Stupid question for the day - 70-291

Discussion in 'MCSE' started by LMC, Oct 29, 2008.

  1. LMC

    LMC Guest

    So here I am asking another stupid question regarding 70-291 (and perparing
    myself to take a punch in the face from MCPGP)...

    I'm sure there will be questions regarding subnetting and such ... all fine
    and good. I'm just curious if the exam provides the most basic calculator
    (the native calc program) so I don't have to waste time counting on my
    fingers and toes.
     
    LMC, Oct 29, 2008
    #1
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  2. LMC

    FrisbeeĀ® Guest

    http://www.learntosubnet.com
     
    FrisbeeĀ®, Oct 29, 2008
    #2
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  3. LMC

    LMF Guest

    I'm pretty sure the calculator is the complete windows one. Scientific and
    all. But i wouldn't know for sure since i can do all the in my head :)
     
    LMF, Oct 29, 2008
    #3
  4. LMC

    CBIC Guest

    You can't subnet in your head? You're sh!tting me! Can you dress yourself in
    the morning? It's not hard just remember /28 is block size of 16 and go from
    there.
     
    CBIC, Oct 29, 2008
    #4
  5. The test environment provides a basic calculator without the scientific
    function. That is more than enough to sail you through. As a tip, do know
    you ip addressing and subnetting very well. I flunked this exam at first try
    and if you as me, that was the culprit.

    Best of luck anyway
     
    Victor Asuquo, Oct 31, 2008
    #5
  6. LMC

    DieHard

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    The way I subnet: Takes around 30 seconds (if that) - with practice!

    I have seen some stupid subnetting questions and thought I'd offer they way I do it to try and help.

    Before you try and learn how to subnet you need to learn binary and the different classes of addresses.

    Forget magic numbers and special tables, if you know binary it's easy, trust me.

    Assumming the ip subnet zero command is in use, we will find the network address, broadcast address and address range.

    191.16.97.150 with a mask of 255.255.255.192


    Prefix notion:255.255.255.192 = /26


    In the mask you always ignore the 255 and the 0 part so we use the 192 part( 4th octet )in the mask and the address.

    192 in binary is
    128 64 32 16 8 4 2 1
    1 1 0 0 0 0 0 0


    What ever the last one is in the mask 64 in this case, this is the number the subnet go up by:

    Network number: 0 range: 0-62 BC Address: 63
    Network number: 64 range: 65-126 BC Address: 127
    Network number 128 range: 129-190 BC Address: 191
    Network number 192 range: 193-254 BC Address: 255
    Network number 256 (not valid as greater than 255)


    Therefore as 192 in the mask is the 4th octet we use the 4th octet in the address: 150

    From the above find what number is below 150, 150 is between 128 and 192 therefore:

    191.16.97.150 /26

    Network number 191.16.97.128 /26
    range: 191.16.97.129 - 191.16.97.190
    Broadcast Address: 191.16.97.191

    After a bit practice as soon as you see the mask, you know the multiples of the subnets.
    They can only be 128, 64, 32, 16, 8, 4, 2 or 1.. Look familiar don't they
     
    DieHard, Nov 3, 2008
    #6
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