Skip to content

Bet You Don’t Know Your Own Address

October 26, 2020

Hey, what’s your address?

172.168.15.10

No, I mean your local address.

127.0.0.1

Oh, you geeky nerd!!! I mean your physical address.

29.01.38.62.31.58
– Saved from purcaholictumbler.com

Ever wonder how your computer knows how to find things? Not on the hard drive, but on the internet? And why would you care? It’s all about addresses.

Wait, before I lose the huge part of the audience that isn’t interested in IP addressing and Natting, hear me out.

What’s your house address. I’m going to show you how understanding addresses on the Internet is just as simple and easy as finding the address in your own home town.

First, let’s talk about how you address a letter:

Rodney Bliss
456 S Main Street
Pleasant Grove, Utah

Let’s start at the top first and then go from the bottom up.

Rodney Bliss

If you wanted to come visit me. You might ask someone in Pleasant Grove, “Where is the Bliss house?” And they would point you at my house. That’s like the URL, also known as the Uniform Resource Locator. (But, no one calls it that.) URLs are typically the bits we remember. Just as you would remember when you got to Pleasant Grove that you are looking for the “Bliss” house, on the internet we going looking for things by web address, or URL.

google.com
cnn.com
byu.edu
whitehouse.gov
army.mil

Another time, I’ll talk about the parts of a URL. But, today, just think of it like the name on the mailbox. In my case, “Bliss.”

When your computer goes looking for a URL, it checks something called DNS, or Domain Name Service. This is the post office, or at least the old phonebook. You ask for a name “www.google.com” and DNS give you an address. That address will look something like 172.217.11.228. This is called an IP address. IP stands for Internet Protocol, but no one calls it that.

That address is broken up into four sub addresses, called octets. Each octect has a range from 0 to 255. So, the following are valid IP addresses.

0.0.0.0
0.0.0.255
255.0.0.0
255.255.255.255

But, anything above 255 is an invalid address. So, the following are invalid IP addresses.

256.0.0.0
0.0.300.0
999.999.999.999

And no IP address can be longer than 4 octets.

What’s that have to do with my street address? Now we are going to start at the bottom of my street address and compare it to an IP address, 011.022.033.044.

The last piece of data in my address is the state, “UTAH.” Think of “UTAH” as the first octet in my address.

UTAH == 011

Next, in my address is the city, Pleasant Grove. Just as there are multiple cities, there are multiple address under 011.x.x.x.

So, the city is roughly comparable to the second octet, 022. So far my address covers two octets.

UTAH == 011
Pleasant Grove == 022

I’m sure you see where this is going. There are many streets in Pleasant Grove. Like most Utah cities and towns, it’s laid out in a grid. Center and Mail cross in the middle. From Main streets going North are 100 N, 200 N, 300 N, etc. Going South it’s 100 S, 200 S, etc. East and West of Main street follow the same pattern. The point is that each street is uniquely named. There can’t be two Center streets. The third octet can be though of as the steet name.

UTAH == 011
Pleasant Grove == 022
Main St == 033

You are almost to my house. You made it to Utah (011). You found Pleasant Grove, UT (011.022.) You’re now on South Main Street. You just have to find my house by it’s street number. (123)

UTAH == 011
Pleasant Grove == 022
S Main Street == 033
456 == 044

UTAH.Pleasant Grove.S Main St.456
011.022.033.044

And here’s why the Internet uses IP addresses. Suppose I move and I sell my house to the Jones family. The house stays at the same address, of course. But, the name associated with it has changed.

In other words, the URL (bliss) has changed to (jones), but the physical address stays the same. How will people know that the URL is different? Because DNS gets updated and now it associates the physical IP address with the new URL.

Having read this far, you know understand the first line of the joke. But, there’s more to addressing than just your IP address.

Tomorrow I’ll going into more detail on why 127.0.0.1 is your home address. And we’ll talk about gnats, I mean NATs.

(BTW, that’s not my actual address. Sorry. Blame the trolls and the stalkers.)

Stay safe

Rodney M Bliss is an author, columnist and IT Consultant. His blog updates every weekday. He lives in Pleasant Grove, UT with his lovely wife, thirteen children and grandchildren.

Follow him on
Twitter (@rodneymbliss)
Facebook (www.facebook.com/rbliss)
LinkedIn (www.LinkedIn.com/in/rbliss)
or email him at rbliss at msn dot com

(c) 2020 Rodney M Bliss, all rights reserved

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: