IPv4 Addressing

What is IP Addressing?

An IP address is a unique number/address used to identify a device on a network.

Every device connected to the internet must have an IP address to communicate with other devices; Xbox games, cell phones, tablets, cars, fax machines etc.

IP address acts as a telephone number or a car registration plate, it shows ownership and location. IP address allows a device to communicate and be located by other devices on the connected world wide web.

Recently, there are two types of IP Addressing: IPv4 and IPv6


 An IPv4 address is made up of 32 binary bits, which is divided into a Network portion and Host portion with the help of a Subnet Mask.
The 32 binary bits are broken into four octets (1 octet = 8 bits). Each octet is converted to decimal and separated by a period (dot).

How IPv4 addresses look:

IP addresses have two common formats. IP version 4 addresses are comprised of four numbers-only segments separated by dots:


The value in each octet ranges from 0 to 255 decimal, or 00000000 – 11111111 binary.

Below is how binary octets are converted to decimal: The rightmost bit, or least significant bit, of an octet, holds a value of 20. The bit just to the left of that holds a value of 21. This continues until the left-most bit, or most significant bit, which holds a value of 27. So if all binary bits are a one, the decimal equivalent would be 255 as shown here:

    1     1   1   1 1  1 1 1
  128 64 32 16 8 4 2 1 = (128+64+32+16+8+4+2+1=255)

And this sample below shows an IP address represented in binary and decimal.
     192     .   168       .    4          .    10         (decimal)
11000000.10101000.00000100.00001010 (binary).


IP version 6 (IPv6) addresses,…well… are more complex. IPv6 addresses are comprised of 8 segments and it looks like this:

e.g. 3ffe:1900:4545:3:200:f8ff:fe21:67cf
e.g. 21DA:D3:0:2F3B:2AA:FF:FE28:9C5A

IPv6 uses 128 binary bits to create a single unique address on the network. An IPv6 address is expressed by eight groups of hexadecimal (base-16) numbers separated by colons, as in 2001:cdba:0000:0000:0000:0000:3257:9652. Groups of numbers that contain all zeros are often omitted to save space, leaving a colon separator to mark the gap (as in 2001:cdba::3257:9652). Read more on IPv6

IP addresses are allocated by the Internet Service Providers (ISP)…that means they act like lenders; who in turn gets a loan loads of IP addresses from the Internet Assigned Numbers Authority (IANA).

The IANA is a non-profit corporation whose main business is the control and coordination of IP addresses and so many other internets whatever. It sounds more or less like the central bank loaning money to the commercial banks who in turn loan it to individuals.

Those ISPs’ gets an allotment of IP addresses…loads of them and assign the IP addresses to every server and every internet user, computer and other devices who logs on.

How IP address works

To sum it up in plain, IP addresses are the numbers that identify devices connected to a network. If your device only needs access to a local network, it can be identified with an address that has only a local context. These are called private addresses.

But when your device needs to access services on other networks, it needs to use a unique address.

IP address works like a house number of a phone number which is what you need as a contact…thats the mindset!

If you want a reply from a letter you need a house number and so also goes to phone number…

In some cases, IP address can be translated from a private address into a unique address at the border between your network and your ISP’s network. 

Sounds more like a Post Office box or a shared house where a group of person receives letters without owning the box or a company phone number with extension to different offices or departments…

This technology is called Network Address Translation, or NAT.

Read more on NAT


Earlier, we said for you to send and receive email on the internet, your connected device as in your laptop or PC needs an IP address.

For this process to work, your IP address has two parts. The first part of an IP address is used as a network address, the last part of a host address.
If you take the example and divide it into these two parts you get the following:

192.168.123. Network
.123 Host
The network part of the address is likened to the house address, number or postcode.
The host part of the address is likened to an individual or person’s name on the mail who lives in that home.

In essence, an IP address is a unique number used to identify a device or machine on the internet…

Related Articles

Type of Addresses in IPv4

Internet Protocol Version 6 (IPv6)

Public and Private IP Addresses

Variable Length Subnet Mask (VLSM)

Subnetting IP Address

CLassless InterDomain Routing (CIDR)

Network Address Translation (NAT)

Dynamic Host Configuration Protocol (DHCP)