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real life subnet question

ja5983ja5983 Member Posts: 129
IP 41.142.215.131
subnet 255.255.255.248
that = 41.142.215.130/30 since 70 is class A...
so that should be 2 hosts and 2 subnets right?
so how is it possible for the subnet range to be
41.142.215.130-37?

(these arent actually the IPs i changed them a little...but the class is the same and it seemed odd to me...)
Josh
A+, Network+, Server+, Security+, TICSA, CCNA, MCSA, AS Network Engineering

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    dmafteidmaftei Member Posts: 83 ■■□□□□□□□□
    ja5983 wrote:
    IP 41.142.215.131
    subnet 255.255.255.248
    You're subnetting a class A network by borrowing 8 + 8 + 5 = 21 bits from the host part. That gives you 2^21 = 2097152 subnets (including all-zeros and all-ones), with 2^3 = 8 IP addresses per subnet, hence the 130-137 range.
    BSEE, MSCS
    www.maftei.net
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    ja5983ja5983 Member Posts: 129
    ahh...i need to look more carefully..thanks!
    Josh
    A+, Network+, Server+, Security+, TICSA, CCNA, MCSA, AS Network Engineering
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    lAwBoYlAwBoY Member Posts: 30 ■■□□□□□□□□
    i thought the range should be 128-136
    where valid host is 129-135

    correct me if i am wrong
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    ja5983ja5983 Member Posts: 129
    depends if you do 2^x=x or 2^x-2=x
    Josh
    A+, Network+, Server+, Security+, TICSA, CCNA, MCSA, AS Network Engineering
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    dmafteidmaftei Member Posts: 83 ■■□□□□□□□□
    lAwBoY wrote:
    i thought the range should be 128-136
    You're right.
    BSEE, MSCS
    www.maftei.net
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    darkuserdarkuser Member Posts: 620 ■■■□□□□□□□
    an when I'm fellin really lazy i use this

    http://www.subnetmask.info/

    the explain feature is nice
    rm -rf /
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