From the following IP address fill in the table.
10.11.12.13
Subnet mask?
Network bits?
Subnet Bits = 5
Network address?
Broad cast address?
Network range?
Number of addresses?
Host bits?
Host range?
Default gateway?
Ok I'm just going to assume that my earlier post was correct and explain how I got what I got.
Ok they have given us the IP address which is:
10.11.12.13
Next. At first glance, it just looks like all we have is an IP address but, they provided the subnet for us. The subnet has
5 bits. The IP address is a class A network (look at the bottom for a reference) which is
10.0.0.0 | 255.0.0.0 or
11111111.00000000.00000000.00000000. Since the subnet has
5 bits, that would make it
255.248.0.0 or
11111111.11111000.00000000.00000000 (I underlined the 5 bits that were added. Also scroll to the bottom for a quick lesson on binary). So now we have our subnet mask. Now to find out what the network address is, we can do a couple things. We can just subtract 248 (255.
248.0.0) from 256 which = 8 or you can do that ANDing process where you take the IP address and subnet in binary form and you stack them on top of each other and wherever there is a matching 1, you copy that down as a 1. Anything else would equal a 0. For example:
10.11.12.13 = 0000
10
10.0000
1011.00001100.00001101
255.248.0.0 = 1111
11
11.1111
1000.00000000.00000000
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10.8.0.0
.....= 0000
10
10.0000
1000.00000000.00000000
Here are the network ranges:
10.0.0.0 - 10.7.255.255
10.8.0.0 - 10.15.255.255
10.16.0.0 - 10.23.255.255
10.24.0.0 - 10.31.255.255
etc...
If you notice, there is a pattern. They are going up by 8 (the number we got earlier). Since the network on the exam is
10.11.12.13, there is only 1 network from that list that fits this, which is:
10.8.0.0. (we already know this from earlier)
Blue = Network bits
Red = Subnet bits
Green = Host bits
11111111.
11111000.00000000.00000000 (8 network bits, 5 subnet bits, 19 host bits = 32 bits, which is what an IP (version 4) is made up of)
Subnet mask =
255.248.0.0
Subnet Bits =
5
Network bits =
8
Network address =
10.8.0.0
Broad cast address =
10.15.255.255
Network range =
10.8.0.0 - 10.15.255.255
Number of addresses =
524288 (we get that by doing: 2^19. Remember that the 0's represent host address. Since there are 19 0's, we do 2^19.)
Host bits =
19
Host range?
10.8.0.1 - 10.15.255.254 (We can't use the first and last IP address in the network. 10.8.0.0 and 10.15.255.255)
Default gateway = Anything between 10.8.0.1 - 10.15.255.254 (as long as it is not being used)
I hope this post does more good than bad lol I tried to make it as clear as possible but sometimes I make it harder. Sorry if that is the case.
SOMEONE PLEASE CORRECT ME IF I MADE A MISTAKE
If you aren't familiar with the binary, here is how I got the values. Remember how an IP address is setup:
128|64|32|16|8|4|2|1
. 128|64|32|16|8|4|2|1
. 128|64|32|16|8|4|2|1
. 128|64|32|16|8|4|2|1
In binary, which ever slot has a 1 in it, then you take that value and add it with any other value within the same octet. For example:
10.8.0.0 | 00001010.00001011.00000000.00000000
10 = 0000
10
10 (There is a 1 in the 8 and 2 slot so you add that and it makes 10)
8 = 0000
1000 (just an 8. No addition needed)
0 = 00000000 (no 1's)
0 = 00000000 (no 1's)
Another example: 192.168.1.1 | 11000000.1010100.00000001.00000001
192 =
11000000 (128 + 64 = 192)
168 =
10
10
1000 (128 + 32 + 8 = 168)
1 = 0000000
1 (No addition needed)
1 = 0000000
1 (No addition needed)
_________________________
Class A
0.0.0.0 - 127.255.255.255
Class B
128.0.0.0 - 191.255.255.255
Class C
192.0.0.0 - 223.255.255.255
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