# Subnet Calculator [closed]

I need test data for a IP Subnet calculator I have developed. I have tested some obvious scenarios, and all seems good, but the person developing can often be the wrong person to test.

The calculator can do one of two things:

1 - given an existing network and CIDR(mask), and a new CIDR it will create a number of networks with the appropriate number of hosts.

2 - given an existing network and CIDR(mask), and a list of c,h, (c = count, h=number of hosts) it will create the networks.

So if you have a subnet problem you think would be good to check, please post here. I'll post the results.

Of the calculators I looked at on the web none seem to have this kind of functionality.

Here is one sample:

``````Given this network 173.73.64.0 /20.

Divide the network block in order to provide the following subnetworks:

1 - with at least 1800 hosts
2 - with at least 500 hosts each
3 - with at least 240 hosts each
``````

Here is the result from the calculator

``````173.73.64.0  /21 -> 1,800  (2,048)
173.73.72.0  /23 -> 500  (512)
173.73.74.0  /23 -> 500  (512)
173.73.76.0  /24 -> 254  (256) ++
173.73.77.0  /24 -> 240  (256)
173.73.78.0  /24 -> 240  (256)
173.73.79.0  /24 -> 240  (256)
``````

The ++ line was inserted by the calculator as an indication of the largest block left available.

Here is a sample of going from /24 to /26

``````192.168.123.0  /26 -> 62  (64)
192.168.123.64  /26 -> 62  (64)
192.168.123.128  /26 -> 62  (64)
192.168.123.192  /26 -> 62  (64)
``````
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## closed as not a real question by Zypher♦, Jim B, Jeff Atwood♦Feb 8 '10 at 8:53

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.If this question can be reworded to fit the rules in the help center, please edit the question.

In the first example, I entered a host in the network, the cidr, and 1,1880 2,500 3,240 Press button. In the second I entered a host in the network, the cidr, and a new cidr. Press button. – dbasnett Feb 6 '10 at 17:59
This is pretty neat. Are you planning on releasing this software? I'll try and come up with a scenario today to help test. – einstiien Feb 6 '10 at 18:09
This should be a community wiki. – Zypher Feb 6 '10 at 18:19
What does "This should be a community wiki." mean? – dbasnett Feb 6 '10 at 22:22
@dbasnett: Marking a post community wiki (check box below and on the right hand side of the text input box) causes upvotes/downvotes to not generate rep. See the FAQ for a full explaination. – Zypher Feb 7 '10 at 0:41

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I have seen a lot of those. None I have seen provides a list based on criteria. – dbasnett Feb 6 '10 at 17:57

Did you think about Non-Contiguous netmasks? While not in widespread use, they are legal according to RFC950.

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The short answer is no, but the tool could be used manually as the other tools do. – dbasnett Feb 6 '10 at 22:21
After thinking about this I couldn't remember ever doing this or seeing, all I remember is hearing about it, and my first Cisco router was an AGS+ around 1990. – dbasnett Feb 6 '10 at 23:29
After further thought (thanks svnklp) I realized that it wouldn't be that hard to do, but if I did it, would someone actually use it, which IMHO would not be a good thing. – dbasnett Feb 7 '10 at 12:15

OK, OCD'ing! Here are the hosts for a non-contiguous netmask.

``````Mask - 11111111111111111111111100111100
192.168.1.0 Network Number
192.168.1.1
192.168.1.2
192.168.1.3
192.168.1.64
192.168.1.65
192.168.1.66
192.168.1.67
192.168.1.128
192.168.1.129
192.168.1.130
192.168.1.131
192.168.1.192
192.168.1.193
192.168.1.194