What is IP Class, Subnet mask and CIDR?
IP Class IPv4 consists of a logical address system consisting of 255.255.255.255 32 bits (4 bytes) in length, and one IP consists of a Network Address and a Host Address. In particular, here, Network Address divides its scope into areas that are easy to manage, and we call it Class. This class consists of five classes from A to E as follows, and the Network Address area and Host Address area of each class are shown in the figure. The starting range of each class is easy to remember by calculating the following equation. There are 256 ranges to input into IP (0 to 255) Divide by 2 from 256. 256 / 2 = 128 - 1 = 127 (range of A class: 0 ~ 127) 128 / 2 = 64 + 127 = 191 (range of B class: 128 ~ 191) 64 /2 = 32 + 191 = 223 (range of C class: 192 ~ 223) the rest of the number of 32 is divided by 16 and separated into a D class and an E class each. Subnet Subnet Mask is used to raise or lower the Network Address value by masking the value to Network Address. In other words, the Subnet mask