IPv4 Subnetting invalid entry causing network address of zero
For example, let’s use take a look at the 10.1.1.1/4 address. The /4 subnet is equivalent to a 240.0.0.0 subnet. Let's look at it in binary:
10.1.1.1 = 00001010.00000001.00000001.00000001
240.0.0.0 = 11110000.00000000.00000000.00000000
To get the network address, we AND the IP address with the subnet mask:
The result is 0.0.0.0, which is not an acceptable network address.
If you try to apply this IP address/subnet mask combination to a Windows PC, you get the following error message: