Dual-nat Routing test, using ospf Dynamic Routing

Test environment:
One router (R2) has three interfaces, one connected to the internal network, two connected to ISP1 (R1) and ISP2 (R3), and the two ISP outlets are connected to the same switch, then, a router (route) is connected outside the vswitch. Two ISPs (R1, R3, and router) use the ospf dynamic route, and then the policy route is made on R2, route is determined based on the next hop address.
　　
　　　　　　　　　　　　　　　　　　　　　
--- R3 ---
Route --- ---- R2 ---- internal network
--- R1 ---
　　

　　
R3 # sh run
Building configuration...
　　
Current configuration: 902 bytes
　　
Version 12.2:
Service timestamps debug uptime
Service timestamps log uptime
No service password-encryption
　　
Hostname R3
　　
Enable secret 5 $1 $ yd5D $ PSCihTgQQhhAsLJRhZYBI.
　　
Ip subnet-zero
No ip domain-lookup
Ip host R3 192.168.23.3
　　
　　
　　
　　
　
Nterface Loopback0
Ip address 3.3.3.3 255.255.255.0
　　
Interface Ethernet0
Ip address 172.16.13.3 255.255.255.0
　　
Interface Serial0
No ip address
Shutdown
　
Interface Serial1
Ip address 192.168.23.3 255.255.255.0
　　
Router ospf 1
Router-id 3.3.3.3
Log-adjacency-changes
Redistribute connected subnets
Redistribute static subnets
Network 172.16.255.0.0.255 area 0
　　
Ip classless
Ip route 192.168.100.0 255.255.255.0 192.168.23.2
Ip http server
　　
Snmp-server community public RO
Snmp-server community private RW
Snmp-server enable traps tty
　　
Line con 0
Logging synchronous
Line aux 0
Line vty 0 4
Password cisco
Logging synchronous
Login
　　
End
　　
R3 #
　　
　　
R2 #
R2 # sh run
Building configuration...
　　
Current configuration: 1667 bytes
　　
Version 12.1:
No service single-slot-reload-enable
Service timestamps debug uptime
Service timestamps log uptime
No service password-encryption
　　
Hostname R2
　　
Logging rate-limit console 10 TB t errors
Enable secret 5 $1 $ yOVt $ dwGkyiFW674ow6bsPMdgZ0
　　
Ip subnet-zero
No ip finger
No ip domain-lookup
Ip host R2 192.168.12.1
Ip host R3 192.168.23.3
　　
Central event-service server
　　
　　
　　
　　
　　
Interface Loopback0
Ip address 2.2.2.2 255.255.255.0
　　
Interface Ethernet0
Ip address 192.168.100.107 255.255.255.0
Ip nat inside
　　
Interface Serial0
Ip address 192.168.12.2 255.255.255.0
Ip nat outside
Clockrate 64000
　　
Interface Serial1
Ip address 192.168.23.2 255.255.255.0
Ip nat outside
Clockrate 64000
　　
Interface serial
No ip address
Shutdown
　
Interface seri_3
No ip address
Shutdown
　　
Interface BRI0
No ip address
Shutdown
　　
Ip kerberos source-interface any
Ip nat inside source route-map nat interface Serial1 overload
Ip nat inside source route-map test interface Serial0 overload
Ip classless
Ip route 172.16.255.255.255.255.255.0 192.168.23.3
Ip route 172.16.20.255.255.255.0 192.168.12.1
No ip http server
　　
Acess-list 1 permit 192.168.100.199
Access-list 1 permit 192.168.100.233
Access-list 1 permit 192.168.100.htm
Access-list 9 permit 192.168.12.1
Access-list 10 permit 192.168.23.3
Route-map test permit 10
Match ip address 1
Match ip next-hop 9
　　
Route-map cisco permit 10
　　
Route-map nat permit 10
Match ip address 1
Match ip next-hop 10
　　
　　
Snmp-server community public RO
Snmp-server community private RW
　　
Line con 0
Logging synchronous
Transport input none
Line aux 0
Line vty 0 4
Password cisco
Logging synchronous
Login
　　
End
　　
R2 #
　　
　　
R1 # sh run
Building configuration...
　　
Current configuration: 1017 bytes
　　
Version 12.1:
No service single-slot-reload-enable
Service timestamps debug uptime
Service timestamps log uptime
No service password-encryption
　　
Hostname R1
　　
No logging rate-limit
Enable secret 5 $1 $ Ogll $ BSpS5/nOBq8HtaKfwOZ8W0
　　
Ip subnet-zero
No ip finger
No ip domain-lookup
　　
Frame-relay switching
Central event-service server
　　
　　
　　
　　
　　
Interface Loopback0
Ip address 4.4.4.4 255.255.255.0
　　
Interface Ethernet0
Ip address 172.16.13.1 255.255.255.0
　　
Interface Serial0
Ip address 192.168.12.1 255.255.255.0
　
Interface Serial1
No ip address
　　
Router ospf 1
Router-id 4.4.4
Log-adjacency-changes
Redistribute connected subnets
Redistribute static subnets
Network 172.16.255.0.0.255 area 0
!
Ip kerberos source-interface any
Ip classless
Ip route 192.168.100.0 255.255.255.0 192.168.12.2
Ip http server
　　
　　
Snmp-server community public RO
Snmp-server community private RW
　　
Line con 0
Logging synchronous
Transport input none
Line aux 0
Line vty 0 4
Password cisco
Logging synchronous
Login
　　
End
　　
R1 #
　　
Router # sh run
Building configuration...
　　
Current configuration: 769 bytes
　
Version 12.2:
Service timestamps debug datetime msec
Service timestamps log datetime msec
No service password-encryption
　　
Hostn