Your company has a remote office that contains 1,600 client computers on a single subnet.
You need to select a subnet mask for the network that will support all of the client computers. The solution must
minimize the number of unused addresses.
Which subnet mask should you select?
A.
255.255.248.0
B.
255.255.252.0
C.
255.255.254.0
D.
255.255.240.0
Explanation:
255.255.252.0 = 11111111.11111111.11111100.00000000=>( 22 bits 1 .. 10 bits 0 ) => 1111111111 = 1023
255.255.254.0 = 11111111.11111111.11111110.00000000=>( 23 bits 1 .. 9 bits 0 ) => 111111111 = 511
255.255.255.0 = 11111111.11111111.11111111.00000000=>( 24 bits 1 .. 8 bits 0 ) => 11111111 = 255
255.255.255.128 = 11111111.11111111.11111111.10000000 =>( 25 bits 1 .. 7 bits 0 ) => 1111111 = 127
http://zeus.fh-brandenburg.de/~ihno/doc/lehre/internet/ip_eng.html
A
A: 2046 Hosts
B: 1011 Hosts
C: 510 Hosts
D: 4090 Hosts
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How to find the host? What is the formula?
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2^n – 2
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A
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255.255.240.0 = 11111111.11111111.11110000.00000000 =>( 20 bits 1 .. 12 bits 0 ) => 2^12 -2 = 4094 hosts
255.255.248.0 = 11111111.11111111.11111000.00000000 =>( 21 bits 1 .. 11 bits 0 ) => 2^11 -2 = 2046 hosts
255.255.252.0 = 11111111.11111111.11111100.00000000 =>( 22 bits 1 .. 10 bits 0 ) => 2^10 -2 = 1022 hosts
255.255.254.0 = 11111111.11111111.11111110.00000000 =>( 23 bits 1 .. 9 bits 0 ) => 2^9 -2 = 510 hosts
255.255.255.0 = 11111111.11111111.11111111.00000000 =>( 24 bits 1 .. 8 bits 0 ) => 2^8 -2 = 254 hosts
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Did not even know about this. This makes it ALL EASIER. Thank you!
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A
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