Excuse Me, Is This IP Address Free or For Sale?

What if I offered you 16,777,216 IP addresses for $100?

Or 1,048,576 IP addresses for $50?

65,536 IP addresses for $25?

Which one is the better deal?

The answer is none of them are a deal, IP addresses within the private IP range are already FREE.

Check out the IP ranges below.  These are the free IP addresses available to anyone in their own private network.  

And only in their own private network, not to be used on the Internet.

(We are going to be using the word “octect”, if you don’t know what that means, check out our post What Is An IP Address?)

 

10.0.0.0 – 10.255.255.255 (16,777,216 total IP addresses)

Whenever you see a “0” – “255” between the first range and the second range, it is way of saying that you can assign any IP address between the numbers 0-255.

But see how the “10” doesn’t change in the first octet in both ranges? That means every IP address has to begin with the number 10 as their first octet.

Here are some examples of how a network engineer might assign IP addresses in the above range.
Server: 10.23.54.111
User Desktop: 10.1.2.3
Mobile Device: 10.123.250.199
Laptop: 10.222.111.51
172.16.0.0 – 172.31.255.255 (1,048,576 total IP addresses)

Using the above logic, in this example the number “172” will not change, every IP address assigned within this range has to begin with “172”.

Check out the second octet in both the ranges “16” – “31”.  This means the every IP in the second octet will have to be between “16” or “31”.

The third and fourth octets however, can be any IP address between “0” – “255”.

Here are some examples of how a network engineer might assign IP addresses in the above range.
Server: 172.19.22.36
User Desktop: 172.16.15.22
Mobile Device: 172.30.200.100
Laptop: 172.20.20.20
192.168.0.0 – 192.168.255.255 (65,536 total IP addresses)

In my IT experience I found this range to be the most common.  The first and second octets do not change, they must begin with “192.168.x.x”.

The third and fourth octets can be anywhere between “0” and “255”.

Server: 192.168.15.22
User Desktop: 192.168.1.10
Mobile Device: 192.168.30.55
Laptop: 192.168.212.212

Private IP addresses allow you, right now, to go buy a server, desktop, a cell phone, or a laptop, and assign all of them IP addresses that fall into the above ranges.

 

There’s just one catch …

Private (and free) IP addresses, cannot be routed across the Internet, they will never leave your house, office, or any other type of local network.  Nobody will ever see them but your private home or local network.

Think about it.  These private IP addresses are free for everyone to use in their local or private network.  What if you assigned a computer in your house an IP addresses of 192.168.5.10?  And your friend who lives in Japan, also assigns the IP of 192.168.5.10 for his computer?  Both of you now have the same IP address, isn’t that a problem?  Won’t the Internet crash and burn because you have the same IP as someone else?

No, because 192.168.5.10 will never traverse the Internet, so you don’t have to worry about your computer’s IP colliding with your friend’s computer in Japan.  Neither of those computers are in the same local network, they are completely geographically separated and in their respective private networks.

So how do you communicate with your friend in Japan? Or even reach the Internet if everyone uses private IPs in their local area networks?

Through the use of NAT, Network Address Translation.  Check out the below link on the what, how, and why of NAT.

An Explanation of Network Address Translation (NAT)

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