An IP address identifies a network interface for Internet Protocol communication. It does not uniquely identify a person or a permanent device. Public addresses, private addresses, IPv4, IPv6, and network translation explain why one device can use several addresses or share an outward-facing address.

What Is an IP Address?

An IP (Internet Protocol) address is a numerical label assigned to a network interface. Think of it as your device's mailing address on the internet. Without it, servers wouldn't know where to deliver the web pages, videos, and data you request.

There are two types of IP addresses you interact with daily:

  • Public IP — assigned by your ISP, visible to every website you visit. This is what FindUtils IP Address Lookup shows you.
  • Private IP — used within your home or office network (like 192.168.1.x). Not visible on the internet.

In a common home IPv4 setup, a router translates private source addresses to an outward-facing address. DHCP often assigns local addresses; NAT performs the translation. Other network arrangements differ.

IPv4 and IPv6 use different address sizes

IPv4 uses 32-bit addresses, giving 2^32 possible bit patterns. IPv6 uses 128-bit addresses, giving 2^128 possible bit patterns. Some ranges have special purposes, so these totals are not counts of ordinary public host addresses.

Dual-stack networks support both protocols. Connection behavior depends on the device, network, destination, and connection-selection algorithm. An unavailable IPv6 path does not imply that the device has no Internet connection.

See RFC 8200 for IPv6. For private IPv4 ranges, see RFC 1918.

IP geolocation is an estimate

An IP lookup combines network and location information from its data sources. A location result can describe a provider network, an exit point, or an approximate service area rather than the user.

Treat country, region, city, coordinates, and timezone as available estimates. Accuracy varies by address, network type, provider, and data freshness. Do not apply a universal city-accuracy percentage.

An IP address alone does not establish a person's name, street address, exact GPS location, or activity. Mobile networks, shared connections, VPNs, and hosting addresses can make interpretation harder.

The IP Address Lookup displays available fields. Missing data is not proof that a location is unknown to every provider. A displayed city is not proof that the person is there.

What a VPN or proxy changes

A VPN can route supported traffic through another network endpoint. Sites reached through that path see its outward-facing address. The tunnel protects traffic between the device and VPN endpoint; it does not make every application anonymous.

A proxy affects the traffic configured to use it. Encryption depends on the proxy protocol and application connection. HTTPS can protect content through a proxy too.

Tor provides a different routing model with its own limits. Choose a privacy tool from the threat you need to address. No tool prevents identification through every account, browser, or application signal.

Use the DNS and WebRTC Leak Test as one diagnostic check. A passing result does not certify complete anonymity.

Use the IP API with its current contract

These examples request the caller's IP information or an individual field:

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# Caller information as JSON
curl https://ip.findutils.com/json

# Individual fields: the actual values depend on the caller
curl https://ip.findutils.com/country
curl https://ip.findutils.com/city

# Expanded response
curl https://ip.findutils.com/all

Check the current IP API documentation for fields, formats, authentication, paid features, and request limits. This article does not pin a current price or quota.

A production client needs timeout handling, status checks, and a policy for missing or approximate values. Do not use a city result as the sole basis for an important access or fraud decision.

Read email headers as routing evidence

Email headers can contain routing entries and authentication results. They do not necessarily reveal the original sender's device address or physical location.

Trust depends on which mail system added a header. Earlier or user-supplied values can be misleading. A passing authentication result also does not prove that a message is harmless.

Use the Email Header Analyzer to inspect available routing and authentication fields. Confirm important findings with the receiving mail system's records.

IP Reputation and Blacklists

If your IP address ends up on a spam blacklist (DNSBL), your emails may be rejected and some websites may block you. This commonly happens to:

  • Shared hosting IPs where another tenant sent spam
  • VPN exit nodes used by spammers
  • Compromised servers sending automated spam

Check your IP against the supported blacklist sources with the FindUtils IP Blacklist Checker. If listed, the tool provides direct links to each provider's delisting page.

Tools Used in This Guide

Frequently asked questions

Does an IP address identify one person?

No. Multiple users can share an address, and one user can use several addresses over time.

Why does an IP lookup show another city?

The result can describe a provider network or exit point. Geolocation data can also be incomplete or stale.

Can an ISP read all HTTPS content?

HTTPS encrypts the content in transit. The network can still observe some connection information. Visibility depends on the protocol and network configuration.

Does a VPN hide every identifier?

No. Logged-in accounts, cookies, application data, and browser signals can still identify activity. Only traffic routed through the VPN uses that path.

Does an email header prove the sender's location?

No. It can show mail routing information. A routing address is not necessarily the sender's device or physical location.

Where can I check API prices and limits?

Use the current service documentation. A price or quota quoted in an older article can become stale.