Supernetting Question !!

Me too, always had a mental block about things mathematical. And up to age 21 your brain cells regenerate at the same rate they die, but after 21 they just die. Well, I'm conserving brain cells!

The braincells ... huh ... i guess they would go anyways if you don't use them :lol:

Yeah i prefer to do it in the brain without a pen & a paper preferably

If you can work out subnetting without requiring a pen and paper, I'll certainly take my hat off to you!

While there are people that can work out complex subnetting without pen and paper, for me its just toooooooo risky! A simple mistake and you can end up with endless problems.

Of course I should clarify that I'm not referring to simple subnetting tasks such as 192.168.0.0/8, 16 or 24 !

I'm one of those people who believe if you do not sit down and write it on paper, you never can be sure 100% your correct. Even now, I find myself making silly mistakes! For example, take the subnetting topic of this site ... its completely incorrect ! (Just joking now!!! :!: )

Not exagerrating at all chris, but yes i am positive here that i can do subnetting of any network on my finger tips without a pen & paper & the most it would take is 2 minutes for any subnetting question. The only calculation that we ( me and a couple of more close friends dwayne, cobra who are also members of this site BTW ... ) might need to do on a piece of paper is when we are calculating the number of hosts in a class A subnet or when our answers don't match

And yes to clarify again on this we are not at all against usng a pen & paper for calculating subnets but its just that it gives you a much better feeling if you do it orally, as Todd says in his books "calculating subnets in the mind". Also what i am against strictly is using a subnet calculator for calculating subnets because then you don't have to apply your brains at all, its just like doing 2 + 2 = 4 on a airthmetic calculator.

And as far as usage of a pen & paper for calculations is concerned i would be doing that myself when i would appear for my CCNA, you don't want to take any risks with your certification & HARD EARNED MONEY :lol:

CIDR rules: :shock:
The only time 192.168.1.0 can be a network number and 192.168.2.255 can be a broadcast address is with a subnet mask of 255.255.255.0 and they would be in two different standard class C networks. The two class C networks 192.168.1.0 and 192.168.2.0 cannot be grouped together by themselves. 192.168.0.0 and 192.168.1.0 can be with the subnet mask 255.255.254.0. So could 192.168.2.0 and 192.168.3.0 with the same mask. All four of these class C networks can be grouped with the subnet mask 255.255.252.0.

Network 192.168.0.0 Range 192.168.0.1 – 192.168.1.254 Broadcast 192.168.1.255 mask 255.255.254.0
Network 192.168.2.0 Range 192.168.2.1 – 192.168.3.254 Broadcast 192.168.3.255 mask 255.255.254.0
Network 192.168.0.0 Range 192.168.0.1 – 192.168.3.254 Broadcast 192.168.3.255 mask 255.255.252.0

I’m glad to see you caught the invalid subnet mask 255.255.253.0 as it breaks the binary format rule of all 1’s (network portion) then all 0’s (host portion). If you are not subnetting in binary you are bound to make mistakes.

Is is really true it only takes two fingers to count in binary? :lol:

I’m glad to see you caught the invalid subnet mask 255.255.253.0 as it breaks the binary format rule of all 1’s (network portion) then all 0’s (host portion). If you are not subnetting in binary you are bound to make mistakes.

That's exactly what i wanted to say, thanx for putting my thoughts into words "mew"

BTW apart from the wonderfull articles that we have on this website, is there any other website with some good articles on CIDR & its applications ?