Basics of Networking and IP addresses.

Rishabh Sharma
4 min readApr 7, 2022

Every device that uses the internet is identified through its own IP address in order for internet communication to work.

An IP address consist of 4 numbers separated by a single dot(.).

Network part identifies the physical network to which the computer is attached.

Host part identifies the the individual computer on the network

Ipv4 limitations and concerns

  • No one imagined or anticipated such huge growth in the users
  • It uses 32 bit addressing which allows 4.3 billion devices which is not sustainable today. (2³² devices)
  • It has security related issues.
  • Some address configuration issues.
  • By using NAT we can map many internal private IPv4 addresses to a single public IPv4 address, which helps in conserving IPv4 addresses

Advantages of IPv6

  • It is 128 bit addressing system which allows 2¹²⁸ devices.
  • The IPv6 protocol can handle packets more efficiently, improve performance and increase security.
  • Eliminates the need of NAT & PAT
  • Transition tools- Tunneling and NAT
  • Tunneling — Tunneling provides a way to use an existing IPv4 routing infrastructure to carry IPv6 traffic

What does IPv4 & IPv6 address look like

IPv4 addresses are written in four parts separated by dots like this: 45.48.241.198. Each part written in conventional Base 10 numerals represents an eight-bit binary number from 0 to 255.

IPv4 Address example

In IPv6 there are 8 parts which are separated by colons. A typical IPv6 address looks like 2620:cc:8000:1c82:544c:cc2e:f2fa:5a9b .

IPv6 Address example

Private vs Public IP address

Private

  • It is used to communicate within the network.
  • Mostly Private IP addresses of the systems connected in a network differ in a uniform manner.
  • Works in LAN.
  • Can be known by using ipconfig command

Public

  • It is used to communicate outside the network.
  • Public IP may differ in uniform or non-uniform manner.

NAT and IPv6

NAT or network address translation takes private IP address and turns them into public IP address. This way corporate machines(think of it as thousands of machine within a office)with private IP address can send and receive data outside the private network.

Without NAT each of these thousands of machine would have there own IP address and as already told there were less IPv4 address. NAT helps to reduce the IPv4 problem to some extent. With NAT thousands of privately address computers can be exposed to public internet by a machine(such as firewall, router etc.)

NAT works when a computer with private IP address sends a packet to public IP address outside network ,it goes through the NAT device and the NAT notes the source and destination in the translation table.

NAT (Source : Wikipedia)

Subnet

A subnet or subnetwork is a smaller piece of a larger network. It is logical portioning of the IP address into multiple smaller networks.

The host part changes in the subnetworks whereas the network part of IP remains same as the subnet is also part of the same network.

Organizations use subnetting to divide large networks into smaller , interconnected and more efficient subnetworks. It helps to minimize the traffic and traffic doesn’t flow from unnecessary large routes and which in turn increases the speed.

Each subnet allows its connected devices to communicate with each other, while routers are used to communicate between subnets. Each organization is responsible for determining the number and size of the subnets it creates, within the limits of the address space available for its use.

Supernet

Supernetting can be thought of exactly opposite of subnetting. In subnet as we divide the network into multiple smaller subnets , whereas in supernet multiple networks are combined into a bigger network termed as supernetwork.

Supernetting is mainly used in Route Summarization, where routes to multiple networks with similar network prefixes are combined into a single routing entry, with the routing entry pointing to a Super network, encompassing all the networks. This in turn significantly reduces the size of routing tables and also the size of routing updates exchanged by routing protocols.

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