This web app uses various innovative techniques to find and reveal your real IP address. It uses different methods (server-side, online-services, webrtc) to detect your real IP address and also bypasses IP spoofing techniques (i.e. VPN, proxy, etc).
From Server Response
IP (Internet Protocol) address is used to connect a device to a network. The IP is either local or remote. The local IP address is used in a local network to allow a computer to be identified among other machines in the same network. This address could be similar in various networks since each network only sees its own internal devices. The remote public IP address, however, is unique for each device and can be used to identify the computer on the world wide web. Since this IP address is unique, it contains information about the region where this device is connected. It is a known method for servers to provide targetted contents for websites, for instance, a localized version of web pages based on the GEO location that is extracted from this IP address. It is also important to note that the IP address can also be used to track users.
Internet Protocol version 4 (IPv4) is the 4th version of the Internet Protocol. It is one of the first protocols designed for the internet and was deployed first in 1983. This protocol uses 32-bit integer value for generating internet addresses.
IPv6 is a new replacement to the traditional IPv4 address. As mentioned above, the IP4 uses 32-bit number to define both network and host address and it is limited to around 4 billion unique numbers. Since nowadays almost all the smart devices and gadgets are connected to the Internet, IPv4 addresses cannot provide enough unique IP addresses as needed, therefore, the new version of the IP protocol (IPv6) is gradually replacing it to offer a virtually limitless number of unique addresses.
In this web app, there are 3 methods available to find the user's IP address:
'REMOTE_ADDR', 'HTTP_CLIENT_IP', 'HTTP_X_FORWARDED_FOR', 'HTTP_X_FORWARDED', 'HTTP_X_CLUSTER_CLIENT_IP', 'HTTP_FORWARDED_FOR', 'HTTP_FORWARDED' properties of the global $_SERVERvariable. If the server is not in PHP, it is still capable of finding equivalent variables.