Rip v2转发问题

jmei

R3
router rip
version 2
network 3.0.0.0
network 23.0.0.0
no auto-summary

Loopback0 is up, line protocol is up
  Internet address is 3.3.3.3/24

     1.0.0.0/30 is subnetted, 1 subnets
R       1.1.1.0 [120/2] via 23.1.1.1, 00:00:06, Serial1/1
     2.0.0.0/24 is subnetted, 1 subnets
R       2.2.2.0 [120/1] via 23.1.1.1, 00:00:06, Serial1/1
     3.0.0.0/24 is subnetted, 1 subnets
C       3.3.3.0 is directly connected, Loopback0
     23.0.0.0/24 is subnetted, 1 subnets
C       23.1.1.0 is directly connected, Serial1/1
     12.0.0.0/24 is subnetted, 1 subnets
R       12.1.1.0 [120/1] via 23.1.1.1, 00:00:06, Serial1/1
R3#ping 1.1.1.1 source loopback 0  能ping通，但是环回口的掩码是/24位的，
路由条目是/30位的，我就感觉应该是不能ping通，请问他是基于怎样的转发原理，不看掩码吗？

chenhoujian

在路由表中查找路由的时候基于掩码最长匹配原则，若路由表中还有1.X.X.X的网络，且掩码更长将会优先长掩码的路由，比如还有32位的路由