subnetting

Discussion in 'Computer Support' started by Sorahl, Nov 25, 2003.

  1. Sorahl

    Sorahl Guest

    Hey all,

    The subject of TCP/IP subnetting befuddles me a bit.

    I have given myself the example scenario of a small company with a C-class
    network ID of 212.78.160.0.
    They need 10 subnets.

    If I correctly understand this, encoding 11 (10+1) into binary needs 4 bits.
    Therefore, I use 4 bits more for the network ID and get a subnetmaks of
    255.255.255.240.

    The lowest bit in 11110000 is worth 16 so I get a multiplier of 16.

    Subnets are then defined as follows:
    212.78.160.16
    212.78.160.32... right on till
    212.78.160.224 as the 14th subnet.

    Each subnet allows for 14 hosts.

    Sounds okay up till now?

    My question is what the ranges of valid IP host addresses look like.

    Greets, Sorahl
     
    Sorahl, Nov 25, 2003
    #1
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  2. Sorahl

    -= Hawk =- Guest

    On Tue, 25 Nov 2003 11:22:00 +0100, "Sorahl" <>
    scribbled:

    >Hey all,
    >
    >The subject of TCP/IP subnetting befuddles me a bit.
    >
    >I have given myself the example scenario of a small company with a C-class
    >network ID of 212.78.160.0.
    >They need 10 subnets.
    >
    >If I correctly understand this, encoding 11 (10+1) into binary needs 4 bits.
    >Therefore, I use 4 bits more for the network ID and get a subnetmaks of
    >255.255.255.240.
    >
    >The lowest bit in 11110000 is worth 16 so I get a multiplier of 16.
    >
    >Subnets are then defined as follows:
    >212.78.160.16
    >212.78.160.32... right on till
    >212.78.160.224 as the 14th subnet.
    >
    >Each subnet allows for 14 hosts.
    >
    >Sounds okay up till now?
    >
    >My question is what the ranges of valid IP host addresses look like.


    # ID Range Broadcast
    1 212.78.160.16 212.78.160.17 - 212.78.160.30 212.78.160.31
    2 212.78.160.32 212.78.160.33 - 212.78.160.46 212.78.160.47
    3 212.78.160.48 212.78.160.49 - 212.78.160.62 212.78.160.63
    4 212.78.160.64 212.78.160.65 - 212.78.160.78 212.78.160.79
    5 212.78.160.80 212.78.160.81 - 212.78.160.94 212.78.160.95
    6 212.78.160.96 212.78.160.97 - 212.78.160.110 212.78.160.111
    7 212.78.160.112 212.78.160.113 - 212.78.160.126 212.78.160.127
    8 212.78.160.128 212.78.160.129 - 212.78.160.142 212.78.160.143
    9 212.78.160.144 212.78.160.145 - 212.78.160.158 212.78.160.159
    10 212.78.160.160 212.78.160.161 - 212.78.160.174 212.78.160.175
    11 212.78.160.176 212.78.160.177 - 212.78.160.190 212.78.160.191
    12 212.78.160.192 212.78.160.193 - 212.78.160.206 212.78.160.207
    13 212.78.160.208 212.78.160.209 - 212.78.160.222 212.78.160.223
    14 212.78.160.224 212.78.160.225 - 212.78.160.238 212.78.160.239

    --
    'What Profiteth It A Kingdom If The Oxen Be Deflated?'
    Riddles II, v3
    - T. Pratchett
     
    -= Hawk =-, Nov 25, 2003
    #2
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  3. Sorahl

    why? Guest

    On Tue, 25 Nov 2003 11:22:00 +0100, Sorahl wrote:

    >Hey all,
    >
    >The subject of TCP/IP subnetting befuddles me a bit.


    That depends on how difficult you make it.

    www.google.com look for
    subnet tutorial
    subnet calculator

    http://www.subnetonline.com/
    http://www.certguide.com/tcpip.asp
    http://www.firewall.cx/ip-subnetting-mask-effect.php
    http://www.microsoft.com/windows2000/techinfo/reskit/samplechapters/cnbb/cnbb_tcp_pnmz.asp

    Searched English pages for
    subnet calculator.

    Results 1 - 10 of about 22,400. Search took 0.36 seconds.


    >I have given myself the example scenario of a small company with a C-class
    >network ID of 212.78.160.0.


    Try and use examples that don't belong to someone
    inetnum: 212.78.160.0 - 212.78.160.255
    netname: NL-COLT
    descr: COLT Internet NL
    country: NL


    >They need 10 subnets.


    It's easier to use, I think the most obvious division of 16 subnets.
    Mind you it depends on how many hosts per subnet there are.
    Too few meand everything needs routed and too many means larger
    collission / broadcast domains.


    Use http://www.faqs.org/rfcs/rfc1918.html
    RFC 1918 - Address Allocation for Private Internets

    If it's that small they don't need subnets, since a default Class C is
    254 hosts maybe move to default B 64k hosts.

    If it's your company you want to connect to the Internet, get a NAT /
    Router, use the priviate address range mapping to the ISP IP.

    <snip>

    >Sounds okay up till now?


    Yes.

    >My question is what the ranges of valid IP host addresses look like.


    You are fairly close already,

    >Subnets are then defined as follows:
    >212.78.160.16
    >212.78.160.32... right on till
    >212.78.160.224 as the 14th subnet.



    Hint(s) -
    You can't use use the 1st IP, it's the subnet address, as you said just
    above.

    The next IP is the 1st host.

    The last but 1 IP is the last host.

    The last IP for each subnet is the broadcast address.

    try figuring it out or use one of the calculators, like
    http://www.subnetonline.com/subcalc/subnet2.html



    Me
     
    why?, Nov 25, 2003
    #3
  4. Sorahl

    Peter H Guest

    "Sorahl" <> wrote in message
    news:3fc32d2c$0$1497$4all.nl...
    > Hey all,
    >
    > The subject of TCP/IP subnetting befuddles me a bit.
    >
    > I have given myself the example scenario of a small company with a C-class
    > network ID of 212.78.160.0.
    > They need 10 subnets.
    >
    > If I correctly understand this, encoding 11 (10+1) into binary needs 4

    bits.
    > Therefore, I use 4 bits more for the network ID and get a subnetmaks of
    > 255.255.255.240.
    >
    > The lowest bit in 11110000 is worth 16 so I get a multiplier of 16.
    >
    > Subnets are then defined as follows:
    > 212.78.160.16
    > 212.78.160.32... right on till
    > 212.78.160.224 as the 14th subnet.
    >
    > Each subnet allows for 14 hosts.
    >
    > Sounds okay up till now?
    >
    > My question is what the ranges of valid IP host addresses look like.
    >
    > Greets, Sorahl
    >
    >
    >


    I remember going through this myself. I've forgotten it all now but remember
    where I found the answers I needed. Try

    alt.certification.network-plus

    Peter H
     
    Peter H, Nov 25, 2003
    #4
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