subnetting

[me19562]

when I do subnetting with an IP calculator and I have an option called Allow 1 Subnet bit, what is means?

 

[L3Guy]

The RFC for subnetting specifics that the network portion of the address cannot be all zero or all one, the subnet portion cannot be all zero or all one, and the host portion cannot be all zero or all ones.

This option allows you to determine if you are using strict RFC compliant subnets or if you are using the all ones subnet.

Doug