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What’s an IP Address?

If you don’t know your IP from your URL or your DNS, this column is for you! Welcome to In Plain English where you’ll learn some techie stuff from a non-tech person who just so happens to have worked with a bunch of computer geniuses for the last 25 years.

Today’s Topic: What’s an IP address?

When you sat down at your PC this morning, everything seemed to be working just fine until you tried to browse the Internet.  Uh oh, what’s wrong? It could be a dozen things. But one thing is for sure—some link in the communication chain has been broken. To understand how computers communicate, you need to know what an IP address is.

Let’s break it down.

What has an IP?

An IP address, short for Internet Protocol address, is an identifying number for computer equipment connected to a network. Having an IP address allows a device to communicate with other devices over an IP-based network like the Internet.  It also allows your PC to talk to your network printer, file server, and your wireless router at home.

IP addresses on a home network might look like this:

If you send a package to a friend in another country, you must have the exact mailing address or the postal service won’t be able to deliver it. The same is true for sending data over a network or the Internet.

An IP address provides an identity to a networked device (physical piece of hardware), enabling devices on a network to differentiate themselves from one another.

How do they communicate?

Computers use DNS (Domain Name Servers) to look up a hostname to find its IP address.

Yikes, more acronyms!

For example, when you enter a website URL (there’s another one!) such as into your browser, your request to view that web page is sent to DNS servers that look up the hostname of to find it’s corresponding IP address.

For example: =

Without the IP address, the computer has no clue what it is that you are looking for. The geniuses behind this protocol have thankfully designed these numbers to allow for trillions of possibilities where IPs might be needed. Hopefully, we will never run out of them!

There are two different types of IP addresses: private IP addresses and public IP addresses.

Private IP addresses:   For inside a network, such as your workplace where desktops, servers, and printers are communicating. Example:

Public IP addresses: For outside of a network, such as communication with the internet. Example:

Both private and public IP addresses can be either dynamic (they can change) or static (they don’t change, hopefully). Let’s save dynamic and static for another column!

Take Away

Your major takeaway—none of your tech devices can communicate without an IP address.

That’s it!  Happy Browsing!


Just for fun, let’s define a few more of the wacky acronyms used in this article:

DNS server – a “Domain Name System” server is a computer that contains a database of public IP addresses and their associated hostnames. Sometimes it is also called a name server. It’s the Internet’s phone book, converting your easy to remember address such as into an IP address.

Hostname – a hostname is the label assigned to a device (host) on a network.  Inside a network, it might look like “MOM-LAPTOP” or “Dad’s iPad”. On public networks, the most common hostname that you probably know is “www” as in

URL – a Uniform Resource Locator is a way of identifying the location of a file on the Internet. In plain English, it’s a website address that you type into your browser’s navigation bar.

ISP – your Internet Service Provider—that company you pay money to so that you can access the Internet (RCN, Service Electric, Verizon, AT&T).

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