Subnetting LIFESAVER!!! Thanks Agustinchernitsky!!

Cessation

I swear it. Subnetting is the worst.
One of the few reasons that helped me leave working on my CCNA.
No matter if it was an instructor, learntosubnet.com, scratch on the internet.
NOTHING and no body has been able to help me out with subnetting until this post.
I understood a bit but never could really grasp it.
Well im not studying 291 and have to face subnetting again which really kills me. I would really like to come back, get my MCSE and CCNA after.
I just wanted to thank Agustin........ for this great help.

agustinchernitsky wrote:

Well, this is how to make it quick (not sure if this is the best but, works for me):

Learn this scale (1): 2 4 8 16 32 64 128 256 512 1024 2048 4096 8192

And this one (2): 128 192 224 240 248 252 254 255

now, to your question:

/28 would be: 11110000

number of subnets: how many 1s you have? 4? good... what number is in position 4 on scale 1?: 16.

Number of hosts: How many 0s you have? 4 again? good... what number is in position 4 on scale 1?: 16... warning: remember to substract 2 ips... 14.

What is the subnet mask?: 4th place of scale 2: 255.255.255.240

And what is the IP block?: look at scale 1, 4th place: 16 IP blocks (remember, as Alien said, if ip subnet-zero is on, start from 0 always).

This at least works for me... and lets you subnet in your head quite easy.

Also, the scale works for subnetting any class A B or C.

agustinchernitsky

LOL! I'm glad I could help... Really.

Good luck with your MS exams and Cisco exams...

elector

CBT Nuggets has a great explanation on this subject. I got it the second time I was watching the video. great teaching

geekie

I got it the second time I was watching the video. great teaching

True except he uses a sci calc and one wasn't provided in my exam. I do agree though his teaching is quality!

Smallguy

what is ment by "ip block"

I'm weak at subnetting and everytihng there makes sense except the ip block info

help me wrap my head around the term please

davenport

Smallguy wrote:

what is ment by "ip block"

I'm weak at subnetting and everytihng there makes sense except the ip block info

help me wrap my head around the term please

If you are just asking about the term. I'm not sure about the cbt videos (cause I've never seen them) but I'm assuming they are referring to a range of ip addresses. "A block of ip addresses"

Is that what you were asking?

Smallguy

davenport wrote:

Smallguy wrote:

what is ment by "ip block"

I'm weak at subnetting and everytihng there makes sense except the ip block info

help me wrap my head around the term please

If you are just asking about the term. I'm not sure about the cbt videos (cause I've never seen them) but I'm assuming they are referring to a range of ip addresses. "A block of ip addresses"

Is that what you were asking?

exactly what I was asking

so it goes up by 16 making the first addressable range assuming class C

maknig the valid subnets

192.168.1.0
192.168.1.16
192.168.1.32
etc

this makes sense ot me now