Does any1 no of a good site where i can get some basic understanding of how subnets and subnet masks work ty?

Question

Does any1 no of a good site where i can get some basic understanding of how subnets and subnet masks work ty?

Answer 1

also look at

http://www.networkcomputing.com/unixworl...

Answer 2

Begin Here:

Binary Code is a BASE 2 number using 1s and 0s.

00000000 8 Bits or Binary Digits

10000000 = 128 = 2^7

01000000 = 64 = 2^6

00100000 = 32 = 2^5

00010000 = 16 = 2^4

00001000 = 8 = 2^3

00000100 = 4 = 2^2

00000010 = 2 = 2^1

00000001 = 1... why 1? 2^0 = 1. Anything to the power of 0 is equal to 1.

When you get this... 00110001 You just figure what THOSE numbers are and add them. Those numbers are 32, 16, and 1. Making 00110001 = 49. Review that a couple times in your head... it will make sense the more you look at it.

Minimum number being 0... Max being 255. 128+64+32....

SUBNETTING

10.120.40.20/24 - What the h**l does that mean....

Subnets devide Network IDs from Host Ids

To figure them out, it's always 2^n-2=

There are 24 Active 1s here... or "On's" Binary is on and off(0)

11111111.11111111.11111111.00000000

We know binary... so 11111111 = 255.

255.255.255.0

How many networks do we have? How many hosts(any device connected to the network) per network??

To figure out the Networks per subnet...

2^n-2= ... well our number is 24 because we have 24 bits turned on. (1's)

2^24-2 = 16,777,214 Networks... 1.1.1.1, 1.1.1.2,..... 255.255.255.1... etc.

How many hosts can we have PER 1 network...

2^n-2 = Now we're counting the Off bits...

2^8-2 = 256-2 = 254 Hosts Per Network.(note the last bit is equal to the decimal number 1)

[Additional! I FORGOT THE MOST IMPORTANT PART! SHEESH!]

Your Sub NETS are divided by last bit...

say you had 255.255.252.0 which is 11111100...

Your last Active bit is a 4. So your subnets are divided like so

So you have 4194302(2^22-2) Networks available and

1022 Hosts per network. The last bit is decimal number 4... so our incriment for subnets is 4.

Our IP Address is 192.168.*.*.. or a "Class C" network.

0-3 = N  -   You have 192.168.N.*** in IP addresses for hosts at one location.

4-7 = N - 192.168.N.*** for another location.

8-11...... so on...

Why 2^n-2? Not 100% sure.. I correct myself by not answering that just yet...

Now you need to learn more about A, B, C, D, E networks.

http://www.harford.edu/faculty/SAnyangw/... Here is an actual presentation from a school who doesn't realize their security of their network. lol

I just realize that they do subnetting coverage in that presentation. Good luck bud. if you need anymore help let me know.

Answer 3

Here you go:

http://compnetworking.about.com/od/worki...