IPv4 addresses look like 203.0.113.42 and have ~4.3 billion combinations. IPv6 addresses look like 2001:db8::1234 and provide a vastly larger address space. IPv6 was implemented to solve IPv4 exhaustion and to enable end-to-end connectivity and modern networking features.
When both are available, your device may choose one based on reachability and latency. This site prefers to display IPv4 first when available.
If you are behind a proxy, VPN, or CDN, the address shown may reflect that service. When using a CDN like Cloudflare, IPv6 may be preferred depending on your network.
Geolocation maps an IP to an approximate location (country, region, city) using databases. To add Geo locally, we can integrate a database such as MaxMind GeoLite2 (free with sign-up) and perform lookups in-process.
ASN stands for Autonomous System Number, which identifies the network (ISP or organization) that announces the IP address on the internet. ASN and ISP info can be added from the same Geo databases or external APIs.