Your IP -- or Internet Protocol -- address differentiates your computer from the billions of other devices that are simultaneously connected to the Web. When a Web-enabled device tries to connect to the Internet, an IP address is assigned from the pool of addresses managed by your Internet Service Provider. Using this numerical data as an identifier, your activity is then tracked and recorded every time you launch a website, Web app or email, and can be used to permit or block you from specific servers and services.

How an IP Address Works

An IP address -- which includes four sets of numbers containing one to three digits each, separated by a dot -- pinpoints your networked location and serves as a sort of virtual handshake when communicating with other computers and servers. The Internet Assigned Number Authority, or IANA, allocates buckets of unused IP addresses to Internet Service Providers, who then distribute them as needed when subscribers attempt to connect to the Web. IP addresses can be either static or dynamic, and once assigned, the machine remains traceable over any wired, wireless or cellular data network.

Dynamic IP Addresses

Dynamic IP addresses are temporary and are assigned to your computer by your Internet service provider at the launch of every new Web session. The number you receive comes from a pool of similar numbers that are rotated and shared between all subscribers. This helps lower service costs, simplifies the process of adding computers to the network and allows the provider to provide more efficient service than would otherwise be possible. Perhaps most importantly, it offers a more secure connection -- since it's ever changing -- and is the more appropriate choice for browsing, email and overall general Web use.

Static IP Addresses

Static IP addresses are permanently embedded in your network settings and offer a reliable, consistent way for your machine to be identified. This type of IP address is effective when you're hosting a main server -- like an Exchange server, VPN access or party playing on a gaming console -- since it recognizes return visitors and encourages increased upload and download times. In contrast to its counterpart, a static IP address is typically more expensive to maintain and carries a greater security risk since a permanent connection is easier to identify and then break.

Remotely Tracing an IP

You can determine the IP of the computer you're currently using by visiting an IP tracking website -- like WhatIsMyIP.com, FindMyIPAddress.com or FindMyIP.co. In addition to identifying the numerical IP address, these sites also display additional information such as your operating system, Internet service provider and general geographical region. Websites and individuals that have access to your IP address from previous Web sessions can use these same IP tracking sites to compile information about your machine, connection and network, as well.

Limitations of IP Tracing

While the gathered data can be helpful, IP tracing can't produce accurate enough measurements to identify exact coordinates or a physical address. The tracker will merely hazard a best guess at the city, area code or Internet provider, possibly providing you with just enough information to guess the author of an anonymous blog comment or a particularly harassing email. If the user of the tracked machine has also implemented an IP hiding service, what little location data that is provided may be useless, as it may originate from a proxy server on the opposite side of the country instead.