Subnetting

Check my subnetting.

126.0.2.99 /24

Net ID IP: 126.0.2.0
1st Valid IP: 126.0.2.1
Last Valid IP: 126.0.2.254
Broadcast IP: 126.0.2.255

155.44.2.2 /21

Net ID IP: 155.44.0.0
1st Valid IP: 155.44.0.1
Last Valid IP: 155.44.7.254
Broadcast IP: 155.44.7.255

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Comments

NetworkVeteran

Net ID IP: 126.0.2.0

No, that's actually the Subnet ID. The Network ID would be 126.0.0.0.

1st Valid IP: 126.0.2.1

No, 126.0.2.0 is the first valid IP address in that range. 126.0.2.1 is the first host address.

Last Valid IP: 126.0.2.254

No, 126.0.2.255 is the last valid IP address in that range. 126.0.2.254 is the last host address.

Broadcast IP: 126.0.2.255

Yes.

chopsticks

NetworkVeteran wrote: »

No, that's actually the Subnet ID. The Network ID would be 126.0.0.0

May I ask how do you arrive at this? Thanks.

NetworkVeteran

chopsticks wrote: »

May I ask how do you arrive at this? Thanks.

It'd take a some time to explain the intricacies, but here are the broad steps in the process--

1. The first number an IP address determines its class. "126" maps to a Class A.
2. Class A addresses have a network mask of 255.0.0.0.
3. 126.0.2.99 & 255.0.0.0 = 126.0.0.0.
4. 126.0.0.0 is the Network ID.

Consult a good book on subnetting for more detail or Google the same.

chopsticks

NetworkVeteran wrote: »

It'd take a some time to explain the intricacies, but here are the broad steps in the process--

1. The first number an IP address determines its class. "126" maps to a Class A.
2. Class A addresses have a network mask of 255.0.0.0.
3. 126.0.2.99 & 255.0.0.0 = 126.0.0.0.
4. 126.0.0.0 is the Network ID.

Consult a good book on subnetting for more detail or Google the same.

Thank you, I fully understood your explanation.
I asked this question is because most books stopped at arriving at the Subnet ID.