2、实验过程
R1：
r1(config)#int lo0
r1(config-if)#ip add 1.1.1.1 255.255.255.0
r1(config-if)#int s1/0
r1(config-if)#ip add 192.168.12.1 255.255.255.0
r1(config-if)#no shut
R2
r2(config)#int lo0
r2(config-if)#ip add 2.2.2.2 255.255.255.0
r2(config-if)#int s1/0
r2(config-if)#ip add 192.168.12.2 255.255.255.0
r2(config-if)#no shut
r2(config-if)#int s1/1
r2(config-if)#ip add 192.168.23.2 255.255.255.0
r2(config-if)#no shut
R3
r3(config)#int s1/1
r3(config-if)#ip add 192.168.23.3 255.255.255.0
r3(config-if)#no shut
r3(config-if)#int lo0
r3(config-if)#ip add 3.3.3.3 255.255.255.0
测试直连的连通性
r2#ping 192.168.12.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.12.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 8/42/104 ms
r2#ping 192.168.23.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.23.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 24/58/144 ms
r2#
实验要求：使得1.1.1.0/24、2.2.2.0/24、3.3.3.0/24网段之间相互通信。
r1(config)#ip route 2.2.2.0 255.255.255.0 192.168.12.2
r1(config)#ip route 3.3.3.0 255.255.255.0 192.168.12.2
r2(config)#ip route 1.1.1.0 255.255.255.0 192.168.12.1
r2(config)#ip route 3.3.3.0 255.255.255.0 192.168.23.3
这是测试：
r2#debug ip packet
r3#debug ip packet
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 0 percent (0/5)
r3#
*Jul 23 18:51:46.923: IP: tableid=0, s=192.168.12.1 (Serial1/1), d=3.3.3.3 (Loopback0), routed via RIB
*Jul 23 18:51:46.923: IP: s=192.168.12.1 (Serial1/1), d=3.3.3.3, len 100, rcvd 4
*Jul 23 18:51:46.927: IP: s=3.3.3.3 (local), d=192.168.12.1, len 100, unroutable
r3#
*Jul 23 18:51:48.851: IP: tableid=0, s=192.168.12.1 (Serial1/1), d=3.3.3.3 (Loopback0), routed via RIB
*Jul 23 18:51:48.851: IP: s=192.168.12.1 (Serial1/1), d=3.3.3.3, len 100, rcvd 4
*Jul 23 18:51:48.855: IP: s=3.3.3.3 (local), d=192.168.12.1, len 100, unroutable
r3#
*Jul 23 18:51:50.835: IP: tableid=0, s=192.168.12.1 (Serial1/1), d=3.3.3.3 (Loopback0), routed via RIB
*Jul 23 18:51:50.835: IP: s=192.168.12.1 (Serial1/1), d=3.3.3.3, len 100, rcvd 4
*Jul 23 18:51:50.839: IP: s=3.3.3.3 (local), d=192.168.12.1, len 100, unroutable
r3#
*Jul 23 18:51:52.851: IP: tableid=0, s=192.168.12.1 (Serial1/1), d=3.3.3.3 (Loopback0), routed via RIB
*Jul 23 18:51:52.851: IP: s=192.168.12.1 (Serial1/1), d=3.3.3.3, len 100, rcvd 4
*Jul 23 18:51:52.855: IP: s=3.3.3.3 (local), d=192.168.12.1, len 100, unroutable
r3#
*Jul 23 18:51:54.859: IP: tableid=0, s=192.168.12.1 (Serial1/1), d=3.3.3.3 (Loopback0), routed via RIB
*Jul 23 18:51:54.859: IP: s=192.168.12.1 (Serial1/1), d=3.3.3.3, len 100, rcvd 4
*Jul 23 18:51:54.859: IP: s=3.3.3.3 (local), d=192.168.12.1, len 100, unroutable
注：在R2上无任何debug信息。
在R3上配置：
r3(config)#ip route 1.1.1.0 255.255.255.0 192.168.23.2
r3(config)#ip route 192.168.12.0 255.255.255.0 192.168.23.2
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 = 12/56/132 ms
r1#ping 192.168.23.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.23.3, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)
r2#ping 1.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 8/44/112 ms
r2#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 = 16/99/384 ms
实验默认路由
1、在R1、R3上删除静态路由
r1(config)#no ip route 2.2.2.0 255.255.255.0 192.168.12.2
r1(config)#no ip route 3.3.3.0 255.255.255.0 192.168.12.2
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 not set
C 192.168.12.0/24 is directly connected, Serial1/0
1.0.0.0/24 is subnetted, 1 subnets
C 1.1.1.0 is directly connected, Loopback0
r3(config)#no ip route 1.1.1.0 255.255.255.0 192.168.23.2
r3(config)#no ip route 192.168.12.0 255.255.255.0 192.168.23.2
r3(config)#do 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
3.0.0.0/24 is subnetted, 1 subnets
C 3.3.3.0 is directly connected, Loopback0
C 192.168.23.0/24 is directly connected, Serial1/1
配置默认路由
r1(config)#ip route 0.0.0.0 0.0.0.0 192.168.12.2
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 192.168.12.2 to network 0.0.0.0
C 192.168.12.0/24 is directly connected, Serial1/0
1.0.0.0/24 is subnetted, 1 subnets
C 1.1.1.0 is directly connected, Loopback0
S*
0.0.0.0/0 [1/0] via 192.168.12.2
r3(config)#ip route 0.0.0.0 0.0.0.0 192.168.23.2
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 192.168.23.2 to network 0.0.0.0
3.0.0.0/24 is subnetted, 1 subnets
C 3.3.3.0 is directly connected, Loopback0
C 192.168.23.0/24 is directly connected, Serial1/1
S*
0.0.0.0/0 [1/0] via 192.168.23.2
实验调试：
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 = 8/54/152 ms
r1#
r3#ping 2.2.2.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/42/92 ms
r2#ping 1.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/32/68 ms
r2#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 = 8/41/124 ms
