How to Subnet Anything in Under 5 Minutes:
This is the below table you have to memories for understanding the subnetting trick.
Subnet Mask

128

192

224

240

248

252

254

Target Number

128

64

32

16

8

4

2

Bit Place

1

2

3

4

5

6

7

No. of valid Subnets

N/A

2

6

14

30

62

126

Question: We have IP address: 192.168.10.1/24 Please find the below parameter.
1. Network ID.
2. Broadcast ID
3.First Valid
4. Last valid.
5.Number of host
6. Subnet Mask
Solution:
Default mask for Class C: 255.255.255.0
Step
1. In the bottom line (Number of Valid Subnets), move from right to left and find the closest number that is bigger than or equal to
what you need:
Ex: Nine subnets—move to 14
Step
2. From that number i.e 14, move up to the line called Bit Place.
Above 14 is bit place 4.
Step
3. The dark line is called the highorder line. If you cross the line, you have to take reverse
direction.
You were moving from right to
left; now you have to move from the left to right.
Step
4. Go to the line called Target Number. Counting from the left, move over the number of
spaces that the bit place number tells you.
Starting number is 128, moving 4
places takes you to 16.
Step
5. This target number is what you need to count by, starting from 0
and going until you hit 255 or greater. Stop before you get to 256:
0
16
32
48
64
80
96
112
128
144
160
176
192
208
224
240
256 Stop—too far:
Step
6. These numbers are your network numbers. Expand to finish your
plan.
Network #

Range of Valid Hosts

Broadcast Number

0
(invalid)

1–14

15

16

17–30
(17 is 1 more than network #
30 is 1 less than broadcast#)

31
(1 less than next network #)

32

33–46

47

48

49–62

63

64

65–78

79

80

81–94

95

96

97–110

111

112

113–126

127

128

129–142

143

144

145–158

159

160

161–174

175

176

177–190

191

192

193–206

207

208

209–222

223

224

225–238

239

240
(notvalid)

241–254

255

You can notice that Notice that there are 14 subnets
created from .16 to .224.
Step
7. Go back to the chart and look above your
target number to the top line. The number above your target number is the subnet mask.
Above 16 is
240. Because We started with a Class C network, the new subnet mask is
255.255.255.240.
i don't understand how you got 255.255.255.240 how did you know where to place the .240 ?
ReplyDeleteAs per the question we have IP address 192.168.10.1/24 so default mask for Class C is 255.255.255.0.We are calculating 9 subnets according to the above table.
Deletethere say 9 subnets
DeleteWe are finding till 9 subnets.
Delete