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Author Topic: ip/subnetting qustion  (Read 5156 times)

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chassmith

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ip/subnetting qustion
« on: June 04, 2007, 08:56:24 AM »
ok here goes I need help to get some extra cred on a test I was told the fallowing


ip = 198.64.5.63

the subnet is = 255.255.240.0

I need to find out the ip of the 19th computer on the 8th subnet ><

I have no clue how to do it and any help would be nice plz give me a full "you get this by doing this explanation"

and no this in no way will be abused it is a purely theoretical question told to us by our teacher

oh and by the way hi :)








ok so now I have done a little work and gotten

11111111.11111111.11110000.00000000

this is the subnet in binary ..... lol but now what ><

we have come up with a 4,094 ip range .... but how would I express 4,094 in ip form ?

it cant be 198.64.5.4094 <<-----right ?_? bahhhh so confused ><


but is any of this right ?

viking



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    Re: ip/subnetting qustion
    « Reply #1 on: June 04, 2007, 09:34:16 AM »
    198 => network class C
    The subnet mask tells us that we are talking about network summarization.
    SM = 255.255.240.0 => we have 2^4 (2 at 4 power = 16) networks class C. Each network has 254 clients (maximum), so 2^4 * 254 = 4096 maximum possible hosts using that subnet mask. 4096 and not 4094! Maybe he tells you about 4094, so that you leave alone the 0 and the 255 addresses, according to your network specifications. I have to check that part, I do not remember any constraint with the 0 and 255 addresses when we are talking about network summarization... Yes, you can talk about this constraint when you are talking about 198.64.5 network, where 198.64.5.0 with subnet mask 255.255.255.0 means the  network and 198.64.5.255 with subnet mask 255.255.255.0 means all computers from that network (subnet).
    240 = 1 1 1 1 0 0 0 0 => the last 4 bits are different, they could be different for networks included according to this subnet mask. Hence the 2^4 (2 at power 4) networks class C.
    In the subnet mask you are interested only by the part 240 (which means 4 bits of 1 and 4 bits of 0).
    240 also means that the 4 bits of the 3rd byte are the same. If you are using the IP 198.64.5, the first 4 bits are 0 for all of your networks included in this summarization.
    240 = 1 1 1 1 0 0 0 0
    5=      0 0 0 0 0 1 0 1
    Only the last 4 bits change. So, you have networks from 198.64.0 to 198.64.16 included in this.
    8th subnet:
    198.64.0
    198.64.1
    198.64.2
    ...
    198.64.7 (we started the count at 0, remember?)
    We have a subnet mask of 255.255.255.0 for this subnet, so, the 19th computer has the IP of 19 (here we start counting computers at 1). Your 19th computer has the IP 198.64.7.19

    Shame on me, I forgot so much... I will check if it is correct what I am writing here. I remember the term summarization, I remember about route agregation, but I forgot about them... This summer I have to study.
    « Last Edit: June 04, 2007, 09:48:31 AM by viking »

    chassmith

    • Guest
    Re: ip/subnetting qustion
    « Reply #2 on: June 04, 2007, 10:23:19 AM »
    "etwork has 254 clients (maximum), so 2^4 * 254 = 4096 maximum possible hosts "


    I put 4094 to rep the useabel ip's  with in the subnet !   :)

    I am happy you have taken the time to reply thanks but I still am a bit ?_?

    so to sum up one more time

    we have a ip of 198.63.5.63

    and a subnet of 255.255.240.0     

    he told us that the subnet was a different class then the ip ip=c sub=b

    as to why he had to make this such a hard a$$ qustion I dont know :P

    any more help would be ....helpfull

    take me throu step by step eg:

    ip= 198.64.XX.XX  <----  and explane



    >< god I ha8 net working !!


    so you are saying the ip is   >>> 198.64.7.19   <<<<          this would be the 19th ip of the 8th sub yah ^_^ ?


    as you said make sure you are correct and get back to me ;)

    -thanks once again!
















    edit            found answer.............

    198.64.133.83


    why this is the ip I still have no clue any insite would be nice
    « Last Edit: June 04, 2007, 12:15:36 PM by chassmith »

    viking



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      Re: ip/subnetting qustion
      « Reply #3 on: June 04, 2007, 02:44:04 PM »
      I don't have much to say... If you want to know the answers then learn, it's your homework, not ours.
      I won't say you everything more, you have to know something before asking for some indications. I won't write a manual for yourself, I think it's clear to you that.

      A question: from where did you get that IP? 198.64.133.83?

      chassmith

      • Guest
      Re: ip/subnetting qustion
      « Reply #4 on: June 05, 2007, 05:08:40 AM »
      "well lmao thanks for the "do you own PUCKING work speech"


      this was just a purely extra cred assignment and it was ment for my class to not be able to get the answer....

      I was just looking for someone to impart some knowledge on me because unlike the useless masses when I get an answer, I look at how and why that  is the answer and I learn from it .....

      as for the final sulotion lmao it is dumb as all *censored* imo

      my networking proff says its 198.64.133.83    but then the other one came up with what I had gotten a while back while pulling out my hair ;) 

      198.64.128.19



      the reasoning behind this is that eatch sub net can have 4096 computer systems so the 19th on the 8th would be

      198.64.128.19   assuming you went from 198.64.1.0 - and up from there

      now my other proff say that if the starting ip was in fact 198.64.5.63

      then you would add the  5+128 = 133     19+63=83      .............

      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
      to me that seems like there is no "real" logic behind it because .128.0 <--is a place holder for a vary large number of computer systems .... but to just go and add 5?...

      why in the *censored* would you ?

      -__________________________________________________________________


      so to sum up yes this is something I should have learned on my own but... it is not something covered in the course nor would I have the foggiest idea how to do it unless I was pointed in the right derection ..... if someone asks for help then lay it out for them tell them the steps needed to be fallowed because thats what I was asking for I did not go "I need this ANSWER now !!"  I asked for someone to go over the logical steps leading up to the answer and the answer itself so that I could better understand the process...


      in the end I found my question baffling but thanks to this form for helping as just as you guys could ;)

      thanks for all the help 

      viking



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        Re: ip/subnetting qustion
        « Reply #5 on: June 05, 2007, 05:34:46 AM »
        I can't be your teacher, my friend :( I have to study for myself and if I am able I will help others. Or I will try to help others...
        If you want to find these informations so you could understand, you may try on any search engine with:
        ip supperneting
        subnet mask
        route summarization
        network agregating
        route agregating
        (etc)


        http://www.subnet-calculator.com/cidr.php
        IP address: you have to enter your IP
        CIDR netmask: your subnet mask
        I do not understand your teacher's answer.

        I understand where I was mistaken: I was subnetting further the subnets. In that "right" case (in my opinion, considering the teacher's answer), the 8th subnet would be 198.64.112.0/20 (that 20 = 255.255.240.0 and it means 20 bits of 1 in the subnet mask). This you can tell him, I think he is wrong here. When he makes supernetting he considers whole ranges of network, he can't jump some "just because". He took an IP and added a number of networks, he did not work with network ranges (error! He should consider only the network address and not the host address).
        He did not added 5 to 128 (2^7) but added 128 to 5 (8th subnet would be 2^7). I'm wondering how he will find the 10th subnet, the 11th subnet...  I'm sure though that he has a shorthand. But it should be applied corectly!
        He added that 19 to IP because 19+63<254. Again, it's a mistake. He should count the 19th computer of the subnet, he can't just simply mess network addresses with host addresses :(

        I launched the question to some of my friends, some work with supernetting, summarization, the whole stuff. I should receive a correct answer today. If you wait for me to learn... There will be a few weeks before I re-read the theory.
        « Last Edit: June 05, 2007, 06:19:09 AM by viking »