.255.0

ip nat inside

ip virtual-reassembly

ip policy route-map 1

duplex auto

speed auto

!

interface FastEthernet3/0

ip address 192.168.2.1 255.255.255.0

ip nat inside

ip virtual-reassembly

ip policy route-map 1

duplex auto

speed auto

!

ip http server

no ip http secure-server

ip route 0.0.0.0 0.0.0.0 13.1.1.1 track 123

ip route 0.0.0.0 0.0.0.0 23.1.1.2 track 124

!

!

ip nat inside source route-map 2 interface FastEthernet0/0 overload

ip nat inside source route-map 3 interface FastEthernet1/0 overload

ip nat inside source route-map 4 interface FastEthernet0/0 overload

ip nat inside source route-map 5 interface FastEthernet1/0 overload

!

ip access-list extended all-net

access-list 1 permit 192.168.1.0 0.0.0.255

access-list 2 permit 192.168.2.0 0.0.0.255

!

route-map 1 permit 10

match ip address 1

set ip next-hop verify-availability 13.1.1.1 1 track 123 （低级别路由器貌似不支持verify-availability ）

set ip next-hop verify-availability 23.1.1.2 2 track 124

!

route-map 1 permit 20

match ip address 2

set ip next-hop verify-availability 23.1.1.2 1 track 124

set ip next-hop verify-availability 13.1.1.1 2 track 123

!

route-map 2 permit 10

match ip address 1

match ip next-hop 3

!

route-map 3 permit 10

match ip address 1

match ip next-hop 4

!

route-map 4 permit 10

match ip address 2

match ip next-hop 3

!

route-map 5 permit 10

match ip address 2

match ip next-hop 4

R2配置

interface FastEthernet0/0

ip address 26.1.1.2 255.255.255.0

duplex auto

speed auto

!

interface FastEthernet1/0

ip address 23.1.1.2 255.255.255.0

duplex auto

speed auto

!

router ospf 1

log-adjacency-changes

network 23.1.1.0 0.0.0.255 area 0

network 26.1.1.0 0.0.0.255 area 0

R1配置

interface FastEthernet0/0

ip address 16.1.1.1 255.255.255.0

duplex auto

speed auto

!

interface FastEthernet1/0

ip address 13.1.1.1 255.255.255.0

duplex auto

speed auto

!

router ospf 1

log-adjacency-changes

network 13.1.1.0 0.0.0.255 area 0

network 16.1.1.0 0.0.0.255 area 0