subnetting and wildcard masks, oo la la

Discussion in 'OT Technology' started by Pro Street, Jan 29, 2006.

  1. Pro Street

    Pro Street New Member

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    ok, the head cisco training guy gave me this question for over the weekend, and I've been racking my brain on it.

    let's say you want to create an ACL to ban all IP's on a class C network from .0 through .127

    example: 192.168.1.0/24

    now, he said the wildcard mask required would be 0.0.0.31

    I'm supposed to figure out why it is such. :hs:

    can someone help me without giving me the actual answer, or point me in a general direction? I'd consider subnetting it but he did specify /24 so I have no idea.
     
  2. dtfromep

    dtfromep New Member

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    /24 is Classless (CIDR) style/protocol.

    Try checking the # of bits in the network address (write out the four octets) and apply the /24 mask.

    Edit: I can elaborate if you like, but it is pretty basic networking stuff.
     
  3. Pro Street

    Pro Street New Member

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    I still don't follow... subnetting is something I never could get completely, I know how they are split and such, but not to the point of how to actually apply them.
     
  4. dtfromep

    dtfromep New Member

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  5. Pro Street

    Pro Street New Member

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    the only way was what I was thinking in the beginning, subnetted to /27:

    Address: 192.168.0.1 11000000.10101000.00000000.000 00001
    Netmask: 255.255.255.224 = 27 11111111.11111111.11111111.11100000
    Wildcard: 0.0.0.31 00000000.00000000.00000000.00011111
    Network: 192.168.0.0/27 11000000.10101000.00000000.000 00000 (Class C)
    Broadcast: 192.168.0.31 11000000.10101000.00000000.000 11111
    HostMin: 192.168.0.1 11000000.10101000.00000000.000 00001
    HostMax: 192.168.0.30 11000000.10101000.00000000.000 11110
    Hosts/Net: 30 (Private Internet)
     

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