300-135 DHCP helper 請問是DSW1還是R4 的問題

jonasTing

這題的解釋跟答案似乎對不起來!

答案是DSW1，Explanation又再說是R4的問題。

但實際去考試的時候似乎又是遇到像R4的問題。

請高手解惑一下。

Ticket 8 DHCP helper
TROUBLE TICKET STATEMENT:
The implementation group has been using the test bed to do a
‘proof-of-concept’ that required both client 1 and client 2 to access the Web
Server at 209.65.200.241. After several changed to interface status, network
addressing, routing schemes and layer 2 connectivity, at trouble ticket has
been opened indicating that client 1 cannot ping the 209.65.200.241
(internet Server).
以下資訊需要自己 show run 獲得:
Client 1 and Client 2 are getting a 169.x.x.x IP address and are not able to ping
DSW1 or the FTP Server.
They are able to ping each other.
Configuration on DSW1:
!
interface Vlan 10
ip address 10.2.1.1 255.255.255.0
ip helper-address 10.2.21.129
!

QUESTION 1
On Which device is the fault condition located?
A. R1
B. R2
C. R3
D. R4
E. DSW1
F. DSW2
G. ASW1
H. ASW2
Correct Answer:E
Section: TROUBLE TICKET
Explanation
Explanation/Reference:
Explanation:
Since Client1 is getting ip address 169.x.x.x, there may be problem in DHCP.
On closer look into the DHCP configuration on DHCP Server i.e R4 you get ip
dhcp excluded-address command has wrongly configured. So the fault
condition is located on R4.
QUESTION 2
The fault condition is related to which technology?
A. NTP
B. IP DHCP Server
C. IPv4 OSPF Routing
D. IPv4 EIGRP Routing
E. IPv4 Route Redistribution
F. IPv6 RIP Routing
G. IPv6 OSPF Routing
H. IPV4 and IPV6 Interoperability
I. IPV4 layer 3 security
Correct Answer: B
Section: TROUBLE TICKET
Explanation
Explanation/Reference:
Explanation:
Since Client1 is getting ip address 169.x.x.x, there may be problem in DHCP.
On closer look into the DHCP configuration on DHCP Server i.e R4 you get ip
dhcp excluded-address command has wrongly configured. So the fault
condition is related to IP DHCP Server.
QUESTION 3
What is the soultion to the fault condition ?
A. Under the global configuration, delete the no ip dhcp use vrf connected
command

B. Under IP DHCP pool configuration, delete the default-router 10.2.1.254
command and enter the default-router 10.1.4.5 command.
C. Under IP DHCP pool configuration, delete the network 10.2.1.0
255.255.255.0 command and enter the network 10.1.4.0 255.255.255.0
command.
D. on DSW1 delete “ip helper-address 10.2.21.129” and apply “ip
helper-address 10.1.21.129” command
Correct Answer: D
Section: TROUBLE TICKET
Explanation
Explanation/Reference:
Explanation:

eleven1984

没有图，信息也很少
从solution来看，根本就没有排除地址错误的解决方案，所以红字显得不那么靠谱（除非第三题的答案给少了）

第三题的B和C选项是肯定不对的，vlan10接口地址 10.2.1.1，所以DHCP pool必然是 10.2.1.0/24，网关也必然是这个网段内的

如果A是正确答案，问题出在DHCP服务器上（R4吧？）

如果D是正确答案，问题出在DSW1上。

判断A还是D谁正确很简单，helper-address是DHCP的接口地址，自己看看到底是 10.2.21 还是 10.1.21 就是了