在上一文中介紹了RIP、EIGRP、OSPF之間的路由重分發，現在再介紹一下怎麼實現默認路由、ISIS和其他協議之間的充分發。
試驗模擬環境：IP分配和拓撲如圖
實驗步驟：
1、 基本配置參考拓撲圖
2、 配置路由器1
配置默認路由
Router(config)#ip route 0.0.0.0 0.0.0.0 172.1.1.2 //配置默認路由
3、配置路由器3
配置IS-IS路由協議
r3(config)#router isis //配置IS-IS
r3(config-router)#net 49.0001.0000.0000.0001.00
r3(config-router)#exit
r3(config)#interface s0/0 //把IS-IS協議作用到接口上
r3(config-if)#ip router isis
r3(config-if)#int loo 0
r3(config-if)#ip router isis
4、配置路由器2
配置一條指向配置默認路由的路由器的靜態路由
r2(config)#ip route 1.1.1.0 255.255.255.0 172.1.1.1 //靜態路由指向外網網段
配置路由重定向
r2 (config)#router isis
r2 (config-router)#net
r2 (config-router)#net 49.0001.0000.0000.0002.00
r2 (config-router)#redistribute connected metric 10 //直連網段重分發
r2 (config-router)#redistribute static metric 10 //默認路由重分發
r2 (config-router)#exit
r2 (config)#int s0/0
r2 (config-if)#ip router isis
r2 (config-if)#int s0/1
r2(config-if)#ip router isis
r2 (config-if)#int loo 0
r2 (config-if)#ip router isis
r2 (config-if)#exit
測試連通性：
在路由器1上查看路由表
r1#show 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 172.1.1.2 to network 0.0.0.0
1.0.0.0/24 is subnetted, 1 subnets
C 1.1.1.0 is directly connected, Loopback0
172.1.0.0/24 is subnetted, 1 subnets
C 172.1.1.0 is directly connected, Serial0/0
S* 0.0.0.0/0 [1/0] via 172.1.1.2
在路由器2上查看路由表
r2#show 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
1.0.0.0/24 is subnetted, 1 subnets
S 1.1.1.0 [1/0] via 172.1.1.1
2.0.0.0/24 is subnetted, 1 subnets
C 2.2.2.0 is directly connected, Loopback0
3.0.0.0/24 is subnetted, 1 subnets
i L1 3.3.3.0 [115/20] via 172.2.1.2, Serial0/1
172.1.0.0/24 is subnetted, 1 subnets
C 172.1.1.0 is directly connected, Serial0/0
172.2.0.0/24 is subnetted, 1 subnets
C 172.2.1.0 is directly connected, Serial0/1
在路由器3上查看路由表
r3#show 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
1.0.0.0/24 is subnetted, 1 subnets
i L2 1.1.1.0 [115/20] via 172.2.1.1, Serial0/0
2.0.0.0/24 is subnetted, 1 subnets
i L1 2.2.2.0 [115/20] via 172.2.1.1, Serial0/0
3.0.0.0/24 is subnetted, 1 subnets
C 3.3.3.0 is directly connected, Loopback0
172.1.0.0/24 is subnetted, 1 subnets
i L1 172.1.1.0 [115/20] via 172.2.1.1, Serial0/0
172.2.0.0/24 is subnetted, 1 subnets
C 172.2.1.0 is directly connected, Serial0/0
用PING命令測試
r1#ping 2.2.2.2 source 1.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds:
Packet sent with a source address of 1.1.1.1
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 48/126/256 ms
r1#ping 3.3.3.3 source 1.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds:
Packet sent with a source address of 1.1.1.1
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 48/120/208 ms
結合上一篇博文，我們可以實現默認路由、RIP、EIGRP、OSPF、IS-IS以及直連網段之間的路由重分發。