What Is an IP Checker? What It Shows and How to Use One

An IP checker is a tool that shows an IP address and what can be learned about it. Some checkers tell you your own public IP address, some look up any address or domain you type in, and some judge whether an address looks like a VPN, a proxy or a source of spam. This guide explains the three kinds, what each result means, and which one to use for the job in front of you.

What are the three kinds of IP checker?

• “What is my IP” checkers show the address your connection uses on the internet. Open the what is my IP address page and it appears at once, with your approximate location and provider.
• IP lookup checkers take an address or domain you type in and report where it is and who runs the network behind it. Use the IP lookup tool.
• IP reputation checkers look for signs that an address is a VPN, a proxy, a Tor exit or a data center, and check it against public spam and abuse blocklists. Use the IP reputation checker.

What do the results mean?

• IP version. IPv4 looks like 203.0.113.7 and IPv6 like 2001:db8::1. Many connections have both.
• Location. Country, region and city. It is an estimate made from network records, not GPS, so it can be wrong. See why an IP address can show the wrong location.
• ISP and organization. The company that provides the connection or owns the block of addresses.
• ASN. The Autonomous System Number identifies the network that announces the address on the internet, such as an internet provider or a hosting company.
• Hostname. The name in the address's reverse DNS record, if its owner set one. Servers usually have one and home connections often do not.
• Network type. Whether the address belongs to a home or mobile provider, a hosting company or a known VPN. Websites use this to decide how far to trust a visitor.
• Blocklist status. Whether the address appears on public lists of spam or abuse sources. This can affect whether your email is delivered.

Which IP checker should you use?

• To see what websites see when you visit them, use “what is my IP”. Check it with a VPN off and then on to confirm the VPN is working; see is my VPN working.
• To investigate an address in a log or a message, use the lookup.
• If your email is being rejected or a site keeps showing CAPTCHAs, use the reputation checker and read is my IP address blacklisted.
• To test a proxy you bought, use the proxy checker, which connects through the proxy and reports the address it exits from.
• To check for leaks, run the WebRTC leak test, because a browser can reveal your real address even behind a VPN.

Limits to keep in mind

An IP address is not an identity. It points at a connection, usually shared by many people, and the location is approximate. VPN and proxy detection is based on clues, so residential proxies and some private VPNs cannot be detected. Treat the results as indicators, not proof. The About page lists how each result is produced.

From a terminal you can get your own address with one command; see how to get your public IP address from the command line.