CCNA 104.4 QUESTION 90

masyou

NA新手，又来给大家添麻烦了。。。不好意思。。。在这里先谢谢了
Refer to the exhibit. Assume that all of the router interfaces are operational and configured correctly. How
will router R2 be affected by the configuration of R1 that is shown in the exhibit?

A. Router R2 will not form a neighbor relationship with R1.
B. Router R2 will obtain a full routing table, including a default route, from R1.
C. R2 will obtain OSPF updates from R1, but will not obtain a default route from R1.
D. R2 will not have a route for the directly connected serial network, but all other directly connected
networks will be present, as well as the two Ethernet networks connected to R1.
Answer: B
Explanation/Reference:
考查OSPF产生默认路由的条件
虽然默认路由出口错误但是邻居仍然回收到 正确答案选：B


能不能解释一下上面红框里的内容啊？？还有为什么默认路由出口是错误的啊？？

ivy2053

router ospf 1----启动osfpf进程，进程号是1
network 172.16.100.0 0.0.0.3 area 0
network 172.16.100.64 0.0.0.63 area 0
network 172.16.100.128 0.0.0.31 area 0
上面这三行是对路由器R1三个子网进行宣告，与ISP连接的S0/1不需要宣告，只对内网宣告网络段。

R1上的默认路由是有错误的，端口S0/0为默认路由出口不对，应该是本路由上的端口，而不是对端的，在R1上正确做默认路由应该是：ip route 0.0.0.0 0.0.0.0 serial0/1

masyou

ivy2053 发表于 2011-9-22 21:24
router ospf 1----启动osfpf进程，进程号是1
network 172.16.100.0 0.0.0.3 area 0
network 172.16.100.6 ...

明白了，谢谢这位高手的解释

逸i云

好吧，我是做了实验才选了答案的

Mrserious

我觉的应该是上图中的ospf进程中的最后一个注入默认路由的语句起到的作用。

332104496

天沐

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