What is my IP?

Here is how “What is my IP?” tools work! Let’s first understand IP Addresses: Especially, let’s clarify the difference between public and private IP addresses:

• Public IP Address: This is the address assigned to your network by your Internet Service Provider (ISP). It’s unique across the entire internet and is used for external communication.
• Private IP Address: These are used within your local network (e.g., your home or office network) and are not routable on the internet. Common ranges include 192.168.x.x, 10.x.x.x, and 172.16.x.x to 172.31.x.x.

How “What is my IP?” Tools Work When you visit a “What is my IP?” website, here’s a step-by-step breakdown of what happens:

1. HTTP Request: When you open the website, your browser sends an HTTP request to the server hosting the website. This request includes several pieces of information, including your public IP address.
2. Server Receives Request: The server receives your request and extracts the public IP address from the request headers. This is the IP address assigned to your network by your ISP, which is visible to any external server you communicate with.
3. IP Address Extraction: The server uses the IP address from the request headers to determine your public IP. This is possible because the request must pass through your router, which uses Network Address Translation (NAT) to map your private IP to your public IP.
4. Response Generation: The server generates a response that includes your public IP address and sends it back to your browser. The website then displays this information to you.

Technical Details

• Network Address Translation (NAT): NAT is a process used by routers to translate private IP addresses to a public IP address and vice versa. When a device on your local network (with a private IP) sends a request to the internet, the router replaces the private IP with its own public IP. This allows multiple devices on a local network to share a single public IP address.
• HTTP Headers: When your browser makes an HTTP request, it includes headers that contain metadata about the request. One of these headers is the X-Forwarded-For header, which can include the public IP address of the client making the request.
• Geolocation: Some “What is my IP?” tools also provide geolocation information. They use databases that map IP addresses to geographic locations. This mapping is not always precise but can give a general idea of the location associated with an IP address.

Example Here’s a simplified example of an HTTP request and response: HTTP Request:

GET / HTTP/1.1
Host: whatismyip.com
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.3
X-Forwarded-For: 203.0.113.195

HTTP Response:

HTTP/1.1 200 OK
Content-Type: text/html

Your public IP address is 203.0.113.195

In this example, the X-Forwarded-For header contains the public IP address 203.0.113.195, which the server extracts and displays in the response. Conclusion “What is my IP?” tools work by leveraging the information included in HTTP requests and the NAT process used by routers. They can reveal your public IP address because this address is necessary for any communication between your device and external servers on the internet.