ip default-information originate 通告默认路由[文档]
默认路由系列文档5/5



在OSPF/ISIS中，ip default-network无效。我们用ip default-information originate来通告默认路由，在高版本的IOS中RIP也可以使用这条命令，但EIGRP不可以。以OSPF为例：

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R1#show run
Building configuration...

Current configuration : 975 bytes
!
version 12.3
!
hostname R1
!
interface Loopback0

ip address 1.1.1.1 255.255.255.0
!
interface Serial1/0

ip address 12.1.1.1 255.255.255.0
!
router ospf 10
network 12.1.1.0 0.0.0.255 area 0
!

end
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R2#show run
Building configuration...

Current configuration : 1057 bytes
!
version 12.3
!
hostname R2
!
interface Loopback0

ip address 2.2.2.2 255.255.255.0
!
interface Serial1/0

ip address 12.1.1.2 255.255.255.0
!
interface Serial1/1

ip address 23.1.1.2 255.255.255.0
!
router ospf 10
network 12.1.1.0 0.0.0.255 area 0

default-information originate always
//发布默认路由，加上参数 [always]
!

//作用是 当静态默认路由失效时，仍然//通告默认路由
ip route 0.0.0.0 0.0.0.0 23.1.1.3
!
end
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R3#show run
Building configuration...

Current configuration : 934 bytes
!
version 12.3
!
hostname R3
!
interface Loopback0

ip address 3.3.3.3 255.255.255.0
!
interface Serial1/0

ip address 23.1.1.3 255.255.255.0
!
ip route 0.0.0.0 0.0.0.0 23.1.1.2
！
end
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R1# show ip ro
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 12.1.1.2 to network 0.0.0.0


1.0.0.0/24 is subnetted, 1 subnets
C
1.1.1.0 is directly connected, Loopback0

12.0.0.0/24 is subnetted, 1 subnets
C
12.1.1.0 is directly connected, Serial1/0
O*E2 0.0.0.0/0 [110/1] via 12.1.1.2, 00:17:47, Serial1/0


R1#ping 3.3.3.3

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 60/114/164 ms



稍后附上默认路由系列文档总结

恩,又有一种新方法,可以选择性地做拉