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GRE Multilink Sim

September 11th, 2017 Go to comments

Refer to the topology below and answer the following questions.


Note: There may be different faults in this sim so please notice the following faults:

1. ACL blocking traffic on interface between R2 and R3
2. The network was not advertised in EIGRP
3. Two routers couldn’t establish adjacency because of ACL
4. Another two routers couldn’t establish adjacency because of wrong IP configuration on interface between them

Question 1


The Branch2 network is communicating to the Server farm, which is connected to R2, via GRE Tunnel so we should check the GRE tunnel first to see if it is in “up/up” state with the “show ip interface brief” command on the two routers.

On Branch2:


On R2:


We see interfaces Tunnel0 at two ends are “up/up” which are good so we should check for the routing part on two routers with the “show running-config” command and pay attention to the static routing of each router. On Branch2 we see:


The destination IP address for this static route is not correct. It should be (Tunnel0’s IP address of R2), not -> Answer C is correct.

Note: You can use the “show ip route” command to check the routing configuration on each router but if the destination is not reachable (for example: we configure “ip route” on Branch2, but if is unknown then Branch2 router will not display this routing entry in its routing table.

Note: The IP address or configuration may be different in the exam.

Question 2


First we should check Branch3 (and R1) with the “show ip interface brief” command to find any Layer1/Layer 2 issue.


We see the interfaces connecting between them are in “up/down” states which indicates an Layer 2 issue so we should check the configuration of these interfaces carefully with the “show running-config” command and pay attention to these interfaces.


and on Branch3:


We learn from above config is R1 is using CHAP to authenticate Branch3 router (via the “ppp authentication chap” command on R1). Branch3 router is sending CHAP hostname “Branch_3” and CHAP password “Branch3_Secret!” to R1 to be authenticated. Therefore we should check if R1 has already been configured with such username and password or not with the “show running-config” command on R1:


On R1 we see the configured username is “Branch3”, not “Branch_3” so the usernames here are mismatched and this is the problem -> Answer A is correct.

Question 3


In this question we have to check each option to see if it is correct. When we check Branch3 router we notice that “network” command is missing under “router eigrp 100” -> Answer D is correct.


Note: In the exam you should check other config as well. There are some reports saying that the answer of this question is different in the exam (answer A).

Question 4


This question clearly stated there is a WAN connectivity issue between R1 and Branch1 so we should check both of them with the “show ip interface brief” command. On R1:


On Branch1:


We can see that although the Multilink1 interfaces are in “up/up” state but they are not in the same subnet. According to the IP address scheme shown on the topology we can deduce the Multilink interface on Branch1 has been misconfigured, it should be instead.

Comments (4) Comments
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  1. mizii
    November 23rd, 2018

    Hello guys, who have this lab in packet tracer ?

  2. wonderskid
    November 30th, 2018

    Passed. There was a few drag and drops I did not see in the dumps. Gre multilink sim came up but I picked different answers as the configuration seemed different. Ospf , and Eirgp sim were the same. There were three questions about where to place a standard or extended acl. You are shown a picture with a network and asked what router and what interface would you place the acl.
    I spent a lot of time on the sims and had less than a minute left when I finished the exam , I rushed the last 15 questions. good luck.

  3. Deus
    December 7th, 2018

    @Wonderskid how many sims were in your exam? Am taking mine next week. I need more clarity about that ACL question.

  4. wonderskid
    December 9th, 2018

    @Deus. I think i had three sims. regarding the Acl , KNow where to put a standard Acl and know where to put an extended acl.

    Standard near the destination; Extended near the source.

    you will be shown a diagram of a network , maybe three routers a few pcs. and asked ” where would you put a standard ACL to stop Pc a from connected to PC e? ”

    So I would put it on the router near the source. ,if the question mentions an extended ACL, then you place it near the destination..as in PC e in this case.

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