As we all know if we have read other guides in this blog, the IP address (which stands for Internet Protocol ) identifies each computer and device connected to the network. When computers communicate with each other on the Internet or within a local network, they send information and exchange data via their respective IP addresses, which can be thought of a bit like home addresses.
Since, however, the IP addresses, which if they are IPv4 (other than IPv6) are made up of 4 numbers separated by a dot, such as 192.168.1.1, cannot be infinite, whoever manages the internet has thought of linking internet connections from a particular vendor to a single public exit IP.
The information requested via the internet therefore first passes through this public IP, which is assigned to a central device capable of then sorting the data to private addresses, which are those assigned to computers.
Each computer, therefore, has (probably and unless it has a special connection) a public IP address exposed on the internet and a different one that we call private, which is that of the internal network, not visible from other devices on the internet.
So, the main difference between Public IP and private IP is that "Public" is an IP that can be reached from the Internet, while the private IP cannot. For example, in a typical home network, the central router has the public IP address on the Internet, while computers, smartphones, game consoles and other devices that connect from the router all have private and unique IP addresses on the network.
The router then acts as an intermediary and forwards the traffic to the local IP addresses that request it
Outwardly, all devices on the home network communicate with the Internet from a single public IP address.
If the computer is connected directly to the Internet without a router, which is only possible in certain circumstances, the computer's IP address is a public IP address.
Furthermore, as explained in the guide on how we connect to the internet and why with the same Public IP, this public IP can also be shared among multiple subscribers to the same provider.
In a configuration like the one described, which is the most common in Italy, each PC has two IP addresses : the IP address of the computer, which is a private IP address and a public IP address which is used to communicate with other computers on the Internet .
Private IP probably always starts with numbers 192.168 which is the range of IP addresses specifically assigned to private networks.
The private IP can also be a static IP, i.e. imposed manually by the user, or dynamic and automatically assigned by the router via the DHCP service.
It is possible to change IP on PC, smartphone and router.
The private IP address is not accessible from the Internet outside the router and without having made a special configuration called Port Forwarding.
The public IP, on the other hand, is assigned directly by the internet provider and can theoretically be used via the internet to connect, from anywhere in the world, to our PC.
For example, if you are hosting a server on your computer, people on the Internet will need to use the router's public IP address to connect to the server.
We explained in another article, focusing mainly on any concerns related to privacy and security, who can see our IP address and what it can do to us.
Also consider that public IP addresses are not necessarily fixed and are almost always dynamic (i.e. they may change occasionally) unless you request for a fixed public IP.
For example, as seen in the guide to configuring the Fastweb router, it is possible to request and obtain a free fixed public IP from Fastweb.
Find out what the private and public IP addresses are.
To find the IP address of a Windows computer, just open the Control Panel and click on the link View network activity and status, then press on the type of Internet connection (it can be Ethernet or wifi) to view the status and go to the Details tab to find the IPv4 address.
A quicker way to find the IP address in Windows is to open the DOS command prompt, look for it in the Start menu, and run the ipconfig command.
In another article we have instead seen how to find the IP address of the home router .
The router usually has 192.168.1.1 as its private IP address and this address can be used on the web browser to access the router configuration screen.
From the router's administration page, you can view the public IP address and other information about the Internet connection.
The easiest way to find our public IP address is to consult a website that automatically detects it.
There are several and one, for example, is IPinfo which immediately tells us our public IP and also gives us the possibility to locate the IP.
The Whatsmyip site, on the other hand, is also able to tell us what our IPv6 is, if we have assigned one as a public IP.
READ ALSO: How to Hide the IP address on PC, Android and iPhone
