The original post: /r/homelab by /u/NathanDTWally on 2025-02-09 01:48:13.

So I just spent the majority of my afternoon following this subnet video series:

https://www.youtube.com/playlist?list=PLIhvC56v63IKrRHh3gvZZBAGvsvOhwrRF

Very great, very informative, but I didn’t learn the one thing I was looking to learn originally.

At my house we use the very standard /24 subnet, I’m looking to start experimenting with home networks and want to make my own subnet for this as to not disturb the rest of the house.

Now obviously I don’t want to steal half of my houses IP address’ for this.

So my desire is to make a /23 subnet so that I can:

Assign 192.168.x.xxx to my homes normal network.

&

Assign 192.168.y.xxx to my personal/testing network.

But even after watching that full series I don’t really understand how I get the third octet in my IP.

So even disregarding the facts of subnetting for the moment:

If my current IP is: 192.168.10.0

Where is that “10” coming from? Is this my ISP or just my routers choice? Am I free to set this to whatever my heart desires from 1-254? Or can I set it from 0-255 since technically the .0 & .255 for network address & broadcast address only worry about the last octet?

Assuming its a hearts desire thing, what would be stopping someone from giving themselves a /16 subnet for their home network with 65536 addresses?

Also as a post post question: If I wanted a 10.0.x.1-254 & 10.0.y.1-254 subnet, can i just set my router to the 10.0.0.0 IP scheme?