ip classless 對路由選路的影響

ip classless 可以改變路由選路的方式，那具體對實際的應用有什麼影響呢？網上流傳的版本挺多，但是通過自己的實驗發現其實他們說的都不是太全面，官方文檔也找不出適合的解釋，還是通過實驗找到了自己想要的答案，下面就和大家分享下我做的實驗吧

一．實驗目的

通過實驗驗證 Ip classless 和no ip classless 對路由選路的影響

二．實驗拓撲

三．實驗配置

在這裏只給了主要配置，地址在圖中已經標明瞭，也不用浪費篇幅了。

R12(config)#ip route 0.0.0.0 0.0.0.0 16.16.16.1

四．驗證結果

R12#show ip route

10.0.0.0/24 is subnetted, 3 subnets

C 10.3.1.0 is directly connected, Loopback2

C 10.2.1.0 is directly connected, Loopback1

C 10.1.1.0 is directly connected, Loopback0

C 16.16.16.0/24 is directly connected, Serial0

S* 0.0.0.0/0 [1/0] via 16.16.16.1

R16#show ip route

10.0.0.0/24 is subnetted, 1 subnets

C 10.4.1.0 is directly connected, Loopback0

11.0.0.0/24 is subnetted, 1 subnets

C 11.4.1.0 is directly connected, Loopback1

C 16.16.16.0/24 is directly connected, Serial0

① 在R12上關閉ip classless

R12(config)#no ip class

R12(config)#end

R12#ping 10.4.1.1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 10.4.1.1, timeout is 2 seconds:

.....

Success rate is 0 percent (0/5)

R12#

R12#debug ip pac

IP packet debugging is on

R12#ping 10.4.1.1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 10.4.1.1, timeout is 2 seconds:

00:10:37: IP: s=10.1.1.1 (local), d=10.4.1.1, len 100, unroutable.

00:10:39: IP: s=10.1.1.1 (local), d=10.4.1.1, len 100, unroutable.

00:10:41: IP: s=10.1.1.1 (local), d=10.4.1.1, len 100, unroutable.

00:10:43: IP: s=10.1.1.1 (local), d=10.4.1.1, len 100, unroutable.

00:10:45: IP: s=10.1.1.1 (local), d=10.4.1.1, len 100, unroutable.

Success rate is 0 percent (0/5)

② 在R12上開啓ip classless

R12(config)#ip class

R12(config)#end

R12#

00:11:03: %SYS-5-CONFIG_I: Configured from console by console

R12#ping 10.4.1.1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 10.4.1.1, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 40/40/44 ms

R12#

00:11:11: IP: s=16.16.16.2 (local), d=10.4.1.1 (Serial0), len 100, sending