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Subnetting Practice Questions: Test 1

Discussion in 'General Cisco Certifications' started by NetEyeBall, Feb 16, 2007.

  1. NetEyeBall

    NetEyeBall Kilobyte Poster

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    Subnetting Practice Work:

    1. Find the Subnet
    2. Find the 1st Usable Host
    3. Find the Last Usable Host
    4. Find the Broadcast Address

    OR

    You will be asked if the IP Address is a valid Host address or a valid Host address for a particular Subnet.

    For Example:

    124.59.10.1 /10

    1. Find the Subnet = 124.0.0.0
    2. Find the 1st Usable Host = 124.0.0.1
    3. Find the Last Usable Host = 124.63.255.254
    4. Find the Broadcast Address = 124.63.255.255

    Please Note I will post the answers tomorrow for you to check your work.


    1.) 55.110.67.205 /16





    2.) 88.248.235.250 255.255.255.248





    3.) 56.58.128.76 255.128.0.0





    4.) 198.13.70.25 255.255.255.192





    5.) 150.75.222.94 /18





    6.) 198.134.190.70 /28





    7.) 47.165.237.34 /21





    8.) Is Ip address 79.246.255.1 with a subnet mask 255.224.0.0 a valid host ip address?





    9.) 107.30.205.80 255.255.255.240





    10.) Is 193.43.65.127 with a 255.255.255.192 mask a vaild Host IP address?
     
    Certifications: CCNA, A+, N+, MCSE 4.0, CCA
    WIP: CCDA, CCNP, Cisco Firewall
  2. NetEyeBall

    NetEyeBall Kilobyte Poster

    279
    10
    45
    Subnetting Practice Work:

    1. Find the Subnet
    2. Find the 1st Usable Host
    3. Find the Last Usable Host
    4. Find the Broadcast Address

    OR

    You will be asked if the IP Address is a valid Host address or a valid Host address for a particular Subnet.

    For Example:

    124.59.10.1 /10

    1. Find the Subnet = 124.0.0.0
    2. Find the 1st Usable Host = 124.0.0.1
    3. Find the Last Usable Host = 124.63.255.254
    4. Find the Broadcast Address = 124.63.255.255

    1.) 157.129.136.141 255.255.255.224

    2.) 44.204.221.73 /27

    3.) 181.39.102.219 255.255.128.0

    4.) 145.177.71.142 255.255.254.0

    5.) Host 215.83.56.220 /27 can't ping Host 215.83.56.225 /27. The newly hired Network Admin can't figure out why since they both have the same /27 subnet mask. Whats wrong?
     
    Certifications: CCNA, A+, N+, MCSE 4.0, CCA
    WIP: CCDA, CCNP, Cisco Firewall
  3. NetEyeBall

    NetEyeBall Kilobyte Poster

    279
    10
    45
    Subnetting Practice Work:

    1. Find the Subnet
    2. Find the 1st Usable Host
    3. Find the Last Usable Host
    4. Find the Broadcast Address

    OR

    You will be asked if the IP Address is a valid Host address or a valid Host address for a particular Subnet.

    For Example:

    124.59.10.1 /10

    1. Find the Subnet = 124.0.0.0
    2. Find the 1st Usable Host = 124.0.0.1
    3. Find the Last Usable Host = 124.63.255.254
    4. Find the Broadcast Address = 124.63.255.255

    1.) 17.46.23.96 255.248.0.0





    2.) 139.7.98.15 255.255.128.0






    3.) 199.180.150.119 /26 can't communicate with 199.180.150.128 /26 what is the problem?






    4.) 205.39.228.185 255.255.255.224






    5.) 15.19.11.2 /15
     
    Certifications: CCNA, A+, N+, MCSE 4.0, CCA
    WIP: CCDA, CCNP, Cisco Firewall
  4. Headache

    Headache Gigabyte Poster

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    Thanks.

    I'll have a crack at those and see how I make out.
     
    Certifications: CCNA
    WIP: CCNP
  5. NetEyeBall

    NetEyeBall Kilobyte Poster

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    So the other night I got an alert on an IP Address. We are implementing some new management software with the goal of having 1 alerting system for our entire enterprise. I am not going to comment on this aspect, but...so I got an alert on an IP Address. I attempted to find the IP. Tracert, NSLookup, Doing a search on our Visio Maps...Tracert is very nice obviously since it shows you all the layer 3 hops. However in our environment now most of the time it stops at our COLOs before it hits the Provider Cloud since we are no longer using
    P2P links. I tried a last ditch effort by checking a piece of software that contains all our IP Scope Information.

    Nothing...Nadda...Zilch. BUT I had a High Priority Auto Ticket on this device that I had to do something with. I could close it. But then someone might ask why I didn't act on a High Priority issue.

    Whos rules are these anyways? Man...

    Ok..so I started to look at the IP Address and then it hit me. It was the Network Address. Not an address actually assigned to an interface. It was a /30. /30 has two usable host ips. This was the network addy. So I incremented it by 1 and found the device. Why it alerted on that? I have no idea.

    Of course with IP Subnet Zero you can use the network ip I believe to assign it to an interface, however I haven't played with that and I really don't see a huge point in doing so. You just add a layer of complexity to troubleshooting. And trust me..there are all ready layers of complexity.

    So the moral of the story is...Knowing Subnetting is a good thing. Plus I feel it is good to practice a couple problems on a regular basis. I do 5 a night every night I work. Probably overkill, but it keeps it in my mind.
     
    Certifications: CCNA, A+, N+, MCSE 4.0, CCA
    WIP: CCDA, CCNP, Cisco Firewall
  6. r.h.lee

    r.h.lee Gigabyte Poster

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    NetEyeBall,

    At least in Cisco world, it also helps to know that you can configure a router to use or not use the Subnet Zero and the default setting based on Cisco IOS version. According to Cisco...


    Link:
     
    Certifications: MCSE, MCP+I, MCP, CCNA, A+
    WIP: CCDA
  7. Headache

    Headache Gigabyte Poster

    1,092
    9
    85

    I hear you.
     
    Certifications: CCNA
    WIP: CCNP
  8. Headache

    Headache Gigabyte Poster

    1,092
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    Okay, I've been playing with some of those subnets and this is what I came up with (for better or worse).


    1.) 55.110.67.205 /16

    55.110.0.0 | 55.110.0.1 | 55.110.255.254 | 55.110.255.255


    2.) 88.248.235.250 255.255.255.248

    88.248.235.248 | 88.248.235.249 | 88.248.235.254 | 88.248.235.255



    3.) 56.58.128.76 255.128.0.0

    56.0.0.0 | 56.0.0.1 | 56.127.255.254 | 56.127.255.255


    4.) 198.13.70.25 255.255.255.192


    192.13.70.0 | 192.13.70.1 | 192.13.70.62 | 192.13.70.63


    5.) 150.75.222.94 /18


    150.75.192.0 | 150.75.192.1 | 150.75.255.254 | 150.75.255.255


    6.) 198.134.190.70 /28

    198.134.190.64 | 198.134.190.65 | 198.134.190.78| 198.134.190.79


    7.) 47.165.237.34 /21

    47.165.232.0 | 47.165.232.1 | 47.165.239.254 | 47.165.239.255


    8.) Is Ip address 79.246.255.1 with a subnet mask 255.224.0.0 a valid host ip address?

    Not sure about this one, but I think yes.

    79. 224.0.0 | 79.224.0.1 | 79.255.255.254 | 79.255.255.255.


    9.) 107.30.205.80 255.255.255.240


    107.30.205.80 | 107.30.205.81 | 107.30.205.94 | 107.30.205.95


    10.) Is 193.43.65.127 with a 255.255.255.192 mask a vaild Host IP address?


    Answer: No, it's a broadcast address.


    193.43.65.64 | 193.43.65.65 | 193.43.65.126| 193.43.65.127
     
    Certifications: CCNA
    WIP: CCNP
  9. NetEyeBall

    NetEyeBall Kilobyte Poster

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    Thanks R.H.Lee for the link. I knew as of release 12.0 that use of subnet zero could be done. I had forgotten that you could do it with all 1s as well.
     
    Certifications: CCNA, A+, N+, MCSE 4.0, CCA
    WIP: CCDA, CCNP, Cisco Firewall
  10. NetEyeBall

    NetEyeBall Kilobyte Poster

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    Answers:

    1.) 55.110.67.205 /16

    1. Find the Subnet = 55.110.0.0
    2. Find the 1st Usable Host = 55.110.0.1
    3. Find the Last Usable Host = 55.110.255.254
    4. Find the Broadcast Address = 55.110.255.255

    2.) 88.248.235.250 255.255.255.248

    1. Find the Subnet = 88.248.235.248
    2. Find the 1st Usable Host = 88.248.235.249
    3. Find the Last Usable Host = 88.248.235.254
    4. Find the Broadcast Address = 88.248.235.255

    3.) 56.58.128.76 255.128.0.0

    1. Find the Subnet = 56.0.0.0
    2. Find the 1st Usable Host = 56.0.0.1
    3. Find the Last Usable Host = 56.127.255.254
    4. Find the Broadcast Address = 56.127.255.255

    4.) 198.13.70.25 255.255.255.192

    1. Find the Subnet = 198.13.70.0
    2. Find the 1st Usable Host = 198.13.70.1
    3. Find the Last Usable Host = 198.13.70.62
    4. Find the Broadcast Address = 198.13.70.63

    5.) 150.75.222.94 /18

    1. Find the Subnet = 150.75.192.0
    2. Find the 1st Usable Host = 150.75.192.1
    3. Find the Last Usable Host = 150.75.255.254
    4. Find the Broadcast Address = 150.75.255.255

    6.) 198.134.190.70 /28

    1. Find the Subnet = 198.134.190.64
    2. Find the 1st Usable Host = 198.134.190.65
    3. Find the Last Usable Host = 198.134.190.78
    4. Find the Broadcast Address = 198.134.190.79

    7.) 47.165.237.34 /21

    1. Find the Subnet = 47.165.232.0
    2. Find the 1st Usable Host = 47.165.232.1
    3. Find the Last Usable Host = 47.165.239.254
    4. Find the Broadcast Address = 47.165.239.255

    8.) Is Ip address 79.246.255.1 with a subnet mask 255.224.0.0 a valid host ip address?

    Yes. It falls in the 79.224.0.0 subnet and is a valid host ip address.

    9.) 107.30.205.80 255.255.255.240

    1. Find the Subnet = 107.30.205.80
    2. Find the 1st Usable Host = 107.30.205.81
    3. Find the Last Usable Host = 107.30.205.94
    4. Find the Broadcast Address = 107.30.205.95

    10.) Is 193.43.65.127 with a 255.255.255.192 mask a vaild Host IP address?

    No. 193.43.65.127 is the broadcast address for the 193.43.65.64 subnet.
     
    Certifications: CCNA, A+, N+, MCSE 4.0, CCA
    WIP: CCDA, CCNP, Cisco Firewall
  11. NetEyeBall

    NetEyeBall Kilobyte Poster

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    Thanks Lee. I just re-read your link. I had the concept incorrect. It has nothing to do with host ips, but rather using the all zeros or all ones SUBNET.

    Damn...this stuff never seems to get easy.
     
    Certifications: CCNA, A+, N+, MCSE 4.0, CCA
    WIP: CCDA, CCNP, Cisco Firewall
  12. scottsilverbullet

    scottsilverbullet New Member

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    subnetting practice test 1

    question 6:

    6.) 198.134.190.70 /28




    Your answer:

    6.) 198.134.190.70 /28

    1. Find the Subnet = 198.134.190.64
    2. Find the 1st Usable Host = 198.134.190.65
    3. Find the Last Usable Host = 198.134.190.78
    4. Find the Broadcast Address = 198.134.190.79


    I just can't see this!!
    My answer:
    196.134.190.1 - first address
    196.134.190.14 - last
    196.134.190.15 Broadcast

    What am I doing wrong???
     
  13. soundian

    soundian Gigabyte Poster

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    198.134.190.70 /28
    look at the last octet in binary
    01000110
    subnet mask is
    11110000
    that means the network portion of the last octect is
    01000000=64 (all host bits set to 0)
    network address is 196.134.190.64
     
    Certifications: A+, N+,MCDST,MCTS(680), MCP(270, 271, 272), ITILv3F, CCENT
    WIP: Knuckling down at my new job
  14. scottsilverbullet

    scottsilverbullet New Member

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    Oh what an arse I am....I see it now...there's 16 subnets
    2^4.....

    many thanks for your response.
     

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