Reverse Lookup is the process of finding people or businesses when you don’t know their name or location, but you do have at least one piece of information to start your search with such as a telephone number, physical address or website URL.
Reverse Lookup is most commonly associated with reverse lookup telephone directories that allow users to search by telephone number only. Unlike standard telephone directories, a Reverse Lookup telephone directory can provide data like name and address for an otherwise anonymous phone number.
This can be very useful in situations when you want to know the person behind a blind telephone number. Reverse lookup allows users to find the identity of the calling company or individual behind a telephone number that showed up on their caller ID. Reverse lookups can show you what state and town your calls come from too.
Law enforcement and emergency services have their own reverse directories that are restricted to internal use, but publicly accessible reverse telephone directories have been produced by the telephone companies for decades, and today reverse directories where you can perform multiple residential and business phone searches are readily available online. It is now a simple matter to search a landline telephone number and obtain the name of the owner, address information and even the providing telephone carrier.
With the proliferation of cellular phones in the country today there has been some opposition to the release of cell phone numbers into public 411 and reverse number directories. Cell phone number databases are only accessible by the specific providing carrier phone company, and as a result, reverse phone directories may not be able to return information on some cell numbers without the cooperation of the provider. Online reverse-number directories that are obtained from utility resources may be able to track more of the numbers though.
Reverse Lookup also applies to computer networking when looking for the domain name behind a particular IP address. The process is called reverse DNS lookup or reverse DNS resolution, as opposed to the more common forward DNS resolution, where a domain name is used to locate an IP address. Reverse DNS lookup is the determination of an IP address back to its registered domain name. A common use of reverse DNS lookup includes checking domain names from dialup users, dynamically assigned addresses, or other inexpensive internet services that are common sources of spam.
Most free reverse lookup directories don’t contain cellular phone numbers and fax numbers because most of the information is held by the carriers and telecommunications companies, but the records do exist, they just are not always free.
Reverse lookup services that pay for access to such information and assemble it in a single useable format will often charge a small one-time fee for access to cell phone owner details, address history, and carrier details. Some may allow users to run unlimited searches, and others might offer a single lookup for a lower one-time fee. The databases from different services will be different, but generally speaking, most can provide data on cell phones, residential phone, business phones and toll-free numbers too.