I thought I understood subnetting until I saw this.

Ha. This is baby stuff. These are just /24s and /25s. Super duper easy. Not in any way a challenge in my field. I can do this in my head without even a moment’s thought. Wake me up when you get to dynamic NAT and BGP failover.

/24 just means 256 IP addresses, 254 usable.

So for the first one, 192.168.1.11/24, that means addresses 192.168.1.0 to 192.168.1.255 are in this network – as mentioned, 256 total IP addresses. Usable range is 192.168.1.1 – 192.168.1.254 with the network address being 192.168.1.0 and the broadcast being 192.168.1.255. You don’t even need to get into the binary to figure that out.

All a /25 means instead of a /24 is that it’s one more bit off, 128 addresses instead of 256 (that’s how binary works). And depending on which side of the bit mask it’s on determines where the /24 is split. So the third address, 192.168.1.22/25, the first one listed with a /25, it’s also very easy. That just means the /24 is split in half, giving a usable range of 192.168.1.1 – 192.168.1.126 with 192.168.1.0 being the network address and 192.168.1.127 being the broadcast address. If any address is above 192.168.1.127 and is a /25, it’s therefore on the other half of the split /24*.

Anyway, the most upvoted commenter (unusually) is correct so I won’t reiterate that. That’s 100% right.

*You don’t have to think about it as split /24s, but it’s easier in this case. This method starts falling apart when you get to talking about /22s, /21s, /20s, etc.