CCNA模拟题求解

ravenlin8

1.The relevantconfiguration files for the Certkiller1 and Certkiller2 routers are displayedbelow:Certkiller1# showrunning-config

<some outputtext omitted>

enable passwordcisco

!

hostnameCertkiller1

usernameCertkiller2 password cisco

!

interface serial0/0

ip address 10.0.8.1255.255.248.0

encapsulation ppp

ppp authenticationchap



Certkiller2# show running-config
<some output text omitted>
enable password cisco1
!
hostname Certkiller2
username Certkiller1 password cisco1
!
interface serial 0/0
ip address 10.0.15.2 255.255.248.0
encapsulation ppp
ppp authentication chap                        

Which of thefollowing reasons would you attribute the connectivity problem between the tworouters?
A. Theauthentication needs to be changed to PAP for both routers.
B. The serial IPaddresses of routers are not on the same subnet.
C. Theusername/password combination is incorrectly configured.
D. The routernames are incorrectly configured.

Answer: C



2.Which of the following IP addresses can be assigned to host devices?(Choose two.)
A. 205.7.8.32/27
B. 191.168.10.2/23
C. 127.0.0.1
D. 224.0.0.10
E. 203.123.45.47/28
F. 10.10.0.0/13

Answer: B, F



3.The ip subnet zero command is notconfigured on a router. What would be the IP address of Ethernet 0/0 using thefirst available address from the sixth subnet of the network 192.168.8.0/29?
A. 192.168.8.25
B. 192.168.8.41
C. 192.168.8.49
D. 192.168.8.113

Answer: C

本人是菜鸟，各位高手能解释一下吗?谢谢

morning

2和3都是子网问题
2：下面的那个地址可以被用作主机地址
简单算法，比如205.7.8.32/27
掩码是：255.255.255.224 用256减224等于32，所以这个地址是一个子网的网络号，不能用作主机地址。
C和D是特殊地址，直接排除，同样算法就能得到答案B和F

3：能给F0/0分配的第六个子网的第一个地址是哪个?

同样算法:192 .168.8.0/29   子网掩码:255.255.255.248  
256-248=8  第六个子网的网络号是192.168.8.48  第一个可用主机IP是192.168.8.49 答案C

第一题没看懂 其实我也很菜 跟帖求指点