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Public IP

Also known as: Public IP address, External IP

An IP address that is globally routable on the internet, assigned by an ISP or cloud provider, as opposed to a private IP that only works inside a local network.

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What is a public IP?

A public IP address is an IP address that is routable on the public internet — any other device, anywhere in the world, can send packets to it (subject to firewalls). Public IPs are allocated by the Regional Internet Registries (ARIN, RIPE, APNIC, LACNIC, AFRINIC) to ISPs, hosting providers, and large organizations, which then assign them to customer connections or datacenter servers.

Contrast this with a private IP, which only works inside a local network and is never routed over the public internet.

How your device gets a public IP

For most home and mobile users:

  • Wired/Wi-Fi at home — your ISP assigns one public IPv4 address to your router, usually via DHCP. All your devices share it via NAT.
  • Mobile data — your carrier gives your device an IP on a large shared pool. Mobile public IPs are often CGNAT-shared across dozens to hundreds of subscribers.
  • Cloud servers — each VM or container gets its own public IPv4 or IPv6 address on creation (or is behind a load balancer that has one).

With IPv6, every device can have its own unique public address — there's no need for NAT when the address space is that large.

What a public IP reveals

Because public IPs sit at the intersection of routing and allocation records, they carry a surprising amount of metadata:

  • Approximate geographic location via GeoIP databases
  • ISP or hosting provider via WHOIS and RDAP
  • ASN ownership via BGP routing data (see ASN)
  • Abuse history via threat feeds and blacklists
  • VPN / proxy / Tor status via known exit-node lists

This is why almost every website, ad platform, and fraud-prevention system logs visitor IPs. Look up your current public IP and the metadata attached to it with our IP lookup tool.

Frequently Asked Questions

Visit any IP-lookup site, run `curl ifconfig.me` or `curl api.ipify.org` from the command line, or check your router's admin page (usually `192.168.1.1` or `192.168.0.1`). The public IP shown by these tools is the address the wider internet sees for your connection — usually your ISP-assigned router address. Devices on your home network share this single public IP via NAT.
For most home and mobile users, yes — ISPs assign IPs dynamically via DHCP, and the address can change every few hours, days, or weeks (rebooting the router often forces a new one). Some ISPs offer "static IP" plans for an extra fee where the address never changes. Mobile carriers rotate IPs almost every connection. Cloud server IPs are stable until you release them. Static IPs are required for hosting servers, VPN endpoints, or anything that needs a fixed name.
Yes — and they almost always do. Every device on your home Wi-Fi shares the single public IP your ISP assigned to your router. Mobile carriers go further with CGNAT, sharing one public IP among hundreds of subscribers. From the destination server's view, all those devices look like one source. This is why IP-based blocking is a blunt tool — banning one bad actor on a mobile network or office Wi-Fi often blocks dozens of innocent users behind the same address.
Partially. Your public IP reveals approximate geographic location (often city-level), your ISP, and any abuse history tied to that IP. It does not reveal your name, exact address, or identity unless your ISP discloses it under a legal process. Persistent tracking across IP changes uses other signals (cookies, browser fingerprint, account logins). VPNs, Tor, and proxies hide your real IP from the destination but not from your ISP.
A public IP is one that is routable on the internet. A static IP is one that does not change over time. The two attributes are independent — most home users have a dynamic public IP (changes regularly), but they are still fully public/routable. You only need a static IP when something else needs to find your address reliably (hosting a server, configuring a site-to-site VPN, allow-listing your office in a partner's firewall).
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