通过ip default-network可以向网络中注入一条默认路由。RIP和EIGRP同样配置。
RB#sh ip route
C 200.200.200.0/24 is directly connected, Loopback1
1.0.0.0/30 is subnetted, 1 subnets
C 1.1.1.0 is directly connected, Serial1/2
10.0.0.0/24 is subnetted, 1 subnets
C 100.100.100.0 is directly connected, Loopback0
R 10.0.0.0/8 [120/1] via 1.1.1.1, 00:00:21, Serial1/2
R 192.168.1.0/24 [120/1] via 1.1.1.1, 00:00:21, Serial1/2
RB(config)#ip default-network 110.0.0.0
RB(config)#int loopback 2
RB(config-if)#ip add 110.0.0.1 255.255.255.0
RB#sh ip route
C 200.200.200.0/24 is directly connected, Loopback1
1.0.0.0/30 is subnetted, 1 subnets
C 1.1.1.0 is directly connected, Serial1/2
100.0.0.0/24 is subnetted, 1 subnets
C 100.100.100.0 is directly connected, Loopback0
* 110.0.0.0/24 is subnetted, 1 subnets
C* 110.0.0.0 is directly connected, Loopback2
R 10.0.0.0/8 [120/1] via 1.1.1.1, 00:00:13, Serial1/2
R 192.168.1.0/24 [120/1] via 1.1.1.1, 00:00:13, Serial1/2
RA#sh ip route
R 200.200.200.0/24 [120/1] via 1.1.1.2, 00:00:13, Serial2/1
1.0.0.0/30 is subnetted, 1 subnets
C 1.1.1.0 is directly connected, Serial2/1
R 100.0.0.0/8 [120/1] via 1.1.1.2, 00:00:13, Serial2/1
10.0.0.0/24 is subnetted, 1 subnets
C 10.0.0.0 is directly connected, Loopback1
C 192.168.1.0/24 is directly connected, Loopback0
R* 0.0.0.0/0 [120/1] via 1.1.1.2, 00:00:13, Serial2/1 ----可见被注入 *表示默认路由
RA#ping 110.0.0.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 110.0.0.1, timeout is 2 seconds: