参考配置：
（1）
Router1>
Router1>en
Router1#show running
Building configuration...
Current configuration : 612 bytes
!
version 12.2
no service timestamps log datetime msec
no service timestamps debug datetime msec
no service password-encryption
!
hostname Router1
!
interface FastEthernet0/0
ip address 192.168.10.254 255.255.255.0
duplex auto
speed auto
!
interface FastEthernet0/1
no ip address
duplex auto
speed auto
shutdown
!
interface Serial0/0
ip address 192.168.20.10 255.255.255.0
!
interface Serial0/1
no ip address
shutdown
!
router rip
network 192.168.10.0
network 192.168.20.0
（2）
Router2>
Router2>en
Route2r#show running
Building configuration...
Current configuration : 806 bytes
!
version 12.2
no service timestamps log datetime msec
no service timestamps debug datetime msec
no service password-encryption
!
hostname Router2
!
interface FastEthernet0/0
ip address 192.168.40.254 255.255.255.0
ip access-group 1 out
duplex auto
speed auto
!
interface FastEthernet0/1
no ip address
duplex auto
speed auto
shutdown
!
interface Serial0/0
no ip address
shutdown
!
interface Serial0/1
ip address 192.168.30.10 255.255.255.0
ip access-group 2 out
clock rate 64000
!
router rip
network 192.168.30.0
network 192.168.40.0
!
ip classless
!
!
access-list 1 permit 192.168.10.0 0.0.0.255
access-list 1 deny any
access-list 2 deny host 192.168.40.11
access-list 2 permit any
（3）
Router0>en
Router0#show running
Building configuration...
Current configuration : 629 bytes
!
version 12.2
no service timestamps log datetime msec
no service timestamps debug datetime msec
no service password-encryption
!
hostname Router0
!
interface FastEthernet0/0
no ip address
duplex auto
speed auto
shutdown
!
interface FastEthernet0/1
no ip address
duplex auto
speed auto
shutdown
!
interface Serial0/0
ip address 192.168.20.11 255.255.255.0
clock rate 64000
!
interface Serial0/1
ip address 192.168.30.11 255.255.255.0
!
router rip
network 192.168.20.0
network 192.168.30.0
