This question was marked as "off-topic" :

divide a network into 2 unequivalent subnetworks

The reason stated was :

Unfortunately, education, certification, or homework questions are off-topic here. There's plenty of learning sites on the Internet. This one isn't one of them. In real world we don't use such large networks.

But _ar provided an interesting answer.

Before asking I did some research, I understand how network addresses and masks works. So I supposed that it was not possible to divide a network into one quater for the first subnet, and the rest in another subnet. But as I'm not a network engineer, I asked here if there is a solution to this.

This is a company network. I'm planning databases migration, and yes, this will be enterprise subnets. There will be a few thousands IPs in each subnets. First I start with 2 networks that the network team gave me, then I divide it.

How is this not professional ?

In JFL comment, stated as a reason :

In real world we don't use such large networks.

First you divide a network into subnets, then you you have smaller subnets. And I could have given an even larger network as an example, since this can be viewed as a theoretical question (but applied to a real enterprise network). The first choice was to use, then divided it in /16 , then again, then again...

Unless questions about sub-networking are not valid here ?

I suppose JFL was referring to (Help Center):

installation, configuration, or use of applications not generally considered to be tools used by network professionals;

Which cannot be the case here, every network engineer has to do these kind of things when they're starting to design their networks ?

1 Answer 1


The entire question is one of Subnet Math™. Questions like this get asked All. The. Time. Any "networking professional" should know this stuff already. Almost all of these questions get closed, instantly, with a pointer to the answer Mike(?) provided eons ago.

This is THE most basic concept of networking. You don't know it. And we're not going to answer it over and over and over...

  • well, ok, I can understand this. I admit I was just a little annoyed by the "In real world we don't use such large networks." Thanks you for your answer. May 7, 2018 at 7:39
  • 1
    @JeanCoiron, typically real world professionals don't use such large networks. It is considered inefficient and wasteful. As such, most questions asking about subnets that large often are sourced by students, which makes many professionals automatically suspect that it is an educational based question rather than a real world question.
    – YLearn
    May 10, 2018 at 22:52

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