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DHCP Sim

October 16th, 2016 Go to comments

Refer to the topology below and answer the questions.

Topology.jpg

You can download this lab and practice with Packet Tracer at http://juquitiba.sp.gov.br/?exams=download/9tut.com_DHCP_Sim.zip (note: In this Packet Tracer file we use FastEthernet instead of Ethernet connections; and interfaces Fa1/0, Fa1/1 instead of interfaces Et0/2, Et0/3)

Question 1

Examine the DHCP configuration between R2 and R3, R2 is configured as the DHCP server and R3 as the client. What is the reason R3 is not receiving the IP address via DHCP?

A. On R3, DHCP is not enabled on the interface that is connected to R2.
B. On R3, the interface that is connected to R2 is in shutdown condition.
C. On R2, the interface that is connected to R3 is in shutdown condition.
D. On R2, the network statement in the DHCP pool configuration is incorrectly configured.

 

Answer: A

Explanation

First we should check which interface on R3 that is connected to R2 via the “show run” command.

R3_show_run.jpg

From the description we learn interface E0/1 is connected to R2. Use the “show ip interface brief” command to verify the IP address of this interface.

R3_show_ip_int_brief.jpg

Therefore we can conclude this interface does not have any IP address and there is no configuration on this interface (except the “description Link to R2” line).

If R3 wants to receive an IP address from R2 via DHCP, interface E0/1 should be configured with the command “ip address dhcp” so the answer “DHCP is not enabled on this interface” is correct.

Question 2

R1 router clock is synchronized with ISP router. R2 is supposed to receive NTP updates from R1. But you observe that R2 clock is not synchronized with R1. What is the reason R2 is not receiving NTP updates from R1?

A. R1 router Ethernet interface that is connected to R2 is placed in shutdown condition.
B. R2 router Ethernet interface that is connected to R1 is placed in shutdown condition.
C. The NTP server command not configured on R2 router.
D. The IP address that is used in the NTP configuration on R2 router is incorrect.

 

Answer: D

Explanation

First we should verify if the ports connected between R1 and R2 is in “up/up” state with the “show ip interface brief” command on R1 & R2.

R1_R2_show_ip_int_brief.jpg

Note: We learn R1 & R2 connect to each other via E0/2 interface because the IP addresses of these interfaces belong to 192.168.10.0/30 subnet. Both of them are “up/up” so the link connecting between R1 & R2 is good.

Next we need to verify the ntp configuration on R2 with the “show running-config” command.

R2_show_run_ntp_part.jpg

So there is only one command related to NTP configuration on R2 so we need to check if the IP address of 192.168.100.1 is correct or not. But from the “show ip interface brief” command on R1 we don’t see this IP -> This IP address is not correct. It should be 192.168.10.1 (IP address of interface E0/2 of R1), not 192.168.100.1.

Question 3

Why applications that are installed on PC’s in R2 LAN network 10.100.20.0/24 are unable to communicate with Server1?

A. A standard ACL statement that is configured on R1 is blocking the traffic sourced from R2 LAN network.
B. A standard ACL statement that is configured on R1 is blocking the traffic sourced from Server1 network.
C. A standard ACL statement that is configured on R2 is blocking the traffic sourced from Server1 network.
D. A standard ACL statement that is configured on R2 is blocking the traffic sourced from R2 LAN network.

 

Answer: C

Explanation

We should check if we can ping from R1 to Server 1 or not:

R1_ping_Server1.jpg

The ping worked well so maybe R1 is good so we should check R2 first. We notice on R2 there is an access-list:

R2_show_run_access_list_part.jpg

This access-list is applied to E0/2 interface with inbound direction. The purpose of this access-list is to block traffic with source IP address of 172.16.200.0/24 so it will block all traffic sent from Server 1 to us.

Question 4

Users complain that they are unable to reach internet sites. You are troubleshooting internet connectivity problem at main office. Which statement correctly identifies the problem on Router R1?

A. NAT configurations on the interfaces are incorrectly configured.
B. NAT translation statement incorrectly configured.
C. Interesting traffic for NAT ACL is incorrectly configured.
D. Only static NAT translation configured from the server, missing Dynamic NAT or Dynamic NAT overloading for internal networks.

 

Answer: A

Explanation

If all users cannot access internet then R1 is most likely to cause the problem so we should check it first. From the “show running-config” command we will see:

R1_show_run_nat_interfaces.jpg

We notice that interface E0/0 (connected to ISP) has been configured as “nat inside” while interfaces E0/1 & E0/2 (connected to our company) have been configured as “nat outside”. This is not correct because “nat inside” should be configured with interfaces connected to our company while “nat outside” should be configured with interfaces connected to the internet. Therefore we can conclude the NAT configuration on these interfaces is not correct.

Comments (20) Comments
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  1. RazorSharp
    February 17th, 2018

    {email not allowed}

  2. sumitra
    April 2nd, 2018

    question no.3 is wrong , don’t be confused..

  3. sumitra
    April 2nd, 2018

    sorry simulation file configuration is different then here so it made me more confuse. but now okay everything.

  4. Marco
    May 4th, 2018

    @sumitra: On my opinnion question N3 is absolutely correct!

  5. YEA
    May 13th, 2018

    @Marco it’s correct but the server number is incorrect in the file, server0 should be named server1

  6. Vlonee
    May 18th, 2018

    Question # needs review please.. question, answer and explanation are not in line

  7. gaurav4u
    May 29th, 2018

    @9tut- Q3 has been wrongly worded. It mentions: “applications that are installed on PCs in R2 LAN network 10.100.20.0/24 are unable to communicate with SERVER 1”?.

    But the “show run” command displays that 172.16.200.0 network which has been blocked by the access-list on R2 is present on R1’s fa0/1 interface connecting to SERVER 0, and not SERVER 1, as mentioned in the Question. So the answer should be like:”A standard ACL statement that is configured on R2 is blocking the traffic sourced from SERVER 0, INSTEAD OF SERVER 1,which has been wrongly worded. Thanks!

  8. gaurav4u
    May 30th, 2018

    you are absolutely wrong the answer c is correct because ACL is denying / blocking traffic coming from 172.16.200.0/24 which is the server ip addresses or network so please dont create confusion……

  9. gaurav4u
    May 30th, 2018

    @9tut- I am sorry, but I am absolutely not wrong. The Whole confusion is due to the fact that the DOWNLOADABLE SIM provide by you on this page has been wrongly labelled!!! My whole assessment was based on the SIM you have provided. In the SIM, the SERVER 1 has been labelled as SERVER 0, and SERVER 2 has been labelled as SERVER 1, thereby creating all the confusion.

    I wonder why anybody has not noticed?. You can check the SIM and see it for yourself.

    Thanks!!!

  10. gaurav4u
    May 31st, 2018

    @9tut- Please get Q3 SIM labelled correctly. It is stll the same and creating lot of confusion.

  11. 9tut
    May 31st, 2018

    @gaurav4u: Thanks for your information. We have just updated this sim with correct labels.

  12. Amigo
    May 31st, 2018

    I got this Sim on the exam yesterday, and many Others. Thanks 9tut, it was really easy and I passed with 9xx…

    confirming all the Simulations from 9tut in the exam and the questions from Chines dumps…

  13. Hiruka
    June 3rd, 2018

    What’s the difference between 9tut questions and the Chinese dumps?

  14. ganzee
    June 6th, 2018

    Hello there!
    I don’t understand, can I just answer on the questions or I must fix all problems or it depends of question?

  15. uwandulu
    June 6th, 2018

    Hello @amigo

    pls help with specific lab and sim you encountered in the exam. thanks

  16. Anonymous
    June 8th, 2018

    So during the exam, are going to have to use Packet Tracert and build a network just to do show commands? Somebody help me understand here?

  17. trends
    June 12th, 2018

    @anonymous,

    in exam there’s a ready net diagram beside the multiple choice question. all you have to do is to “show run” on every router needed to be checked. Example here in DHCP question#1

    1. Examine the DHCP configuration between R2 and R3, R2 is configured as the DHCP server and R3 as the client. What is the reason R3 is not receiving the IP address via DHCP?

    First you must checked what are the routers asked in this question. So it is R2 and R3, you must use the “show interface” command and checked its differences/ wrong config based on question asked

    :D

  18. Anonymous
    June 25th, 2018

    Has anyone had this question in the exam

  19. Anonymous
    June 25th, 2018

    can you please explain the 3rd question as it seems too confusing. Thanks

  20. Anonymous
    July 14th, 2018

    hi guys, i’ill do CCNA exam next week, if you all is good people, please give me ccna dumb file and send to imdarassyatir1 @ gmail dot com

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