Whole internet stands on the foundation of IP addresses, today lets go back and brush up on our technical skills relating to IP addresses.
The Internet Assigned Numbers Authority (IANA) manages the IP address space allocations globally.
IP addresses are classified into 3 main classes. Class A, Class B, Class C
Class A 0*******.********.********.********
Class B 10******.********.********.********
Class C 110*****.********.********.********
IP addresses are divided into 4 parts separated by a dot (.), each part is known as OCTET.
Each octet is equal to 8 bits. IPv4 => 8*4(octets) = 32bits
Class A
IP addresses will always have first bit under first octet as 0
Lowest value under Class A is 0, where as highest is 127. (How? see below)
Lowest 0
Highest 127
0 and 127 are reserved IPs. 0 is the network address, 127 is loopback testing address.
Above 2 IP address cannot be used for any device in the network.
Any IP falling in the range of 0 and 126 are Class A IP address.
Ex :
Binary 01110101.10011000.01000011.00001111
Decimal 117.152.67.15
Class B
First 2 bits in the first octet under Class B IP addresses will be occupied by 1 0
Lowest value under Class B is 128, highest is 191.
Lowest 128
Highest 191
Any IP falling in the range of 128 and 191 are Class B IP address.
Ex :
Binary 10100111.00100010.01110101.01011110
Decimal 167.34.117.94
Class C
First 3 bits in the first octet under Class C IP addresses will be occupied by 1 1 0
Lowest value under Class B is 192, highest is 223.
Lowest 192
Highest 223
Any IP falling in the range of 192 and 223 are Class C IP address.
Ex :
Binary 11000001.01111111.01010010.01000000
Decimal 193.127.85.64
Above details are just few pointers to give you an overview of the IP addresses which we use day in and day out.
I will share more details on IP addresses in coming days. Hope this document helped you in understanding the classes under IP addresses.
Please feel free to correct and comment.