A public IP address can provide us with a large amount of user information. With the appropriate tools, it is easy to geolocate with relative accuracy where the user of that public IP address is geographically, and even what is your Internet service provider, what routes are there to reach that IP and, of course, to which autonomous system that public IP address belongs. Today in this article we are going to explain what information we can get through a public IP address.
The first thing we must know in depth is the concept of IP, and the two different types that exist. Once we know the IP addresses, we will be able to know a lot of information about someone’s public IP addresses, and we will have very valuable information.
The IP classes we have in a home network
We can define IP addresses as a logical and unique identifier for each of the computers connected to a network . Also, an IP address in IPv4 networks is composed of four groups of numbers between 0 and 255 separated by periods, with a length of 32 bits. These addresses will be represented in decimal notation separated by periods, such as the address 80.34.48.180.
Regarding IPs, we could say that there are basically two types:
- Public IP
- Private IP
Regarding the public IP, we could consider it as the identifier of our network facing the Internet. In this case, it is the one that you have assigned in your home router in the Internet WAN interface. In addition, we cannot assign this public IP the one we want. In this case, our ISP (Internet Service Provider) will be in charge of assigning you one. Also, within the public IP we have two classes:
- A static public IP is the one that will never change and we will always have the same one.
- The dynamic public IP , however, is the one that can be changed to another. Our internet provider will assign us a new one when turning off the router or after a period of time established by it.
Regarding the private IP , it is the one that identifies each of the devices that we have connected to our home network. Therefore, we refer to each of the IP addresses that the router assigns to the PC, the smartphone, the tablet, the Smart TV and the Android TV equipment. Also others related to home automation, IoT and security have their private IP. An example could be smart plugs, IP cameras, and more.
Currently, the vast majority of users have a dynamic public IP in their homes. The great advantage they have is that by changing from time to time, their security increases since today we could be reachable, but tomorrow it is possible that not when changing this IP. This is known as “security by obscurity.” The drawback is that it is somewhat more complicated to set up a server, since we will depend on dynamic DNS services to always have a new IP address located.
On the other hand, the static IP is the one that companies usually hire to mount their servers. For example, to host an FTP or web server. In this case, in addition to paying for the Internet connection, they must add a small extra cost for having that static public IP. The advantage that it is easier to mount those servers.
What can we find out with a public IP
If we have an IP address, either our own or from a connection, we can find out a lot of information about it. The first thing we are going to do is find out what our public IP is, that is, the one that identifies us outside our own network. In this case we are going to do it using a website easily and quickly. In your usual browser on Windows, Android or Linux you can find out easily. We are going to use the web which-es-mi-ip.net and by clicking on the previous link we will be able to know our public IP address.
This is the result I have obtained from my Windows 10 PC:
Just with this I have obtained a lot of information:
- Public IP: 213.97.xx
- The internet provider or ISP: Telefónica de España.
- Public IP class: put static ip which means that it is static or fixed. If it is dynamic, it does not usually put anything.
- Country Spain.
- Proxy: no, which means that we enter the Internet directly, we do not navigate through a proxy.
But that’s not all, we can still get more information. If we click on Geolocate IP , it will offer us a more precise location on where that IP address is located, in most cases this geolocation is quite exact. These are the only data that you would offer us after pressing the button:
Some information such as the country, the operator (ISP) or if it is dynamic or static I already told us before, but now this IP address is geolocated in a fairly exact way in our case.
Now we have new data like the following:
- A map that places our public IP with a red pin. In this case, it indicates that it is a population near Madrid, and that it is located to the south of this population.
- That the city is about Parla.
- It also offers latitude and longitude.
This is what anyone who knows our public IP could know. However, if we know for example a public IP that we want to check. Imagine that an alarm goes off on your firewall that they have tried to access your network.
Then we write it down and we can check it here using the same website that we used before. In IP Address we put the one that we have just pointed out and we give the magnifying glass icon to carry out the search. Thus we will obtain the following results.
Thanks to this, we have found out that the possible attacker could be from the Netherlands, that he would be located in Eindhoven and that his internet provider is Ziggo . Also another way to obtain information from that public IP is to check the open ports that your router has. In this case we are going to use a website that is used to check which ports are open. For this we are going to use this port test to check them quickly and easily.
Once we have entered the web, we will simply write our public IP address, and add the port or ports that we want to check. This tool allows you to check port ranges, also ports separated by commas or by putting the name of the application.
For example, here we can see that port 20 is closed but 21 is open. That one of those ports, specifically 21 is open, could indicate that it has an FTP server. As you have seen now, you know everything that can be known about an IP.
Another way to know data is knowing its path / URL of the web. For example, if we choose the popular sports website and Marca newspaper from here we can also extract information. Also from its URL, it is easy to get the domain. Thanks to the nominalia website that we will access by clicking on the link we will be able to obtain some additional information.
There in the domain name we put marca.com and it will offer us extensive information about them. As it offers very extensive information, I have compiled an extract from it.
Finally, if we want to obtain more information from public sources of information, we can make use of the best search engines for hackers , where we will have Shodan, which is one of the best. Thanks to Shodan we can see the autonomous system where our public IP address is located, what services we have exposed to the Internet, and a lot of other advanced information.
Other information provided by the web browser
Now we are going to know information about our team and other additional information that we provide when we visit the websites of this style. For this we go to another website myip.com . In its first section, it offers us the following information.
Here we could see our public IP, operator and other information that we have seen previously, but it will also show us the web browser with which we have accessed the web, the operating system that we are using, and even other very valuable information such as screen resolution and the headers of the request that we have sent.
Therefore, it is proven that you can know a lot about a public IP address using the right tools