Z Tech Blog

IP Addresses

A look into IP addresses, what they are, their different types and what they are used for.

In another entry in our series on the Cloud, in this article we look into IP addresses. An IP (Internet Protocol) Address is an address of your network hardware. It helps in connecting devices to other devices on the network and all over the world. It is the address of devices routers use to determine routes data traffic should take. An IP Address is made up of numbers or characters, such as 123.456.789.123

All devices that are connected to a network have a unique IP address. This means that for the internet there is a need for billions of IP addresses. This requirement is fulfilled by the new IP version IPv6. However for internal networks, which have fewer devices than the billions of devices connected to the network, there isn’t a need for so many addresses and so the older IPv4 version is still widely used.

IPv4 has space of over 4 billion IP addresses. However, the new IPv6 version can provide up to trillions of IP addresses.

IPv4 uses numerical values to configure IP addresses which may conflict with other IP addresses. That’s why IPv6 adopted the hexadecimal method to provide unique IP addresses to billions of users in the world. An example of an IPv6 IP address would be: 4aar:1935:5664:3:400:b4cb:dc32:98de

There are a few types of IP addresses like private IP addresses, public IP addresses, static IP addresses and dynamic IP addresses. Let’s talk about these different types of IP addresses one by one:

Private IP Address

A private IP address is the address of your device connected to the network. This IP address cannot be accessed from devices outside your home or business network. For example: 192.168.0.1

Private IP addresses are unique to the network they reside in, however, other networks, not connected to that network, would be using the same IP addresses.

As an aside, for anyone interested in finding out more about how different devices on different networks but with the same IP addresses can communicate with each other, they can find out more about the widely used technique Network Address Translation here.

Public IP Address

This IP address connects the device directly to the internet and is unique for all devices.

Static and Dynamic IP Addresses

All private and public IP addresses can be either static or dynamic. IP addresses that cannot change automatically and are permanently assigned to a device are called static IP addresses. IP addresses that are assigned automatically by the DHCP server (the server responsible for assigning and re-assigning IP addresses) and can change either throughout the life of a device (such as when it is rebooted) are called dynamic IP addresses. Structurally, static and dynamic IP addresses are the same – they do not have different characters, lengths etc.

Subnets, IP Address Ranges and Network Prefixes

In most setups, there are usually more than one type of server for an application (for load bearing and security purposes), such as many web servers being used to run one website. In order to manage the network more easily and for security, segments of the network, called zones, are setup where the same type of servers are placed. Strictly speaking, within networking, these segments are called subnetworks/subnets (with the zoning nomenclature mainly used in Solution Architecture). Each subnet will have a range of unique IP addresses from where servers in that subnet are given addresses. These set of IP addresses are often depicted using the Classless Inter-Domain Routing (CIDR) notation <IP address> / <network prefix>, where the prefix determines the number of addresses within the range of IP Addresses of the subnet. Further details of subnets, CIDR notation and network masks are beyond the scope of this blog post however the following example should help explain the concepts further: 192.156.1.0/24 depicts all 256 IP addresses within the range 192.156.1.0 - 192.156.1.255 for the subnet 192.156.1.x; and 192.156.0.0/16 depicts all IP addresses within the range 192.156.0-255.0-255 for the larger subnet 192.156.x.x

Z Tech is a technologist, senior programme director, business change lead and Agile methodology specialist. He is a former solutions architect, software engineer, infrastructure engineer and cyber security manager. He writes here in his spare time about technology, tech driven business change, how best to adopt Agile practices and cyber security.

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