How Do IP Addresses Work?

Internet Network

By Jayne MillerMay 9, 2017


 What’s an IP address and how does it work?

Good question—and one that we’re sure has been dominating Google searches as of late. Here are the basics.

What’s an IP Address?

An IP address is a unique identifier for every machine using the internet. Known as your “internet protocol address,” this identifier is written as a string of numbers separated by periods. (Google “what is my IP address” to see yours.)

That’s the big-picture explanation.

If you want to go a little deeper, we could talk about the two different standards for IP addresses. Internet Protocol Version 6 (IPv6) is the most recent version of IP, while Internet Protocol Version 4 (IPv4) was the first IP address used by the public. Most addresses are IPv4. It’s the most widely-deployed IP used to connected devices to the internet.

When we crunch the numbers, we see that IPv4’s 32-bit address allows for about 4 billion addresses. While that sounds like a lot, we can safely assume that we already have 4 billion devices that want to connect to the internet. (See for yourself: these guys track how many IPv4s are left.)

IPv6 uses eight blocks of four hexadecimal digits; it was designed as an upgrade that also satisfies the need for more addresses. In pure theory, there are 340 undecillion IPv6 addresses. That's more addresses than atoms on the surface of the Earth.

How Do IP Addresses Work?

When you jump online to send an email, you’re accessing a network that is connected to the internet itself or one that gives you access to the internet. Perhaps that’s connecting to whatever internet service provider (ISP) you have at home or using a company network in the office.

To do this successfully, your computer uses internet protocol, and your IP address is used as a virtual return address to establish a connection.

Sidebar: Reading an IP Address

The blocks of hexadecimal digits that make up an address are called octets. These octets create an addressing scheme that accommodates different network types. (There are five different classes of networks, A-E.)

IP addresses are broken into two parts: network address and host address (host = the specific device on the network).

This is where it all comes together. The first few octets in an IP address identify the network. The exact amount of octets depends on the class of network. For example, in a Class A address, the network portion is contained within the first octet, while the rest of the address is used to denote subnets and hosts. In a Class B address, the first two octets are the network portion, while the rest is for subnets and hosts, etc.

How Are IP Addresses Assigned?

All of these addresses are allocated by the Internet Assigned Numbers Authority. This nonprofit U.S. corporation coordinates global IP addresses, which you can read all about here.

More specifically, IANA assigns blocks of IP addresses to regional internet registries. In turn, these regional registries allocate addresses to ISP, companies, schools, and similar institutions within their zone.

That means your IP address probably comes from your company network or ISP, which received that address from a regional internet registry, which was allocated a block of addresses from IANA. (It’s a process.)

Where Does a Router Fit in?

Yes. Routers matter. That box full of ports collecting dust in your living room is translating data to connect you to the internet, as well as keeping you safe via firewall.

In its simplest form, routing is what we call the process of forwarding IP packets from network to network. You probably know a router as the device you set up to obtain internet access. To do that, your router is actually joining networks and routing traffic between them like a switchboard.

To join networks, a router uses network cards, each one physically connected to a network and communicating with one another across the IP system to ensure  data is moved to and from the correct endpoints.

This means that when you visit the TeleGeography homepage, a packet of data comes from your computer and another packet is recieved by it, which loads your request. This communication bounces between two endpoints, all because routers transmitted and guided this information. 

Related: you might also be interested in knowing about Border Gateway Protocol (BGP), a specific protocol that exchanges information between autonomous systems on the internet. Put more simply, BGP is the protocol often used by ISPs, which is why it's worth scoping out.

You can read up on how BGP routers work here.

Does This Relate to VPNs?

You might have been reading more and more about virtual private networks (VPNs) as of late. Yes, IP addresses are related. 

In short? A VPN is a private network that shares data through a public network like the internet. When using a VPN, a user's IP address will actually be replaced by their VPN provider, but that's a whole separate blog post. 


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