Surfing the Internet, from the point of view of privacy, is like going around in the car. When driving, the car has an identification plate so, if we make an irregularity, it is easy to trace the owner.
The plate, when surfing the internet, is the IP address assigned to that computer, to make anyone traceable (see also the explanation on how computers talk to each other on the network via TCP / IP)
Every time you use a program or an application such as the web browser, to open a web page, one or more connections are established with the server hosting that site.
Once the connection is established, the computer downloads the data from these servers and displays the web page in the browser.
Each connection reveals the IP address of the device used to open the site, to the server to which it connects which, vice versa, sees the IP address of the server.
The IP address cannot be chosen, it is assigned by the connection manager (which can be Telecom, Fastweb and Wind) randomly and, sometimes, also dynamically.
This very simplified discussion applies to every internet connection, even for e-mail programs, chats, smartphone applications etc.
Just as for the plate of the machine, from the IP address it is not necessarily possible to trace the identity of who is using it, but only the owner of the connection.
If you connect from home, the same address applies to anyone who connects to the internet: parents, siblings, children, friends, etc.
If the connection is established in an office, this IP address can be valid for all the people who work there.
Indeed, in some cases, the public IP address is the same for internet connections from entire condominiums or neighborhoods or cities (this has already been explained in the article on how we connect to the internet with the same public IP address).
Furthermore, IP addresses are often assigned dynamically and are hardly fixed for a particular user like we can be at home.
The IP address therefore reveals little public information and only in certain cases can it be traced back to a person's home address.
Depending on the network provider used to access the internet, the information that an IP address can reveal is different and often confidential.
Theoretically, these managers cannot store data to control what users are doing on the internet and must ensure customer privacy.
However, if, for example, a person commits an online computer crime, the police may need to contact the network operator who assigns the IP addresses to trace his identity.
After what has been explained, it is clear that even if a stranger knew the public IP address of my current internet connection, he could do nothing about it.
Basically, from a public IP address only the network provider can, if requested, trace the identity of a person.
Anyone else can just try to figure out where it comes from, find the IP address of another computer and locate it, but spying on what it does is not possible.
This is because behind each connection there is a router (private or from the same network provider) that creates an internal network and protects any external device from external connections.
We have already explained how a router works in another article.
The matter changes if a computer is used within the same network created by the router, which is not the internet but a private home or office subnet.
The router in fact assigns to the connected devices another IP address, this time internal, which is always the same for each private network and usually starts with 192.168 .
This address is not visible and, in any case, it cannot be reached (unless a desired opening is set) from outside the network.
Theoretically it is possible not only to find all the computers connected to the network, but also to sniff the connection and spy on it.
For this reason it is naive to let a wifi network not protected from extraneous access and, conversely, also connect to the neighbor's wifi network left free, because they could one day wake up and know everything we do on the internet.
Routers often have the function of monitoring which sites the devices connect to and can therefore monitor each site visited.
Returning to the public IP visible on the internet, if you want to protect your identity, see How to Hide the IP address on PC, Android and iPhone .
