Class A Subnetting

Find the network, broadcast, first and last usable host addresses in a class A subnet -
http://danscourses.com

Category:

Education

Tags:

• Cisco
• CCNA
• subnet
• 'class
• A'

[sbrave]

I still don't get how you're defining these addresses?

How can you start with a lower number than what you had? ex, you started with 110.8.67.101 After the magic number thing, you're going lower to 110.8.0.0

Also how do you know to stop at 110.10.0.0? What defines that range from 110.0-110.10?

[danscourses]

@sbrave 110.8.0.0 is the network or subnet that the host 110.8.67.101 belongs in. The goal is to find the network/subnet that the host belongs to... To really understand the whole process I recommend that you watch the playlist of videos that I made for the CCNA at youtube/danscourses You need to understand that the computer sees the addresses in binary and that the router finds the network by ANDing the host address and the subnet mask together in binary. It helps to see it in binary...

[Jblessify]

Thanks Dan, i wish you were teaching this at my college..shhh don't tell them i said that!

[2007Russdog]

@sbrave

Try downloading Advance Subnet calculator. It will also help you realize the pattern better.

[2007Russdog]

Because you disregard the network octets. They are unchanging. Only the host octets are changed for the subnet mask. I find it easier to use the all ones from the /# then it is simple to do what he does.

[cristigres]

Oh my God!!!!! Thanks sooooooooooo much! I've been struggling the past 6 weeks with subnetting, then I find your courses, and in one day, boom! I'm the best in the class when it comes to subnetting. You are awesome! Thank you, thank you, thank you!!!!!!!

[FallenPatriotic]

very helpful



[urdhu]

This question come in one range class of ip and subnetmask. The IP is class A and the /cidr is in class A also, but how do you reverse that if let say the IP is class A range of 126.125.2.3 and the /cidr is /17 or /25 ?

[NothingsSomething]

sry but you did use a confusing octal being both places are 2's so it's hard to say if 252 would advance 3 places or 4 places at a time. sry, i'm dyslexic (with dis-calculus ), it's a-little harder for me. you might be hearing from me again in another CBT. thanks!

[NothingsSomething]

if i understand correctly, then, if the interesting octet was , oh say, 252, then the network's would be increased in numbers of 4, is that correct??

and the next network would be 110.12.X.X and the broadcast = 110.12.255.255

first would still = 110.8.0.1

but last would = 110.12.255.254??

[cjd0013]

im wondering if whats the significance of the network part thru anding..?