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What is an IP address and why do I need it?

IP addresses are one of the first crucial steps for connecting devices on private and public networks. Here’s why.

Of all the usually invisible back-end networking systems that help get us online, the IP address is the essential first step.

Without an IP address, you wouldn’t be able to do anything on the internet. Let’s explore why this string of four sets of numbers is so crucial for networking communication, whether locally (private) or online (public).

What is an IP address?

The Internet Protocol is in charge of addressing, delivering and correctly routing online requests for connected devices.

Think of IP addresses as crucial in the same way as written addresses on an envelope.

If you want to send a letter that requires a reply, you need to include the address of the recipient on the front of the envelope, and a return address on the back.

Without IP addresses, connected devices and online destinations wouldn’t know where to send information to and from.

When you want to visit a web destination, your connected device needs to know the web destination IP address to request data from it, and the destination needs to know the IP address of your connected device to return the requested data to the correct place. 

The domain name system

As an extension of this, domain name system (DNS) is crucial for translating alphabetical web addresses typed by the user into numerical IP addresses used by computers, and the latter part of that translation process is only able to occur because the connected devices speak the same numerical IP networking language.

Local vs public: Why the divide?

IP addresses are separated into private local area networks (LANs) and public wide area networks (WANs).

In simpler terms, LAN refers to your home network of connected devices and WAN refers to internet connectivity.

These two numbers need to be kept separate for a simple reason: the once-ubiquitous IP standard ‘IPv4’ was established back in the 80s and was limited to just over 4 billion addresses.

This address limitation of IPv4 was exhausted in 2011, and is slowly being replaced by the larger IPv6 protocol, but our LAN/WAN divide is already well-established and will likely to continue to be normal practice well into the future.

As you may have guessed, the LAN/WAN divide exists because, before IPv6 came along, a way was needed to downsize the number of public IP addresses being used, otherwise it would have been exhausted long before 2011.

The solution was to separate IP addresses into local (LAN) and public (WAN). This way, your modem/router assigns all of your devices local addresses so that they can talk to it and your other devices, but your modem, and subsequently your entire local network, has only one address as far as the internet is concerned.

Internet connectivity from a computer, for instance, is actually indirect because it first has to connect to your local network (LAN) that is in turn connected to the internet via a unique WAN address.

Both LAN and WAN IP addresses follow the same format – four sets of numbers, where each set has one to three numbers in each grouping, which range from 0 to 255.

By combining both a LAN and WAN IP address, every connected device on a private network has a unique identifier that allows requested online information to be relayed back to the requesting device.

Local IP addresses

Ultimately, in terms of your home network, your device’s LAN IP address will be determined by your router. You can learn about the difference between a modem and a router (and a modem/router) from our article covering the subject.

Routers tend to assign addresses automatically, but can also be configured for manual assignment.

These local IP addresses follow the numerical logic of the router.

If, for instance, your router’s local IP address is, then your computer might be recognised locally as, your tablet might be, your smart TV might be, and so on.

If your router is set to automatically assign addresses, each device’s local IP might change as they connect, disconnect and reconnect to the network.

You can set local IP addresses manually, and ensure that they remain “static”, but this is usually not necessary.

Public IP addresses

In terms of WAN, your retail service provider will determine whether your public IP address is static or dynamic.

Your modem (or modem/router) is assigned a public IP address by your retail service provider, which allows it – and every device connected to it – to send and receive information to and from the internet.

A WAN IP address contains information such as your country, region, and city.                                                     

This public IP address follows a different class of numerical logic to your router (or modem/router) to relay traffic, first to or from your modem, then to or from the relevant connected device on your home network.

If you’re interested, you can see your public WAN IP address on websites like this one.

IPv4 vs IPv6

Because NAT (the WAN/LAN divide) only acts as a temporary solution for the limited IP address allocation of IPv4, Internet Protocol version 6 (IPv6) was created as the successor to IPv4. (If you’re wondering what happened to IPv5, it was used as an experimental streaming system.)

The benefit of IPv6 is that it offers roughly 340-undecillion (that’s 340 with 36 zeroes on the end) IP addresses – there are so many IP addresses that should mean no shortage of addresses in the foreseeable future.

The transition from IPv4 to IPv6 has actually been underway for the last 15 years, and because the two protocols act as parallel networks, it means they require special networking gateways in order to exchange data.

Despite misinformation about IPv6 being faster than IPv4 (and vice versa), tests suggest that speed differences between the two networking protocols are largely negligible.

Google has been tracking IPv6 usage since January 2009 and adoption of the networking protocol is trending upwards.

As of January 2017, IPv6 accounts for 38.4% of unique IP addresses in Australia, and has 8.01% adoption.

Private and public IP addresses may be mostly invisible to the average user, but they’re essential to the numerical language of the internet that helps make getting online a straightforward process.

Are you set to net? Check out our guide to wi-fi vs Ethernet in the home.

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