[juner]

How to subnet the following IP:
10.96.42.37 /28


1) Determine your subnet mask based on the “slash” or “CIDR” notation (the /28).  It is about which bit is on and off in each octet, which I can explain more if anyone wants.  A quick reference to all relevant IPv4 subnet masks:

/1 - 128.0.0.0
/2 - 192.0.0.0
/3 - 224.0.0.0
/4 - 240.0.0.0
/5 - 248.0.0.0
/6 - 252.0.0.0
/7 - 254.0.0.0
/8 - 255.0.0.0
/9 - 255.128.0.0
/10 - 255.192.0.0
/11 - 255.224.0.0
/12 - 255.240.0.0
/13 - 255.248.0.0
/14 - 255.252.0.0
/15 - 255.254.0.0
/16 - 255.255.0.0
/17 - 255.255.128.0
/18 - 255.255.192.0
/19 - 255.255.224.0
/20 - 255.255.240.0
/21 - 255.255.248.0
/22 - 255.255.252.0
/23 - 255.255.254.0
/24 - 255.255.255.0
/25 - 255.255.255.128
/26 - 255.255.255.192
/27 - 255.255.255.224
/28 - 255.255.255.240
/29 - 255.255.255.248
/30 - 255.255.255.252

So the subnet mask of /28 is 255.255.255.240


2) Determine block size.  Simple, 256 - (the value of the octet you are subnetting in)

   In this case, “256 - 240” which is 16


3) Determine the network address of the subnet.  This is the first IP in the subnet, but it is not useable.  Start at 0, then count by the block size until you reach the range of the octet you are subnetting in.  In this case /28 is in the last octet, so based on IP 10.96.42.37 you are trying to find the range where .37 falls.  0, 16, 32, 48…  .37 falls in between 32 and 48, so 32 is the network address, more specifically 10.96.42.32 is the network address.


4) Determine the broadcast address of the subnet.  This is always the IP before the next network address.  Since, in step 3 we determined 10.96.42.32 is a network address, and 10.96.42.48 is the next network, 10.96.42.47 is the broadcast address.  The broadcast address is also not a useable IP.


5) Determine the number of useable host IPs.  Easy step…  (2^n)-2 where n = 32 - (the CIDR number).  In this case, 2^(32-28)-2=14.  It makes sense, the block size is 16, so there are 16 IPs in the subnet, you can’t use the network address or the broadcast address, so subtract 2.


6) Determine the useable host range.  Steps 3 and 4 are great, but you can’t use the IP addresses.  So, find out what you can use.  This is easy, the range starts at the IP after the network address, and ends at the IP before the broadcast address.  So, in this instance, the useable range is 10.96.42.33-10.96.42.47.



I have no idea why I posted this, but if you have any questions, or want to know more about networking in general please ask.


DISCLAIMER:  I AM NOT QUALIFIED

[Saddam Hussein]

How do I use YouTube to hack a website?

[juner]

How do I use YouTube to hack a website?

THAT IS OUTSIDE OF THE SCOPE OF THIS THREAD

I AM NOT QUALIFIED

[jroa]

junker, good job.  My only suggestion would be to actually explain the purpose of a subnetwork, what the subnet mask does as far as dividing a network up, and a little better explanation on how the subnets interact with the networks. 

[juner]

junker, good job.  My only suggestion would be to actually explain the purpose of a subnetwork, what the subnet mask does as far as dividing a network up, and a little better explanation on how the subnets interact with the networks.

Oh, fuck that.  If people have questions, they can ask and I will answer.

You subnet to get IPs.  I can also teach you all about the OSI, especially layers 2 and 3.  I am a pro, almost qualified.

[bj1234]

How does subnetting let me hack youtube videos?

[xasop]

You subnet to get IPs.  I can also teach you all about the OSI, especially layers 2 and 3.  I am a pro, almost qualified.

Can you teach me about layer 6? It's the one I know least about.

[juner]

You subnet to get IPs.  I can also teach you all about the OSI, especially layers 2 and 3.  I am a pro, almost qualified.

Can you teach me about layer 6? It's the one I know least about.

lol no one uses presenation layer willingly

[xasop]

lol no one uses presenation layer willingly

How would you know? You're not qualified.

[juner]

lol no one uses presenation layer willingly

How would you know? You're not qualified.

I know

[jroa]

Can I subsnets with IVP6?

[juner]

Can I subsnets with IVP6?

Yes.

[jroa]

Please explain. 

[Lord Dave]

I used to know this stuff but its been years.  Thanks for the refresher.

[juner]

Please explain.

https://supportforums.cisco.com/docs/DOC-17232

Cisco does it better.

This thread is based on IPv4 which I am nearly qualified in.  Keep questions related to that.  I can only hope to be qualified on IPv6 in the coming decades.

[Rushy]

How do I brute force AES-256?

[juner]

How do I brute force AES-256?

A lot of super computers, and a lot of time.

[Rushy]

A lot of super computers, and a lot of time.

Well, you're not wrong.

[juner]

A lot of super computers, and a lot of time.

Well, you're not wrong.

I am also not qualified.

[Fortuna]

The worst thing about this shit is that everyone explains it a little bit differently. It's not even that difficult but there are 1000 explanations for it. I'm taking the Network+ next week and I'm just going to memorize the number of hosts and subnets for the /25 - /31 networks. Well, Get fucked CompTIA, if I have to do this IRL I'll just use a subnet calculator lmfao. What is this, 2001?

Also I tried to do your example in my head without looking at the answer and got to 16 subnets with 14 hosts in each, but class Cs are ez. If they ask me abnoout class A or B networks I'll just turn my computer off.