An IP address (Internet Protocol Address) is a unique numerical identifier assigned to each device connected to the Internet, similar to a physical home address or phone number in real life. It operates at the network layer (Layer 3) of the OSI model, allowing devices to locate and communicate with each other, ensuring data packets are correctly routed and sent to their destinations. Without IP addresses, devices on the Internet would not be able to find each other.
There are currently two main versions of IP addresses in widespread use: **IPv4** and **IPv6**. IPv4 uses a 32-bit address space, formatted as four groups of decimal numbers 0-255 separated by dots (e.g., `192.168.1.1`), with a total of approximately 4.3 billion addresses. Due to the explosive growth of mobile Internet and IoT devices, IPv4 addresses were fully exhausted as early as 2019. **IPv6** uses a 128-bit address space, represented as eight groups of hexadecimal numbers separated by colons (e.g., `2001:0db8:85a3:0000:0000:8a2e:0370:7334`), providing approximately 3.4×10³⁸ addresses, completely solving the address exhaustion problem.
IP addresses are typically divided into two categories: **Public IP** and **Private IP**. A public IP is a globally uniquely routable address on the Internet, assigned by ISPs (Internet Service Providers), and can be directly accessed by other devices on the Internet. Private IPs are addresses used within local area networks (LANs), reserved by IANA specifically for internal networks - they cannot be routed directly on the public Internet and require **NAT** (Network Address Translation) technology to convert private addresses to public IPs before accessing the Internet. Common private IP address ranges include `10.0.0.0/8`, `172.16.0.0/12`, and `192.168.0.0/16`.
This page displays your **public exit IP**, which is the IP address exposed by your device that other servers on the Internet see. If you are using a router, proxy server, VPN, or CDN service, the displayed IP may be the address of these intermediate devices rather than your device's own LAN private address. When you visit a website, this is the public exit IP that the website server sees.
IP addresses can roughly infer a visitor's geographic location, usually accurate to country, province, and city level, along with corresponding ISP information. However, please note: IP geolocation **cannot pinpoint to street, neighborhood, or specific room level**, nor does it directly contain personal identity information such as your name or phone number. IP geolocation information is queried from IP address databases (such as MaxMind GeoIP, IP2Location, etc.), which record registration allocation information for different IP ranges.
In HTTP requests, when passing through reverse proxies (Nginx, HAProxy), CDNs (Cloudflare, CloudFront), or load balancers, the real client IP is passed through specific request headers. The most common ones include: `X-Forwarded-For` (records the entire proxy chain), `X-Real-IP` (commonly used by Nginx), `CF-Connecting-IP` (Cloudflare-specific), `True-Client-IP` (Akamai/Cloudflare Enterprise). This tool automatically parses these headers and displays the complete request chain.
