Privex's IPv4 / IPv6 Information Page

An IP address (IP being short for "Internet Protocol") most commonly refers to your public IPv4 address, and sometimes to your IPv6 address (if you have one).

Generally, there are two kinds of IP addresses: public, and private. Most home internet users will have ONE public IPv4 address, plus a separate private "LAN" IPv4 address for each device on their network.

An IP address is similar to a phone number; much like how a phone call happens between two phone numbers, computer networking uses "connections" between two IP addresses.

On an average home network, accessing a website results in a connection that looks like this:

192.168.1.123 (Laptop) <--> 192.168.1.1 |(Router)| 23.45.67.89 (Public IP) <--> 12.34.56.78 (A website on the internet)

The server 12.34.56.78 can only see the public IP (in the example, 23.45.67.89), but home routers use a technique known as Network Address Translation (NAT) allowing network traffic coming from the internet to be routed back to the device which originally sent it (e.g. The laptop 192.168.1.123 in the example).

IPv4 (short for IP Version 4) is the most used IP networking protocol, and the oldest still in common use (The first major standard for IPv4 was released in 1978 - over 3 decades ago).

Practically every website on the internet supports IPv4, with a good portion of websites which support both IPv4 and IPv6 at the same time.

An IPv4 address is made up of 4 numbers between 0 and 255, separated by dots. For example:

192.168.12.34

Nerd Details

IPv4 uses a 32 bit address address system, meaning each address is composed of 32 binary one's and zero's. Each number "chunk" of 0-255 is known as an Octet because 8 binary digits (0000 0000 to 1111 1111) can represent at most 256 different numbers (one of those 256 numbers is zero, thus it ranges from 0 to 255).

CIDR Subnetting

To allow for IP addresses to be organised into small blocks - forming networks, we use an organisation system known as CIDR (Classless Inter-Domain Routing). CIDR allows us to break down the rather large 4.2 billion IPv4 address space into small chunks, allowing for simple routing (finding where a certain IP is located), plus helping to mitigate Broadcast Storms.

Grouping a block of IPv4 addresses together with CIDR is done by choosing the amount of "bits" you want. The standard CIDR notation looks like this:

192.168.1.0/24

The above notation means:

• The first 24 binary bits of this address (which make up 3 octets from the left: 192.168.1) are locked - they identify the "network".
• Thus, if we do 32 - 24 this leaves us with 8 remaining bits. Those 8 bits (the last octet of the address) are the "host" bits.
• As a visual example, the IP address 255.255.255.0 would be represented in binary as:

  11111111 11111111 11111111 00000000

One host bit (/32) can represent one address, two host bits (/31) represent two addresses, three host bits (/30) represent four addresses, and four bits (/29) represent eight addresses (doubling each time).

The most common block sizes are /24 (32 - 24 = 8 bits = 256 addresses), /16 (32 - 16 = 16 bits = 65,536 addresses), and /8 (16,777,216 addresses)

IPv6 (short for IP Version 6) is the successor to IPv4 (version 4), and is slowly being rolled out across the world.

An IPv6 address looks like this:

2a07:e01:abcd:1234::4321

As of 2019, most server providers (including ourselves, Privex) include a block of IPv6 addresses as standard with all server purchases, and many major companies such as Google and Facebook already have their websites IPv6 ready.

Unfortunately for the average home user, in most countries only a small selection of home ISPs offer IPv6 connectivity, however, adoption by mobile data networks is quickly increasing - due to the growing shortage of IPv4 addresses.

If you'd like to add IPv6 support to your home network without having to switch ISPs, you can use an IPv6 tunnel such as HE.NET TunnelBroker, or a VPN provider that offers IPv6 such as AzireVPN

(DISCLAIMER: We are not affiliated with TunnelBroker nor AzireVPN, nor do we get any form of sponsorship/referral benefits for linking you to them).