Why are 192.168.1.0/23 and 192.168.0.0/23 the same thing?

Question

Computer networks

There is a network 192.168.1.0/23, why the IP addresses of hosts in it start with 192.168.0.1, as if we took the network 192.168.0.0/23, i.e. network range: 192.168.0.0 - 192.168.1.255 instead of 192.168.1.0 - 192.168.2.255. And so with all the odd "subnets"

Answer 1

You simply do not understand the meaning of the short mask notation.
/23 means that the first 23 bits of the mask are 1 and the last 32-23 = 9 bits are 0.
Thus, the mask will be 11111111.11111111.11111110.00000000 = 255.255.254.0
Now let's expand your addresses bit by bit:

Маска:   11111111.11111111.11111110.00000000 = 255.255.254.0
Адрес 1: 11000000.10101000.00000000.00000000 = 192.168.0.0
Адрес 2: 11000000.10101000.00000001.00000000 = 192.168.1.0

To translate these addresses on the network, you need to perform a bitwise logical AND of the address with a mask. Get

192.168.0.0 & 255.255.254.0 = 192.168.0.0
192.168.1.0 & 255.255.254.0 = 192.168.0.0

Thus, both addresses are included in the same network of size /23.
The correct designation for this network is 192.168.0.0/23.

Answer 2

Recall the binary AND operation that is performed on an address and a mask to get the base address of a network. The /23 mask is 11111111 11111111 11111110 00000000, for reference. And since .1.x and .2.x differ not only in those bits where the /23 mask is zero, the addresses end up on different subnets with this mask.

Answer 3

Just look at those octets in binary and the mask too. Decimal numbers are used for ease of notation.