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Nat Sim

June 24th, 2011 in LabSim Go to comments

Question

A network associate is configuring a router for the TUT company to provide internet access. The ISP has provided the company six public IP addresses of 198.18.184.105 198.18.184.110. The company has 14 hosts that need to access the internet simultaneously. The hosts in the company LAN have been assigned private space addresses in the range of 192.168.100.17 – 192.168.100.30.

The following have already been configured on the router:

– The basic router configuration
– The appropriate interfaces have been configured for NAT inside and NAT outside
– The appropriate static routes have also been configured (since the company will be a stub network, no routing protocol will be required.)
– All passwords have been temporarily set to “cisco”

Tasks:
+ Use NAT to provide Internet access to all hosts in the company LAN.
+ Name the router TUT
+ Inside global addresses: 198.18.184.105 198.18.184.110/29
+ Inside local addresses: 192.168.100.17 – 192.168.100.30/28
+ Numer of inside hosts: 14

NAT_sim_topology.jpg

Solution:

Note: If you are not sure about NAT or Access list, my read my NAT tutorial and Access-list tutorial.

The company has 14 hosts that need to access the internet simultaneously but we just have 6 public IP addresses from 198.18.184.105 to 198.18.184.110/29. Therefore we have to use NAT overload (or PAT) Double click on the Weaver router to open it

Router>enable
Router#
configure terminal

First you should change the router’s name to TUT

Router(config)#hostname TUT

Create a NAT pool of global addresses to be allocated with their subnet mask.

TUT(config)#ip nat pool mypool 198.18.184.105 198.18.184.110 netmask 255.255.255.248

Create a standard access control list that permits the addresses that are to be translated

TUT(config)#access-list 1 permit 192.168.100.16 0.0.0.15

Establish dynamic source translation, specifying the access list that was defined in the prior step

TUT(config)#ip nat inside source list 1 pool mypool overload

This command translates all source addresses that pass access list 1, which means a source address from 192.168.100.17 to 192.168.100.30, into an address from the pool named mypool (the pool contains addresses from 198.18.184.105 to 198.18.184.110).

Overload keyword allows to map multiple IP addresses to a single registered IP address (many-to-one) by using different ports.

The question said that appropriate interfaces have been configured for NAT inside and NAT outside statements. This is how to configure the NAT inside and NAT outside, just for your understanding:

TUT(config)#interface fa0/0
TUT(config-if)#
ip nat inside
TUT(config-if)#
exit
TUT(config)#
interface s0/0
TUT(config-if)#
ip nat outside
TUT(config-if)#end

Finally, we should save all your work with the following command:

TUT#copy running-config startup-config

Check your configuration by going to “Host for testing” and type:

C:\>ping 192.0.2.114

The ping should work well and you will be replied from 192.0.2.114

You can download this sim and practice with Packet Tracer here: http://www.9tut.com/download/9tut.com_CCNA_NAT_sim_question.zip

(Notice: you can find other NAT Sim Question here)

Other lab-sims in ICND2 Exam:

ICND 2 – OSPF Sim
VTP SIM (on 9tut.com)

EIGRP Lab sim (on 9tut.com)

Other lab-sims might appear in the real ICND 2 exam, read and understand them if you have enough time!

Comments
Comment pages
1 2 3 56
  1. TT
    July 19th, 2015

    @smti – This site is done for, I paid for full access and you are able to access the same questions I can. I am requesting a refund, 9tut, how do we go about getting a refund, or do I have to file a fraud case with my Cc company?

  2. 9tut
    July 19th, 2015

    @TT: Premium Membership supports many features you can use to practice. Could you please tell us why you see the same questions? If you want a refund or have any questions, please send an email to support@9tut.com, we will help you.

  3. Jay
    August 4th, 2015

    Passed ICND2 today, this sim was not on the exam.
    Had EIGRP, OSPF and Frame Relay sims.

  4. UK
    September 8th, 2015

    Hi can you use wr to save the config ?

    cheers

  5. ChaserZX
    September 9th, 2015

    Why do you need a refund? Even if you get the same questions this website deserves the donation. don’t be selfish

  6. Mucci
    October 12th, 2015

    Can you guys mail the latest ICDN1 DUMPS at genieluce@icloud.com

  7. John
    November 25th, 2015

    I don’t know about subnestmask /29 /28
    please explain for me?

  8. John
    November 25th, 2015

    I don’t know about subnestmask /29 /28
    please explain for me?
    my mail thuan.phanthanh@doosan.com
    thanks

  9. sikorka
    January 17th, 2016

    Great Explanation 😉

  10. ghawkguy
    February 14th, 2016

    John,

    /29 refers to how many bits are used in the subnet mask. This is the same as writing 255.255.255.248, if that helps. Of 32 bits, 29 are used, leaving 3 bits for host IP addresses; 000, 001, 011, 111, 110, 100, etc. Use formula 2^n-2 to get usable host bits: 2^3-2=6. First and last addresses cannot be used. Same math for any /x number.

  11. kvant
    February 16th, 2016

    wonderfull

  12. nope
    May 20th, 2016

    studying for the CCNA… I am taking it on Monday and feeling extremely scared! I completely forgot everything and now Im just memorizing the questions and answers. I hope its enough to get me a passing score. Wish me luck guys!!

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