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Dotted decimal notation

(also IPv4 address notation)

Dotted decimal notation definition

Dotted decimal notation is a human-readable representation of IP addresses in the IPv4 (Internet Protocol version 4) format. It is expressed as a series of four decimal numbers, each ranging from 0 to 255, separated by periods (dots). Each decimal number represents an 8-bit binary value (octet), and the entire IP address comprises 32 bits.

Dotted decimal notation examples

  • Localhost IP address:
  • Google's public DNS server IP address:

Dotted decimal notation compared to other notations

IPv6 notation: The IPv6 address format uses 128 bits and is expressed in hexadecimal notation, separated by colons. An example of an IPv6 address is 2001:0db8:85a3:0000:0000:8a2e:0370:7334.

Understanding dotted decimal notation

Dotted decimal notation is essential for configuring network devices, such as routers and firewalls, and for troubleshooting network issues. It's crucial to understand how to convert dotted decimal notation to binary and vice versa, as well as how to use subnet masks and calculate network addresses.

Pros and cons of dotted decimal notation


  • Easily readable and understandable by humans.
  • Widely used and supported by network devices.


  • Limited address space, with IPv4 addresses nearing exhaustion.
  • Less secure compared to IPv6, which has built-in security features.

Tips for using dotted decimal notation

  • Use a subnet calculator to determine the appropriate subnet mask for your network.
  • Familiarize yourself with common private IP address ranges, such as and
  • Utilize IPv6 alongside IPv4 in a dual-stack configuration to support future network growth and enhance security.