Frequently Asked Questions

An IP address is a unique numeric identifier assigned to every device connected to the Internet. It routes data packets between devices — like a postal address for the digital world. IPv4 addresses look like 192.0.2.42 and there are about 4.3 billion of them in total. Every website, phone, and server you communicate with has an IP address.

IPv4 uses 32-bit addresses (4.3 billion total), written as four numbers separated by dots (192.0.2.42). IPv6 uses 128-bit addresses (340 undecillion total), written in hex separated by colons (2001:db8::1). IPv4 ran out of unassigned blocks in 2011 — IPv6 is the long-term replacement, but most of the Internet still uses both in parallel.

192.168.1.1 is a private IP address commonly used as the default gateway for home and small-business routers (Netgear, Linksys, TP-Link). It is part of the 192.168.0.0/16 RFC 1918 private range — not routable on the public Internet. Your home devices use it to reach your router's admin page.

10.0.0.1 is another private IP address from the 10.0.0.0/8 RFC 1918 range. Enterprise networks, VPNs, and some ISP-provided routers use it as a gateway. Like 192.168.x.x, it is not accessible from the public Internet — only from within the network that assigns it.

127.0.0.1 is the loopback address — it always refers to the device you're using. When a program connects to 127.0.0.1, it's talking to itself. Developers use it for local testing ("there's no place like 127.0.0.1"). The entire 127.0.0.0/8 block is reserved for loopback.

8.8.8.8 is Google Public DNS — a free, fast DNS resolver operated by Google. It's owned by Google LLC (AS15169). Many people configure their devices to use it for faster, more private DNS lookups than their ISP's default. Its partner address is 8.8.4.4.

1.1.1.1 is Cloudflare's public DNS resolver, also known as one.one.one.one. Launched in 2018, it emphasizes privacy (zero query logging) and speed. It's announced by Cloudflare (AS13335) from hundreds of edge locations globally.

An ASN is a unique identifier for a network operator that announces routes on the Internet via BGP (Border Gateway Protocol). Google is AS15169, Cloudflare is AS13335, Amazon AWS is AS16509. There are about 77,000 active ASNs. ASNs group IP prefixes under a single routing policy — when you visit a website, your packets traverse several ASNs to get there.

CIDR (Classless Inter-Domain Routing) describes a range of IP addresses using a network/prefix-length notation. 8.8.8.0/24 means "the 256 IPs starting at 8.8.8.0". The /24 is the prefix length — how many bits are fixed. Larger CIDRs have smaller prefix numbers (a /16 has 65,536 IPs, a /8 has 16.7M). Internet routing relies entirely on CIDR.

The five RIRs manage IPv4 and IPv6 allocation for their geographic region: ARIN (North America), RIPE NCC (Europe, Middle East, Central Asia), APNIC (Asia-Pacific), LACNIC (Latin America, Caribbean), and AfriNIC (Africa). ISPs request IP blocks from their RIR, which originally received them from IANA.

WHOIS is a protocol (and the associated databases) for looking up who owns a domain name or IP address. For IPs, WHOIS tells you the RIR, the allocation date, the responsible organization, and abuse contact. This site merges WHOIS data with MaxMind geolocation so you get both in one lookup.

IP geolocation maps an IP address to a physical location (country, city, lat/lng) using datasets compiled by companies like MaxMind. They source the data from RIR allocations, ISP announcements, GPS traces in mobile apps, and user-reported feedback. Geolocation is approximate — typically accurate to country level, often to city, rarely to street. WorldIP.io uses MaxMind GeoLite2 CSV, refreshed weekly.

IANA reserves several ranges for special uses: 0.0.0.0/8 (default route), 10/8, 172.16/12, 192.168/16 (private networks — RFC 1918), 127/8 (loopback), 169.254/16 (link-local / APIPA), 224/4 (multicast), 240/4 (reserved for future use). Reserved addresses are not routable on the public Internet.

Yes — at the top level. IANA allocated its last five unassigned /8 blocks to the RIRs in February 2011. APNIC (2011), RIPE (2012), LACNIC (2014), ARIN (2015), and AfriNIC (2019) have since exhausted their own free pools. New allocations now come from returns, transfers (sold between organizations at $25–50 per IP), and waitlists. See our live exhaustion tracker.

Most home users have dynamic IP addresses — the ISP's DHCP server leases you an IP for a period (usually hours to days) and may give you a different one on renewal. Mobile carriers often use CGNAT (Carrier-Grade NAT, 100.64.0.0/10) and share a single public IP among many customers. To get a consistent IP, you need a static IP service or a VPN.

An IP address alone cannot identify an individual with certainty — it identifies a device or network. Multiple people often share an IP (family Wi-Fi, NAT, CGNAT). However, combined with other data (browser fingerprint, login, subscriber records held by the ISP), an IP can be traced to a household. Law enforcement obtains subscriber info via legal process, not by the IP alone.

In the EU, IP addresses are considered personal data under GDPR when they can be combined with other info to identify a natural person. The European Court of Justice (Breyer v. Germany, 2016) confirmed this for dynamic IPs too. Websites operating in the EU must handle IPs with appropriate legal basis and privacy controls.

Reverse DNS maps an IP address back to a hostname — the reverse of normal DNS. For 8.8.8.8, reverse DNS returns dns.google. It's implemented via PTR records in the .in-addr.arpa zone, managed by whoever owns the IP block. Email servers rely heavily on rDNS: mail from an IP with no PTR record is often rejected as spam.

Three ways: (1) enter it into WorldIP.io — we show owner, ASN, country, and allocation source; (2) run whois 8.8.8.8 on a Unix system — queries the RIR directly; (3) visit the RIR's web WHOIS. For abuse reporting, use the abuse-c contact from WHOIS, not the customer.

We refresh every Tuesday at 04:00 UTC from MaxMind GeoLite2 (which publishes Tuesdays 00:00 UTC) plus the latest RIR delegation files. Over a full year, about 1–2% of ranges change ownership, are reassigned geographically, or are newly allocated. See our data sources page for full methodology.