Computer Advice

Nice little tool that displays your IP address. It should only show your internet connection IP even if you are on a LAN (well it does here in me office).

This is very useful if you are opening any ports for any virtual server you use, remote desktop, p2p software etc. I also use it to find my WAN IP when setting up my IP webcam.
If you need you’re LAN IP, have a look see in windows help.

Wikipedia says,

An IP address (Internet Protocol address) is a unique number that devices use in order to identify and communicate with each other on a computer network utilizing the Internet Protocol standard (IP). Any participating network device — including routers, computers, time-servers, printers, Internet fax machines, and some telephones — must have its own unique address. An IP address can also be thought of as the equivalent of a street address or a phone number (compare: VoIP) for a computer or other network device on the internet. Just as each street address and phone number uniquely identifies a building or telephone, an IP address can uniquely identify a specific computer or other network device on a network.

An IP address can appear to be shared by multiple client devices either because they are part of a shared hosting web server environment or because a proxy server (e.g. an ISP or anonymizer service) acts as an intermediary agent on behalf of its customers, in which case the real originating IP addresses might be hidden from the server receiving a request. The analogy to telephone systems would be the use of predial numbers (proxy) and extensions (shared).