3 Easy Steps Subnetting
Simple, easy, fast way of the CCNA subnet training
Question:
If PC1’s ip address is : 10.1.1.149/30 or 10.1.1.149 255.255.255.252
what could be PC2’s ip address?
Answer:
Step 1: What is the SIZE of each subnet ?
we have 2 bits for host parts, so the SIZE of each subnet is 4
Step 2: List all the subnets, the SIZE of each subnet is 4
subnet: 10.1.1.0 ~ 10.1.1.3
subnet: 10.1.1.4 ~ 10.1.1.7
subnet: 10.1.1.8 ~ 10.1.1.11
subnet: 10.1.1.12 ~ 10.1.1.15
…
subnet: 10.1.1.140 ~ 10.1.1.143
subnet: 10.1.1.144 ~ 10.1.1.147
subnet: 10.1.1.148 ~ 10.1.1.151 ( PC1 10.1.1.149 is here )
subnet: 10.1.1.152 ~ 10.1.1.155
…
Step 3: Get PC2’s address
We must put PC2 in the same subnet as PC1
Three IPs we can not use for PC2:
We can not use 10.1.1.148, which is the first ip –> the Network ID
We can not use 10.1.1.149, which is used by PC1
We can not use 10.1.1.151, which is the last ip –> the Broadcast address
Any other ip in the range 10.1.1.148 ~ 10.1.1.151 is good for PC2
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Question:
If PC1’s ip address is : 10.1.1.149/29 or 10.1.1.149 255.255.255.248
what could be PC2’s ip address ?
Step 1: size is 23 = 8
Step 2: subnets list
10.1.1.0 ~ 10.1.1.7
10.1.1.8 ~ 10.1.1.15
…
10.1.1.148 ~ 10.1.1.155 10.1.1.149 falls in this range !
10.1.1.156 ~ 10.1.1.163
…
Step 3:
PC2 ‘s IP could be any of: 10.1.1.150 ~ 10.1.1.154
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Question:
If PC1’s ip address is : 10.1.1.149/28 or 10.1.1.149 255.255.255.240
what could be PC2’s ip address ?
Step 1: size is 24 = 16
Step 2: subnets list
10.1.1.0 ~ 10.1.1.15
10.1.1.16 ~ 10.1.1.31
…
10.1.1.128 ~ 10.1.1.143
10.1.1.144 ~ 10.1.1.159 10.1.1.149 falls in this range !
…
Step 3:
PC2 ‘s IP could be any of: 10.1.1.145 ~ 10.1.1.158 except 10.1.1.149
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Question:
If PC1’s ip address is : 10.1.1.149/27 or 10.1.1.149 255.255.255.224
what could be PC2’s ip address ?
Step 1: size is 25 = 32
Step 2: subnets list
…
10.1.1.128 ~ 10.1.1.159 10.1.1.149 falls in this range !
…
Step 3:
PC2 ‘s IP could be any of: 10.1.1.129 ~ 10.1.1.158 except 10.1.1.149
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Question:
If PC1’s ip address is : 10.1.1.149/26 or 10.1.1.149 255.255.255.192
what could be PC2’s ip address ?
Step 1: size is 26= 64
Step 2: subnets list
…
10.1.1.128 ~ 10.1.1.191 10.1.1.149 falls in this range !
…
Step 3:
PC2 ‘s IP could be any of: 10.1.1.129 ~ 10.1.1.190 except 10.1.1.149
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Question:
If PC1’s ip address is : 10.1.1.149/25 or 10.1.1.149 255.255.255.128
what could be PC2’s ip address ?
Step 1: size is 27= 128
Step 2: subnets list
…
10.1.1.128 ~ 10.1.1.255 10.1.1.149 falls in this range !
…
Step 3:
PC2 ‘s IP could be any of: 10.1.1.129 ~ 10.1.1.254 except 10.1.1.149
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Question:
If PC1’s ip address is : 10.1.1.149/24 or 10.1.1.149 255.255.255.0
what could be PC2’s ip address ?
PC2 ‘s IP could be any of: 10.1.1.1 ~ 10.1.1.254 except 10.1.1.149
Given ip address: 149.149.149.149/23
What is the subnet mask ?
What is the ip address range for this subnet ?
Answer: subnet mask: 255.255.254.0 Ip address Range: 149.149.148.0 ~ 149.149.149.255
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Given ip address: 149.149.149.149/22
What is the subnet mask ?
What is the ip address range for this subnet ?
Answer: subnet mask: 255.255.252.0 Ip address Range: 149.149.148.0 ~ 149.149.151.255
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Given ip address: 149.149.149.149/21
What is the subnet mask ?
What is the ip address range for this subnet ?
Answer: subnet mask: 255.255.248.0 Ip address Range: 149.149.144.0 ~ 149.149.151.255
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Given ip address: 149.149.149.149/20
What is the subnet mask ?
What is the ip address range for this subnet ?
Answer: subnet mask: 255.255.240.0 Ip address Range: 149.149.144.0 ~ 149.149.159.255
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Given ip address: 149.149.149.149/19
What is the subnet mask ?
What is the ip address range for this subnet ?
Answer: subnet mask: 255.255.224.0 Ip address Range: 149.149.128.0 ~ 149.149.159.255
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Given ip address: 149.149.149.149/18
What is the subnet mask ?
What is the ip address range for this subnet ?
Answer: subnet mask: 255.255.192.0 Ip address Range: 149.149.128.0 ~ 149.149.191.255
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Given ip address: 149.149.149.149/17
What is the subnet mask ?
What is the ip address range for this subnet ?
Answer: subnet mask: 255.255.128.0 Ip address Range: 149.149.128.0 ~ 149.149.255.255
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Given ip address: 149.149.149.149/16
What is the subnet mask ?
What is the ip address range for this subnet ?
Answer: subnet mask: 255.255.0.0 Ip address Range: 149.149.0.0 ~ 149.149.255.255
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Given ip address: 149.149.149.149/15
What is the subnet mask ?
What is the ip address range for this subnet ?
Answer: subnet mask: 255.254.0.0 Ip address Range: 149.148.0.0 ~ 149.149.255.255
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Given ip address: 149.149.149.149/9
What is the subnet mask ?
What is the ip address range for this subnet ?
Answer: subnet mask: 255.128.0.0 Ip address Range: 149.128.0.0 ~ 149.255.255.255
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Given ip address: 149.149.149.149/2
What is the subnet mask ?
What is the ip address range for this subnet ?
Answer: subnet mask: 192.0.0.0 Ip address Range: 128.0.0.0 ~ 191.255.255.255
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Given ip address: 149.149.149.149/1
What is the subnet mask ?
What is the ip address range for this subnet ?
Answer: subnet mask: 128.0.0.0 Ip address Range: 128.0.0.0 ~ 255.255.255.255
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Given ip address: 149.149.149.149/0
What is the subnet mask ?
What is the ip address range for this subnet ?
Answer: subnet mask: 0.0.0.0 Ip address Range: 0.0.0.0 ~ 255.255.255.255
