Q: Which IPv4 Static Routes Could be Useful?

CCENTSkills
By CCENTSkills October 8, 2015 09:05

This week’s sample question is about static IPv4 routes. The question makes you think not only about syntax, but also about the meaning of the parameters of the ip route command. The wording is a bit tricky because I’ve attempted to not give away the answers to how the commands work. However, I don’t want the wording to cause unnecessary problems, so ask questions if you have them,

The question is below the fold; as usual, I’ll post an answer several days from now.

Scenario

A small Enterprise network has four routers. Each router connects to a single switch, and each switch uses all default settings, which places all switch ports into VLAN 1. Each router has all default configuration except for the configuration mentioned here in the scenario description for this problem set, plus any configuration suggested by an individual question in this question set.

The routers have been correctly configured with the IP addresses shown in the following figure. All interfaces have been enabled, and all interfaces come up and work. The four hosts have been statically configured with the IP addresses and default gateway settings shown in the figure.

The routers begin with all interfaces in the figure in an up/up state, so that each router has connected IP routes. However, no other IP routes exist on the routers.

 

Question

Which of the following commands would be good commands to add to either router R2 or router R3? To be “good”, the routes must be both 1) syntactically correct, and 2) be a route that would help the respective router forward packets correctly to hosts A, B, C, and D.

A. ip route 10.1.1.0 255.255.255.0 10.1.12.2

B. ip route 10.1.3.0 255.255.255.0 10.1.23.2

C. ip route 172.16.2.0 255.255.255.128 10.1.23.2

D. ip route 10.1.14.0 255.255.255.0 S0/0/1

 

A: Which ARP and Where
A: Which IPv4 Static Routes Could be Useful?
CCENTSkills
By CCENTSkills October 8, 2015 09:05
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10 Comments

  1. KevLev March 28, 23:32

    Hey Wendell,
    Love your site, but don’t know where’s the right place to leave questions/comments? Anyways, I just got the CCNA Simulator (official) and read your document “The sim-lab-study-plan.doc” that corresponds to the chapters in your book as to where you are in the simulator. Very cool work indeed! Question, how or what is your best recommendation as to how to attack the sim? 250 labs is great, but with all the different cattagories Skill Builder, PartI, PartII, etc, “Where should I start”? From the 1st until the very last?,,, or approach it differently? As always, keep up the great work, Thanks!!

    KevLev

    Reply to this comment
    • certskills Author March 29, 05:41

      Hi Kev,
      As for Q&A, this blog’s the best place. For now, it’s not too busy; ongoing, we’ll see if I can keep up with general questions, or not.
      Glad you like the site! I just published some pages on the ICND1 Exam Cert Guide just yesterday – look for the study tab.
      Regardless, I’d say use them with each chapter as detailed in that doc. start with Skill Builders.Then I’d suggest a couple of options at that point:
      1) Ignore Configuration Scenario (CS) and Troubleshooting Scenario (TS) labs during your first read through the chapter, and save them for your first review pass
      or
      2) do the CS labs once finished with the first read of each chapter

      Regardless, I’d save those few TS labs until you’ve finished the “part” of the book (parts have multiple chapters in them), particularly until you’ve read the section or chapter specific to troubleshooting in that part of the book.

      Hope this helps. And thanks for the encouragement!
      Wendell

      Reply to this comment
      • KevLev April 15, 14:35

        Hey Wendell,
        Quick question for you. As per the document “Sim-lab-study-plan.pdf”, most of it I find helpful when using it with the sim, but I’m up to Static Routes IV, and it says that is Ch14, but I would think it’s more one of the subnetting chapters in the book no? In Step 1 of the lab you have to configure and figure out the subnet numbers and masks. Good lab. Thanks.

        Reply to this comment
        • certskills Author April 15, 15:08

          Nice idea – I’ll at least add it to the Chapter 12 section as an option, and probably also list it with chapter 14 to practice the static routes. Thanks!
          Wendell

          Reply to this comment
  2. KevLev April 15, 17:46

    Cool, thanks for getting back to me so soon. All in all this “CCNA Simulator” isn’t half that bad. From what I’ve used so far anyways. I’ve done it in order and am now up to partIII of Skill Builder and obviously on the Static Routes IV lab. I really wish you can enlarge the window, but no biggie.

    Reply to this comment
  3. Mike October 8, 09:50

    Hmmm not sure if many of them are useful. Here is what I came up with:

    R2
    A. ip route 10.1.1.0 255.255.255.0 10.1.12.2 – next hop is self, not valid
    B. ip route 10.1.3.0 255.255.255.0 10.1.23.2 – next hop is self, not valid
    C. ip route 172.16.2.0 255.255.255.128 10.1.23.2 – not needed due to directly connected network
    D. ip route 10.1.14.0 255.255.255.0 S0/0/1 – it will work, but not useful to reach the hosts

    R3
    A. ip route 10.1.1.0 255.255.255.0 10.1.12.2- will work, but unless you have a recursive route to 10.1.12.0 its not useful
    B. ip route 10.1.3.0 255.255.255.0 10.1.23.2 – not needed due to directly connected network
    C. ip route 172.16.2.0 255.255.255.128 10.1.23.2 – this is useful and can be added
    D. ip route 10.1.14.0 255.255.255.0 S0/0/1 – not the best path and not useful to reach the hosts

    Reply to this comment
  4. Bojan October 8, 14:35

    A good on R3 but not on R2 (wrong end)
    B not good on R2 (wrong end) and useless on R3
    C good on R3 but useless on R2 (wrong end)
    D Useless, it’s for PTP

    So all would be useful on R2 or R3 except for D.

    Reply to this comment
  5. theurge14 February 20, 17:52

    Not sure if this matters for this exercise, but it appear the LAN block on R4 is out of range for PC D. /26 block ends at 172.30.4.62

    Reply to this comment
    • CCENTSkills Author March 7, 09:49

      I agree it’s immaterial to the question, but I also agree it’s incorrect! 🙂 I’ll add it to the list. Don’t have the source figure any more. 🙁

      Reply to this comment
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