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Subnneting problem on Final Teste of Network Fundamentals

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  • 1.  Subnneting problem on Final Teste of Network Fundamentals

    Posted 09-22-2017 03:46

    Hi guys,

     

    I do not know if it's just me that's doing it wrong the exercice or for some other reason it gives the wrong answer when i submit.
    the exercice is the following:
     
    sender or source computer ip address: 10.10.1.8
    Destination ip address: 10.10.1.50
    Netmask: 255.255.255.240 
     
    The question is?
     
    - What is the network Address of source IP Address?
    - What is the network Address of Destination IP Address?
     
    My answer was:
    A: I know that 255.255.255.240 = /28
     
    What is the network Address of source IP Address?
    A: 10.10.1.0/28
     
     - What is the network Address of Destination ip Address?
    A: 10.10.1.48/28
     
    am i wrong?
     
    thank you for your attention guys.
     
    Regards
     
    W.M
     


  • 2.  RE: Subnneting problem on Final Teste of Network Fundamentals

    Posted 09-22-2017 06:36

    I got that question wrong too, I took for granted that I entered a wrong number but it could be an error in the system. Here is the calculation focusing only on the last octet, the "turned on" relevant bits are in bold:

     

    240 in binary:
    11110000

    8 in binary:
    00001000

    The network address will be the relevant bits as they are, and the last four bits turned to 0, so it is 10.10.10.0

    50 in binary:
    00110010
    The network address will be 10.10.10.48

     

    The CIDR is also correct, a 240 in the last octet is a /28

    Links relevant to this answer:

    http://www.rapidtables.com/convert/number/decimal-to-binary.htm
    http://www.subnet-calculator.com/
    https://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing

     

    If my calculations are correct, then there may be an issue with this question.

    Hope this helps,
    Franco



  • 3.  RE: Subnneting problem on Final Teste of Network Fundamentals

    Posted 09-22-2017 07:11

    Thanks Franco, 

     

    I am checking this one out. I'll post what I find. Take care. 

     

     



  • 4.  RE: Subnneting problem on Final Teste of Network Fundamentals

    Posted 09-22-2017 07:10

    Hello Wilson, 

     

    Thanks for using the forum. 

     

    I just ran through the review and after doing subnetting on my end I came up with the same answer you did. 

    It doesn't seem to like the 10.10.1.40/28 network for some reason. Let me ask around and I'll post what I find.

     

    This is a great opportunity for others in this community to jump in and help as well. 

     

    Take care Wilson



  • 5.  RE: Subnneting problem on Final Teste of Network Fundamentals
    Best Answer

    Posted 09-22-2017 07:12

    Hi Wilson,

     

    Your calculations are correct. I am unable to reproduce the error though. See the screenshot below. Are you trying to add the /28 somewhere?

    netfun.jpg

     

     

     



  • 6.  RE: Subnneting problem on Final Teste of Network Fundamentals

    Posted 09-22-2017 07:28

    Hello Everyone, 

     

    I worked through this with a colleague of mine and he figured this out. I didn't go far enough in my subnetting before I answered the question but this is correct. 

     

    so with a .240 subnet mask there are 16 subnets-- .0 through .15, .16 through .31, .32 through .47, .48 through .63 etc.

    the first address in each of those ranges is the network ID

    so .50 falls within the .48 network

     

    It's been a while since I subnetted so I am out of shape in that department. 

     

    Thanks a lot everyone for working together on this



  • 7.  RE: Subnneting problem on Final Teste of Network Fundamentals

    Posted 09-22-2017 09:25

    Hi Guys,

     

    thats right Jas. i was typing wrong. (ex: 10.10.1.0/28) in the answer you can not type "/28"

     

    Thanks for the support all of you Team.