An IP or Internet Protocol address is a unique numerical address assigned to a computer as it logs on to the Internet. The IP address can be mapped back to a specific individual with help from Internet Service Provider (ISP) records. Virtually every website on the World Wide Web (Web) will track and record IP addresses as visitors click through the site’s pages. Two primary reasons for this are security and site improvement.

Every website is hosted on a server. When a visitor clicks his or her way to a website, the user’s browser sends a request to the server for a webpage at the location. The server returns the webpage to the IP address on the request. The page subsequently loads on the visitor’s computer screen.

If the server is bogged down by traffic (handling many requests at once), pages might load slower for visitors. In the case of an overload of simultaneous requests, the server will “crash” or go down, leaving the site temporarily unavailable. This can be a form of attack, called a Denial Of Service (DoS) attack. If the attack comes from a network of infected computers called a botnet, it is referred to a Distributed Denial of Service (DDoS) attack.

A malicious hacker might infiltrate a Web server in an attempt to gain information from protected databases that hold customer data such as credit card numbers. So-called “script kiddies” might simply want to malign a site by uploading images or text to the website.

For these reasons and more, websites track and record IP addresses as a matter of course, storing the numerical addresses in server logs. Each request from the IP address is recorded, along with a time stamp. Older data is routinely purged from logs to make room for newer data. The length of time a website holds on to IP logs is variable, configured by the site’s administrator, and dependent upon many factors.

Websites also track and record IP addresses to learn which pages are most popular. The site can build on popular pages to increase site traffic. Tracking IP addresses across the site can also reveal traffic leaks. For example, a page that provides information about a product might have a link to a remote site with additional information. If server logs reveal that a large amount of traffic is clicking through to the other site, the administrator can improve the page’s content or design to keep traffic longer.

Website policies generally refer to IP addresses as “anonymous” data. However, with the help of computer cookies there are many ways for websites to link identities to IP addresses, even when the address is dynamic, or changes with each Web session. Many websites also contain “Web bugs” or a few pixels linked to an advertising firm that can track and record IP addresses across the Web, from one site to another, surreptitiously compiling detailed surfing profiles of individuals over a period of months or years.

A visitor need not register at a website to be tracked and profiled. Typically all visits to a site are time-stamped and recorded to a cookie, if cookies are enabled in the Web browser. All pages and links visited within the site are commonly added to the cookie (in addition to the sever logs). While server logs are purged, cookies are commonly retained. Deleting a cookie from a user’s computer does not remove the duplicate cookie on the Web server. Upon a subsequent visit to the site, the server might “recognize” the surfer by various system and software data that browsers routinely hand over; even when the surfer is careful to allow temporary cookies only, or no cookies.

Due to these concerns, many savvy netizens prefer to surf anonymously. In this case a proxy server stands between the surfer’s computer and the Web. All browser requests are sent to the proxy which relays them to the Internet. Web servers return pages to the proxy’s IP address, logging its address instead. The proxy receives the page, forwarding it on to the surfer, acting as a go-between. Web servers have no record of the surfer’s IP address, (however, the proxy server will track and record IP addresses).

If using a proxy service, it is important to know if it is truly anonymous. Some proxy servers forward the requester’s IP address in their headers, defeating the purpose. Only anonymous proxy servers hide this information. Some proxy’s claim to be anonymous but are not, so personal checking through available proxy tools is advisable. Using international proxies can also increase anonymity because the proxy’s logs will not be subject to jurisdiction of the netizen’s home country. That said, proxy services are designed to help maintain freedom and privacy for legal activity, not protect illegal activity.

The Firefox™ browser has an add-on plug-in called FoxyProxy which allows users to keep a list of proxies and easily switch between them to keep records from accumulating on just one proxy server. One can also link proxies, placing two or three proxy servers in a chain, however, this slows surfing. Also, if one of the proxies is down requests get lost. Additionally, there are various shareware programs for proxy surfing.

Web-based anonymous services allow visitors to surf the Web through an onsite interface. Surfing from the site, requested pages appear in a window. The only IP address revealed to the Internet is the website’s own address. But once again, the website itself will track and record IP addresses of those that use its services.