IPv4 Addressing Overview

Comprehensive guide covering various aspects of IPv4 addressing, including subnetting, CIDR notation, IP address classes, reserved private ranges, and the complete IPv4 address table.

Decimal to Binary Conversion

Converting Decimal to Binary is based on the positions of the digits in the number and is typically computed in groups of 8, given IPv4 addresses are 32-bit numbers.

For example:

  • Decimal to Binary: 192.168.1.1 = 11000000.10101000.00000001.00000001

Binary to Decimal Conversion

Binary to Decimal conversion is the reverse process, where binary numbers are converted back to decimal numbers.

  • Binary to Decimal: 11000000.10101000.00000001.00000001 = 192.168.1.1

IPv4 Address Classes

IPv4 addresses are categorized into five classes: A, B, C, D, and E.

  • Class A: 0.0.0.0 to 127.255.255.255
  • Class B: 128.0.0.0 to 191.255.255.255
  • Class C: 192.0.0.0 to 223.255.255.255
  • Class D: 224.0.0.0 to 239.255.255.255 (Reserved for Multicast)
  • Class E: 240.0.0.0 to 255.255.255.255 (Reserved for Research)

Subnetting and CIDR

CIDR (Classless Inter-Domain Routing) introduced a new method to allocate IP addresses more flexibly.

It uses the slash notation (/) to define the subnet mask in terms of the number of bits used for the network portion of the address.

For example:

  • /24 Subnet: 255.255.255.0
  • /16 Subnet: 255.255.0.0
  • /8 Subnet: 255.0.0.0

Complete Table of Subnet Masks (CIDR Notation)

This table represents the CIDR notation, the corresponding subnet mask, and the wildcard mask for all possible subnet sizes in IPv4 addressing.

CIDR NotationSubnet MaskWildcard Mask
/00.0.0.0255.255.255.255
/1128.0.0.0127.255.255.255
/2192.0.0.063.255.255.255
/3224.0.0.031.255.255.255
/4240.0.0.015.255.255.255
/5248.0.0.07.255.255.255
/6252.0.0.03.255.255.255
/7254.0.0.01.255.255.255
/8255.0.0.00.255.255.255
/9255.128.0.00.127.255.255
/10255.192.0.00.63.255.255
/11255.224.0.00.31.255.255
/12255.240.0.00.15.255.255
/13255.248.0.00.7.255.255
/14255.252.0.00.3.255.255
/15255.254.0.00.1.255.255
/16255.255.0.00.0.255.255
/17255.255.128.00.0.127.255
/18255.255.192.00.0.63.255
/19255.255.224.00.0.31.255
/20255.255.240.00.0.15.255
/21255.255.248.00.0.7.255
/22255.255.252.00.0.3.255
/23255.255.254.00.0.1.255
/24255.255.255.00.0.0.255
/25255.255.255.1280.0.0.127
/26255.255.255.1920.0.0.63
/27255.255.255.2240.0.0.31
/28255.255.255.2400.0.0.15
/29255.255.255.2480.0.0.7
/30255.255.255.2520.0.0.3
/31255.255.255.2540.0.0.1
/32255.255.255.2550.0.0.0

Reserved Private Ranges

Private IP addresses are not routable on the internet. They are reserved for internal networks.

Private Address Ranges

  • Class A: 10.0.0.0 to 10.255.255.255
  • Class B: 172.16.0.0 to 172.31.255.255
  • Class C: 192.168.0.0 to 192.168.255.255

Complete IPv4 Address Table

Creating a complete IPv4 address table here might be too extensive. However, it consists of 4,294,967,296 unique addresses (0.0.0.0 to 255.255.255.255) when considering all possible combinations of four octets each ranging from 0 to 255.

This vast pool of IP addresses provides a unique identification for every device on the internet.

This information should give a comprehensive understanding of IPv4 addressing, subnetting, CIDR, IP address classes, and reserved private ranges for your blog post.