this post was submitted on 04 Nov 2026
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Why not 255?
255 is reserved for broadcast.
Edit: Yes, 255 is technically not 'reserved' by itself. I was only thinking about the addresses scoped to /24 for a simple answer. A broadcast address is reserved, though.
When in doubt: https://www.calculator.net/ip-subnet-calculator.html
10.233.213.255 is broadcast, 10.233.212.255 is a usable address ..
How big of an IP scope do you use at home?
Do you really need something larger than a /24?
Iβm quite fond of 10.0.0.0/8. That gives you a lot of wiggle room, just in case.
Just a little bit of wiggle room....
It's useful to keep the 16 million IoT devices you have running on WiFi segregated a bit.
Well technically a 10. network could be a /8 if you really wanted to. But in this case the /23 was specified above. I don't think it's necessary but that's what op was talking about and the 212.255 is a valid address, as is 213.0
Sure, you could. But you'd be going out of your way to setup an internal IP scope you'll never fully utilize.
I suppose it doesn't really matter, but it just feels wrong.
Yeah that's fair. Maybe OP is planning a nonsense amount of IoT devices and cameras? or they just want to use some unorthodox IPs like .255 or .0 for fun π€·
Thanks for the correction on the the broadcast address, btw. The details are important.
At home, I have 172.16/12 scoped out for my cluster subnet and just use the second and third octet to denote service function. It's excessive scoping, but it's an internal scope for a private network and broadcasts are generally contained to the cluster network. It would be trivial to split that into a 172.16/16 if I ever had the desire. (Speaking bluntly, it really doesn't matter much in this case. I'll need to split it out to keep Longhorn traffic segregated later, but it's not an issue now.)
The rest of the network is reasonably scoped out across 192.168 ranges and chopped up across a few VLANs.
My addressing scheme is split into "public" and "stay the fuck out", with most 172 addresses being the latter. At home this is great. In a large network, scoping out such a large 172 subnet could be detrimental. ("It depends" on the detrimental bit and requires proper planning and understanding about why subnets were even built into IPv4 from the get-go.)
Edit: Most addressing is static on my cluster network, with DHCP only handing out addresses based on MAC address. The 172 subnet has very restricted dynamic IP ranges.
Regardless of what is what, it's a scheme I recognize and that is the more important bit.
It might also make you really grumpy if you decide to use a VPN or containers - those often use 10/24 subnets and having an overlap with your LAN can make things spicy.
I could see something like /20 being useful not so much for the number of addresses but to group things by use case, then /8 because you don't care and it doesn't matter. Also 10.0 is quicker to type and cleaner to look at than 192.168
The highest address of a subnet is the broadcast address. You can't assign it to a host.
But 10.233.212.225 is middle of the range for the /23.
I had students like you when teaching Cisco classes...
Their peers heads would always explode, lol.
If you use a /23 you can use the middle .0 too.
My favourite dumb networking trick though is that Linux lets you use an IPv6 address as an IPv4 gateway.
That works so long as the gateway is running dual stack.
But why can't I use IPX in my routing table for IPv4????
Thanks I hate it.
Makes sense, the gateway is never a target of the ip packet, so it's really only used to find the MAC address of the gateway.
It makes sense if you think about it, but seeing IPv6 addresses in the IPv4 routing table still makes professional network engineers stop and boggle for a moment