R1
Router>en
Router#conf t
Router(config)#hostname R1
R1(config)#no ip domain loo
R1(config)#line console 0
R1(config-line)#exec-time 0 0
R1(config-line)#logg syn
R1(config-line)#exit
R1(config)#inter f0/0
R1(config-if)#ip address 192.168.1.1 255.255.255.0
R1(config-if)#no sh
R1(config-if)#exit
R1(config)#inter s1/1
R1(config-if)#ip address 192.168.5.1 255.255.255.0
R1(config-if)#no sh
R1(config-if)#exit
R1(config)#inter f0/1
R1(config-if)#ip address 192.168.4.2 255.255.255.0
R1(config-if)#no sh
R1(config-if)#exit
R1(config)#ip route 192.168.2.0 255.255.255.0 192.168.1.2
R1(config)#ip route 192.168.6.0 255.255.255.0 192.168.1.2
R1(config)#ip route 192.168.3.0 255.255.255.0 192.168.1.2
R1(config)#ip route 0.0.0.0 0.0.0.0 192.168.1.2         
R1(config)#end
R1#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route
 
Gateway of last resort is 192.168.1.2 to network 0.0.0.0
 
C    192.168.4.0/24 is directly connected, FastEthernet0/1
C    192.168.5.0/24 is directly connected, Serial1/1
S    192.168.6.0/24 [1/0] via 192.168.1.2
C    192.168.1.0/24 is directly connected, FastEthernet0/0
S    192.168.2.0/24 [1/0] via 192.168.1.2
S    192.168.3.0/24 [1/0] via 192.168.1.2
S*   0.0.0.0/0 [1/0] via 192.168.1.2
 
R2
Router>en
Router#conf t
Router(config)#hostname R2
R2(config)#no ip domain loo
R2(config)#line console 0
R2(config-line)#exec-time 0 0
R2(config-line)#logg syn
R2(config-line)#exit
R2(config)#inter f0/1
R2(config-if)#ip address 192.168.1.2 255.255.255.0
R2(config-if)#no sh
R2(config-if)#exit
R2(config)#inter s1/1
R2(config-if)#ip address 192.168.6.1 255.255.255.0
R2(config-if)#no sh
R2(config-if)#exit
R2(config)#inter f0/0
R2(config-if)#ip address 192.168.2.1 255.255.255.0
R2(config-if)#no sh
R2(config-if)#exit
R2(config)#ip route 192.168.3.0 255.255.255.0 192.168.2.2
R2(config)#ip route 192.168.4.0 255.255.255.0 192.168.2.2
R2(config)#ip route 192.168.5.0 255.255.255.0 192.168.2.2
R2(config)#ip route 0.0.0.0 0.0.0.0 192.168.2.2
R2(config)#end
R2#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route
 
Gateway of last resort is not set
 
S    192.168.4.0/24 [1/0] via 192.168.2.2
S    192.168.5.0/24 [1/0] via 192.168.2.2
C    192.168.6.0/24 is directly connected, Serial1/1
C    192.168.1.0/24 is directly connected, FastEthernet0/1
C    192.168.2.0/24 is directly connected, FastEthernet0/0
S    192.168.3.0/24 [1/0] via 192.168.2.2
S*   0.0.0.0/0 [1/0] via 192.168.2.2
 
R3
 
Router>en
Router#conf t
Router(config)#hostname R3
R3(config)#no ip domain loo
R3(config)#line console 0
R3(config-line)#exec-time 0 0
R3(config-line)#logg syn
R3(config-line)#exit
R3(config)#inter f0/1
R3(config-if)#ip address 192.168.2.2 255.255.255.0
R3(config-if)#no sh
R3(config-if)#exit
R3(config)#inter s1/1
R3(config-if)#ip address 192.168.5.2 255.255.255.0
R3(config-if)#no sh
R3(config-if)#exit
R3(config)#inter f0/0
R3(config-if)#ip address 192.168.3.1 255.255.255.0
R3(config-if)#no sh
R3(config)#ip route 192.168.1.0 255.255.255.0 192.168.3.2
R3(config)#ip route 192.168.4.0 255.255.255.0 192.168.3.2
R3(config)#ip route 192.168.6.0 255.255.255.0 192.168.3.2
R3(config)#ip route 0.0.0.0 0.0.0.0 192.168.3.2
R3(config)#end
R3#sh ip route     
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route
 
Gateway of last resort is not set
 
S    192.168.4.0/24 [1/0] via 192.168.3.2
C    192.168.5.0/24 is directly connected, Serial1/1
S    192.168.6.0/24 [1/0] via 192.168.3.2
S    192.168.1.0/24 [1/0] via 192.168.3.2
C    192.168.2.0/24 is directly connected, FastEthernet0/1
C    192.168.3.0/24 is directly connected, FastEthernet0/0
S*   0.0.0.0/0 [1/0] via 192.168.3.2
 
R4
Router>en
Router#conf t
Router(config)#hostname R4
R4(config)#no ip domain loo
R4(config)#line console 0
R4(config-line)#exec-time 0 0
R4(config-line)#logg syn
R4(config-line)#exit
R4(config)#inter f0/1
R4(config-if)#ip address 192.168.3.2 255.255.255.0
R4(config-if)#no sh
R4(config-if)#exit
R4(config)#inter s1/1
R4(config-if)#ip address 192.168.6.2 255.255.255.0
R4(config-if)#no sh
R4(config-if)#exit
R4(config)#inter f0/0
R4(config-if)#ip address 192.168.4.1 255.255.255.0
R4(config-if)#no sh
R4(config-if)#exit
R4(config)#ip route 192.168.1.0 255.255.255.0 192.168.4.1
%Invalid next hop address (it's this router)
R4(config)#ip route 192.168.1.0 255.255.255.0 192.168.4.2
R4(config)#ip route 192.168.2.0 255.255.255.0 192.168.4.2
R4(config)#ip route 192.168.5.0 255.255.255.0 192.168.4.2
R4(config)#ip route 0.0.0.0 0.0.0.0 192.168.4.2
R4(config)#end
R4#s
*Mar  1 01:07:55.235: %SYS-5-CONFIG_I: Configured from console by console
R4#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route
 
Gateway of last resort is not set
 
C    192.168.4.0/24 is directly connected, FastEthernet0/0
S    192.168.5.0/24 [1/0] via 192.168.4.2
C    192.168.6.0/24 is directly connected, Serial1/1
S    192.168.1.0/24 [1/0] via 192.168.4.2
S    192.168.2.0/24 [1/0] via 192.168.4.2
C    192.168.3.0/24 is directly connected, FastEthernet0/1
S*   0.0.0.0/0 [1/0] via 192.168.4.2
以上配置过于理想化了,如果您的网络负载比较大的话,建议在不同的连接口上配置ROUTE信息,这样避免网络拥堵!