Why do other people have the same IP address as me?

Answer: If you access the Internet from a local network (LAN) in your home or business, it is possible that you share an IP address with other users. This is because, while you might use different computers or devices, you all use the same Internet connection.

In the early days of the Internet, people connected their modem directly to their computer. After all, most homes only had one computer. Today, most homes contain several devices that connect to the Internet. Therefore, it is far more common to connect a DSL or cable modem to a router that can be accessed by multiple devices. Some modems even include a built-in wireless router.

▶ Read more about the difference between a router and modem.

Your router gives each connected device a unique internal IP address that distinguishes different devices on the local network. This addresses are automatically distributed by the router using a protocol called DCHP. Typical IP addresses of local devices might be 10.0.1.1, 10.0.1.2, 10.0.1.3, etc. Some routers may also use IP addresses that use the "192.168.x.x" format, such as 192.168.1.1, 192.168.1.2, and 192.168.1.3.

When you use the Internet, your internal IP address is hidden and only your external IP address is seen by other computers on the Internet. This IP address is provided by your ISP and is assigned to the device that your modem is connected to, which is typically your router. Therefore, all devices connected to the router (whether wired or wirelessly) will share the same external IP address. The external IP address is used to identify your computer to other systems on the Internet. For example, whenever you access a website, the web server can recognize and record your external IP address.

Since your IP address is publicly available and may be shared by multiple computers, it is important to know what devices are connected to your network. Therefore, it is best not to share your Internet connection with strangers or people that you don't know very well.

Important: To see what your current IP address is, you can use PC.net's "Your IP Address" tool.

Published: March 21, 2013 — by Per Christensson