IP Address Lookup

An IP address is the network identifier other systems use to reach or recognize a device or connection. For most users, the important value is the public egress IP seen by websites, because that is what VPNs, proxies, firewalls, allowlists, CDNs, and login security checks normally care about. This lookup page helps show the IP address visible to the service, and may also return approximate location, ASN, and provider information from IP databases. IP location is not GPS: it often points to an ISP, city, data center, or proxy node rather than a precise physical address. If you are behind NAT, using mobile data, a corporate gateway, or a CDN, the result may represent the shared network exit rather than the exact device in your hand.

Looking up your own public IP works by having the browser send an HTTP request to an external IP-identification service; the server reads the client's IP from the source address of the TCP connection and returns it. This relies on a network-layer fact rather than user input, so it accurately reflects the address your current egress uses to the outside world. Note that most home broadband uses carrier-grade NAT (CGNAT) - the 'public IP' you look up is actually one address shared by hundreds of households, and your own device still has a 192.168.x.x private address that's unreachable from outside. If you deploy a reverse proxy or CDN, the IPs in the web server's logs are the proxy nodes', and you need to parse the X-Forwarded-For header to get the real visitor. On IPv6, every device usually gets a globally unique address, and the X-Real-IP header is often used together with nginx's set_real_ip_from directive. Geolocation lookups depend on offline databases like MaxMind GeoIP2, IP2Location, and IP2Region, and are usually city-level accurate; street-level accuracy is limited by ISP base-station distribution and database update lag.

• IPv4 uses 32-bit addresses (~4.3 billion), already fully allocated; 192.168.x.x, 10.x.x.x, 172.16-31.x.x are RFC 1918 private ranges and not in the public routing table.
• IPv6 uses 128-bit addresses (2^128 of them); with a home router enabled, every device gets a globally unique address and no longer needs NAT.
• X-Forwarded-For is a chained HTTP header that records every proxy IP, e.g. 'client, proxy1, proxy2'; the leftmost is usually the real client.
• X-Real-IP is a single-value header written by the reverse proxy to tell the backend 'this is the real client IP' - simpler than XFF but cannot reconstruct the full chain.
• GeoIP databases are maintained by MaxMind, IP2Location, and similar; the free version is city-level accurate, the commercial version can pinpoint the ISP, postal code, or even street.
• CDN and reverse proxies change the request's source IP; ops must configure a trusted proxy list (nginx's set_real_ip_from) to recover the real visitor IP.